WorldWideScience

Sample records for allometry

  1. On Allometry Relations

    Science.gov (United States)

    2012-07-06

    German polymath Gauss64 and the Amer- ican mathematician Adrian1 introduced into science the law of frequency of errors, the French physicist ...00-2012 4. TITLE AND SUBTITLE On Allometry Relations 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT ...AR was given by Sarrus and Rameaux.188 Schmidt–Nielsen195 records that this team of a mathematician and a physician reasoned that the heat gener- ated

  2. The Allometry of Prey Preferences

    Science.gov (United States)

    Kalinkat, Gregor; Rall, Björn Christian; Vucic-Pestic, Olivera; Brose, Ulrich

    2011-01-01

    The distribution of weak and strong non-linear feeding interactions (i.e., functional responses) across the links of complex food webs is critically important for their stability. While empirical advances have unravelled constraints on single-prey functional responses, their validity in the context of complex food webs where most predators have multiple prey remain uncertain. In this study, we present conceptual evidence for the invalidity of strictly density-dependent consumption as the null model in multi-prey experiments. Instead, we employ two-prey functional responses parameterised with allometric scaling relationships of the functional response parameters that were derived from a previous single-prey functional response study as novel null models. Our experiments included predators of different sizes from two taxonomical groups (wolf spiders and ground beetles) simultaneously preying on one small and one large prey species. We define compliance with the null model predictions (based on two independent single-prey functional responses) as passive preferences or passive switching, and deviations from the null model as active preferences or active switching. Our results indicate active and passive preferences for the larger prey by predators that are at least twice the size of the larger prey. Moreover, our approach revealed that active preferences increased significantly with the predator-prey body-mass ratio. Together with prior allometric scaling relationships of functional response parameters, this preference allometry may allow estimating the distribution of functional response parameters across the myriads of interactions in natural ecosystems. PMID:21998724

  3. The allometry of prey preferences.

    Directory of Open Access Journals (Sweden)

    Gregor Kalinkat

    Full Text Available The distribution of weak and strong non-linear feeding interactions (i.e., functional responses across the links of complex food webs is critically important for their stability. While empirical advances have unravelled constraints on single-prey functional responses, their validity in the context of complex food webs where most predators have multiple prey remain uncertain. In this study, we present conceptual evidence for the invalidity of strictly density-dependent consumption as the null model in multi-prey experiments. Instead, we employ two-prey functional responses parameterised with allometric scaling relationships of the functional response parameters that were derived from a previous single-prey functional response study as novel null models. Our experiments included predators of different sizes from two taxonomical groups (wolf spiders and ground beetles simultaneously preying on one small and one large prey species. We define compliance with the null model predictions (based on two independent single-prey functional responses as passive preferences or passive switching, and deviations from the null model as active preferences or active switching. Our results indicate active and passive preferences for the larger prey by predators that are at least twice the size of the larger prey. Moreover, our approach revealed that active preferences increased significantly with the predator-prey body-mass ratio. Together with prior allometric scaling relationships of functional response parameters, this preference allometry may allow estimating the distribution of functional response parameters across the myriads of interactions in natural ecosystems.

  4. On the relationship between ontogenetic and static allometry.

    Science.gov (United States)

    Pélabon, Christophe; Bolstad, Geir H; Egset, Camilla K; Cheverud, James M; Pavlicev, Mihaela; Rosenqvist, Gunilla

    2013-02-01

    Ontogenetic and static allometries describe how a character changes in size when the size of the organism changes during ontogeny and among individuals measured at the same developmental stage, respectively. Understanding the relationship between these two types of allometry is crucial to understanding the evolution of allometry and, more generally, the evolution of shape. However, the effects of ontogenetic allometry on static allometry remain largely unexplored. Here, we first show analytically how individual variation in ontogenetic allometry and body size affect static allometry. Using two longitudinal data sets on ontogenetic and static allometry, we then estimate variances and covariances for the different parameters of the ontogenetic allometry defined in our model and assess their relative contribution to the static allometric slope. The mean ontogenetic allometry is the main parameter that determines the static allometric slope, while the covariance between the ontogenetic allometric slope and body size generates most of the discrepancies between ontogenetic and static allometry. These results suggest that the apparent evolutionary stasis of the static allometric slope is not generated by internal (developmental) constraints but more likely results from external constraints imposed by selection.

  5. Unusual allometry for sexual size dimorphism in a cichlid where ...

    Indian Academy of Sciences (India)

    Prakash

    In most organisms, males and females have different body sizes as a result of ... Therefore, sexual size allometry will be violated by body size divergence induced by multiple selection ..... complies with the laws of each country. References.

  6. Shoot allometry of Jatropha curcas | Ghezehei | Southern Forests: a ...

    African Journals Online (AJOL)

    Jatropha), potentially a multipurpose tree and biofuel source, owing to insufficient knowledge about the species. Use of allometry as a non-destructive method of monitoring growth and biomass attributes of Jatropha was investigated. The objectives ...

  7. Multiplicative by nature: Logarithmic transformation in allometry.

    Science.gov (United States)

    Packard, Gary C

    2014-06-01

    The traditional allometric method, which is at the heart of research paradigms used by comparative biologists around the world, entails fitting a straight line to logarithmic transformations of the original bivariate data and then back-transforming the resulting equation to form a two-parameter power function in the arithmetic scale. The method has the dual advantages of enabling investigators to fit statistical models that describe multiplicative growth while simultaneously addressing the multiplicative nature of residual variation in response variables (heteroscedasticity). However, important assumptions of the traditional method seldom are assessed in contemporary practice. When the assumptions are not met, mean functions may fail to capture the dominant pattern in the original data and incorrect form for error may be imposed upon the fitted model. A worked example from metabolic allometry in doves and pigeons illustrates both the power of newer statistical procedures and limitations of the traditional allometric method. © 2014 Wiley Periodicals, Inc.

  8. Allometry of Sapwood Depth in Five Boreal Trees

    OpenAIRE

    M. Rebeca Quiñonez-Piñón; Caterina Valeo

    2017-01-01

    This paper analyzes sapwood variability and allometry within individuals of Populus tremuloides, Pinus contorta, Pinus banksiana, Picea mariana, and Picea glauca. Outside bark diameter at breast height (DBH) and sapwood depth (sd) in four cardinal directions were measured in individuals in stands in Alberta and Saskatchewan, Canada. The microscopical analysis of wood anatomy was used to measure sd, and the error associated with the measures was observed. Sapwood allometry analyses examined th...

  9. Tree height-diameter allometry across the United States.

    Science.gov (United States)

    Hulshof, Catherine M; Swenson, Nathan G; Weiser, Michael D

    2015-03-01

    The relationship between tree height and diameter is fundamental in determining community and ecosystem structure as well as estimates of biomass and carbon storage. Yet our understanding of how tree allometry relates to climate and whole organismal function is limited. We used the Forest Inventory and Analysis National Program database to determine height-diameter allometries of 2,976,937 individuals of 293 tree species across the United States. The shape of the allometric relationship was determined by comparing linear and nonlinear functional forms. Mixed-effects models were used to test for allometric differences due to climate and floristic (between angiosperms and gymnosperms) and functional groups (leaf habit and shade tolerance). Tree allometry significantly differed across the United States largely because of climate. Temperature, and to some extent precipitation, in part explained tree allometric variation. The magnitude of allometric variation due to climate, however, had a phylogenetic signal. Specifically, angiosperm allometry was more sensitive to differences in temperature compared to gymnosperms. Most notably, angiosperm height was more negatively influenced by increasing temperature variability, whereas gymnosperm height was negatively influenced by decreasing precipitation and increasing altitude. There was little evidence to suggest that shade tolerance influenced tree allometry except for very shade-intolerant trees which were taller for any given diameter. Tree allometry is plastic rather than fixed and scaling parameters vary around predicted central tendencies. This allometric variation provides insight into life-history strategies, phylogenetic history, and environmental limitations at biogeographical scales.

  10. Tree height–diameter allometry across the United States

    Science.gov (United States)

    Hulshof, Catherine M; Swenson, Nathan G; Weiser, Michael D

    2015-01-01

    The relationship between tree height and diameter is fundamental in determining community and ecosystem structure as well as estimates of biomass and carbon storage. Yet our understanding of how tree allometry relates to climate and whole organismal function is limited. We used the Forest Inventory and Analysis National Program database to determine height–diameter allometries of 2,976,937 individuals of 293 tree species across the United States. The shape of the allometric relationship was determined by comparing linear and nonlinear functional forms. Mixed-effects models were used to test for allometric differences due to climate and floristic (between angiosperms and gymnosperms) and functional groups (leaf habit and shade tolerance). Tree allometry significantly differed across the United States largely because of climate. Temperature, and to some extent precipitation, in part explained tree allometric variation. The magnitude of allometric variation due to climate, however, had a phylogenetic signal. Specifically, angiosperm allometry was more sensitive to differences in temperature compared to gymnosperms. Most notably, angiosperm height was more negatively influenced by increasing temperature variability, whereas gymnosperm height was negatively influenced by decreasing precipitation and increasing altitude. There was little evidence to suggest that shade tolerance influenced tree allometry except for very shade-intolerant trees which were taller for any given diameter. Tree allometry is plastic rather than fixed and scaling parameters vary around predicted central tendencies. This allometric variation provides insight into life-history strategies, phylogenetic history, and environmental limitations at biogeographical scales. PMID:25859325

  11. Three-dimensional geometric analysis of felid limb bone allometry.

    Directory of Open Access Journals (Sweden)

    Michael Doube

    Full Text Available Studies of bone allometry typically use simple measurements taken in a small number of locations per bone; often the midshaft diameter or joint surface area is compared to body mass or bone length. However, bones must fulfil multiple roles simultaneously with minimum cost to the animal while meeting the structural requirements imposed by behaviour and locomotion, and not exceeding its capacity for adaptation and repair. We use entire bone volumes from the forelimbs and hindlimbs of Felidae (cats to investigate regional complexities in bone allometry.Computed tomographic (CT images (16435 slices in 116 stacks were made of 9 limb bones from each of 13 individuals of 9 feline species ranging in size from domestic cat (Felis catus to tiger (Panthera tigris. Eleven geometric parameters were calculated for every CT slice and scaling exponents calculated at 5% increments along the entire length of each bone. Three-dimensional moments of inertia were calculated for each bone volume, and spherical radii were measured in the glenoid cavity, humeral head and femoral head. Allometry of the midshaft, moments of inertia and joint radii were determined. Allometry was highly variable and related to local bone function, with joint surfaces and muscle attachment sites generally showing stronger positive allometry than the midshaft.Examining whole bones revealed that bone allometry is strongly affected by regional variations in bone function, presumably through mechanical effects on bone modelling. Bone's phenotypic plasticity may be an advantage during rapid evolutionary divergence by allowing exploitation of the full size range that a morphotype can occupy. Felids show bone allometry rather than postural change across their size range, unlike similar-sized animals.

  12. Developmental model of static allometry in holometabolous insects.

    Science.gov (United States)

    Shingleton, Alexander W; Mirth, Christen K; Bates, Peter W

    2008-08-22

    The regulation of static allometry is a fundamental developmental process, yet little is understood of the mechanisms that ensure organs scale correctly across a range of body sizes. Recent studies have revealed the physiological and genetic mechanisms that control nutritional variation in the final body and organ size in holometabolous insects. The implications these mechanisms have for the regulation of static allometry is, however, unknown. Here, we formulate a mathematical description of the nutritional control of body and organ size in Drosophila melanogaster and use it to explore how the developmental regulators of size influence static allometry. The model suggests that the slope of nutritional static allometries, the 'allometric coefficient', is controlled by the relative sensitivity of an organ's growth rate to changes in nutrition, and the relative duration of development when nutrition affects an organ's final size. The model also predicts that, in order to maintain correct scaling, sensitivity to changes in nutrition varies among organs, and within organs through time. We present experimental data that support these predictions. By revealing how specific physiological and genetic regulators of size influence allometry, the model serves to identify developmental processes upon which evolution may act to alter scaling relationships.

  13. Aruscular mycorhizal fungi alter plant allometry and biomass - density relationships

    DEFF Research Database (Denmark)

    Zhang, Qian; Zhang, Lu; Weiner, Jacob

    2011-01-01

    Background and Aims Plant biomass–density relationships during self-thinning are determined mainly by allometry. Both allometry and biomass–density relationship have been shown to vary with abiotic conditions, but the effects of biotic interactions have not been investigated. Arbuscular mycorrhizal....... In self-thinning populations, the slope of the log (mean shoot biomass) vs. log density relationship was significantly steeper for the high AMF treatment (slope = –1·480) than for the low AMF treatment (–1·133). The canopy radius–biomass allometric exponents were not significantly affected by AMF level...

  14. Ecological allometries and niche use dynamics across Komodo dragon ontogeny.

    Science.gov (United States)

    Purwandana, Deni; Ariefiandy, Achmad; Imansyah, M Jeri; Seno, Aganto; Ciofi, Claudio; Letnic, Mike; Jessop, Tim S

    2016-04-01

    Ontogenetic allometries in ecological habits and niche use are key responses by which individuals maximize lifetime fitness. Moreover, such allometries have significant implications for how individuals influence population and community dynamics. Here, we examined how body size variation in Komodo dragons (Varanus komodoensis) influenced ecological allometries in their: (1) prey size preference, (2) daily movement rates, (3) home range area, and (4) subsequent niche use across ontogeny. With increased body mass, Komodo dragons increased prey size with a dramatic switch from small (≤10 kg) to large prey (≥50 kg) in lizards heavier than 20 kg. Rates of foraging movement were described by a non-linear concave down response with lizard increasing hourly movement rates up until ∼20 kg body mass before decreasing daily movement suggesting reduced foraging effort in larger lizards. In contrast, home range area exhibited a sigmoid response with increased body mass. Intrapopulation ecological niche use and overlap were also strongly structured by body size. Thus, ontogenetic allometries suggest Komodo dragon's transition from a highly active foraging mode exploiting small prey through to a less active sit and wait feeding strategy focused on killing large ungulates. Further, our results suggest that as body size increases across ontogeny, the Komodo dragon exhibited marked ontogenetic niche shifts that enabled it to function as an entire vertebrate predator guild by exploiting prey across multiple trophic levels.

  15. Ecological allometries and niche use dynamics across Komodo dragon ontogeny

    Science.gov (United States)

    Purwandana, Deni; Ariefiandy, Achmad; Imansyah, M. Jeri; Seno, Aganto; Ciofi, Claudio; Letnic, Mike; Jessop, Tim S.

    2016-04-01

    Ontogenetic allometries in ecological habits and niche use are key responses by which individuals maximize lifetime fitness. Moreover, such allometries have significant implications for how individuals influence population and community dynamics. Here, we examined how body size variation in Komodo dragons ( Varanus komodoensis) influenced ecological allometries in their: (1) prey size preference, (2) daily movement rates, (3) home range area, and (4) subsequent niche use across ontogeny. With increased body mass, Komodo dragons increased prey size with a dramatic switch from small (≤10 kg) to large prey (≥50 kg) in lizards heavier than 20 kg. Rates of foraging movement were described by a non-linear concave down response with lizard increasing hourly movement rates up until ˜20 kg body mass before decreasing daily movement suggesting reduced foraging effort in larger lizards. In contrast, home range area exhibited a sigmoid response with increased body mass. Intrapopulation ecological niche use and overlap were also strongly structured by body size. Thus, ontogenetic allometries suggest Komodo dragon's transition from a highly active foraging mode exploiting small prey through to a less active sit and wait feeding strategy focused on killing large ungulates. Further, our results suggest that as body size increases across ontogeny, the Komodo dragon exhibited marked ontogenetic niche shifts that enabled it to function as an entire vertebrate predator guild by exploiting prey across multiple trophic levels.

  16. Height-diameter allometry of tropical forest trees

    Science.gov (United States)

    T.R. Feldpausch; L. Banin; O.L. Phillips; T.R. Baker; S.L. Lewis; C.A. Quesada; K. Affum-Baffoe; E.J.M.M. Arets; N.J. Berry; M. Bird; E.S. Brondizio; P de Camargo; J. Chave; G. Djagbletey; T.F. Domingues; M. Drescher; P.M. Fearnside; M.B. Franca; N.M. Fyllas; G. Lopez-Gonzalez; A. Hladik; N. Higuchi; M.O. Hunter; Y. Iida; K.A. Salim; A.R. Kassim; M. Keller; J. Kemp; D.A. King; J.C. Lovett; B.S. Marimon; B.H. Marimon-Junior; E. Lenza; A.R. Marshall; D.J. Metcalfe; E.T.A. Mitchard; E.F. Moran; B.W. Nelson; R. Nilus; E.M. Nogueira; M. Palace; S. Patiño; K.S.-H. Peh; M.T. Raventos; J.M. Reitsma; G. Saiz; F. Schrodt; B. Sonke; H.E. Taedoumg; S. Tan; L. White; H. Woll; J. Lloyd

    2011-01-01

    Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical...

  17. The biomechanical origin of extreme wing allometry in hummingbirds.

    Science.gov (United States)

    Skandalis, Dimitri A; Segre, Paolo S; Bahlman, Joseph W; Groom, Derrick J E; Welch, Kenneth C; Witt, Christopher C; McGuire, Jimmy A; Dudley, Robert; Lentink, David; Altshuler, Douglas L

    2017-10-19

    Flying animals of different masses vary widely in body proportions, but the functional implications of this variation are often unclear. We address this ambiguity by developing an integrative allometric approach, which we apply here to hummingbirds to examine how the physical environment, wing morphology and stroke kinematics have contributed to the evolution of their highly specialised flight. Surprisingly, hummingbirds maintain constant wing velocity despite an order of magnitude variation in body weight; increased weight is supported solely through disproportionate increases in wing area. Conversely, wing velocity increases with body weight within species, compensating for lower relative wing area in larger individuals. By comparing inter- and intraspecific allometries, we find that the extreme wing area allometry of hummingbirds is likely an adaptation to maintain constant burst flight capacity and induced power requirements with increasing weight. Selection for relatively large wings simultaneously maximises aerial performance and minimises flight costs, which are essential elements of humming bird life history.

  18. Dinosaur Metabolism and the Allometry of Maximum Growth Rate

    OpenAIRE

    Myhrvold, Nathan P.

    2016-01-01

    The allometry of maximum somatic growth rate has been used in prior studies to classify the metabolic state of both extant vertebrates and dinosaurs. The most recent such studies are reviewed, and their data is reanalyzed. The results of allometric regressions on growth rate are shown to depend on the choice of independent variable; the typical choice used in prior studies introduces a geometric shear transformation that exaggerates the statistical power of the regressions. The maximum growth...

  19. Dinosaur Metabolism and the Allometry of Maximum Growth Rate.

    Science.gov (United States)

    Myhrvold, Nathan P

    2016-01-01

    The allometry of maximum somatic growth rate has been used in prior studies to classify the metabolic state of both extant vertebrates and dinosaurs. The most recent such studies are reviewed, and their data is reanalyzed. The results of allometric regressions on growth rate are shown to depend on the choice of independent variable; the typical choice used in prior studies introduces a geometric shear transformation that exaggerates the statistical power of the regressions. The maximum growth rates of extant groups are found to have a great deal of overlap, including between groups with endothermic and ectothermic metabolism. Dinosaur growth rates show similar overlap, matching the rates found for mammals, reptiles and fish. The allometric scaling of growth rate with mass is found to have curvature (on a log-log scale) for many groups, contradicting the prevailing view that growth rate allometry follows a simple power law. Reanalysis shows that no correlation between growth rate and basal metabolic rate (BMR) has been demonstrated. These findings drive a conclusion that growth rate allometry studies to date cannot be used to determine dinosaur metabolism as has been previously argued.

  20. Dinosaur Metabolism and the Allometry of Maximum Growth Rate

    Science.gov (United States)

    Myhrvold, Nathan P.

    2016-01-01

    The allometry of maximum somatic growth rate has been used in prior studies to classify the metabolic state of both extant vertebrates and dinosaurs. The most recent such studies are reviewed, and their data is reanalyzed. The results of allometric regressions on growth rate are shown to depend on the choice of independent variable; the typical choice used in prior studies introduces a geometric shear transformation that exaggerates the statistical power of the regressions. The maximum growth rates of extant groups are found to have a great deal of overlap, including between groups with endothermic and ectothermic metabolism. Dinosaur growth rates show similar overlap, matching the rates found for mammals, reptiles and fish. The allometric scaling of growth rate with mass is found to have curvature (on a log-log scale) for many groups, contradicting the prevailing view that growth rate allometry follows a simple power law. Reanalysis shows that no correlation between growth rate and basal metabolic rate (BMR) has been demonstrated. These findings drive a conclusion that growth rate allometry studies to date cannot be used to determine dinosaur metabolism as has been previously argued. PMID:27828977

  1. Sexual selection and allometry: a critical reappraisal of the evidence and ideas.

    Science.gov (United States)

    Bonduriansky, Russell

    2007-04-01

    One of the most pervasive ideas in the sexual selection literature is the belief that sexually selected traits almost universally exhibit positive static allometries (i.e., within a sample of conspecific adults, larger individuals have disproportionally larger traits). In this review, I show that this idea is contradicted by empirical evidence and theory. Although positive allometry is a typical attribute of some sexual traits in certain groups, the preponderance of positively allometric sexual traits in the empirical literature apparently results from a sampling bias reflecting a fascination with unusually exaggerated (bizarre) traits. I review empirical examples from a broad range of taxa illustrating the diversity of allometric patterns exhibited by signal, weapon, clasping and genital traits, as well as nonsexual traits. This evidence suggests that positive allometry may be the exception rather than the rule in sexual traits, that directional sexual selection does not necessarily lead to the evolution of positive allometry and, conversely, that positive allometry is not necessarily a consequence of sexual selection, and that many sexual traits exhibit sex differences in allometric intercept rather than slope. Such diversity in the allometries of secondary sexual traits is to be expected, given that optimal allometry should reflect resource allocation trade-offs, and patterns of sexual and viability selection on both trait size and body size. An unbiased empirical assessment of the relation between sexual selection and allometry is an essential step towards an understanding of this diversity.

  2. Evolutionary allometry of the thoracolumbar centra in felids and bovids.

    Science.gov (United States)

    Jones, Katrina E

    2015-07-01

    Mammals have evolved a remarkable range of body sizes, yet their overall body plan remains unaltered. One challenge of evolutionary biology is to understand the mechanisms by which this size diversity is achieved, and how the mechanical challenges associated with changing body size are overcome. Despite the importance of the axial skeleton in body support and locomotion, and much interest in the allometry of the appendicular skeleton, little is known about vertebral allometry outside primates. This study compares evolutionary allometry of the thoracolumbar centra in two families of quadrupedal running mammals: Felidae and Bovidae. I test the hypothesis that, as size increases, the thoracolumbar region will resist increasing loads by becoming a) craniocaudally shorter, and b) larger in cross-sectional area, particularly in the sagittal plane. Length, width, and height of the thoracolumbar centra of 23 felid and 34 bovid species were taken. Thoracic, prediaphragmatic, lumbar, and postdiaphragmatic lengths were calculated, and diameters were compared at three equivalent positions: the midthoracic, the diaphragmatic and the midlumbar vertebra. Allometric slopes were calculated using a reduced major axis regression, on both raw and independent contrasts data. Slopes and elevations were compared using an ANCOVA. As size increases the thoracolumbar centra become more robust, showing preferential reinforcement in the sagittal plane. There was less allometric shortening of the thoracic than the lumbar region, perhaps reflecting constraints due to its connection with the respiratory apparatus. The thoracic region was more robust in bovids than felids, whereas the lumbar region was longer and more robust in felids than bovids. Elongation of lumbar centra increases the outlever of sagittal bending at intervertebral joints, increasing the total pelvic displacement during dorsomobile running. Both locomotor specializations and functional regionalization of the axial skeleton

  3. Positive allometry and the prehistory of sexual selection.

    Science.gov (United States)

    Tomkins, Joseph L; LeBas, Natasha R; Witton, Mark P; Martill, David M; Humphries, Stuart

    2010-08-01

    The function of the exaggerated structures that adorn many fossil vertebrates remains largely unresolved. One recurrent hypothesis is that these elaborated traits had a role in thermoregulation. This orthodoxy persists despite the observation that traits exaggerated to the point of impracticality in extant organisms are almost invariably sexually selected. We use allometric scaling to investigate the role of sexual selection and thermoregulation in the evolution of exaggerated traits of the crested pterosaur Pteranodon longiceps and the sail-backed eupelycosaurs Dimetrodon and Edaphosaurus. The extraordinarily steep positive allometry of the head crest of Pteranodon rules out all of the current hypotheses for this trait's main function other than sexual signaling. We also find interspecific patterns of allometry and sexual dimorphism in the sails of Dimetrodon and patterns of elaboration in Edaphosaurus consistent with a sexually selected function. Furthermore, small ancestral, sail-backed pelycosaurs would have been too small to need adaptations to thermoregulation. Our results question the popular view that the elaborated structures of these fossil species evolved as thermoregulatory organs and provide evidence in support of the hypothesis that Pteranodon crests and eupelycosaur sails are among the earliest and most extreme examples of elaborate sexual signals in the evolution of terrestrial vertebrates.

  4. Allometry of Sapwood Depth in Five Boreal Trees

    Directory of Open Access Journals (Sweden)

    M. Rebeca Quiñonez-Piñón

    2017-11-01

    Full Text Available This paper analyzes sapwood variability and allometry within individuals of Populus tremuloides, Pinus contorta, Pinus banksiana, Picea mariana, and Picea glauca. Outside bark diameter at breast height (DBH and sapwood depth (sd in four cardinal directions were measured in individuals in stands in Alberta and Saskatchewan, Canada. The microscopical analysis of wood anatomy was used to measure sd, and the error associated with the measures was observed. Sapwood allometry analyses examined the influence of DBH on sd and on sapwood area (SA. All species were observed to have varying sapwood depths around the trunk with statistical analyses showing that Pinus banksiana has a well defined preference to grow thicker in the North-East side. The largest sd values were observed for the Populus tremuloides set. Unlike Populus tremuloides and Picea glauca, for the species Pinus contorta, Pinus banksiana, and Picea mariana, incremental growth in DBH does not directly drive sapwood growth in any direction. For these three species, SA increases only because of increases in DBH as sd remains nearly constant. These results show that sapwood depth and sapwood area seem to behave differently in each studied species and are not always proportional to the tree size as is normally assumed.

  5. Squamate hatchling size and the evolutionary causes of negative offspring size allometry.

    Science.gov (United States)

    Meiri, S; Feldman, A; Kratochvíl, L

    2015-02-01

    Although fecundity selection is ubiquitous, in an overwhelming majority of animal lineages, small species produce smaller number of offspring per clutch. In this context, egg, hatchling and neonate sizes are absolutely larger, but smaller relative to adult body size in larger species. The evolutionary causes of this widespread phenomenon are not fully explored. The negative offspring size allometry can result from processes limiting maximal egg/offspring size forcing larger species to produce relatively smaller offspring ('upper limit'), or from a limit on minimal egg/offspring size forcing smaller species to produce relatively larger offspring ('lower limit'). Several reptile lineages have invariant clutch sizes, where females always lay either one or two eggs per clutch. These lineages offer an interesting perspective on the general evolutionary forces driving negative offspring size allometry, because an important selective factor, fecundity selection in a single clutch, is eliminated here. Under the upper limit hypotheses, large offspring should be selected against in lineages with invariant clutch sizes as well, and these lineages should therefore exhibit the same, or shallower, offspring size allometry as lineages with variable clutch size. On the other hand, the lower limit hypotheses would allow lineages with invariant clutch sizes to have steeper offspring size allometries. Using an extensive data set on the hatchling and female sizes of > 1800 species of squamates, we document that negative offspring size allometry is widespread in lizards and snakes with variable clutch sizes and that some lineages with invariant clutch sizes have unusually steep offspring size allometries. These findings suggest that the negative offspring size allometry is driven by a constraint on minimal offspring size, which scales with a negative allometry. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary

  6. Adaptive diversification of growth allometry in the plant Arabidopsis thaliana.

    Science.gov (United States)

    Vasseur, François; Exposito-Alonso, Moises; Ayala-Garay, Oscar J; Wang, George; Enquist, Brian J; Vile, Denis; Violle, Cyrille; Weigel, Detlef

    2018-03-27

    Seed plants vary tremendously in size and morphology; however, variation and covariation in plant traits may be governed, at least in part, by universal biophysical laws and biological constants. Metabolic scaling theory (MST) posits that whole-organismal metabolism and growth rate are under stabilizing selection that minimizes the scaling of hydrodynamic resistance and maximizes the scaling of resource uptake. This constrains variation in physiological traits and in the rate of biomass accumulation, so that they can be expressed as mathematical functions of plant size with near-constant allometric scaling exponents across species. However, the observed variation in scaling exponents calls into question the evolutionary drivers and the universality of allometric equations. We have measured growth scaling and fitness traits of 451 Arabidopsis thaliana accessions with sequenced genomes. Variation among accessions around the scaling exponent predicted by MST was correlated with relative growth rate, seed production, and stress resistance. Genomic analyses indicate that growth allometry is affected by many genes associated with local climate and abiotic stress response. The gene with the strongest effect, PUB4 , has molecular signatures of balancing selection, suggesting that intraspecific variation in growth scaling is maintained by opposing selection on the trade-off between seed production and abiotic stress resistance. Our findings suggest that variation in allometry contributes to local adaptation to contrasting environments. Our results help reconcile past debates on the origin of allometric scaling in biology and begin to link adaptive variation in allometric scaling to specific genes. Copyright © 2018 the Author(s). Published by PNAS.

  7. Male mate choice scales female ornament allometry in a cichlid fish

    Directory of Open Access Journals (Sweden)

    Kullmann Harald

    2010-10-01

    Full Text Available Abstract Background Studies addressing the adaptive significance of female ornamentation have gained ground recently. However, the expression of female ornaments in relation to body size, known as trait allometry, still remains unexplored. Here, we investigated the allometry of a conspicuous female ornament in Pelvicachromis taeniatus, a biparental cichlid that shows mutual mate choice and ornamentation. Females feature an eye-catching pelvic fin greatly differing from that of males. Results We show that allometry of the female pelvic fin is scaled more positively in comparison to other fins. The pelvic fin exhibits isometry, whereas the other fins (except the caudal fin show negative allometry. The size of the pelvic fin might be exaggerated by male choice because males prefer female stimuli that show a larger extension of the trait. Female pelvic fin size is correlated with individual condition, suggesting that males can assess direct and indirect benefits. Conclusions The absence of positive ornament allometry might be a result of sexual selection constricted by natural selection: fins are related to locomotion and thus may be subject to viability selection. Our study provides evidence that male mate choice might scale the expression of a female sexual ornament, and therefore has implications for the understanding of the relationship of female sexual traits with body size in species with conventional sex-roles.

  8. Brain evolution and development: adaptation, allometry and constraint

    Science.gov (United States)

    Barton, Robert A.

    2016-01-01

    Phenotypic traits are products of two processes: evolution and development. But how do these processes combine to produce integrated phenotypes? Comparative studies identify consistent patterns of covariation, or allometries, between brain and body size, and between brain components, indicating the presence of significant constraints limiting independent evolution of separate parts. These constraints are poorly understood, but in principle could be either developmental or functional. The developmental constraints hypothesis suggests that individual components (brain and body size, or individual brain components) tend to evolve together because natural selection operates on relatively simple developmental mechanisms that affect the growth of all parts in a concerted manner. The functional constraints hypothesis suggests that correlated change reflects the action of selection on distributed functional systems connecting the different sub-components, predicting more complex patterns of mosaic change at the level of the functional systems and more complex genetic and developmental mechanisms. These hypotheses are not mutually exclusive but make different predictions. We review recent genetic and neurodevelopmental evidence, concluding that functional rather than developmental constraints are the main cause of the observed patterns. PMID:27629025

  9. Allometry of sexual size dimorphism in domestic dog.

    Directory of Open Access Journals (Sweden)

    Daniel Frynta

    Full Text Available The tendency for male-larger sexual size dimorphism (SSD to scale with body size - a pattern termed Rensch's rule - has been empirically supported in many animal lineages. Nevertheless, its theoretical elucidation is a subject of debate. Here, we exploited the extreme morphological variability of domestic dog (Canis familiaris to gain insights into evolutionary causes of this rule.We studied SSD and its allometry among 74 breeds ranging in height from less than 19 cm in Chihuahua to about 84 cm in Irish wolfhound. In total, the dataset included 6,221 individuals. We demonstrate that most dog breeds are male-larger, and SSD in large breeds is comparable to SSD of their wolf ancestor. Among breeds, SSD becomes smaller with decreasing body size. The smallest breeds are nearly monomorphic.SSD among dog breeds follows the pattern consistent with Rensch's rule. The variability of body size and corresponding changes in SSD among breeds of a domestic animal shaped by artificial selection can help to better understand processes leading to emergence of Rensch's rule.

  10. Tradeoff between stem hydraulic efficiency and mechanical strength affects leaf-stem allometry in 28 Ficus tree species

    NARCIS (Netherlands)

    Fan, Ze Xin; Sterck, Frank; Zhang, Shi Bao; Fu, Pei Li; Hao, Guang You

    2017-01-01

    Leaf-stem allometry is an important spectrum that linked to biomass allocation and life history strategy in plants, although the determinants and evolutionary significance of leaf-stem allometry remain poorly understood. Leaf and stem architectures - including stem area/mass, petiole area/mass,

  11. Deciduous and evergreen trees differ in juvenile biomass allometries because of differences in allocation to root storage

    NARCIS (Netherlands)

    Tomlinson, K.W.; Langevelde, van F.; Ward, D.; Bongers, F.J.J.M.; Alves da Silva, D.; Prins, H.H.T.; Bie, de S.; Sterck, F.J.

    2013-01-01

    Background and Aims - Biomass partitioning for resource conservation might affect plant allometry, accounting for a substantial amount of unexplained variation in existing plant allometry models. One means of resource conservation is through direct allocation to storage in particular organs. In this

  12. BAAD: a Biomass And Allometry Database for woody plants

    Energy Technology Data Exchange (ETDEWEB)

    Falster, Daniel; Duursma, Remko; Ishihara, Masae; Barneche, Diego; Fitzjohn, Richard; Varhammar, Angelica; Aiba, Masahiro; Ando, M.; Anten, Niels; Aspinwall, Michael J.; Baltzer, Jennifer; Baraloto, Christopher; Battaglia, Michael; Battles, John; Bond-Lamberty, Benjamin; van Breugel, Michiel; Camac, James; Claveau, Yves; Coll Mir, Llus; Dannoura, Dannoura; Delagrange, Sylvain; Domec, Jean-Cristophe; Fatemi, Farrah; Feng, Wang; Gargaglione, Veronica; Goto, Yoshiaki; Hagihara, Akio; Hall, Jefferson S.; Hamilton, Steve; Harja, Degi; Hiura, Tsutom; Holdaway, Robert; Hutley, L. B.; Ichie, Tomoaki; Jokela, Eric; Kantola, Anu; Kelly, Jeffery W.; Kenzo, Tanaka; King, David A.; Kloeppel, Brian; Kohyama, Takashi; Komiyama, Akira; Laclau, Jean-Paul; Lusk, Christopher; Maguire, Doug; le Maire, Guerric; Makela, Annikki; Markesteijn, Lars; Marshall, John; McCulloh, Kate; Miyata, Itsuo; Mokany, Karen; Mori, Shigeta; Myster, Randall; Nagano, Masahiro; Naidu, Shawna; Nouvellon, Yann; O' Grady, Anthony; O' Hara, Kevin; Ohtsuka, Toshiyuki; Osada, Noriyuki; Osunkoya, Olusegun O.; Luis Peri, Pablo; Petritan, Mary; Poorter, Lourens; Portsmuth, Angelika; Potvin, Catherine; Ransijn, Johannes; Reid, Douglas; Ribeiro, Sabina C.; Roberts, Scott; Rodriguez, Rolando; Saldana-Acosta, Angela; Santa-Regina, Ignacio; Sasa, Kaichiro; Gailia Selaya, Nadezhda; Sillett, Stephen; Sterck, Frank; Takagi, Kentaro; Tange, Takeshi; Tanouchi, Hiroyuki; Tissue, David; Umehara, Tohru; Utsugi, Hajime; Vadeboncoeur, Matthew; Valladares, Fernando; Vanninen, Petteri; Wang, Jian; Wenk, Elizabeth; Williams, Dick; Ximenes, Fabiano de Aquino; Yamaba, Atsushi; Yamada, Toshihiro; Yamakura, Takuo; Yanai, Ruth; York, Robert

    2015-05-07

    Quantifying the amount of mass or energy invested in plant tissues is of fundamental interest across a range of disciplines, including ecology, forestry, ecosystem science, and climate change science (Niklas, 1994; Chave et al. 2005; Falster et al. 2011). The allocation of net primary production into different plant components is an important process affecting the lifetime of carbon in ecosystems, and resource use and productivity by plants (Cannell & Dewar, 1994; Litton et al. 2007; Poorter et al. 2012). While many studies in have destructively harvested woody plants in the name of science, most of these data have only been made available in the form of summary tables or figures included in publications. Until now, the raw data has resided piecemeal on the hard drives of individual scientists spread around the world. Several studies have gathered together the fitted (allometric) equations for separate datasets (Ter-Mikaelian & Korzukhin, 1997; Jenkins et al. 2003; Zianis et al. 2005; Henry et al. 2013), but none have previously attempted to organize and share the raw individual plant data underpinning these equations on a large scale. Gathered together, such data would represent an important resource for the community, meeting a widely recognised need for rich, open data resources to solve ecological problems (Costello et al. 2013; Fady et al. 2014; Harfoot & Roberts, 2014; Costello et al. 2013). We (D.S. Falster and R.A. Duursma, with the help of D.R. Barneche, R.G. FitzJohn and A. Vårhammar) set out to create such a resource, by asking authors directly whether they would be willing to make their raw data files freely available. The response was overwhelming: nearly everyone we contacted was interested to contribute their raw data. Moreover, we were invited to incorporate another compilation led by M. Ishihara and focussing on Japanese literature. As a result, we present BAAD: a Biomass And Allometry Database for woody plants, comprising data collected in 174

  13. Limb bone allometry during postnatal ontogeny in non-avian dinosaurs

    Science.gov (United States)

    Kilbourne, Brandon M; Makovicky, Peter J

    2010-01-01

    Although the interspecific scaling of tetrapods is well understood, remarkably little work has been done on the ontogenetic scaling within tetrapod species, whether fossil or recent. Here the ontogenetic allometry of the femur, humerus, and tibia was determined for 23 species of non-avian dinosaur by regressing log-transformed length against log-transformed circumference for each bone using reduced major axis bivariate regression. The femora of large theropod species became more robust during ontogeny, whereas growth in the femora of sauropodomorphs and most ornithischians was not significantly different from isometry. Hadrosaur hindlimb elements became significantly more gracile during ontogeny. Scaling constants were higher in all theropods than in any non-theropod taxa. Such clear taxonomically correlated divisions were not evident in the ontogenetic allometry of the tibia and hindlimb bones did not scale uniformly within larger taxonomic groups. For taxa in which the ontogenetic allometry of the humerus was studied, only Riojasaurus incertus exhibited a significant departure from isometry. Using independent contrasts, the regression of femoral allometry against the log of adult body mass was found to have a significant negative correlation but such a relationship could not be established for other limb elements or growth parameters, mainly due to the small sample size. The intraspecific scaling patterns observed in dinosaurs and other amniotes do not support earlier hypotheses that intraspecific scaling differs between endothermic and ectothermic taxa. PMID:20557400

  14. Allometry in primates, with emphasis on scaling and the evolution of the brain.

    Science.gov (United States)

    Gould, S J

    1975-01-01

    Allometry should be defined broadly as the study of size and its consequences, not narrowly as the application of power functions to the data of growth. Variation in size may be ontogenetic, static or phyletic. Errors of omission and treatment have plagued the study of allometry in primates. Standard texts often treat brain size as an independent measure, ignoring its allometric relation with body size - on this basis, gracile australopithecines have been accorded the mental status of gorillas. Intrinsic allometries of the brain/body are likewise neglected: many authors cite cerebral folding as evidence of man's mental superiority, but folding is a mechanical correlate of brain size itself. Confusion among types of scaling heads errors of treatment in both historical primacy [Dubois' ontogenetic inferences from interspecific curves] and current frequency. The predicted parameters of brain-body plots differ greatly for ontogenetic, intrapopulational, interspecific and phyletic allometries. I then discuss basic trends in bivariate allometry at the ordinal level for internal organ weights, skeletal dimensions, lifespan and fetal weight. In considering the causes of basic bivariate allometries, I examine the reason for differences among types of scaling in brain-body relationships. The interspecific exponent of 0.66 strongly suggests a relationship to body surfaces, but we have no satisfactory explanation for why this should be so. The tripartite ontogenetic plot is a consequence of patterns in neuronal differentiation. We do not know why intraspecific exponents fall between 0.2 and 0.4; several partial explanations have been offered. Multivariate techniques have transcended the pictorial representation of transformed coordinates and offer new, powerful approaches to total allometric patterns. Allometry is most often used as a 'criterion for subtraction'. In order to assess the nature and purpose of an adaptation, we must be able to identify and isolate the aspect of

  15. Oak bark allometry and fire survival strategies in the Chihuahuan desert Sky Islands, Texas, USA.

    Science.gov (United States)

    Schwilk, Dylan W; Gaetani, Maria S; Poulos, Helen M

    2013-01-01

    Trees may survive fire through persistence of above or below ground structures. Investment in bark aids in above-ground survival while investment in carbohydrate storage aids in recovery through resprouting and is especially important following above-ground tissue loss. We investigated bark allocation and carbohydrate investment in eight common oak (Quercus) species of Sky Island mountain ranges in west Texas. We hypothesized that relative investment in bark and carbohydrates changes with tree age and with fire regime: We predicted delayed investment in bark (positive allometry) and early investment in carbohydrates (negative allometry) under lower frequency, high severity fire regimes found in wetter microclimates. Common oaks of the Texas Trans-Pecos region (Quercus emoryi, Q. gambelii, Q. gravesii, Q. grisea, Q. hypoleucoides, Q. muehlenbergii, and Q. pungens) were sampled in three mountain ranges with historically mixed fire regimes: the Chisos Mountains, the Davis Mountains and the Guadalupe Mountains. Bark thickness was measured on individuals representing the full span of sizes found. Carbohydrate concentration in taproots was measured after initial leaf flush. Bark thickness was compared to bole diameter and allometries were analyzed using major axis regression on log-transformed measurements. We found that bark allocation strategies varied among species that can co-occur but have different habitat preferences. Investment patterns in bark were related to soil moisture preference and drought tolerance and, by proxy, to expected fire regime. Dry site species had shallower allometries with allometric coefficients ranging from less than one (negative allometry) to near one (isometric investment). Wet site species, on the other hand, had larger allometric coefficients, indicating delayed investment to defense. Contrary to our expectation, root carbohydrate concentrations were similar across all species and sizes, suggesting that any differences in below ground

  16. Oak bark allometry and fire survival strategies in the Chihuahuan desert Sky Islands, Texas, USA.

    Directory of Open Access Journals (Sweden)

    Dylan W Schwilk

    Full Text Available Trees may survive fire through persistence of above or below ground structures. Investment in bark aids in above-ground survival while investment in carbohydrate storage aids in recovery through resprouting and is especially important following above-ground tissue loss. We investigated bark allocation and carbohydrate investment in eight common oak (Quercus species of Sky Island mountain ranges in west Texas. We hypothesized that relative investment in bark and carbohydrates changes with tree age and with fire regime: We predicted delayed investment in bark (positive allometry and early investment in carbohydrates (negative allometry under lower frequency, high severity fire regimes found in wetter microclimates. Common oaks of the Texas Trans-Pecos region (Quercus emoryi, Q. gambelii, Q. gravesii, Q. grisea, Q. hypoleucoides, Q. muehlenbergii, and Q. pungens were sampled in three mountain ranges with historically mixed fire regimes: the Chisos Mountains, the Davis Mountains and the Guadalupe Mountains. Bark thickness was measured on individuals representing the full span of sizes found. Carbohydrate concentration in taproots was measured after initial leaf flush. Bark thickness was compared to bole diameter and allometries were analyzed using major axis regression on log-transformed measurements. We found that bark allocation strategies varied among species that can co-occur but have different habitat preferences. Investment patterns in bark were related to soil moisture preference and drought tolerance and, by proxy, to expected fire regime. Dry site species had shallower allometries with allometric coefficients ranging from less than one (negative allometry to near one (isometric investment. Wet site species, on the other hand, had larger allometric coefficients, indicating delayed investment to defense. Contrary to our expectation, root carbohydrate concentrations were similar across all species and sizes, suggesting that any differences in

  17. Does allometry account for shape variability in Ephedrus persicae Froggatt (Hymenoptera: Braconidae: Aphidiinae) parasitic wasps?

    Czech Academy of Sciences Publication Activity Database

    Žikić, V.; Tomanović, Ž.; Kavallieratos, N. G.; Starý, Petr; Ivanović, A.

    2010-01-01

    Roč. 10, č. 5 (2010), s. 373-380 ISSN 1439-6092 R&D Projects: GA AV ČR IBS5007102 Grant - others:The Ministry of Science and Technological Development of the Republic of Serbia(SR) 143006B Institutional research plan: CEZ:AV0Z50070508 Keywords : allometry * morphometric variability * geometric morphometrics Subject RIV: EA - Cell Biology Impact factor: 1.581, year: 2010

  18. Ontogenetic allometry in the foot size of Oligoryzomys flavescens (Waterhouse, 1837 (Rodentia, Sigmodontinae

    Directory of Open Access Journals (Sweden)

    R. Maestri

    Full Text Available Ontogenetic allometry is the study of how the size or shape of certain structures changes over the course of an animal’s development. In this study, using Huxley's formula of allometric growth (1932, we assessed the changes in the rate of growth of the feet size of the sigmodontine rodent Oligoryzomys flavescens during its ontogeny and compared differences between males and females. We find evidence of a change of polarity during the ontogenetic development of the species, with the presence of positive allometry during pregnancy and negative allometry in adulthood. Moreover, we note the presence of sexual dimorphism in the size of the feet, in which males of the species have a higher rate of growth than females. This growth pattern is positively related to escape from predators in childhood in both sexes and, in adulthood, provides a higher encounter rate of females by males, due to the larger displacement of the latter. We suggest that both the forces of natural selection and sexual selection have acted to shape the evolution of foot size in this species.

  19. Ontogenetic allometry in the foot size of Oligoryzomys flavescens (Waterhouse, 1837) (Rodentia, Sigmodontinae).

    Science.gov (United States)

    Maestri, R; Fornel, R; Freitas, T R O; Marinho, J R

    2015-05-01

    Ontogenetic allometry is the study of how the size or shape of certain structures changes over the course of an animal's development. In this study, using Huxley's formula of allometric growth (1932), we assessed the changes in the rate of growth of the feet size of the sigmodontine rodent Oligoryzomys flavescens during its ontogeny and compared differences between males and females. We find evidence of a change of polarity during the ontogenetic development of the species, with the presence of positive allometry during pregnancy and negative allometry in adulthood. Moreover, we note the presence of sexual dimorphism in the size of the feet, in which males of the species have a higher rate of growth than females. This growth pattern is positively related to escape from predators in childhood in both sexes and, in adulthood, provides a higher encounter rate of females by males, due to the larger displacement of the latter. We suggest that both the forces of natural selection and sexual selection have acted to shape the evolution of foot size in this species.

  20. The allometry of parrot BMR: seasonal data for the Greater Vasa Parrot, Coracopsis vasa, from Madagascar.

    Science.gov (United States)

    Lovegrove, Barry G; Perrin, Mike R; Brown, Mark

    2011-12-01

    In this study we examined the allometry of basal metabolic rate (BMR) of 31 parrot species. Unlike previous reports, we show that parrots per se do not display BMRs that are any different to other captive-raised birds of their body size. An ordinary least squares regression fitted the data best and body mass explained 95% of the variation in BMR. There was no phylogenetic signal in the BMR data. We also provide new data for the Greater Vasa Parrot (Coracopsis vasa) of Madagascar. We tested the hypotheses that C. vasa may, because of its insular existence, display conservative energetic traits (low BMR, use of adaptive heterothermy) similar to those observed in several Malagasy mammals. However, this was not the case. C. vasa had a higher BMR than other parrots, especially during summer, when BMR was up-regulated by 50.5% and was 95.7% higher than predicted from an ordinary least squares (OLS) allometry of parrots (BMR = 0.042M (b) (0.649) , BMR in Watts, M (b) in grammes). Compared with BMR data for 94 captive-raised bird species, the winter and summer BMRs were, respectively, 45.5 and 117.8% higher than predicted by a phylogenetic generalised least squares (PGLS) allometry (BMR = 0.030M (b) (0.687) , BMR in Watts, M (b) in grammes). The summer up-regulation of BMR is the highest recorded for a bird of any size to date. We suggest that the costs of a high summer BMR may be met by the unusual cooperative breeding system of C. vasa in which groups of males feed the female and share paternity. The potential breeding benefits of a high summer BMR are unknown.

  1. Caudal fin allometry in the white shark Carcharodon carcharias: implications for locomotory performance and ecology

    Science.gov (United States)

    Lingham-Soliar, Theagarten

    2005-05-01

    Allometric scaling analysis was employed to investigate the consequences of size evolution on hydrodynamic performance and ecology in the white shark Carcharodon carcharias. Discriminant analysis using the power equation y=axb was negative for caudal fin span (S) versus fork length (FL) in C. carcharias. In contrast in two delphinid species, Delphinus capensis and Tursiops aduncus, the span of the flukes versus fork length rises in positive allometric fashion, and strong positive allometry of S versus √A (area) was also recorded. The latter reflects a high lift/drag ratio. S versus √A in C. carcharias displays negative allometry and consequently a lower lift/drag ratio. A lower aspect ratio (AR) caudal fin in C. carcharias compared to that of the delphinids (mean 3.33 and 4.1, respectively) and other thunniform swimmers provides the potential for better maneuverability and acceleration. The liver in sharks is frequently associated with a buoyancy function and was found to be positively allometric in C. carcharias. The overall findings suggest that the negatively allometric caudal fin morphometrics in C. carcharias are unlikely to have deleterious evolutionary fitness consequences for predation. On the contrary, when considered in the context of positive liver allometry in C. carcharias it is hereby suggested that buoyancy may play a dominant role in larger white sharks in permitting slow swimming while minimizing energy demands needed to prevent sinking. In contrast hydrodynamic lift is considered more important in smaller white sharks. Larger caudal fin spans and higher lift/drag ratio in smaller C. carcharias indicate greater potential for prolonged, intermediate swimming speeds and for feeding predominantly on fast-moving fish, in contrast to slow-swimming search patterns of larger individuals for predominantly large mammalian prey. Such data may provide some answers to the lifestyle and widespread habitat capabilities of this still largely mysterious animal.

  2. Genotypic Diversity for Biomass Accumulation and Shoot-Root Allometry in the Grass Brachypodium distachyon

    Science.gov (United States)

    Jansson, C.; Handakumbura, P. P.; Fortin, D.; Stanfill, B.; Rivas-Ubach, A.

    2017-12-01

    Predicting carbon uptake, assimilation and allocation for current and future biogeographical environments, including climate, is critical for our ability to select and/or design plant genotypes to meet increasing demand for plant biomass going into food, feed and energy production, while at the same time maintain or increase soil organic matter (SOM for soil fertility and carbon storage, and reduce emission of greenhouse gasses. As has been demonstrated for several plant species allometric relationships may differ between plant genotypes. Exploring plant genotypic diversity for biomass accumulation and allometry will potentially enable selection of genotypes with high CO2 assimilation and favorable allocation of recent photosynthate into above-ground and below-ground biomass. We are investigating genotypic diversity for PFTs in natural accessions of the annual C3 grass Brachypodium distachyon under current and future climate scenarios and how genotypic diversity correlates with metabolite profiles in aboveground and below-ground biomass. In the current study, we compare effects from non-stressed and drought conditions on biomass accumulation and shoot-root allometry.

  3. Evolution of static allometries: adaptive change in allometric slopes of eye span in stalk-eyed flies.

    Science.gov (United States)

    Voje, Kjetil L; Hansen, Thomas F

    2013-02-01

    Julian Huxley showed that within-species (static) allometric (power-law) relations can arise from proportional growth regulation with the exponent in the power law equaling the factor of proportionality. Allometric exponents may therefore be hard to change and act as constraints on the independent evolution of traits. In apparent contradiction to this, many empirical studies have concluded that static allometries are evolvable. Many of these studies have been based, however, on a broad definition of allometry that includes any monotonic shape change with size, and do not falsify the hypothesis of constrained narrow-sense allometry. Here, we present the first phylogenetic comparative study of narrow-sense allometric exponents based on a reanalysis of data on eye span and body size in stalk-eyed flies (Diopsidae). Consistent with a role in sexual selection, we found strong evidence that male slopes were tracking "optima" based on sexual dimorphism and relative male trait size. This tracking was slow, however, with estimated times of 2-3 million years for adaptation to exceed ancestral influence on the trait. Our results are therefore consistent with adaptive evolution on million-year time scales, but cannot rule out that static allometry may act as a constraint on eye-span adaptation at shorter time scales. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  4. Effect of the relative time of emergence on the growth allometry of Galium aparine in competition with Triticum aestivum

    Czech Academy of Sciences Publication Activity Database

    Klem, Karel; Rajsnerová, Petra; Novotná, Kateřina; Urban, Otmar; Marek, Michal V.

    2014-01-01

    Roč. 14, č. 4 (2014), s. 262-270 ISSN 1444-6162 R&D Projects: GA MZe QI111A133; GA TA ČR TA02010780 Institutional support: RVO:67179843 Keywords : cleaver * competition * growth allometry * relative time of emergence * wheat Subject RIV: GC - Agronomy Impact factor: 0.537, year: 2014

  5. Sex-specific patterns of morphological diversification: evolution of reaction norms and static allometries in neriid flies.

    Science.gov (United States)

    Cassidy, Elizabeth J; Bath, Eleanor; Chenoweth, Stephen F; Bonduriansky, Russell

    2014-02-01

    The consequences of sex-specific selection for patterns of diversification remain poorly known. Because male secondary sexual traits are typically costly to express, and both costs and benefits are likely to depend on ambient environment and individual condition, such traits may be expected to diversify via changes in reaction norms as well as the scaling of trait size with body size (static allometry). We investigated morphological diversification within two species of Australian neriid flies (Telostylinus angusticollis, Telostylinus lineolatus) by rearing larvae from several populations on larval diets varying sixfold in nutrient concentration. Mean body size varied among populations of T. angusticollis, but body size reaction norms did not vary within either species. However, we detected diversification of reaction norms for body shape in males and females within both species. Moreover, unlike females, males also diversified in static allometry slope and reaction norms for static allometry slope of sexual and nonsexual traits. Our findings reveal qualitative sex differences in patterns of morphological diversification, whereby shape-size relationships diversify extensively in males, but remain conserved in females despite extensive evolution of trait means. Our results highlight the importance of incorporating plasticity and allometry in studies of adaptation and diversification. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  6. Allometry of sexual size dimorphism in turtles: a comparison of mass and length data.

    Science.gov (United States)

    Regis, Koy W; Meik, Jesse M

    2017-01-01

    The macroevolutionary pattern of Rensch's Rule (positive allometry of sexual size dimorphism) has had mixed support in turtles. Using the largest carapace length dataset and only large-scale body mass dataset assembled for this group, we determine (a) whether turtles conform to Rensch's Rule at the order, suborder, and family levels, and (b) whether inferences regarding allometry of sexual size dimorphism differ based on choice of body size metric used for analyses. We compiled databases of mean body mass and carapace length for males and females for as many populations and species of turtles as possible. We then determined scaling relationships between males and females for average body mass and straight carapace length using traditional and phylogenetic comparative methods. We also used regression analyses to evalutate sex-specific differences in the variance explained by carapace length on body mass. Using traditional (non-phylogenetic) analyses, body mass supports Rensch's Rule, whereas straight carapace length supports isometry. Using phylogenetic independent contrasts, both body mass and straight carapace length support Rensch's Rule with strong congruence between metrics. At the family level, support for Rensch's Rule is more frequent when mass is used and in phylogenetic comparative analyses. Turtles do not differ in slopes of sex-specific mass-to-length regressions and more variance in body size within each sex is explained by mass than by carapace length. Turtles display Rensch's Rule overall and within families of Cryptodires, but not within Pleurodire families. Mass and length are strongly congruent with respect to Rensch's Rule across turtles, and discrepancies are observed mostly at the family level (the level where Rensch's Rule is most often evaluated). At macroevolutionary scales, the purported advantages of length measurements over weight are not supported in turtles.

  7. Thin-plate spline analysis of allometry and sexual dimorphism in the human craniofacial complex.

    Science.gov (United States)

    Rosas, Antonio; Bastir, Markus

    2002-03-01

    The relationship between allometry and sexual dimorphism in the human craniofacial complex was analyzed using geometric morphometric methods. Thin-plate splines (TPS) analysis has been applied to investigate the lateral profile of complete adult skulls of known sex. Twenty-nine three-dimensional (3D) craniofacial and mandibular landmark coordinates were recorded from a sample of 52 adult females and 52 adult males of known age and sex. No difference in the influence of size on shape was detected between sexes. Both size and sex had significant influences on shape. As expected, the influence of centroid size on shape (allometry) revealed a shift in the proportions of the neurocranium and the viscerocranium, with a marked allometric variation of the lower face. Adjusted for centroid size, males presented a relatively larger size of the nasopharyngeal space than females. A mean-male TPS transformation revealed a larger piriform aperture, achieved by an increase of the angulation of the nasal bones and a downward rotation of the anterior nasal floor. Male pharynx expansion was also reflected by larger choanae and a more posteriorly inclined basilar part of the occipital clivus. Male muscle attachment sites appeared more pronounced. In contrast, the mean-female TPS transformation was characterized by a relatively small nasal aperture. The occipital clivus inclined anteriorly, and muscle insertion areas became smoothed. Besides these variations, both maxillary and mandibular alveolar regions became prognathic. The sex-specific TPS deformation patterns are hypothesized to be associated with sexual differences in body composition and energetic requirements. Copyright 2002 Wiley-Liss, Inc.

  8. Allometric scaling of population variance with mean body size is predicted from Taylor's law and density-mass allometry.

    Science.gov (United States)

    Cohen, Joel E; Xu, Meng; Schuster, William S F

    2012-09-25

    Two widely tested empirical patterns in ecology are combined here to predict how the variation of population density relates to the average body size of organisms. Taylor's law (TL) asserts that the variance of the population density of a set of populations is a power-law function of the mean population density. Density-mass allometry (DMA) asserts that the mean population density of a set of populations is a power-law function of the mean individual body mass. Combined, DMA and TL predict that the variance of the population density is a power-law function of mean individual body mass. We call this relationship "variance-mass allometry" (VMA). We confirmed the theoretically predicted power-law form and the theoretically predicted parameters of VMA, using detailed data on individual oak trees (Quercus spp.) of Black Rock Forest, Cornwall, New York. These results connect the variability of population density to the mean body mass of individuals.

  9. Foraging and vulnerability traits modify predator-prey body mass allometry: freshwater macroinvertebrates as a case study

    Czech Academy of Sciences Publication Activity Database

    Klečka, Jan; Boukal S., David

    2013-01-01

    Roč. 82, č. 5 (2013), s. 1031-1041 ISSN 0021-8790 Grant - others:AquaMod(CZ) PERG04-GA-2008-239543; GA JU(CZ) GAJU 145/2010/P; MŠMT(CZ) 7947/2010 30 Institutional support: RVO:60077344 Keywords : allometry * aquatic insects * Dytiscidae Subject RIV: EH - Ecology, Behaviour Impact factor: 4.726, year: 2013 http://onlinelibrary.wiley.com/doi/10.1111/1365-2656.12078/full

  10. Process-based allometry describes the influence of management on orchard tree aboveground architecture

    Directory of Open Access Journals (Sweden)

    Zachary T. Brym

    2018-06-01

    Full Text Available We evaluated allometric relationships in length, diameter, and mass of branches for two variably managed orchard tree species (tart cherry, Prunus cerasus; apple, Malus spp.. The empirically estimated allometric exponents (a of the orchard trees were described in the context of two processed-based allometry models that make predictions for a: the West, Brown and Enquist fractal branching model (WBE and the recently introduced Flow Similarity model (FS. These allometric models make predictions about relationships in plant morphology (e.g., branch mass, diameter, length, volume, surface area based on constraints imposed on plant growth by physical and physiological processes. We compared our empirical estimates of a to the model predictions to interpret the physiological implications of pruning and management in orchard systems. Our study found strong allometric relationships among the species and individuals studied with limited agreement with the expectations of either model. The 8/3-power law prediction of the mass ∼ diameter relationship by the WBE, indicative of biomechanical limitations, was marginally supported by this study. Length-including allometric relationships deviated from predictions of both models, but shift toward the expectation of flow similarity. In this way, managed orchard trees deviated from strict adherence to the idealized expectations of the models, but still fall within the range of model expectations in many cases despite intensive management.

  11. Sexual dimorphism and allometry in the sphecophilous rove beetle Triacrus dilatus

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    Maxwell H. Marlowe

    2015-07-01

    Full Text Available The rove beetle Triacrus dilatus is found in the Atlantic forest of South America and lives in the refuse piles of the paper wasp Agelaia vicina. Adults of T. dilatus are among the largest rove beetles, frequently measuring over 3 cm, and exhibit remarkable variation in body size. To examine sexual dimorphism and allometric relationships we measured the length of the left mandible, ocular distance and elytra. We were interested in determining if there are quantifiable differences between sexes, if there are major and minor forms within each sex and if males exhibit mandibular allometry. For all variables, a t-test was run to determine if there were significant differences between the sexes. Linear regressions were run to examine if there were significant relationships between the different measurements. A heterogeneity of slopes test was used to determine if there were significant differences between males and females. Our results indicated that males had significantly larger mandibles and ocular distances than females, but the overall body length was not significantly different between the sexes. Unlike most insects, both sexes showed positive linear allometric relationships for mandible length and head size (as measured by the ocular distance. We found no evidence of major and minor forms in either sex.

  12. Sexual dimorphism and allometry in the sphecophilous rove beetle Triacrus dilatus.

    Science.gov (United States)

    Marlowe, Maxwell H; Murphy, Cheryl A; Chatzimanolis, Stylianos

    2015-01-01

    The rove beetle Triacrus dilatus is found in the Atlantic forest of South America and lives in the refuse piles of the paper wasp Agelaia vicina. Adults of T. dilatus are among the largest rove beetles, frequently measuring over 3 cm, and exhibit remarkable variation in body size. To examine sexual dimorphism and allometric relationships we measured the length of the left mandible, ocular distance and elytra. We were interested in determining if there are quantifiable differences between sexes, if there are major and minor forms within each sex and if males exhibit mandibular allometry. For all variables, a t-test was run to determine if there were significant differences between the sexes. Linear regressions were run to examine if there were significant relationships between the different measurements. A heterogeneity of slopes test was used to determine if there were significant differences between males and females. Our results indicated that males had significantly larger mandibles and ocular distances than females, but the overall body length was not significantly different between the sexes. Unlike most insects, both sexes showed positive linear allometric relationships for mandible length and head size (as measured by the ocular distance). We found no evidence of major and minor forms in either sex.

  13. Interannual variability of growth and reproduction in Bursera simaruba: the role of allometry and resource variability.

    Science.gov (United States)

    Hulshof, Catherine M; Stegen, James C; Swenson, Nathan G; Enquist, Carolyn A F; Enquist, Brian J

    2012-01-01

    Plants are expected to differentially allocate resources to reproduction, growth, and survival in order to maximize overall fitness. Life history theory predicts that the allocation of resources to reproduction should occur at the expense of vegetative growth. Although it is known that both organism size and resource availability can influence life history traits, few studies have addressed how size dependencies of growth and reproduction and variation in resource supply jointly affect the coupling between growth and reproduction. In order to understand the relationship between growth and reproduction in the context of resource variability, we utilize a long-term observational data set consisting of 670 individual trees over a 10-year period within a local population of Bursera simaruba (L.) Sarg. We (1) quantify the functional form and variability in the growth-reproduction relationship at the population and individual-tree level and (2) develop a theoretical framework to understand the allometric dependence of growth and reproduction. Our findings suggest that the differential responses of allometric growth and reproduction to resource availability, both between years and between microsites, underlie the apparent relationship between growth and reproduction. Finally, we offer an alternative approach for quantifying the relationship between growth and reproduction that accounts for variation in allometries.

  14. APPLICATION OF ALLOMETRY FOR DETERMINATION OF STRENGTH PROFILE IN YOUNG FEMALE ATHLETES FROM DIFFERENT SPORTS

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    J. Gajewski

    2011-11-01

    Full Text Available The goal of the study was to determine a strength profile in young female athletes practising different sports and to use allometry to evaluate muscular strength with respect to body mass. The study included 42 women who practised taekwondo (n = 10, weightlifting (n = 10, canoeing (n = 14 and speed skating (n = 8. Measurements of maximal muscle torques under static conditions in 10 groups of flexors and extensors of the elbow, shoulder, hip, knee and trunk were carried out. The MANCOVA procedure was employed to compare means between the groups. A logarithm of body mass was adopted as a covariate. Relationships between body mass and muscle torques in each muscle group were determined using a procedure of linear regression. The analysis of residuals was employed for the evaluation of maximal muscle torques. Mean values of logarithms of maximal muscle torques were significantly different for the representatives of individual sports and they depended on the logarithm of body mass. It was proposed to use a mean of residuals normalized for individual muscle groups as a synthetic strength index (mean of the strength profile. The women practising canoeing were characterized by the highest strength index. Its lowest values were obtained by weightlifting and taekwondo athletes. Differences in strength profiles in the tested athletes were attributed to the specific nature of their sports. It is suggested to use an allometric relationship scaled by body mass for strength assessment.

  15. Why Does Not the Leaf Weight-Area Allometry of Bamboos Follow the 3/2-Power Law?

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    Shuyan Lin

    2018-05-01

    Full Text Available The principle of similarity (Thompson, 1917 states that the weight of an organism follows the 3/2-power law of its surface area and is proportional to its volume on the condition that the density is constant. However, the allometric relationship between leaf weight and leaf area has been reported to greatly deviate from the 3/2-power law, with the irregularity of leaf density largely ignored for explaining this deviation. Here, we choose 11 bamboo species to explore the allometric relationships among leaf area (A, density (ρ, length (L, thickness (T, and weight (W. Because the edge of a bamboo leaf follows a simplified two-parameter Gielis equation, we could show that A ∝ L2 and that A ∝ T2. This then allowed us to derive the density-thickness allometry ρ ∝ Tb and the weight-area allometry W ∝ A(b+3/2 ≈ A9/8, where b approximates −3/4. Leaf density is strikingly negatively associated with leaf thickness, and it is this inverse relationship that results in the weight-area allometry to deviate from the 3/2-power law. In conclusion, although plants are prone to invest less dry mass and thus produce thinner leaves when the leaf area is sufficient for photosynthesis, such leaf thinning needs to be accompanied with elevated density to ensure structural stability. The findings provide the insights on the evolutionary clue about the biomass investment and output of photosynthetic organs of plants. Because of the importance of leaves, plants could have enhanced the ratio of dry material per unit area of leaf in order to increase the efficiency of photosynthesis, relative the other parts of plants. Although the conclusion is drawn only based on 11 bamboo species, it should also be applicable to the other plants, especially considering previous works on the exponent of the weight-area relationship being less than 3/2 in plants.

  16. Tradeoff between Stem Hydraulic Efficiency and Mechanical Strength Affects Leaf–Stem Allometry in 28 Ficus Tree Species

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    Ze-Xin Fan

    2017-09-01

    Full Text Available Leaf–stem allometry is an important spectrum that linked to biomass allocation and life history strategy in plants, although the determinants and evolutionary significance of leaf–stem allometry remain poorly understood. Leaf and stem architectures – including stem area/mass, petiole area/mass, lamina area/mass, leaf number, specific leaf area (LA, and mass-based leafing intensity (LI – were measured on the current-year branches for 28 Ficus species growing in a common garden in SW China. The leaf anatomical traits, stem wood density (WD, and stem anatomical and mechanical properties of these species were also measured. We analyzed leaf–stem allometric relationships and their associations with stem hydraulic ad mechanical properties using species-level data and phylogenetically independent contrasts. We found isometric relationship between leaf lamina area/mass and stem area/mass, suggesting that the biomass allocation to leaf was independent to stem size. However, allometric relationship between LA/mass and petiole mass was found, indicating large leaves invest a higher fractional of biomass in petiole than small ones. LI, i.e., leaf numbers per unit of stem mass, was negatively related with leaf and stem size. Species with larger terminal branches tend to have larger vessels and theoretical hydraulic conductivity, but lower WD and mechanical strength. The size of leaf lamina, petiole, and stem was correlated positively with stem theoretical hydraulic conductivity, but negatively with stem WD and mechanical strength. Our results suggest that leaf–stem allometry in Ficus species was shaped by the trade-off between stem hydraulic efficiency and mechanical stability, supporting a functional interpretation of the relationship between leaf and stem dimensions.

  17. Allometry of a neotropical palm, Euterpe edulis Mart. Alometria de uma palmeira Neotropical, Euterpe edulis Mart

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    Luciana F. Alves

    2004-06-01

    Full Text Available The stem allometry (stem diameter vs. tree height of a Neotropical palm (Euterpe edulis found in rain and seasonal forest of Southeastern Brazil was examined. Observed height-diameter relationships along the stem (diameter at ground level, (dgl, and diameter at breast height (dbh were compared to three theoretical stability mechanical models: elastic similarity, stress similarity and geometric similarity. Slopes of log-transformed height-diameter relationships did not lie near those predicted by any stability mechanical models. Significant differences in stem allometry were found when comparing dgl to dbh, suggesting greater increase in dbh with height. The relationship between stability safety factor (SSF and palm height showed that both dgl and dbh were found to be above McMahon's theoretical buckling limit for dicotyledonous trees, but some individuals approached this limit in relation to dbh. Despite displaying a similar decreasing pattern of SSF with height, differences found in SSF along the stem - greater SSF for dgl when compared to dbh - indicate that the risk of mechanism failure in palms depends upon the size and varies along the stem. Distinct allometric relationships along the stem obtained for Euterpe edulis may be reflecting possible differences in stem design and growth strategies.Neste trabalho foram analisadas as relações entre o diâmetro e a altura de uma palmeira Neotropical (Euterpe edulis comum na Floresta Atlântica do SE do Brasil. As relações observadas entre a altura e o diâmetro ao longo do estipe (diâmetro ao nível do solo (DAS, e diâmetro ao nível do peito (DAP foram comparadas a três modelos teóricos de estabilidade mecânica: similaridade elástica, similaridade de estresse e similaridade geométrica. As inclinações das regressões altura-diâmetro não se ajustaram a nenhum dos modelos de estabilidade mecânica. Diferenças significativas na alometria do estipe foram encontradas comparando-se as rela

  18. Plant allometry, leaf nitrogen and phosphorus stoichiometry, and interspecific trends in annual growth rates.

    Science.gov (United States)

    Niklas, Karl J

    2006-02-01

    Life forms as diverse as unicellular algae, zooplankton, vascular plants, and mammals appear to obey quarter-power scaling rules. Among the most famous of these rules is Kleiber's (i.e. basal metabolic rates scale as the three-quarters power of body mass), which has a botanical analogue (i.e. annual plant growth rates scale as the three-quarters power of total body mass). Numerous theories have tried to explain why these rules exist, but each has been heavily criticized either on conceptual or empirical grounds. N,P-STOICHIOMETRY: Recent models predicting growth rates on the basis of how total cell, tissue, or organism nitrogen and phosphorus are allocated, respectively, to protein and rRNA contents may provide the answer, particularly in light of the observation that annual plant growth rates scale linearly with respect to standing leaf mass and that total leaf mass scales isometrically with respect to nitrogen but as the three-quarters power of leaf phosphorus. For example, when these relationships are juxtaposed with other allometric trends, a simple N,P-stoichiometric model successfully predicts the relative growth rates of 131 diverse C3 and C4 species. The melding of allometric and N,P-stoichiometric theoretical insights provides a robust modelling approach that conceptually links the subcellular 'machinery' of protein/ribosomal metabolism to observed growth rates of uni- and multicellular organisms. Because the operation of this 'machinery' is basic to the biology of all life forms, its allometry may provide a mechanistic explanation for the apparent ubiquity of quarter-power scaling rules.

  19. Vision in semi-aquatic snakes: Intraocular morphology, accommodation, and eye: Body allometry

    Science.gov (United States)

    Plylar, Helen Bond

    Vision in vertebrates generally relies on the refractive power of the cornea and crystalline lens to facilitate vision. Light from the environment enters the eye and is refracted by the cornea and lens onto the retina for production of an image. When an animal with a system designed for air submerges underwater, the refractive power of the cornea is lost. Semi-aquatic animals (e.g., water snakes, turtles, aquatic mammals) must overcome this loss of corneal refractive power through visual accommodation. Accommodation relies on change of the position or shape of the lens to change the focal length of the optical system. Intraocular muscles and fibers facilitate lenticular displacement and deformation. Snakes, in general, are largely unstudied in terms of visual acuity and intraocular morphology. I used light microscopy and scanning electron microscopy to examine differences in eye anatomy between five sympatric colubrid snake species (Nerodia cyclopion, N. fasciata, N. rhombifer, Pantherophis obsoletus, and Thamnophis proximus) from Southeast Louisiana. I discovered previously undescribed structures associated with the lens in semi-aquatic species. Photorefractive methods were used to assess refractive error. While all species overcame the expected hyperopia imposed by submergence, there was interspecific variation in refractive error. To assess scaling of eye size with body size, I measure of eye size, head size, and body size in Nerodia cyclopion and N. fasciata from the SLU Vertebrate Museum. In both species, body size increases at a significantly faster rate than head size and eye size (negative allometry). Small snakes have large eyes relative to body size, and large snakes have relatively small eyes. There were interspecific differences in scaling of eye size with body size, where N. fasciata had larger eye diameter, but N. cyclopion had longer eyes (axial length).

  20. Hydraulic architecture and tracheid allometry in mature Pinus palustris and Pinus elliottii trees.

    Science.gov (United States)

    Gonzalez-Benecke, C A; Martin, T A; Peter, G F

    2010-03-01

    Pinus palustris Mill. (longleaf pine, LL) and Pinus elliottii Engelm. var. elliottii (slash pine, SL) frequently co-occur in lower coastal plain flatwoods of the USA, with LL typically inhabiting slightly higher and better-drained microsites than SL. The hydraulic architecture and tracheid dimensions of roots, trunk and branches of mature LL and SL trees were compared to understand their role in species microsite occupation. Root xylem had higher sapwood-specific hydraulic conductivity (k(s)) and was less resistant to cavitation compared with branches and trunk sapwood. Root k(s) of LL was significantly higher than SL, whereas branch and trunk k(s) did not differ between species. No differences in vulnerability to cavitation were observed in any of the organs between species. Across all organs, there was a significant but weak trade-off between water conduction efficiency and safety. Tracheid hydraulic diameter (D(h)) was strongly correlated with k(s) across all organs, explaining >73% of the variation in k(s). In contrast, tracheid length (L(t)) explained only 2.4% of the variability. Nevertheless, for trunk xylem, k(s) was 39.5% higher at 20 m compared with 1.8 m; this increase in k(s) was uncorrelated with D(h) and cell-wall thickness but was strongly correlated with the difference in L(t). Tracheid allometry markedly changed between sapwood of roots, trunks and branches, possibly reflecting different mechanical constraints. Even though vulnerability to cavitation was not different for sapwood of roots, branches or the trunks of LL and SL, higher sapwood to leaf area ratio and higher maximum sapwood-specific hydraulic conductivity in roots of LL are functional traits that may provide LL with a competitive advantage on drier soil microsites.

  1. Is allometry for aboveground organ’s mass estimation in young Norway spruce stands aff ected by diff erent type of thinning?

    Czech Academy of Sciences Publication Activity Database

    Krejza, Jan; Pokorný, Radek; Marková, I.

    2013-01-01

    Roč. 61, č. 6 (2013), s. 1755-1761 ISSN 1211-8516 R&D Projects: GA TA ČR TA02010945 Institutional support: RVO:67179843 Keywords : allometry * mass * Norway spruce * thinning Subject RIV: EH - Ecology, Behaviour http://dx.doi.org/10.11118/actaun201361061755

  2. Height-diameter allometry and above ground biomass in tropical montane forests: Insights from the Albertine Rift in Africa.

    Science.gov (United States)

    Imani, Gérard; Boyemba, Faustin; Lewis, Simon; Nabahungu, Nsharwasi Léon; Calders, Kim; Zapfack, Louis; Riera, Bernard; Balegamire, Clarisse; Cuni-Sanchez, Aida

    2017-01-01

    Tropical montane forests provide an important natural laboratory to test ecological theory. While it is well-known that some aspects of forest structure change with altitude, little is known on the effects of altitude on above ground biomass (AGB), particularly with regard to changing height-diameter allometry. To address this we investigate (1) the effects of altitude on height-diameter allometry, (2) how different height-diameter allometric models affect above ground biomass estimates; and (3) how other forest structural, taxonomic and environmental attributes affect above ground biomass using 30 permanent sample plots (1-ha; all trees ≥ 10 cm diameter measured) established between 1250 and 2600 m asl in Kahuzi Biega National Park in eastern Democratic Republic of Congo. Forest structure and species composition differed with increasing altitude, with four forest types identified. Different height-diameter allometric models performed better with the different forest types, as trees got smaller with increasing altitude. Above ground biomass ranged from 168 to 290 Mg ha-1, but there were no significant differences in AGB between forests types, as tree size decreased but stem density increased with increasing altitude. Forest structure had greater effects on above ground biomass than forest diversity. Soil attributes (K and acidity, pH) also significantly affected above ground biomass. Results show how forest structural, taxonomic and environmental attributes affect above ground biomass in African tropical montane forests. They particularly highlight that the use of regional height-diameter models introduces significant biases in above ground biomass estimates, and that different height-diameter models might be preferred for different forest types, and these should be considered in future studies.

  3. A validation of 11 body-condition indices in a giant snake species that exhibits positive allometry.

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    Bryan G Falk

    Full Text Available Body condition is a gauge of the energy stores of an animal, and though it has important implications for fitness, survival, competition, and disease, it is difficult to measure directly. Instead, body condition is frequently estimated as a body condition index (BCI using length and mass measurements. A desirable BCI should accurately reflect true body condition and be unbiased with respect to size (i.e., mean BCI estimates should not change across different length or mass ranges, and choosing the most-appropriate BCI is not straightforward. We evaluated 11 different BCIs in 248 Burmese pythons (Python bivittatus, organisms that, like other snakes, exhibit simple body plans well characterized by length and mass. We found that the length-mass relationship in Burmese pythons is positively allometric, where mass increases rapidly with respect to length, and this allowed us to explore the effects of allometry on BCI verification. We employed three alternative measures of 'true' body condition: percent fat, scaled fat, and residual fat. The latter two measures mostly accommodated allometry in true body condition, but percent fat did not. Our inferences of the best-performing BCIs depended heavily on our measure of true body condition, with most BCIs falling into one of two groups. The first group contained most BCIs based on ratios, and these were associated with percent fat and body length (i.e., were biased. The second group contained the scaled mass index and most of the BCIs based on linear regressions, and these were associated with both scaled and residual fat but not body length (i.e., were unbiased. Our results show that potential differences in measures of true body condition should be explored in BCI verification studies, particularly in organisms undergoing allometric growth. Furthermore, the caveats of each BCI and similarities to other BCIs are important to consider when determining which BCI is appropriate for any particular taxon.

  4. Comparative morphology of the prothoracic leg in heliconian butterflies: Tracing size allometry, podite fusions and losses in ontogeny and phylogeny.

    Science.gov (United States)

    Moreira, Gilson R P; Silva, Denis S; Gonçalves, Gislene L

    2017-07-01

    Prothoracic legs of heliconian butterflies (Nymphalidae, Heliconiinae, Heliconiini) are reduced in size compared to mesothoracic and metathoracic legs. They have no apparent function in males, but are used by females for drumming on host plants, a behavior related to oviposition site selection. Here, taking into account all recognized lineages of heliconian butterflies, we described their tarsi using optical and scanning electron microscopy and searched for podite fusions and losses, and analyzed allometry at the static, ontogenetic and phylogenetic levels. Female tarsi were similar, club-shaped, showing from four to five tarsomeres, each bearing sensilla chaetica and trichodea. Male tarsi were cylindrical, formed from five (early diverging lineages) to one (descendant lineages) either partially or totally fused tarsomeres, all deprived of sensilla. Pretarsi were reduced in both sexes, in some species being either vestigial or absent. Tarsal lengths were smaller for males in almost all species. An abrupt decrease in size was detected for the prothoracic legs during molting to the last larval instar at both histological and morphometric levels. In both sexes, most allometric coefficients found at the population level for the prothoracic legs were negative compared to the mesothoracic leg and also to wings. Prothoracic tarsi decreased proportionally in size over evolutionary time; the largest and smallest values being found for nodes of the oldest and youngest lineages, respectively. Our results demonstrate that evolution of the prothoracic leg in heliconian butterflies has been based on losses and fusions of podites, in association with negative size allometry at static, ontogenetic and phylogenetic levels. These processes have been more pronounced in males. Our study provided further support to the hypothesis that evolution of these leg structures is driven by females, by changing their use from walking to drumming during oviposition site selection. In males the

  5. "allometry" Deterministic Approaches in Cell Size, Cell Number and Crude Fiber Content Related to the Physical Quality of Kangkong (Ipomoea reptans) Grown Under Different Plant Density Pressures

    Science.gov (United States)

    Selamat, A.; Atiman, S. A.; Puteh, A.; Abdullah, N. A. P.; Mohamed, M. T. M.; Zulkeefli, A. A.; Othman, S.

    Kangkong, especially the upland type (Ipomoea reptans) is popularly consumed as a vegetable dish in the South East Asian countries for its quality related to Vitamins (A and C) and crude fiber contents. Higher fiber contents would prevent from the occurrence of colon cancer and diverticular disease. With young stem edible portion, its cell number and size contribute to the stem crude fiber content. The mathematical approach of allometry of cell size, number, and fiber content of stem could be used in determining the 'best' plant density pressure in producing the quality young stem to be consumed. Basically, allometry is the ratio of relative increment (growth or change) rates of two parameters, or the change rate associated to the log of measured variables relationship. Kangkog grown equal or lower than 55 plants m-2 produced bigger individual plant and good quality (physical) kangkong leafy vegetable, but with lower total yield per unit area as compared to those grown at higher densities.

  6. Shoot allometry and biomass productivity in poplar and willow varieties grown as short rotation coppice. Summary of results 1995-2000

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, R.; Henshall, P.; Tubby, I.

    2003-07-01

    This report summarises the results of a 4 year study assessing shoot diameters and lengths using non-destructive measurements in order to establish allometric relationships between biomass and non-destructive measurements and also to provide estimates of increments for the development of a model of short rotation cultivation growth and yield. Details are given of the basic methodology and measurement conventions; the data preparation, quality assurance classification and storage; and shoot diameter and length assessments and allometry analyses.

  7. Improving LiDAR Biomass Model Uncertainty through Non-Destructive Allometry and Plot-level 3D Reconstruction with Terrestrial Laser Scanning

    Science.gov (United States)

    Stovall, A. E.; Shugart, H. H., Jr.

    2017-12-01

    Future NASA and ESA satellite missions plan to better quantify global carbon through detailed observations of forest structure, but ultimately rely on uncertain ground measurement approaches for calibration and validation. A significant amount of the uncertainty in estimating plot-level biomass can be attributed to inadequate and unrepresentative allometric relationships used to convert plot-level tree measurements to estimates of aboveground biomass. These allometric equations are known to have high errors and biases, particularly in carbon rich forests because they were calibrated with small and often biased samples of destructively harvested trees. To overcome this issue, a non-destructive methodology for estimating tree and plot-level biomass has been proposed through the use of Terrestrial Laser Scanning (TLS). We investigated the potential for using TLS as a ground validation approach in LiDAR-based biomass mapping though virtual plot-level tree volume reconstruction and biomass estimation. Plot-level biomass estimates were compared on the Virginia-based Smithsonian Conservation Biology Institute's SIGEO forest with full 3D reconstruction, TLS allometry, and Jenkins et al. (2003) allometry. On average, full 3D reconstruction ultimately provided the lowest uncertainty estimate of plot-level biomass (9.6%), followed by TLS allometry (16.9%) and the national equations (20.2%). TLS offered modest improvements to the airborne LiDAR empirical models, reducing RMSE from 16.2% to 14%. Our findings suggest TLS plot acquisitions and non-destructive allometry can play a vital role for reducing uncertainty in calibration and validation data for biomass mapping in the upcoming NASA and ESA missions.

  8. Intersexual allometry differences and ontogenetic shifts of coloration patterns in two aquatic turtles, Graptemys oculifera and Graptemys flavimaculata

    Science.gov (United States)

    Ennen, Joshua R.; Lindeman, Peter V.; Lovich, Jeffrey E.

    2015-01-01

    Coloration can play critical roles in a species' biology. The allometry of color patterns may be useful for elucidating the evolutionary mechanisms responsible for shaping the traits. We measured characteristics relating to eight aspects of color patterns from Graptemys oculifera and G. flavimaculata to investigate the allometric differences among male, female, and unsexed juvenile specimens. Additionally, we investigated ontogenetic shifts by incorporating the unsexed juveniles into the male and female datasets. In general, male color traits were isometric (i.e., color scaled with body size), while females and juvenile color traits were hypoallometric, growing in size more slowly than the increase in body size. When we included unsexed juveniles in our male and female datasets, our linear regression analyses found all relationships to be hypoallometric and our model selection analysis found support for nonlinear models describing the relationship between body size and color patterns, suggestive of an ontogenetic shift in coloration traits for both sexes at maturity. Although color is critical for many species' biology and therefore under strong selective pressure in many other species, our results are likely explained by an epiphenomenon related to the different selection pressures on body size and growth rates between juveniles and adults and less attributable to the evolution of color patterns themselves.

  9. Allometry as evidence of sexual selection in monochromatic birds: the case of the Coscoroba Swan (Anseriformes: Anatidae

    Directory of Open Access Journals (Sweden)

    Cecilia P. Calabuig

    2013-08-01

    Full Text Available The Coscoroba Swan, Coscoroba coscoroba (Molina, 1782, is a poorly known aberrant Anserine endemic to South America. We captured adult birds (189 male, 157 female from the largest population in Brazil at the Taim Ecological Reserve, State of Rio Grande do Sul, Brazil. Different patterns between sexes can reflect differences in selection, and positive allometry may indicate that a character is sexually selected. We used body weight and 10 morphological measurements to examine allometric differences between males and females of C. coscoroba. Males were consistently larger than females. Analysis of scaling relationships against body mass showed that nostril, tail, wing and bill height were positively allometric (i.e., heavier birds had relatively larger character lengths, but there were no sexual differences in allometric slopes. However, for a given mass, mature females had longer tails, longer wings (up to metacarpophalangeal articulation and shorter heads than males. In the light of current debate in the literature, we discuss whether such positively allometric traits and sexual differences in scaling may be indicative of sexual selection. Although Coscoroba Swan is a monogamous species, increasing the size of some attributes may confer some advantage for mate selection or male-male competition and, contrary to other studies, we suggest that positively allometric slopes alone should not be considered as evidence for sexual selection of the considered traits.

  10. Differential influences of allometry, phylogeny and environment on the rostral shape diversity of extinct South American notoungulates

    Science.gov (United States)

    Gomes Rodrigues, Helder; Cornette, Raphaël; Clavel, Julien; Cassini, Guillermo; Bhullar, Bhart-Anjan S.; Fernández-Monescillo, Marcos; Moreno, Karen; Herrel, Anthony; Billet, Guillaume

    2018-01-01

    Understanding the mechanisms responsible for phenotypic diversification, and the associated underlying constraints and ecological factors represents a central issue in evolutionary biology. Mammals present a wide variety of sizes and shapes, and are characterized by a high number of morphological convergences that are hypothesized to reflect similar environmental pressures. Extinct South American notoungulates evolved in isolation from northern mammalian faunas in highly disparate environments. They present a wide array of skeletal phenotypes and convergences, such as ever-growing dentition. Here, we focused on the origins of the rostral diversity of notoungulates by quantifying the shape of 26 genera using three-dimensional geometric morphometric analysis. We tested the influence of allometry and phylogeny on rostral shape and evaluated rates of evolutionary change in the different clades. We found strong allometric and phylogenetic signals concerning the rostral shape of notoungulates. Despite convergent forms, we observed a diffuse diversification of rostral shape, with no significant evidence of influence by large-scaled environmental variation. This contrasts with the increase in dental crown height that occurred in four late-diverging families in response to similar environmental pressures. These results illustrate the importance of considering both biological components and evolutionary rates to better understand some aspects of phenotypic diversity.

  11. New Insights into Non-Avian Dinosaur Reproduction and Their Evolutionary and Ecological Implications: Linking Fossil Evidence to Allometries of Extant Close Relatives

    Science.gov (United States)

    Werner, Jan; Griebeler, Eva Maria

    2013-01-01

    It has been hypothesized that a high reproductive output contributes to the unique gigantism in large dinosaur taxa. In order to infer more information on dinosaur reproduction, we established allometries between body mass and different reproductive traits (egg mass, clutch mass, annual clutch mass) for extant phylogenetic brackets (birds, crocodiles and tortoises) of extinct non-avian dinosaurs. Allometries were applied to nine non-avian dinosaur taxa (theropods, hadrosaurs, and sauropodomorphs) for which fossil estimates on relevant traits are currently available. We found that the reproductive traits of most dinosaurs conformed to similar-sized or scaled-up extant reptiles or birds. The reproductive traits of theropods, which are considered more bird-like, were indeed consistent with birds, while the traits of sauropodomorphs conformed better to reptiles. Reproductive traits of hadrosaurs corresponded to both reptiles and birds. Excluding Massospondylus carinatus , all dinosaurs studied had an intermediary egg to body mass relationship to reptiles and birds. In contrast, dinosaur clutch masses fitted with either the masses predicted from allometries of birds (theropods) or to the masses of reptiles (all other taxa). Theropods studied had probably one clutch per year. For sauropodomorphs and hadrosaurs, more than one clutch per year was predicted. Contrary to current hypotheses, large dinosaurs did not have exceptionally high annual egg numbers (AEN). Independent of the extant model, the estimated dinosaur AEN did not exceed 850 eggs (75,000 kg sauropod) for any of the taxa studied. This estimated maximum is probably an overestimation due to unrealistic assumptions. According to most AEN estimations, the dinosaurs studied laid less than 200 eggs per year. Only some AEN estimates obtained for medium to large sized sauropods were higher (200-400 eggs). Our results provide new (testable) hypotheses, especially for reproductive traits that are insufficiently

  12. New insights into non-avian dinosaur reproduction and their evolutionary and ecological implications: linking fossil evidence to allometries of extant close relatives.

    Directory of Open Access Journals (Sweden)

    Jan Werner

    Full Text Available It has been hypothesized that a high reproductive output contributes to the unique gigantism in large dinosaur taxa. In order to infer more information on dinosaur reproduction, we established allometries between body mass and different reproductive traits (egg mass, clutch mass, annual clutch mass for extant phylogenetic brackets (birds, crocodiles and tortoises of extinct non-avian dinosaurs. Allometries were applied to nine non-avian dinosaur taxa (theropods, hadrosaurs, and sauropodomorphs for which fossil estimates on relevant traits are currently available. We found that the reproductive traits of most dinosaurs conformed to similar-sized or scaled-up extant reptiles or birds. The reproductive traits of theropods, which are considered more bird-like, were indeed consistent with birds, while the traits of sauropodomorphs conformed better to reptiles. Reproductive traits of hadrosaurs corresponded to both reptiles and birds. Excluding Massospondyluscarinatus, all dinosaurs studied had an intermediary egg to body mass relationship to reptiles and birds. In contrast, dinosaur clutch masses fitted with either the masses predicted from allometries of birds (theropods or to the masses of reptiles (all other taxa. Theropods studied had probably one clutch per year. For sauropodomorphs and hadrosaurs, more than one clutch per year was predicted. Contrary to current hypotheses, large dinosaurs did not have exceptionally high annual egg numbers (AEN. Independent of the extant model, the estimated dinosaur AEN did not exceed 850 eggs (75,000 kg sauropod for any of the taxa studied. This estimated maximum is probably an overestimation due to unrealistic assumptions. According to most AEN estimations, the dinosaurs studied laid less than 200 eggs per year. Only some AEN estimates obtained for medium to large sized sauropods were higher (200-400 eggs. Our results provide new (testable hypotheses, especially for reproductive traits that are insufficiently

  13. New insights into non-avian dinosaur reproduction and their evolutionary and ecological implications: linking fossil evidence to allometries of extant close relatives.

    Science.gov (United States)

    Werner, Jan; Griebeler, Eva Maria

    2013-01-01

    It has been hypothesized that a high reproductive output contributes to the unique gigantism in large dinosaur taxa. In order to infer more information on dinosaur reproduction, we established allometries between body mass and different reproductive traits (egg mass, clutch mass, annual clutch mass) for extant phylogenetic brackets (birds, crocodiles and tortoises) of extinct non-avian dinosaurs. Allometries were applied to nine non-avian dinosaur taxa (theropods, hadrosaurs, and sauropodomorphs) for which fossil estimates on relevant traits are currently available. We found that the reproductive traits of most dinosaurs conformed to similar-sized or scaled-up extant reptiles or birds. The reproductive traits of theropods, which are considered more bird-like, were indeed consistent with birds, while the traits of sauropodomorphs conformed better to reptiles. Reproductive traits of hadrosaurs corresponded to both reptiles and birds. Excluding Massospondyluscarinatus, all dinosaurs studied had an intermediary egg to body mass relationship to reptiles and birds. In contrast, dinosaur clutch masses fitted with either the masses predicted from allometries of birds (theropods) or to the masses of reptiles (all other taxa). Theropods studied had probably one clutch per year. For sauropodomorphs and hadrosaurs, more than one clutch per year was predicted. Contrary to current hypotheses, large dinosaurs did not have exceptionally high annual egg numbers (AEN). Independent of the extant model, the estimated dinosaur AEN did not exceed 850 eggs (75,000 kg sauropod) for any of the taxa studied. This estimated maximum is probably an overestimation due to unrealistic assumptions. According to most AEN estimations, the dinosaurs studied laid less than 200 eggs per year. Only some AEN estimates obtained for medium to large sized sauropods were higher (200-400 eggs). Our results provide new (testable) hypotheses, especially for reproductive traits that are insufficiently documented

  14. Quantifying the Variability of Internode Allometry within and between Trees for Pinus tabulaeformis Carr. Using a Multilevel Nonlinear Mixed-Effect Model

    Directory of Open Access Journals (Sweden)

    Jun Diao

    2014-11-01

    Full Text Available Allometric models of internodes are an important component of Functional-Structural Plant Models (FSPMs, which represent the shape of internodes in tree architecture and help our understanding of resource allocation in organisms. Constant allometry is always assumed in these models. In this paper, multilevel nonlinear mixed-effect models were used to characterize the variability of internode allometry, describing the relationship between the last internode length and biomass of Pinus tabulaeformis Carr. trees within the GreenLab framework. We demonstrated that there is significant variability in allometric relationships at the tree and different-order branch levels, and the variability decreases among levels from trees to first-order branches and, subsequently, to second-order branches. The variability was partially explained by the random effects of site characteristics, stand age, density, and topological position of the internode. Tree- and branch-level-specific allometric models are recommended because they produce unbiased and accurate internode length estimates. The model and method developed in this study are useful for understanding and describing the structure and functioning of trees.

  15. Pitch (F0) and formant profiles of human vowels and vowel-like baboon grunts: The role of vocalizer body size and voice-acoustic allometry

    Science.gov (United States)

    Rendall, Drew; Kollias, Sophie; Ney, Christina; Lloyd, Peter

    2005-02-01

    Key voice features-fundamental frequency (F0) and formant frequencies-can vary extensively between individuals. Much of the variation can be traced to differences in the size of the larynx and vocal-tract cavities, but whether these differences in turn simply reflect differences in speaker body size (i.e., neutral vocal allometry) remains unclear. Quantitative analyses were therefore undertaken to test the relationship between speaker body size and voice F0 and formant frequencies for human vowels. To test the taxonomic generality of the relationships, the same analyses were conducted on the vowel-like grunts of baboons, whose phylogenetic proximity to humans and similar vocal production biology and voice acoustic patterns recommend them for such comparative research. For adults of both species, males were larger than females and had lower mean voice F0 and formant frequencies. However, beyond this, F0 variation did not track body-size variation between the sexes in either species, nor within sexes in humans. In humans, formant variation correlated significantly with speaker height but only in males and not in females. Implications for general vocal allometry are discussed as are implications for speech origins theories, and challenges to them, related to laryngeal position and vocal tract length. .

  16. Ontogenetic Tooth Reduction in Stenopterygius quadriscissus (Reptilia: Ichthyosauria: Negative Allometry, Changes in Growth Rate, and Early Senescence of the Dental Lamina.

    Directory of Open Access Journals (Sweden)

    Daniel G Dick

    Full Text Available We explore the functional, developmental, and evolutionary processes which are argued to produce tooth reduction in the extinct marine reptile Stenopterygius quadriscissus (Reptilia: Ichthyosauria. We analyze the relationship between mandible growth and tooth size, shape, and count, to establish an ontogenetic trend. The pattern in S. quadriscissus is consistent with hypotheses of tooth size reduction by neutral selection, and this unusual morphology (a functionally edentulous rostrum was produced by a series of different evolutionary developmental changes that are known for other taxa showing tooth reduction and loss. Specifically, this species evolved functional edentulism by evolutionary changes in the growth allometry of the dentition and by altering growth rates through ontogeny. This observation supports previous hypotheses that S. quadriscissus underwent ontogenetic tooth reduction. Tooth reduction in S. quadriscissus may be caused by unique selective pressures resulting from prey choice and feeding behavior, expanding our current understanding of the mechanisms producing tooth reduction.

  17. Adaptation, allometry, and hypertension.

    Science.gov (United States)

    Weder, A B; Schork, N J

    1994-08-01

    Essential hypertension is a "disease of civilization" but has a clear genetic component. From an evolutionary perspective, persistence in the human genome of elements capable of raising blood pressure presupposes their adaptive significance. Recently, two hypotheses that explicitly appeal to selectionist arguments, the "slavery" and "thrifty gene" theories, have been forwarded. We find neither completely successful, and we advance an alternative explanation of the adaptive importance of genes responsible for hypertension. We propose that blood pressure rises during childhood and adolescence to subserve homeostatic needs of the organism. Specifically, we contend that blood pressure is a flexible element in the repertoire of renal homeostatic mechanisms serving to match renal function to growth. The effect of modern diet and lifestyle on human growth stimulates earlier and more vigorous development, straining biologically necessary relationships between renal and general somatic growth and requiring compensation via homeostatic mechanisms preserved during evolution. Prime among such mechanisms is blood pressure, which rises as a compensation to maintain renal function in the face of greater growth. Since virtually all members of acculturated societies share in the modern lifestyle, the demands imposed by accelerated growth and development result in a populational shift to higher blood pressures, with a consequent increase in the prevalence of hypertension. We propose that hypertension is the product of maladaptation of highly genetically conserved mechanisms subserving important biological homeostatic needs. Elucidation of the mechanisms underlying hypertension will require approaches that examine the developmental processes linking growth to blood pressure.

  18. Towards a better prediction of peak concentration, volume of distribution and half-life after oral drug administration in man, using allometry.

    Science.gov (United States)

    Sinha, Vikash K; Vaarties, Karin; De Buck, Stefan S; Fenu, Luca A; Nijsen, Marjoleen; Gilissen, Ron A H J; Sanderson, Wendy; Van Uytsel, Kelly; Hoeben, Eva; Van Peer, Achiel; Mackie, Claire E; Smit, Johan W

    2011-05-01

    It is imperative that new drugs demonstrate adequate pharmacokinetic properties, allowing an optimal safety margin and convenient dosing regimens in clinical practice, which then lead to better patient compliance. Such pharmacokinetic properties include suitable peak (maximum) plasma drug concentration (C(max)), area under the plasma concentration-time curve (AUC) and a suitable half-life (t(½)). The C(max) and t(½) following oral drug administration are functions of the oral clearance (CL/F) and apparent volume of distribution during the terminal phase by the oral route (V(z)/F), each of which may be predicted and combined to estimate C(max) and t(½). Allometric scaling is a widely used methodology in the pharmaceutical industry to predict human pharmacokinetic parameters such as clearance and volume of distribution. In our previous published work, we have evaluated the use of allometry for prediction of CL/F and AUC. In this paper we describe the evaluation of different allometric scaling approaches for the prediction of C(max), V(z)/F and t(½) after oral drug administration in man. Twenty-nine compounds developed at Janssen Research and Development (a division of Janssen Pharmaceutica NV), covering a wide range of physicochemical and pharmacokinetic properties, were selected. The C(max) following oral dosing of a compound was predicted using (i) simple allometry alone; (ii) simple allometry along with correction factors such as plasma protein binding (PPB), maximum life-span potential or brain weight (reverse rule of exponents, unbound C(max) approach); and (iii) an indirect approach using allometrically predicted CL/F and V(z)/F and absorption rate constant (k(a)). The k(a) was estimated from (i) in vivo pharmacokinetic experiments in preclinical species; and (ii) predicted effective permeability in man (P(eff)), using a Caco-2 permeability assay. The V(z)/F was predicted using allometric scaling with or without PPB correction. The t(½) was estimated from

  19. Allometry of individual reproduction and defense in eusocial colonies: A comparative approach to trade-offs in social sponge-dwelling Synalpheus shrimps.

    Directory of Open Access Journals (Sweden)

    Sarah L Bornbusch

    Full Text Available Eusociality, one of the most complex forms of social organization, is thought to have evolved in several animal clades in response to competition for resources and reproductive opportunities. Several species of snapping shrimp in the genus Synalpheus, the only marine organisms known to exhibit eusociality, form colonies characterized by high reproductive skew, and aggressive territoriality coupled with cooperative defense. In eusocial Synalpheus colonies, individual reproduction is limited to female 'queens', whose fecundity dictates colony growth. Given that individual reproduction and defense are both energetically costly, individual and colony fitness likely depend on the optimal allocation of resources by these reproducing individuals towards these potentially competing demands. Synalpheus species, however, display varying degrees of eusociality, suggesting that reproducing females have adopted different strategies for allocation among reproduction and defense. Here, we use structural equation modeling to characterize the relationships between the allometry of queen reproductive capacity and defensive weaponry, and colony size in six eusocial Synalpheus species, estimating trade-offs between reproduction and defense. We document strong trade-offs between mass of the fighting claw (defense and egg number (reproduction in queens from weakly eusocial species, while the trade-off is reduced or absent in those from strongly eusocial species. These results suggest that in less cooperative species, intra-colony conflict selects for queen retention of weapons that have significant costs to fecundity, while reproducing females from highly eusocial species, i.e., those with a single queen, have been able to reduce the cost of weapons as a result of protection by other colony members.

  20. Bioaccumulation Potential Of Air Contaminants: Combining Biological Allometry, Chemical Equilibrium And Mass-Balances To Predict Accumulation Of Air Pollutants In Various Mammals

    Energy Technology Data Exchange (ETDEWEB)

    Veltman, Karin; McKone, Thomas E.; Huijbregts, Mark A.J.; Hendriks, A. Jan

    2009-03-01

    In the present study we develop and test a uniform model intended for single compartment analysis in the context of human and environmental risk assessment of airborne contaminants. The new aspects of the model are the integration of biological allometry with fugacity-based mass-balance theory to describe exchange of contaminants with air. The developed model is applicable to various mammalian species and a range of chemicals, while requiring few and typically well-known input parameters, such as the adult mass and composition of the species, and the octanol-water and air-water partition coefficient of the chemical. Accumulation of organic chemicals is typically considered to be a function of the chemical affinity forlipid components in tissues. Here, we use a generic description of chemical affinity for neutral and polar lipids and proteins to estimate blood-air partition coefficients (Kba) and tissue-air partition coefficients (Kta) for various mammals. This provides a more accurate prediction of blood-air partition coefficients, as proteins make up a large fraction of total blood components. The results show that 75percent of the modeled inhalation and exhalation rate constants are within a factor of 2 from independent empirical values for humans, rats and mice, and 87percent of the predicted blood-air partition coefficients are within a factor of 5 from empirical data. At steady-state, the bioaccumulation potential of air pollutants is shown to be mainly a function of the tissue-air partition coefficient and the biotransformation capacity of the species and depends weakly on the ventilation rate and the cardiac output of mammals.

  1. Allometry in dinosaurs and mammals

    Science.gov (United States)

    Lee, Scott

    2015-03-01

    The proportions of the leg bones change as the size of an animal becomes larger since the mass of the animal increases at a faster rate than the cross-sectional area of its leg bones. For the case of elastic similarity (in which the longitudinal stress in the legs remains constant in animals of all sizes), the diameter d and length L of the femur should be related as d = A L3/2. For geometric similarity (in which all dimensions are scaled by the same factor), d = A L. For animals with femora longer than 20 cm, we find the power law relationship to be d = A Lb with b = 1.13 +/- 0.06 for extant mammals (the largest mammal being Loxodonta africana with a 1.00-m-long femur) and b = 1.18 +/- 0.02 for dinosaurs (the largest dinosaur being Brachiosaurus brancai with a 2.03-m-long femur). These data show that extinct dinosaurs and extant animals scale in the same basic manner. The large sauropods (with femora twice as long as found in elephants) scale in a manner consistent with extrapolation of the scaling shown by extant mammals. These results argue that extinct dinosaurs moved in a manner very similar to extant mammals.

  2. Swimbladder Allometry of Selected Midwater Fish Species

    Science.gov (United States)

    1976-01-05

    Gibbs, R. II., Jr., 1971. "Notes on Fishes of the Genus Eustomias ( Stomiatoidei , Melanstomiatidae) in Bermuda Waters, With the Description of...N00140-70-C-0307, Smithsonian Institution. Goodyear, R. H. and R. H. Gibbs, Jr., 1970. "Systematics and Zoogeography of Stomiatoid Fishes of the

  3. Scaling and allometry in the building geometries of Greater London

    Science.gov (United States)

    Batty, M.; Carvalho, R.; Hudson-Smith, A.; Milton, R.; Smith, D.; Steadman, P.

    2008-06-01

    Many aggregate distributions of urban activities such as city sizes reveal scaling but hardly any work exists on the properties of spatial distributions within individual cities, notwithstanding considerable knowledge about their fractal structure. We redress this here by examining scaling relationships in a world city using data on the geometric properties of individual buildings. We first summarise how power laws can be used to approximate the size distributions of buildings, in analogy to city-size distributions which have been widely studied as rank-size and lognormal distributions following Zipf [ Human Behavior and the Principle of Least Effort (Addison-Wesley, Cambridge, 1949)] and Gibrat [ Les Inégalités Économiques (Librarie du Recueil Sirey, Paris, 1931)]. We then extend this analysis to allometric relationships between buildings in terms of their different geometric size properties. We present some preliminary analysis of building heights from the Emporis database which suggests very strong scaling in world cities. The data base for Greater London is then introduced from which we extract 3.6 million buildings whose scaling properties we explore. We examine key allometric relationships between these different properties illustrating how building shape changes according to size, and we extend this analysis to the classification of buildings according to land use types. We conclude with an analysis of two-point correlation functions of building geometries which supports our non-spatial analysis of scaling.

  4. Geometrical approach to length-biomass allometry in predominantly ...

    African Journals Online (AJOL)

    SERVER

    2008-04-17

    2006b). An allometric scaling law between gray matter and white matter of cerebral cortex, Chaos Soliton. Fract., 27: 864-867. He JH (2006c). Application of E-infinity theory to biology, Chaos Soliton. Fract., 28: 285-289. He JH ...

  5. Surface facial modelling and allometry in relation to sexual dimorphism

    Czech Academy of Sciences Publication Activity Database

    Velemínská, J.; Bigoni, L.; Krajíček, V.; Borský, J.; Šmahelová, D.; Cigáňová, V.; Peterka, Miroslav

    2012-01-01

    Roč. 63, č. 2 (2012), s. 81-93 ISSN 0018-442X Grant - others:GA MZd(CZ) NS10560; GA MZd(CZ) NS10012; GA MŠk(CZ) GA UK 674812 Institutional research plan: CEZ:AV0Z50390703 Keywords : craniofacial identification * morphology * cranial shape Subject RIV: FP - Other Medical Disciplines Impact factor: 0.844, year: 2012

  6. DBH Prediction Using Allometry Described by Bivariate Copula Distribution

    Science.gov (United States)

    Xu, Q.; Hou, Z.; Li, B.; Greenberg, J. A.

    2017-12-01

    Forest biomass mapping based on single tree detection from the airborne laser scanning (ALS) usually depends on an allometric equation that relates diameter at breast height (DBH) with per-tree aboveground biomass. The incapability of the ALS technology in directly measuring DBH leads to the need to predict DBH with other ALS-measured tree-level structural parameters. A copula-based method is proposed in the study to predict DBH with the ALS-measured tree height and crown diameter using a dataset measured in the Lassen National Forest in California. Instead of exploring an explicit mathematical equation that explains the underlying relationship between DBH and other structural parameters, the copula-based prediction method utilizes the dependency between cumulative distributions of these variables, and solves the DBH based on an assumption that for a single tree, the cumulative probability of each structural parameter is identical. Results show that compared with the bench-marking least-square linear regression and the k-MSN imputation, the copula-based method obtains better accuracy in the DBH for the Lassen National Forest. To assess the generalization of the proposed method, prediction uncertainty is quantified using bootstrapping techniques that examine the variability of the RMSE of the predicted DBH. We find that the copula distribution is reliable in describing the allometric relationship between tree-level structural parameters, and it contributes to the reduction of prediction uncertainty.

  7. BAAD: a biomass and allometry database for woody plants

    Science.gov (United States)

    Daniel S. Falster; Remko A. Duursma; Masae I. Ishihara; Diego R. Barneche; Richard G. FitzJohn; Angelica Varhammar; Masahiro Aiba; Makoto Ando; Niels Anten; Michael J. Aspinwall; Jennifer L. Baltzer; Christopher Baraloto; Michael Battaglia; John J. Battles; Ben Bond-Lamberty; Michiel van Breugel; Yves Claveau; Masako Dannoura; Sylvain Delagrange; Jean-Christophe Domec; Farrah Fatemi; Wang Feng; Veronica Gargaglione; Yoshiaki Goto; Akio Hagihara; Jefferson S. Hall; Steve Hamilton; Degi Harja; Tsutom Hiura; Robert Holdaway; Lindsay S. Hutley; Tomoaki Ichie; Eric J. Jokela; Anu Kantola; Jeff W. G. Kelly; Tanaka Kenzo; David King; Brian D. Kloeppel; Takashi Kohyama; Akira Komiyama; Jean-Paul Laclau; Christopher H. Lusk; Douglas A. Maguire; Guerric Le Maire; Ammikki Makela; Lars Markesteijn; John Marshall; Katherine McCulloh; Itsuo Miyata; Karel Mokany; Shugeta Mori; Randall W. Myster; Masahiro Nagano; Shawna L. Naidu; Yann Nouvellon; Anthony P. O' Grady; Kevin L. O' Hara; Toshiyuki Ohtsuka; Noriyuki Osada; Olusegun O. Osunkoya; Pablo Luis Peri; Any Mary Petritan; Lourens Poorter; Angelika Portsmuth; Catherine Potvin; Johannes Ransijn; Douglas Reid; Sabina C. Ribeiro; Scott D. Roberts; Rolando Rodriguez; Angela Saldana-Acosta; Ignacio Santa-Regina; Kaichiro Sasa; N. Galia Selaya; Stephen C. Sillett; Frank Sterck; Kentaro Takagi; Takeshi Tange; Hiroyuki Tanouchi; David Tissue; Toru Umehara; Matthew A. Vadeboncoeur; Fernando Valladares; Petteri Vanninen; Jian R. Wang; Elizabeth Wenk; Richard Williams; Fabiano de Aquino Ximenes; Atsushi Yamaba; Toshihiro Yamada; Takuo Yamakura; Ruth D. Yanai; Robert A. York

    2015-01-01

    Understanding how plants are constructed—i.e., how key size dimensions and the amount of mass invested in different tissues varies among individuals—is essential for modeling plant growth, carbon stocks, and energy fluxes in the terrestrial biosphere. Allocation patterns can differ through ontogeny, but also among coexisting species and among species adapted to...

  8. Positive allometry and the prehistory of sexual selection

    OpenAIRE

    Tomkins, Joseph L.; LeBas, Natasha R.; Witton, Mark P.; Martill, David M.; Humphries, Stuart

    2010-01-01

    The function of the exaggerated structures that adorn many fossil vertebrates remains largely unresolved. One recurrent hypothesis is that these elaborated traits had a role in thermoregulation. This orthodoxy persists despite the observation that traits exaggerated to the point of impracticality in extant organisms are almost invariably sexually selected. We use allometric scaling to investigate the role of sexual selection and thermoregulation in the evolution of exaggerated traits of the c...

  9. Human midsagittal brain shape variation: patterns, allometry and integration

    Science.gov (United States)

    Bruner, Emiliano; Martin-Loeches, Manuel; Colom, Roberto

    2010-01-01

    Midsagittal cerebral morphology provides a homologous geometrical reference for brain shape and cortical vs. subcortical spatial relationships. In this study, midsagittal brain shape variation is investigated in a sample of 102 humans, in order to describe and quantify the major patterns of correlation between morphological features, the effect of size and sex on general anatomy, and the degree of integration between different cortical and subcortical areas. The only evident pattern of covariation was associated with fronto-parietal cortical bulging. The allometric component was weak for the cortical profile, but more robust for the posterior subcortical areas. Apparent sex differences were evidenced in size but not in brain shape. Cortical and subcortical elements displayed scarcely integrated changes, suggesting a modular separation between these two areas. However, a certain correlation was found between posterior subcortical and parietal cortical variations. These results should be directly integrated with information ranging from functional craniology to wiring organization, and with hypotheses linking brain shape and the mechanical properties of neurons during morphogenesis. PMID:20345859

  10. Allometry indicates giant eyes of giant squid are not exceptional.

    Science.gov (United States)

    Schmitz, Lars; Motani, Ryosuke; Oufiero, Christopher E; Martin, Christopher H; McGee, Matthew D; Gamarra, Ashlee R; Lee, Johanna J; Wainwright, Peter C

    2013-02-18

    The eyes of giant and colossal squid are among the largest eyes in the history of life. It was recently proposed that sperm whale predation is the main driver of eye size evolution in giant squid, on the basis of an optical model that suggested optimal performance in detecting large luminous visual targets such as whales in the deep sea. However, it is poorly understood how the eye size of giant and colossal squid compares to that of other aquatic organisms when scaling effects are considered. We performed a large-scale comparative study that included 87 squid species and 237 species of acanthomorph fish. While squid have larger eyes than most acanthomorphs, a comparison of relative eye size among squid suggests that giant and colossal squid do not have unusually large eyes. After revising constants used in a previous model we found that large eyes perform equally well in detecting point targets and large luminous targets in the deep sea. The eyes of giant and colossal squid do not appear exceptionally large when allometric effects are considered. It is probable that the giant eyes of giant squid result from a phylogenetically conserved developmental pattern manifested in very large animals. Whatever the cause of large eyes, they appear to have several advantages for vision in the reduced light of the deep mesopelagic zone.

  11. Allometria da palmeira babaçu em um agroecossistema de derruba-e-queima na periferia este da Amazônia Allometry of the babassu palm growing on a slash-and-burn agroecosystem of the eastern periphery of Amazonia

    Directory of Open Access Journals (Sweden)

    Christoph Gehring

    2011-03-01

    .Babassu (Attalea speciosa C.Martius, Arecaceae is a palm with extraordinary socioeconomic and ecologic importance in large areas of tropical Brazil, especially in frequently burned and degraded landscapes. Nevertheless, surprisingly little is known about this keystone species. This paper investigates the allometry of babassu, in order to improve understanding on palm architecture and to provide researchers with an efficient tool for aboveground biomass estimation of juvenile and adult palms. Juvenile leaf biomass can be accurately predicted with the easily measurable minimum diameter of rachis at 30 cm extension. Adult palm biomass can be estimated based on woody stem height, a variable fairly easily measurable on-field. Leaf biomass of adult palms was highly variable, averaged 31.7% of aboveground biomass and can be estimated only indirectly through the relationships between wood:leaf-ratio and total aboveground biomass. Carbon contents varied little in the babassu palm, without size- or growth-stage related differences, suggesting the general applicability of values (42.5% C for stems, 39.8% C for leaves. As a consequence of the limited secondary diameter growth inherent to palms, stem diameter of adult palms is unrelated to palm height and biomass. Stem tapering decreases with increasing palm height. This is partially compensated by increasing wood density in near cylindrical stems. Nevertheless, maximum babassu palm height of about 30 meters appears to be dictated by mechanical stability constraints. All allometric relationships of babassu described in this study are not affected by vegetation stand age, indicating the general applicability of these relationships.

  12. AISLE: an automatic volumetric segmentation method for the study of lung allometry.

    Science.gov (United States)

    Ren, Hongliang; Kazanzides, Peter

    2011-01-01

    We developed a fully automatic segmentation method for volumetric CT (computer tomography) datasets to support construction of a statistical atlas for the study of allometric laws of the lung. The proposed segmentation method, AISLE (Automated ITK-Snap based on Level-set), is based on the level-set implementation from an existing semi-automatic segmentation program, ITK-Snap. AISLE can segment the lung field without human interaction and provide intermediate graphical results as desired. The preliminary experimental results show that the proposed method can achieve accurate segmentation, in terms of volumetric overlap metric, by comparing with the ground-truth segmentation performed by a radiologist.

  13. Reproductive allometry in Pedicularis species changes with elevation

    DEFF Research Database (Denmark)

    Guo, Hui; Weiner, Jacob; Mazer, Susan J.

    2012-01-01

    1. Plants produce biomass and then allocate some of it to reproductive structures, so the relationship between reproductive (R) and vegetative (V) mass is a fundamental aspect of a plant’s reproductive strategy. 2. Differences among populations or taxa in the allometric relationship between R and V...... reproductive allocation at smaller sizes and a smaller investment in reproduction per additional unit of biomass accumulated. 3. We investigated variation in the allometric relationship between R and V among 44 naturally occurring populations representing 24 species of Pedicularis in the Tibetan Plateau...... at smaller sizes and less at larger sizes than plants growing at lower elevations. 5. Synthesis. The allometric slope (exponent) of the R–V relationship decreases with increasing elevation among Pedicularis populations and species, reflecting fundamental changes in the costs and benefits of increased...

  14. Intraspecific allometry of standard metabolic rate in green iguanas, Iguana iguana.

    Science.gov (United States)

    Maxwell, Lara K; Jacobson, Elliott R; McNab, Brian K

    2003-10-01

    To study the allometric relationship between standard metabolic rate and body mass (mass range 16-3627 g) in green iguanas, Iguana iguana (n=32), we measured rates of oxygen consumption (V(O(2))) at 30 degrees C during scotophase. The relationship could be described as: V(O(2))(ml h(-1))=0.478W(0.734). The resulting mass exponent was similar to the 3/4 power commonly used in interspecific curves (P>0.05), but differed from a proposed intraspecific value of 2/3 (Piguanas did not differ (P>0.05). The mass adjusted V(O(2)) was higher than predicted from generalized squamate curves. The mean mass exponent of intra-individual allometric equations of iguanas (n=7) at varying masses during ontogeny did not differ from that of the pooled equation, indicating that scaling of V(O(2)) is similar for both between and within individuals. Thermal acclimation, compensatory changes in V(O(2)) with prolonged exposure to a constant temperature, was not observed in juvenile iguanas (n=11) between 1 and 5 weeks of acclimation at 30 degrees C.

  15. Allometries for Widely Spaced Populus ssp. and Betula ssp. in Nurse Crop Systems

    Directory of Open Access Journals (Sweden)

    Hendrik Stark

    2013-11-01

    Full Text Available Nurse crops of widely spaced pioneer trees are a silvicultural approach to protect the regeneration of frost sensitive target tree species. If overstorey nurse crops are harvested, they can provide additional short-term benefits through increased biomass production, e.g., for bioenergy. However, the intensification of biomass exports from forests might impact negatively on ecosystem nutrient pools. Thus, precise allometric biomass equations are required to quantify biomass and nutrient removals. Since an analysis of published allometric equations developed for typical, dense aspen or birch forests showed that the tree height-to-diameter ratio correlated positively and the proportion of branch biomass negatively with stand density, we developed new allometric biomass equations for widely spaced aspen and birch growing at 4 x 4 m spacing. These equations yielded a root mean squared error of 13% when predicting total aboveground woody biomass for our sample trees. In contrast, the corresponding root mean squared error produced by allometric biomass equations from the literature ranged between 17% to 106% of actual dry biomass. Our results show that specific allometric biomass equations are needed for widely spaced pioneer trees both for accurate estimates of biomass and the nutrients contained within.

  16. Uncertainty of Forest Biomass Estimates in North Temperate Forests Due to Allometry: Implications for Remote Sensing

    Directory of Open Access Journals (Sweden)

    Razi Ahmed

    2013-06-01

    Full Text Available Estimates of above ground biomass density in forests are crucial for refining global climate models and understanding climate change. Although data from field studies can be aggregated to estimate carbon stocks on global scales, the sparsity of such field data, temporal heterogeneity and methodological variations introduce large errors. Remote sensing measurements from spaceborne sensors are a realistic alternative for global carbon accounting; however, the uncertainty of such measurements is not well known and remains an active area of research. This article describes an effort to collect field data at the Harvard and Howland Forest sites, set in the temperate forests of the Northeastern United States in an attempt to establish ground truth forest biomass for calibration of remote sensing measurements. We present an assessment of the quality of ground truth biomass estimates derived from three different sets of diameter-based allometric equations over the Harvard and Howland Forests to establish the contribution of errors in ground truth data to the error in biomass estimates from remote sensing measurements.

  17. From Evolutionary Allometry to Sexual Display: (A Reply to Holman and Bro-Jørgensen).

    Science.gov (United States)

    Raia, Pasquale; Passaro, Federico; Carotenuto, Francesco; Meiri, Shai; Piras, Paolo

    2016-08-01

    Conventional wisdom holds that the complex shapes of deer antlers are produced under the sole influence of sexual selection. We questioned this view by demonstrating that trends for increased body size evolution passively yield more-complex ornaments, even in organisms where no effect of sexual selection is possible, with similar allometric slopes. Recent investigations suggest that sexual selection on antlers of larger deer species is stronger than that in smaller species; hence, the use of conspicuous antlers for display in large male deer is a secondary function driven by especially intense sexual selection on these large-bodied species. Since ancestral deer were small and had very simple antlers, such an intense selection on antlers shape was probably absent in early deer. Therefore, the evolution of complex ornaments is coupled with body size evolution, even in deer.

  18. Mandible shape and dwarfism in squirrels (Mammalia, Rodentia): interaction of allometry and adaptation

    Science.gov (United States)

    Hautier, Lionel; Fabre, Pierre-Henri; Michaux, Jacques

    2009-06-01

    Squirrels include several independent lineages of dwarf forms distributed into two ecological groups: the dwarf tree and flying squirrels. The mandible of dwarf tree squirrels share a highly reduced coronoid process and a condylar process drawn backwards. Dwarf flying squirrels on the other hand, have an elongated coronoid process and a well-differentiated condylar process. To interpret such a difference, Elliptic Fourier Transform was used to evaluate how mandible shape varies with dwarfism in sciurids. The results obtained show that this clear-cut difference cannot be explained by a simple allometric relationship in relation with size decrease. We concluded that the retention of anteriorly positioned eye sockets, in relation with distance estimation, allowed the conservation of a well-differentiated coronoid process in all flying species, despite the trend towards its reduction observed among sciurids as their size decreases.

  19. Compacting coastal plain soils changes midrotation loblolly pine allometry by reducing root biomass

    Science.gov (United States)

    Kim H. Ludovici

    2008-01-01

    Factorial combinations of soil compaction and organic matter removal were replicated at the Long Term Site Productivity study in the Croatan National Forest, near New Bern, North Carolina, USA. Ten years after planting, 18 preselected loblolly pine (Pinus taeda L.) trees were destructively harvested to quantify treatment effects on total above- and...

  20. The Allometry of Bee Proboscis Length and Its Uses in Ecology.

    Directory of Open Access Journals (Sweden)

    Daniel P Cariveau

    Full Text Available Allometric relationships among morphological traits underlie important patterns in ecology. These relationships are often phylogenetically shared; thus quantifying allometric relationships may allow for estimating difficult-to-measure traits across species. One such trait, proboscis length in bees, is assumed to be important in structuring bee communities and plant-pollinator networks. However, it is difficult to measure and thus rarely included in ecological analyses. We measured intertegular distance (as a measure of body size and proboscis length (glossa and prementum, both individually and combined of 786 individual bees of 100 species across 5 of the 7 extant bee families (Hymenoptera: Apoidea: Anthophila. Using linear models and model selection, we determined which parameters provided the best estimate of proboscis length. We then used coefficients to estimate the relationship between intertegular distance and proboscis length, while also considering family. Using allometric equations with an estimation for a scaling coefficient between intertegular distance and proboscis length and coefficients for each family, we explain 91% of the variance in species-level means for bee proboscis length among bee species. However, within species, individual-level intertegular distance was a poor predictor of individual proboscis length. To make our findings easy to use, we created an R package that allows estimation of proboscis length for individual bee species by inputting only family and intertegular distance. The R package also calculates foraging distance and body mass based on previously published equations. Thus by considering both taxonomy and intertegular distance we enable accurate estimation of an ecologically and evolutionarily important trait.

  1. Changes in biomass allocation in species rich meadow after abandonment: Ecological strategy or allometry?

    Czech Academy of Sciences Publication Activity Database

    Bartušková, Alena; Doležal, Jiří; Janeček, Štěpán; Lanta, V.; Klimešová, Jitka

    2015-01-01

    Roč. 17, č. 5 (2015), s. 379-387 ISSN 1433-8319 R&D Projects: GA ČR GB14-36079G Institutional support: RVO:67985939 Keywords : Biomass allocation * species-rich meadow * abandonment Subject RIV: EF - Botanics Impact factor: 3.578, year: 2015

  2. Functional differences in the allometry of the water, carbon and nitrogen content of gelatinous organisms

    KAUST Repository

    Molina-Ramírez, Axayacatl

    2015-05-19

    We have supplemented available, concurrent measurements of fresh weight (W, g) and body carbon (C, g) (46 individuals, 14 species) and nitrogen (N, g) (11 individuals, 9 species) of marine gelatinous animals with data obtained during the global ocean MALASPINA 2010 Expedition (totalling 267 individuals and 33 species for the W versus C data; totalling 232 individuals and 31 species for the N versus C data). We then used those data to test the allometric properties of the W versus C and N versus C relationships. Overall, gelatinous organisms contain 1.13 ± 1.57% of C (by weight, mean ± SD) in their bodies and show a C:N of 4.56 ± 2.46, respectively, although estimations can be improved by using separate conversion coefficients for the carnivores and the filter feeders. Reduced major axis regression indicates that W increases isometrically with C in the carnivores (cnidarians and ctenophores), implying that their water content can be described by a single conversion coefficient of 173.78 gW(g C)-1, or a C content of 1.17 ± 1.90% by weight, although there is much variability due to the existence of carbon-dense species. In contrast, W increases more rapidly than C in the filter feeders (salps and doliolids), according to a power relationship W = 446.68C1.54. This exponent is not significantly different from 1.2, which is consistent with the idea that the watery bodies of gelatinous animals represent an evolutionary response towards increasing food capture surfaces, i.e. a bottom-up rather than a top-down mechanism. Thus, the available evidence negates a bottom-up mechanism in the carnivores, but supports it in the filter feeders. Last, N increases isometrically with C in both carnivores and filter feeders with C:N ratios of 3.89 ± 1.34 and 4.38 ± 1.21, respectively. These values are similar to those of compact, non-gelatinous organisms and reflect a predominantly herbivorous diet in the filter feeders, which is confirmed by a difference of one trophic level between filter feeders and carnivores, according to stable N isotope enrichment data. © 2015 The Author.

  3. Allometry, biomass, and chemical content of novel African Tulip Tree (Spathodea campanulata) forests in Puerto Rico

    Science.gov (United States)

    Ariel E. Lugo; Oscar J. Abelleira; Alexander Collado; Christian A. Viera; Cynthia Santiago; Diego O. Velez; Emilio Soto; Giovanni Amaro; Graciela Charon; Jr. Colon; Jennifer Santana; Jose L. Morales; Katherine Rivera; Luis Ortiz; Luis Rivera; Mianel Maldonado; Natalia Rivera; Norelis J. Vazquez

    2011-01-01

    The African tulip tree, Spathodea campanulata, the most common tree in Puerto Rico, forms novel forest types with mixtures of native and other introduced tree species. Novel forests increase in area in response to human activity and there is no information about their biomass accumulation and nutrient cycling. We established allometric relationships and chemically...

  4. Allometry and Scaling of the Intraocular Pressure and Aqueous Humour Flow Rate in Vertebrate Eyes

    Science.gov (United States)

    Zouache, Moussa A.; Eames, Ian; Samsudin, Amir

    2016-01-01

    In vertebrates, intraocular pressure (IOP) is required to maintain the eye into a shape allowing it to function as an optical instrument. It is sustained by the balance between the production of aqueous humour by the ciliary body and the resistance to its outflow from the eye. Dysregulation of the IOP is often pathological to vision. High IOP may lead to glaucoma, which is in man the second most prevalent cause of blindness. Here, we examine the importance of the IOP and rate of formation of aqueous humour in the development of vertebrate eyes by performing allometric and scaling analyses of the forces acting on the eye during head movement and the energy demands of the cornea, and testing the predictions of the models against a list of measurements in vertebrates collated through a systematic review. We show that the IOP has a weak dependence on body mass, and that in order to maintain the focal length of the eye, it needs to be an order of magnitude greater than the pressure drop across the eye resulting from gravity or head movement. This constitutes an evolutionary constraint that is common to all vertebrates. In animals with cornea-based optics, this constraint also represents a condition to maintain visual acuity. Estimated IOPs were found to increase with the evolution of terrestrial animals. The rate of formation of aqueous humour was found to be adjusted to the metabolic requirements of the cornea, scaling as Vac0.67, where Vac is the volume of the anterior chamber. The present work highlights an interdependence between IOP and aqueous flow rate crucial to ocular function that must be considered to understand the evolution of the dioptric apparatus. It should also be taken into consideration in the prevention and treatment of glaucoma. PMID:26990431

  5. Allometry and growth of six tree species in a terra firme forest in colombian amazonia

    International Nuclear Information System (INIS)

    Giraldo Pamplona Wilson A; Dairon, Alvaro; Cardenas Montoya J, Duque

    2011-01-01

    In this study carried out in the Amacayacu National Park in the Colombian Amazonia, we assessed the allometric relationship among different tree structural variables and the growth in diameter and biomass of six species classified according to their wood specific gravity. The tree species chosen were Eschweilera rufolia, Eschweilera itayensis, Conceveiba guianensis, Otoba parvifolia, Pseudolmedia laevis, and Apeiba aspera. The dbh was the most important structural explanatory variable. Regarding the total height dbh model, the allometric coefficient b changed between species showing a trend to increase, and thus a taper decrease, proportional to. There were o significant differences in diameter growth between species (P=0.119, F=1.80) or functional groups (P=0.153, F= 1.19). Likewise, biomass growth did not show significant differences neither between species (P=0.0784, F=2.05) nor functional groups (P=0.0711, F=2.71). However, there was a positive trend between and diameter growth and a negative one between and biomass growth. The results of this study suggest that this forest is recovering in biomass at a constant rate independent of the patch age, which emphasizes on the importance of pioneer species and gap formation on the carbon dynamics and the species coexistence in Amazonian tierra firme forests.

  6. Functional differences in the allometry of the water, carbon and nitrogen content of gelatinous organisms

    KAUST Repository

    Molina-Ramí rez, Axayacatl; Cá ceres, Carlos; Romero-Romero, Sonia; Bueno, Juan; Gonzá lez-Gordillo, J. Ignacio; Irigoien, Xabier; Sostres, Jorge; Bode, Antonio; Mompeá n, Carmen; Ferná ndez Puelles, Mariluz; Echevarria, Fidel; Duarte, Carlos M.; Acuñ a, José Luis

    2015-01-01

    We have supplemented available, concurrent measurements of fresh weight (W, g) and body carbon (C, g) (46 individuals, 14 species) and nitrogen (N, g) (11 individuals, 9 species) of marine gelatinous animals with data obtained during the global ocean MALASPINA 2010 Expedition (totalling 267 individuals and 33 species for the W versus C data; totalling 232 individuals and 31 species for the N versus C data). We then used those data to test the allometric properties of the W versus C and N versus C relationships. Overall, gelatinous organisms contain 1.13 ± 1.57% of C (by weight, mean ± SD) in their bodies and show a C:N of 4.56 ± 2.46, respectively, although estimations can be improved by using separate conversion coefficients for the carnivores and the filter feeders. Reduced major axis regression indicates that W increases isometrically with C in the carnivores (cnidarians and ctenophores), implying that their water content can be described by a single conversion coefficient of 173.78 gW(g C)-1, or a C content of 1.17 ± 1.90% by weight, although there is much variability due to the existence of carbon-dense species. In contrast, W increases more rapidly than C in the filter feeders (salps and doliolids), according to a power relationship W = 446.68C1.54. This exponent is not significantly different from 1.2, which is consistent with the idea that the watery bodies of gelatinous animals represent an evolutionary response towards increasing food capture surfaces, i.e. a bottom-up rather than a top-down mechanism. Thus, the available evidence negates a bottom-up mechanism in the carnivores, but supports it in the filter feeders. Last, N increases isometrically with C in both carnivores and filter feeders with C:N ratios of 3.89 ± 1.34 and 4.38 ± 1.21, respectively. These values are similar to those of compact, non-gelatinous organisms and reflect a predominantly herbivorous diet in the filter feeders, which is confirmed by a difference of one trophic level between filter feeders and carnivores, according to stable N isotope enrichment data. © 2015 The Author.

  7. Oak Bark Allometry and Fire Survival Strategies in the Chihuahuan Desert Sky Islands, Texas, USA

    OpenAIRE

    Schwilk, Dylan W.; Gaetani, Maria S.; Poulos, Helen M.

    2013-01-01

    Trees may survive fire through persistence of above or below ground structures. Investment in bark aids in above-ground survival while investment in carbohydrate storage aids in recovery through resprouting and is especially important following above-ground tissue loss. We investigated bark allocation and carbohydrate investment in eight common oak (Quercus) species of Sky Island mountain ranges in west Texas. We hypothesized that relative investment in bark and carbohydrates changes with tre...

  8. Minimizing bias in biomass allometry: Model selection and log transformation of data

    Science.gov (United States)

    Joseph Mascaro; undefined undefined; Flint Hughes; Amanda Uowolo; Stefan A. Schnitzer

    2011-01-01

    Nonlinear regression is increasingly used to develop allometric equations for forest biomass estimation (i.e., as opposed to the raditional approach of log-transformation followed by linear regression). Most statistical software packages, however, assume additive errors by default, violating a key assumption of allometric theory and possibly producing spurious models....

  9. [Tree above-ground biomass allometries for carbon stocks estimation in the Caribbean mangroves in Colombia].

    Science.gov (United States)

    Yepes, Adriana; Zapata, Mauricio; Bolivar, Jhoanata; Monsalve, Alejandra; Espinosa, Sandra Milena; Sierra-Correa, Paula Cristina; Sierra, Andrés

    2016-06-01

    The distribution of carbon in “Blue Carbon” ecosystems such as mangroves is little known, when compared with the highly known terrestrial forests, despite its particular and recognized high productivity and carbon storage capacity. The objective of this study was to analyze the above ground biomass (AGB) of the species Rhizophora mangle and Avicennia germinans from the Marine Protected Area of Distrito de Manejo Integrado (DMI), Cispatá-Tinajones-La Balsa, Caribbean Colombian coast. With official authorization, we harvested and studied 30 individuals of each species, and built allometric models in order to estimate AGB. Our AGB results indicated that the studied mangrove forests of the DMI Colombian Caribbean was of 129.69 ± 20.24 Mg/ha, equivalent to 64.85 ± 10.12 MgC/ha. The DMI has an area of 8 570.9 ha in mangrove forests, and we estimated that the total carbon potential stored was about 555 795.93 Mg C. The equations generated in this study can be considered as an alternative for the assessment of carbon stocks in AGB of mangrove forests in Colombia; as other available AGB allometric models do not discriminate mangrove forests, despite being particular ecosystems. They can be used for analysis at a more detailed scale and are considered useful to determine the carbon storage potential of mangrove forests, as a country alternative to support forest conservation and emission reduction strategies. In general, the potential of carbon storage from Colombian Caribbean mangrove forests is important and could promote the country leadership of the “blue carbon” stored.

  10. The cost of myrmecophytism: insights from allometry of stem secondary growth.

    Science.gov (United States)

    Blatrix, Rumsaïs; Renard, Delphine; Djieto-Lordon, Champlain; McKey, Doyle

    2012-10-01

    Plant defence traits against herbivores incur production costs that are usually difficult to measure. However, estimating these costs is a prerequisite for characterizing the plant defence strategy as a whole. Myrmecophytes are plants that provide symbiotic ants with specialized nesting cavities, called domatia, in exchange for protection against herbivores. In the particular case of stem domatia, production of extra wood seems to be the only associated cost, making this indirect defence trait a particularly suitable model for estimating the cost of defence. Measurements were made of growth pattern and cumulative production cost of domatia over secondary growth in the myrmecophyte Leonardoxa africana subsp. africana, whose internodes display both a solid basal segment and a hollow distal part (the domatium), thus allowing paired comparison of investment in wood. Previous studies showed that 'overconstruction' of the hollow part of internodes during primary growth is needed for mechanical support. In this study, it is shown that the relationship between the woody cross-sectional area of the solid and hollow parts of internodes is negatively allometric at the beginning of secondary growth and nearly isometric later on. Thus, in hollow stems, the first phase of slow secondary growth compensates for the 'overconstruction' of the ring of wood during primary growth. Moreover, the cumulative production cost of a domatium (estimated as the additional volume of wood required for a hollow stem compared with a solid one) is very high at the beginning of secondary growth and then quickly tends to zero. Making domatia incurs high costs early in ontogeny, costs that are then amortized later in development of stems and of individual plants. Characterizing ontogenetic variation of the net cost of this peculiar defence mechanism will help us build more accurate theoretical models of resource allocation in myrmecophytes.

  11. Measuring and modelling above-ground carbon and tree allometry along a tropical elevation gradient

    DEFF Research Database (Denmark)

    Marshall, A.R.; Willcock, S.; Platts, P.J.

    2012-01-01

    of physical, climatic and edaphic predictors of AGC and tree stature. AGC estimates using stem diameter, height and wood density, gave a mean value of 174.6 t ha−1, compared with 229.6 t ha−1 when height was excluded. Regression models revealed that stems were tallest for a given diameter at mid......:benefit of different measurements and recommend a tiered approach to AGC monitoring, depending on available resources. AGC assessments in African forests could exclude small stems, but should aim to record disturbance, topography and species. Stem height is vital for AGC estimation and valuation; when excluding height...... our 55 t ha−1 over-estimation of AGC would have over-valued the carbon resource by 24% (US$3300 ha−1)....

  12. Evolution and Allometry of Calcaneal Elongation in Living and Extinct Primates

    Science.gov (United States)

    Boyer, Doug M.; Seiffert, Erik R.; Gladman, Justin T.; Bloch, Jonathan I.

    2013-01-01

    Specialized acrobatic leaping has been recognized as a key adaptive trait tied to the origin and subsequent radiation of euprimates based on its observed frequency in extant primates and inferred frequency in extinct early euprimates. Hypothesized skeletal correlates include elongated tarsal elements, which would be expected to aid leaping by allowing for increased rates and durations of propulsive acceleration at takeoff. Alternatively, authors of a recent study argued that pronounced distal calcaneal elongation of euprimates (compared to other mammalian taxa) was related primarily to specialized pedal grasping. Testing for correlations between calcaneal elongation and leaping versus grasping is complicated by body size differences and associated allometric affects. We re-assess allometric constraints on, and the functional significance of, calcaneal elongation using phylogenetic comparative methods, and present an evolutionary hypothesis for the evolution of calcaneal elongation in primates using a Bayesian approach to ancestral state reconstruction (ASR). Results show that among all primates, logged ratios of distal calcaneal length to total calcaneal length are inversely correlated with logged body mass proxies derived from the area of the calcaneal facet for the cuboid. Results from phylogenetic ANOVA on residuals from this allometric line suggest that deviations are explained by degree of leaping specialization in prosimians, but not anthropoids. Results from ASR suggest that non-allometric increases in calcaneal elongation began in the primate stem lineage and continued independently in haplorhines and strepsirrhines. Anthropoid and lorisid lineages show stasis and decreasing elongation, respectively. Initial increases in calcaneal elongation in primate evolution may be related to either development of hallucal-grasping or a combination of grasping and more specialized leaping behaviors. As has been previously suggested, subsequent increases in calcaneal elongation are likely adaptations for more effective acrobatic leaping, highlighting the importance of this behavior in early euprimate evolution. PMID:23844094

  13. Allometry, sexual size dimorphism, and niche partitioning in the Mediterranean gecko (Hemidactylus turcicus)

    Science.gov (United States)

    James B. Johnson; Lance D. McBrayer; Daniel Saenz

    2005-01-01

    Hemidactylus tucrius is a small gekkonid lizard native to the Middle East and Asia that is known to exhibit sexual dimorphism in head size. Several potential explanations exist for the evolution and maintenance of sexual dimorphism in lizards. We tested 2 of these competing hypotheses concerning diet partitioning and differential growth. We found no...

  14. Nitrogen:phosphorous supply ratio and allometry in five alpine plant species

    DEFF Research Database (Denmark)

    Luo, Xi; Mazer, Susan J.; Guo, Hui

    2016-01-01

    - versus belowground biomass (MA and MB). Biomass allocation among individual plants is broadly size-dependent, and this can often be described as an allometric relationship between MA and MB, as represented by the equation MA=αMBβ, or log MA = logα + βlog MB. Here, we investigated whether the scaling...

  15. An approach to scoring cursorial limb proportions in carnivorous dinosaurs and an attempt to account for allometry

    Science.gov (United States)

    Persons, W. Scott, IV; Currie, Philip J.

    2016-01-01

    From an initial dataset of 53 theropod species, the general relationship between theropod lower-leg length and body mass is identified. After factoring out this allometric relationship, theropod hindlimb proportions are assessed irrespective of body mass. Cursorial-limb-proportion (CLP) scores derived for each of the considered theropod taxa offer a measure of the extent to which a particular species deviates in favour of higher or lower running speeds. Within the same theropod species, these CLP scores are found to be consistent across multiple adult specimens and across disparate ontogenetic stages. Early theropods are found to have low CLP scores, while the coelurosaurian tyrannosauroids and compsognathids are found to have high CLP scores. Among deinonychosaurs, troodontids have consistently high CLP scores, while many dromaeosaur taxa, including Velociraptor and Deinonychus, have low CLP scores. This indicates that dromaeosaurs were not, overall, a particularly cursorily adapted group. Comparisons between the CLP scores of Tyrannosaurus and specimens referred to the controversial genus Nanotyrannus indicate a strong discrepancy in cursorial adaptations, which supports the legitimacy of Nanotyrannus and the previous suggestions of ecological partitioning between Nanotyrannus and the contemporaneous Tyrannosaurus.

  16. The Gavialis-Tomistoma debate: the contribution of skull ontogenetic allometry and growth trajectories to the study of crocodylian relationships.

    Science.gov (United States)

    Piras, Paolo; Colangelo, Paolo; Adams, Dean C; Buscalioni, Angela; Cubo, Jorge; Kotsakis, Tassos; Meloro, Carlo; Raia, Pasquale

    2010-01-01

    The phylogenetic placement of Tomistoma and Gavialis crocodiles depends largely upon whether molecular or morphological data are utilized. Molecular analyses consider them as sister taxa, whereas morphological/paleontological analyses set Gavialis apart from Tomistoma and other crocodylian species. Here skull allometric trajectories of Tomistoma and Gavialis were contrasted with those of two longirostral crocodylian taxa, Crocodylus acutus and Mecistops cataphractus, to examine similarities in growth trajectories in light of this phylogenetic controversy. Entire skull shape and its two main modules, rostrum and postrostrum, were analyzed separately. We tested differences for both multivariate angles between trajectories and for shape differences at early and late stages of development. Based on a multivariate regression of shape data and size, Tomistoma seems to possess a peculiar rate of growth in comparison to the remaining taxa. However, its morphology at both juvenile and adult sizes is always closer to those of Brevirostres crocodylians, for the entire head shape, as well as the shape of the postrostrum and rostrum. By contrast, the allometric trajectory of Gavialis always begins and ends in a unique region of the multidimensional morphospace. These findings concur with a morphological hypothesis that places Gavialis separate from Brevirostres, and Tomistoma closer to other crocodylids, and provides an additional, and independent, data set to inform on this ongoing phylogenetic discussion. © 2010 Wiley Periodicals, Inc.

  17. Shell shape analysis and spatial allometry patterns of Manila Clam (Ruditapes philippinarium) in a mesotidal coastal lagoon

    OpenAIRE

    Caill-Milly, Nathalie; Bru, Noëlle; Mahé, Kélig; D'Amico, Franck

    2012-01-01

    While gradual allometric changes of shells are intrinsically driven by genotype, morphometrical shifts can also be modulated by local environmental conditions. Consequently the common use of a unique dimension (usually length) to assess bivalves’ growth may mask phenotypic differences in valve shape among populations. A morphometric exhaustive study was conducted on Manila clam, Ruditapes philippinarum, by acquiring data in the French Arcachon Bay (intrasite phenotypic variability) and by com...

  18. Shell Shape Analysis and Spatial Allometry Patterns of Manila Clam (Ruditapes philippinarum in a Mesotidal Coastal Lagoon

    Directory of Open Access Journals (Sweden)

    Nathalie Caill-Milly

    2012-01-01

    Full Text Available While gradual allometric changes of shells are intrinsically driven by genotype, morphometrical shifts can also be modulated by local environmental conditions. Consequently the common use of a unique dimension (usually length to assess bivalves’ growth may mask phenotypic differences in valve shape among populations. A morphometric exhaustive study was conducted on Manila clam, Ruditapes philippinarum, by acquiring data in the French Arcachon Bay (intrasite phenotypic variability and by comparing with other sites in the literature (intersite phenotypic variability. 2070 shells were subsampled, weighted, and automatically measured using TNPC software. Some ratios’ values indicate a relatively round and globular shape shell in comparison with other sites confirming poor conditions for some individuals. Among adult clams, three main morphological groups were identified and discussed according to spatial considerations. Allometric relations for pairs of shell descriptors were determined by testing classical linear and piecewise regression models on log-transformed relation of Huxley. A significant shape change correlated to size was observed; it corresponds to the second year of life of the clam. Relationships between density, disease, and shell shape are demonstrated and discussed related to other potential factors affecting shell shape. Finally, consequences on population regulation are addressed.

  19. Allometry and partitioning of above- and below-ground biomass in farmed eucalyptus species dominant in Western Kenyan agricultural landscapes

    International Nuclear Information System (INIS)

    Kuyah, Shem; Dietz, Johannes; Muthuri, Catherine; Noordwijk, Meine van; Neufeldt, Henry

    2013-01-01

    Farmers in developing countries are one of the world's largest and most efficient producers of sequestered carbon. However, measuring, monitoring and verifying how much carbon trees in smallholder farms are removing from the atmosphere has remained a great challenge in developing nations. Devising a reliable way for measuring carbon associated with trees in agricultural landscapes is essential for helping smallholder farmers benefit from emerging carbon markets. This study aimed to develop biomass equations specific to dominant eucalyptus species found in agricultural landscapes in Western Kenya. Allometric relationships were developed by regressing diameter at breast height (DBH) alone or DBH in combination with height, wood density or crown area against the biomass of 48 trees destructively sampled from a 100 km 2 site. DBH alone was a significant predictor variable and estimated aboveground biomass (AGB) with over 95% accuracy. The stems, branches and leaves formed up to 74, 22 and 4% of AGB, respectively, while belowground biomass (BGB) of the harvested trees accounted for 21% of the total tree biomass, yielding an overall root-to-shoot ratio (RS) of 0.27, which varied across tree size. Total tree biomass held in live Eucalyptus trees was estimated to be 24.4 ± 0.01 Mg ha −1 , equivalent to 11.7 ± 0.01 Mg of carbon per hectare. The equations presented provide useful tools for estimating tree carbon stocks of Eucalyptus in agricultural landscapes for bio-energy and carbon accounting. These equations can be applied to Eucalyptus in most agricultural systems with similar agro-ecological settings where tree growth parameters would fall within ranges comparable to the sampled population. -- Highlights: ► Equation with DBH alone estimated aboveground biomass with about 95% accuracy. ► Local generic equations overestimated above- and below-ground biomass by 10 and 48%. ► Height, wood density and crown area data did not improve model accuracy. ► Stems, roots, branches and leaves formed 58, 21, 18 and 3% of total tree biomass

  20. Intraspecific Allometry of Basal Metabolic Rate : Relations with Body Size, Temperature, Composition, and Circadian Phase in the Kestrel, Falco tinnunculus

    NARCIS (Netherlands)

    Daan, Serge; Masman, Dirkjan; Strijkstra, Arjen; Verhulst, Simon

    1989-01-01

    The relationship between body size and basal metabolic rate (BMR) in homeotherms has been treated in the literature primarily by comparison between species of mammals or birds. This paper focuses on the intraindividual changes in BMR when body mass (W) varies with different maintenance regimens. BMR

  1. Herbivory and body size: allometries of diet quality and gastrointestinal physiology, and implications for herbivore ecology and dinosaur gigantism.

    Science.gov (United States)

    Clauss, Marcus; Steuer, Patrick; Müller, Dennis W H; Codron, Daryl; Hummel, Jürgen

    2013-01-01

    Digestive physiology has played a prominent role in explanations for terrestrial herbivore body size evolution and size-driven diversification and niche differentiation. This is based on the association of increasing body mass (BM) with diets of lower quality, and with putative mechanisms by which a higher BM could translate into a higher digestive efficiency. Such concepts, however, often do not match empirical data. Here, we review concepts and data on terrestrial herbivore BM, diet quality, digestive physiology and metabolism, and in doing so give examples for problems in using allometric analyses and extrapolations. A digestive advantage of larger BM is not corroborated by conceptual or empirical approaches. We suggest that explanatory models should shift from physiological to ecological scenarios based on the association of forage quality and biomass availability, and the association between BM and feeding selectivity. These associations mostly (but not exclusively) allow large herbivores to use low quality forage only, whereas they allow small herbivores the use of any forage they can physically manage. Examples of small herbivores able to subsist on lower quality diets are rare but exist. We speculate that this could be explained by evolutionary adaptations to the ecological opportunity of selective feeding in smaller animals, rather than by a physiologic or metabolic necessity linked to BM. For gigantic herbivores such as sauropod dinosaurs, other factors than digestive physiology appear more promising candidates to explain evolutionary drives towards extreme BM.

  2. Herbivory and body size: allometries of diet quality and gastrointestinal physiology, and implications for herbivore ecology and dinosaur gigantism.

    Directory of Open Access Journals (Sweden)

    Marcus Clauss

    Full Text Available Digestive physiology has played a prominent role in explanations for terrestrial herbivore body size evolution and size-driven diversification and niche differentiation. This is based on the association of increasing body mass (BM with diets of lower quality, and with putative mechanisms by which a higher BM could translate into a higher digestive efficiency. Such concepts, however, often do not match empirical data. Here, we review concepts and data on terrestrial herbivore BM, diet quality, digestive physiology and metabolism, and in doing so give examples for problems in using allometric analyses and extrapolations. A digestive advantage of larger BM is not corroborated by conceptual or empirical approaches. We suggest that explanatory models should shift from physiological to ecological scenarios based on the association of forage quality and biomass availability, and the association between BM and feeding selectivity. These associations mostly (but not exclusively allow large herbivores to use low quality forage only, whereas they allow small herbivores the use of any forage they can physically manage. Examples of small herbivores able to subsist on lower quality diets are rare but exist. We speculate that this could be explained by evolutionary adaptations to the ecological opportunity of selective feeding in smaller animals, rather than by a physiologic or metabolic necessity linked to BM. For gigantic herbivores such as sauropod dinosaurs, other factors than digestive physiology appear more promising candidates to explain evolutionary drives towards extreme BM.

  3. An approach to scoring cursorial limb proportions in carnivorous dinosaurs and an attempt to account for allometry.

    Science.gov (United States)

    Persons, W Scott; Currie, Philip J

    2016-01-27

    From an initial dataset of 53 theropod species, the general relationship between theropod lower-leg length and body mass is identified. After factoring out this allometric relationship, theropod hindlimb proportions are assessed irrespective of body mass. Cursorial-limb-proportion (CLP) scores derived for each of the considered theropod taxa offer a measure of the extent to which a particular species deviates in favour of higher or lower running speeds. Within the same theropod species, these CLP scores are found to be consistent across multiple adult specimens and across disparate ontogenetic stages. Early theropods are found to have low CLP scores, while the coelurosaurian tyrannosauroids and compsognathids are found to have high CLP scores. Among deinonychosaurs, troodontids have consistently high CLP scores, while many dromaeosaur taxa, including Velociraptor and Deinonychus, have low CLP scores. This indicates that dromaeosaurs were not, overall, a particularly cursorily adapted group. Comparisons between the CLP scores of Tyrannosaurus and specimens referred to the controversial genus Nanotyrannus indicate a strong discrepancy in cursorial adaptations, which supports the legitimacy of Nanotyrannus and the previous suggestions of ecological partitioning between Nanotyrannus and the contemporaneous Tyrannosaurus.

  4. Testing the generality of above-ground biomass allometry across plant functional types at the continent scale.

    Science.gov (United States)

    Paul, Keryn I; Roxburgh, Stephen H; Chave, Jerome; England, Jacqueline R; Zerihun, Ayalsew; Specht, Alison; Lewis, Tom; Bennett, Lauren T; Baker, Thomas G; Adams, Mark A; Huxtable, Dan; Montagu, Kelvin D; Falster, Daniel S; Feller, Mike; Sochacki, Stan; Ritson, Peter; Bastin, Gary; Bartle, John; Wildy, Dan; Hobbs, Trevor; Larmour, John; Waterworth, Rob; Stewart, Hugh T L; Jonson, Justin; Forrester, David I; Applegate, Grahame; Mendham, Daniel; Bradford, Matt; O'Grady, Anthony; Green, Daryl; Sudmeyer, Rob; Rance, Stan J; Turner, John; Barton, Craig; Wenk, Elizabeth H; Grove, Tim; Attiwill, Peter M; Pinkard, Elizabeth; Butler, Don; Brooksbank, Kim; Spencer, Beren; Snowdon, Peter; O'Brien, Nick; Battaglia, Michael; Cameron, David M; Hamilton, Steve; McAuthur, Geoff; Sinclair, Jenny

    2016-06-01

    Accurate ground-based estimation of the carbon stored in terrestrial ecosystems is critical to quantifying the global carbon budget. Allometric models provide cost-effective methods for biomass prediction. But do such models vary with ecoregion or plant functional type? We compiled 15 054 measurements of individual tree or shrub biomass from across Australia to examine the generality of allometric models for above-ground biomass prediction. This provided a robust case study because Australia includes ecoregions ranging from arid shrublands to tropical rainforests, and has a rich history of biomass research, particularly in planted forests. Regardless of ecoregion, for five broad categories of plant functional type (shrubs; multistemmed trees; trees of the genus Eucalyptus and closely related genera; other trees of high wood density; and other trees of low wood density), relationships between biomass and stem diameter were generic. Simple power-law models explained 84-95% of the variation in biomass, with little improvement in model performance when other plant variables (height, bole wood density), or site characteristics (climate, age, management) were included. Predictions of stand-based biomass from allometric models of varying levels of generalization (species-specific, plant functional type) were validated using whole-plot harvest data from 17 contrasting stands (range: 9-356 Mg ha(-1) ). Losses in efficiency of prediction were <1% if generalized models were used in place of species-specific models. Furthermore, application of generalized multispecies models did not introduce significant bias in biomass prediction in 92% of the 53 species tested. Further, overall efficiency of stand-level biomass prediction was 99%, with a mean absolute prediction error of only 13%. Hence, for cost-effective prediction of biomass across a wide range of stands, we recommend use of generic allometric models based on plant functional types. Development of new species-specific models is only warranted when gains in accuracy of stand-based predictions are relatively high (e.g. high-value monocultures). © 2015 John Wiley & Sons Ltd.

  5. Habitat Effect on Allometry of a Xeric Shrub (Artemisia ordosica Krasch in the Mu Us Desert of Northern China

    Directory of Open Access Journals (Sweden)

    Weiwei She

    2015-12-01

    Full Text Available Allometric models are useful for assessment of aboveground net primary productivity (ANPP and aboveground biomass (AGB of forests and shrubs, and are widely implemented in forest inventory and management. Multiple forms of allometric models have been used to estimate vegetation carbon storage for desert shrubland, but their validity for biomass estimation has not been tested at a region scale with different habitats. To verify the validity of habitat-specific models, general models (combining data from all habitats/sites, and previously developed models for biomass prediction, we developed both general models and habitat-specific models for aboveground biomass and ANPP of Artemisia ordosica Krasch, a dominant shrub of the Mu Us Desert. Our results showed that models based on crown area or canopy volume consistently explained large parts of the variations in aboveground biomass and ANPP. Model fitting highlighted that general allometric models were inadequate across different habitats, and habitat-specific models were useful for that specific habitat. Previous models might be inappropriate for other sites because of site quality differences. There was a strong habitat effect on the allometric relationships of A. ordosica. Although our study is a case in point, the results indicate that allometric models for desert shrubs should be used with caution and require robust validation if adopted from other studies or applied to different sites/habitats.

  6. Static allometry of unicellular green algae: scaling of cellular surface area and volume in the genus Micrasterias (Desmidiales).

    Science.gov (United States)

    Neustupa, J

    2016-02-01

    The surface area-to-volume ratio of cells is one of the key factors affecting fundamental biological processes and, thus, fitness of unicellular organisms. One of the general models for allometric increase in surface-to-volume scaling involves fractal-like elaboration of cellular surfaces. However, specific data illustrating this pattern in natural populations of the unicellular organisms have not previously been available. This study shows that unicellular green algae of the genus Micrasterias (Desmidiales) have positive allometric surface-to-volume scaling caused by changes in morphology of individual species, especially in the degree of cell lobulation. This allometric pattern was also detected within most of the cultured and natural populations analysed. Values of the allometric S:V scaling within individual populations were closely correlated to the phylogenetic structure of the clade. In addition, they were related to species-specific cellular morphology. Individual populations differed in their allometric patterns, and their position in the allometric space was strongly correlated with the degree of allometric S:V scaling. This result illustrates that allometric shape patterns are an important correlate of the capacity of individual populations to compensate for increases in their cell volumes by increasing the surface area. However, variation in allometric patterns was not associated with phylogenetic structure. This indicates that the position of the populations in the allometric space was not evolutionarily conserved and might be influenced by environmental factors. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  7. Geographic variation in floral allometry suggests repeated transitions between selfing and outcrossing in a mixed mating plant.

    Science.gov (United States)

    Summers, Holly E; Hartwick, Sally M; Raguso, Robert A

    2015-05-01

    Isometric and allometric scaling of a conserved floral plan could provide a parsimonious mechanism for rapid and reversible transitions between breeding systems. This scaling may occur during transitions between predominant autogamy and xenogamy, contributing to the maintenance of a stable mixed mating system. We compared nine disjunct populations of the polytypic, mixed mating species Oenothera flava (Onagraceae) to two parapatric relatives, the obligately xenogamous species O. acutissima and the mixed mating species O. triloba. We compared floral morphology of all taxa using principal component analysis (PCA) and developmental trajectories of floral organs using ANCOVA homogeneity of slopes. The PCA revealed both isometric and allometric scaling of a conserved floral plan. Three principal components (PCs) explained 92.5% of the variation in the three species. PC1 predominantly loaded on measures of floral size and accounts for 36% of the variation. PC2 accounted for 35% of the variation, predominantly in traits that influence pollinator handling. PC3 accounted for 22% of the variation, primarily in anther-stigma distance (herkogamy). During O. flava subsp. taraxacoides development, style elongation was accelerated relative to anthers, resulting in positive herkogamy. During O. flava subsp. flava development, style elongation was decelerated, resulting in zero or negative herkogamy. Of the two populations with intermediate morphology, style elongation was accelerated in one population and decelerated in the other. Isometric and allometric scaling of floral organs in North American Oenothera section Lavauxia drive variation in breeding system. Multiple developmental paths to intermediate phenotypes support the likelihood of multiple mating system transitions. © 2015 Botanical Society of America, Inc.

  8. The Fat-Dachsous signaling pathway regulates growth of horns in Trypoxylus dichotomus, but does not affect horn allometry.

    Science.gov (United States)

    Hust, James; Lavine, Mark D; Worthington, Amy M; Zinna, Robert; Gotoh, Hiroki; Niimi, T; Lavine, Laura

    Males of the Asian rhinoceros beetle, Trypoxylus dichotomus, possess exaggerated head and thoracic horns that scale dramatically out of proportion to body size. While studies of insulin signaling suggest that this pathway regulates nutrition-dependent growth including exaggerated horns, what regulates disproportionate growth has yet to be identified. The Fat signaling pathway is a potential candidate for regulating disproportionate growth of sexually-selected traits, a hypothesis we advanced in a previous paper (Gotoh et al., 2015). To investigate the role of Fat signaling in the growth and scaling of the sexually dimorphic, condition-dependent traits of the in the Asian rhinoceros beetle T. dichotomus, we used RNA interference to knock down expression of fat and its co-receptor dachsous. Knockdown of fat, and to a lesser degree dachsous, caused shortening and widening of appendages, including the head and thoracic horns. However, scaling of horns to body size was not affected. Our results show that Fat signaling regulates horn growth in T. dichotomus as it does in appendage growth in other insects. However, we provide evidence that Fat signaling does not mediate the disproportionate, positive allometric growth of horns in T. dichotomus. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Clutch and egg allometry of the turtle Mauremys leprosa (Chelonia: Geoemydidae) from a polluted peri-urban river in west-central Morocco

    Science.gov (United States)

    Naimi, Mohamed; Znari, Mohammed; Lovich, Jeffrey E.; Feddadi, Youssef; Baamrane, Moulay Abdeljalil Ait

    2012-01-01

    We examined the relationships of clutch size (CS) and egg size to female body size (straight-line carapace length, CL) in a population of the turtle Mauremys leprosa from a polluted segment of oued (river) Tensift in arid west-central Morocco. Twenty-eight adult females were collected in May–July, 2009 and all were gravid. Each was weighed, measured, humanely euthanized and then dissected. Oviductal shelled eggs were removed, weighed (egg mass, EM) and measured for length (EL) and width (EW). Clutch mass (CM) was the sum of EM for a clutch. Pelvic aperture width (PAW) was measured at the widest point between the ilia bones through which eggs must pass at oviposition. The smallest gravid female had a CL of 124.0 mm. Mean CS was relatively large (9.7±2.0 eggs, range: 3–13) and may reflect high productivity associated with polluted (eutrophic) waters. Regression analyses were conducted using log-transformed data. CM increased isometrically with maternal body size. CS, EW and EM were all significantly hypoallometric in their relationship with CL. EL did not change significantly with increases in CL. EW increased at a hypoallometric rate with increasing CL but was unconstrained by PAW since the widest egg was smaller than the narrowest PAW measurement when excluding the three smallest females. Smaller females may have EW constrained by PAW. As females increase in size they increase both clutch size and egg width in contradiction to predictions of optimal egg size theory.

  10. Comparison of Stem Map Developed from Crown Geometry Allometry Linked Census Data to Airborne and Terrestrial Lidar at Harvard Forest, MA

    Science.gov (United States)

    Sullivan, F.; Palace, M. W.; Ducey, M. J.; David, O.; Cook, B. D.; Lepine, L. C.

    2014-12-01

    Harvard Forest in Petersham, MA, USA is the location of one of the temperate forest plots established by the Center for Tropical Forest Science (CTFS) as a joint effort with Harvard Forest and the Smithsonian Institute's Forest Global Earth Observatory (ForestGEO) to characterize ecosystem processes and forest dynamics. Census of a 35 ha plot on Prospect Hill was completed during the winter of 2014 by researchers at Harvard Forest. Census data were collected according to CTFS protocol; measured variables included species, stem diameter, and relative X-Y locations. Airborne lidar data were collected over the censused plot using the high spatial resolution Goddard LiDAR, Hyperspectral, and Thermal sensor package (G-LiHT) during June 2012. As part of a separate study, 39 variable radius plots (VRPs) were randomly located and sampled within and throughout the Prospect Hill CTFS/ForestGEO plot during September and October 2013. On VRPs, biometric properties of trees were sampled, including species, stem diameter, total height, crown base height, crown radii, and relative location to plot centers using a 20 Basal Area Factor prism. In addition, a terrestrial-based lidar scanner was used to collect one lidar scan at plot center for 38 of the 39 VRPs. Leveraging allometric equations of crown geometry and tree height developed from 374 trees and 16 different species sampled on 39 VRPs, a 3-dimensional stem map will be created using the Harvard Forest ForestGEO Prospect Hill census. Vertical and horizontal structure of 3d field-based stem maps will be compared to terrestrial and airborne lidar scan data. Furthermore, to assess the quality of allometric equations, a 2d canopy height raster of the field-based stem map will be compared to a G-LiHT derived canopy height model for the 35 ha census plot. Our automated crown delineation methods will be applied to the 2d representation of the census stem map and the G-LiHT canopy height model. For future work related to this study, high quality field-based stem maps with species and crown geometry information will allow for better comparisons and interpretations of individual tree spectra from the G-LiHT hyperspectral sensor as estimated by automated crown delineation of the G-LiHT lidar canopy height model.

  11. Geometry, Allometry and Biomechanics of Fern Leaf Petioles: Their Significance for the Evolution of Functional and Ecological Diversity Within the Pteridaceae

    Directory of Open Access Journals (Sweden)

    Jennifer N. Mahley

    2018-03-01

    Full Text Available Herbaceous plants rely on a combination of turgor, ground tissues and geometry for mechanical support of leaves and stems. Unlike most angiosperms however, ferns employ a sub-dermal layer of fibers, known as a hypodermal sterome, for support of their leaves. The sterome is nearly ubiquitous in ferns, but nothing is known about its role in leaf biomechanics. The goal of this research was to characterize sterome attributes in ferns that experience a broad range of mechanical stresses, as imposed by their aquatic, xeric, epiphytic, and terrestrial niches. Members of the Pteridaceae meet this criteria well. The anatomical and functional morphometrics along with published values of tissue moduli were used to model petiole flexural rigidity and susceptibility to buckling in 20 species of the Pteridaceae. Strong allometric relationships were observed between sterome thickness and leaf size, with the sterome contributing over 97% to petiole flexural rigidity. Surprisingly, the small-statured cheilanthoid ferns allocated the highest fraction of their petiole to the sterome, while large leaves exploited aspects of geometry (second moment of area to achieve bending resistance. This pattern also revealed an economy of function in which increasing sterome thickness was associated with decreasing fiber cell reinforcement, and fiber wall fraction. Lastly, strong petioles were associated with durable leaves, as approximated by specific leaf area. This study reveals meaningful patterns in fern leaf biomechanics that align with species leaf size, sterome attributes and life-history strategy.

  12. Understanding the partitioning and concentration of trace elements in the plant organs of some food crops : influence of the plant allometry and of the growth stage

    OpenAIRE

    Liñero Campo , Olaia

    2016-01-01

    This work is focuded on the accumulation of essential and non-essential elements, paying a special attention to the dible part of the plants, in terms of food safety and human health. The thesis work has been divided in two main parts. The first one is related to a field expeiment performed in open-air plots, where Swiss chards and tomato plants were grown from seedlings to maturity in a natural soil during five months, using organic or conventional agricultural practices. Plants were harvest...

  13. Allometry, nitrogen status, and carbon stable isotope composition of Pinus ponderosa seedlings in two growing media with contrasting nursery irrigation regimes

    Science.gov (United States)

    R. Kasten Dumroese; Deborah S. Page-Dumroese; Robert E. Brown

    2011-01-01

    Nursery irrigation regimes that recharged container capacity when target volumetric water content reached 72%, 58%, and 44% (by volume) influenced Pinus ponderosa Douglas ex Lawson & C. Lawson growth more than either a 1:1 (by volume) Sphagnum peat - vermiculite (PV) or a 7:3 (by volume) Sphagnum peat - sawdust (PS) medium. Exponential fertilization avoided...

  14. Allometries of Maximum Growth Rate versus Body Mass at Maximum Growth Indicate That Non-Avian Dinosaurs Had Growth Rates Typical of Fast Growing Ectothermic Sauropsids

    Science.gov (United States)

    Werner, Jan; Griebeler, Eva Maria

    2014-01-01

    We tested if growth rates of recent taxa are unequivocally separated between endotherms and ectotherms, and compared these to dinosaurian growth rates. We therefore performed linear regression analyses on the log-transformed maximum growth rate against log-transformed body mass at maximum growth for extant altricial birds, precocial birds, eutherians, marsupials, reptiles, fishes and dinosaurs. Regression models of precocial birds (and fishes) strongly differed from Case’s study (1978), which is often used to compare dinosaurian growth rates to those of extant vertebrates. For all taxonomic groups, the slope of 0.75 expected from the Metabolic Theory of Ecology was statistically supported. To compare growth rates between taxonomic groups we therefore used regressions with this fixed slope and group-specific intercepts. On average, maximum growth rates of ectotherms were about 10 (reptiles) to 20 (fishes) times (in comparison to mammals) or even 45 (reptiles) to 100 (fishes) times (in comparison to birds) lower than in endotherms. While on average all taxa were clearly separated from each other, individual growth rates overlapped between several taxa and even between endotherms and ectotherms. Dinosaurs had growth rates intermediate between similar sized/scaled-up reptiles and mammals, but a much lower rate than scaled-up birds. All dinosaurian growth rates were within the range of extant reptiles and mammals, and were lower than those of birds. Under the assumption that growth rate and metabolic rate are indeed linked, our results suggest two alternative interpretations. Compared to other sauropsids, the growth rates of studied dinosaurs clearly indicate that they had an ectothermic rather than an endothermic metabolic rate. Compared to other vertebrate growth rates, the overall high variability in growth rates of extant groups and the high overlap between individual growth rates of endothermic and ectothermic extant species make it impossible to rule out either of the two thermoregulation strategies for studied dinosaurs. PMID:24586409

  15. Formal comment on: Myhrvold (2016) Dinosaur metabolism and the allometry of maximum growth rate. PLoS ONE; 11(11): e0163205.

    Science.gov (United States)

    Griebeler, Eva Maria; Werner, Jan

    2018-01-01

    In his 2016 paper, Myhrvold criticized ours from 2014 on maximum growth rates (Gmax, maximum gain in body mass observed within a time unit throughout an individual's ontogeny) and thermoregulation strategies (ectothermy, endothermy) of 17 dinosaurs. In our paper, we showed that Gmax values of similar-sized extant ectothermic and endothermic vertebrates overlap. This strongly questions a correct assignment of a thermoregulation strategy to a dinosaur only based on its Gmax and (adult) body mass (M). Contrary, Gmax separated similar-sized extant reptiles and birds (Sauropsida) and Gmax values of our studied dinosaurs were similar to those seen in extant similar-sized (if necessary scaled-up) fast growing ectothermic reptiles. Myhrvold examined two hypotheses (H1 and H2) regarding our study. However, we did neither infer dinosaurian thermoregulation strategies from group-wide averages (H1) nor were our results based on that Gmax and metabolic rate (MR) are related (H2). In order to assess whether single dinosaurian Gmax values fit to those of extant endotherms (birds) or of ectotherms (reptiles), we already used a method suggested by Myhrvold to avoid H1, and we only discussed pros and cons of a relation between Gmax and MR and did not apply it (H2). We appreciate Myhrvold's efforts in eliminating the correlation between Gmax and M in order to statistically improve vertebrate scaling regressions on maximum gain in body mass. However, we show here that his mass-specific maximum growth rate (kC) replacing Gmax (= MkC) does not model the expected higher mass gain in larger than in smaller species for any set of species. We also comment on, why we considered extant reptiles and birds as reference models for extinct dinosaurs and why we used phylogenetically-informed regression analysis throughout our study. Finally, we question several arguments given in Myhrvold in order to support his results.

  16. Does basal metabolic rate contain a useful signal? Mammalian BMR allometry and correlations with a selection of physiological, ecological, and life-history variables.

    Science.gov (United States)

    White, Craig R; Seymour, Roger S

    2004-01-01

    Basal metabolic rate (BMR, mL O2 h(-1)) is a useful measurement only if standard conditions are realised. We present an analysis of the relationship between mammalian body mass (M, g) and BMR that accounts for variation associated with body temperature, digestive state, and phylogeny. In contrast to the established paradigm that BMR proportional to M3/4, data from 619 species, representing 19 mammalian orders and encompassing five orders of magnitude variation in M, show that BMR proportional to M2/3. If variation associated with body temperature and digestive state are removed, the BMRs of eutherians, marsupials, and birds do not differ, and no significant allometric exponent heterogeneity remains between orders. The usefulness of BMR as a general measurement is supported by the observation that after the removal of body mass effects, the residuals of BMR are significantly correlated with the residuals for a variety of physiological and ecological variables, including maximum metabolic rate, field metabolic rate, resting heart rate, life span, litter size, and population density.

  17. Allometries of maximum growth rate versus body mass at maximum growth indicate that non-avian dinosaurs had growth rates typical of fast growing ectothermic sauropsids.

    Science.gov (United States)

    Werner, Jan; Griebeler, Eva Maria

    2014-01-01

    We tested if growth rates of recent taxa are unequivocally separated between endotherms and ectotherms, and compared these to dinosaurian growth rates. We therefore performed linear regression analyses on the log-transformed maximum growth rate against log-transformed body mass at maximum growth for extant altricial birds, precocial birds, eutherians, marsupials, reptiles, fishes and dinosaurs. Regression models of precocial birds (and fishes) strongly differed from Case's study (1978), which is often used to compare dinosaurian growth rates to those of extant vertebrates. For all taxonomic groups, the slope of 0.75 expected from the Metabolic Theory of Ecology was statistically supported. To compare growth rates between taxonomic groups we therefore used regressions with this fixed slope and group-specific intercepts. On average, maximum growth rates of ectotherms were about 10 (reptiles) to 20 (fishes) times (in comparison to mammals) or even 45 (reptiles) to 100 (fishes) times (in comparison to birds) lower than in endotherms. While on average all taxa were clearly separated from each other, individual growth rates overlapped between several taxa and even between endotherms and ectotherms. Dinosaurs had growth rates intermediate between similar sized/scaled-up reptiles and mammals, but a much lower rate than scaled-up birds. All dinosaurian growth rates were within the range of extant reptiles and mammals, and were lower than those of birds. Under the assumption that growth rate and metabolic rate are indeed linked, our results suggest two alternative interpretations. Compared to other sauropsids, the growth rates of studied dinosaurs clearly indicate that they had an ectothermic rather than an endothermic metabolic rate. Compared to other vertebrate growth rates, the overall high variability in growth rates of extant groups and the high overlap between individual growth rates of endothermic and ectothermic extant species make it impossible to rule out either of the two thermoregulation strategies for studied dinosaurs.

  18. Did saber-tooth kittens grow up musclebound? A study of postnatal limb bone allometry in felids from the Pleistocene of Rancho La Brea.

    Science.gov (United States)

    Long, Katherine; Prothero, Donald; Madan, Meena; Syverson, Valerie J P

    2017-01-01

    Previous studies have demonstrated that the Pleistocene saber-toothed cat Smilodon fatalis had many forelimb adaptations for increased strength, presumably to grapple with and subdue prey. The Rancho La Brea tar pits yield large samples of juvenile limb bones forming a growth series that allow us to examine how Smilodon kittens grew up. Almost all available juvenile limb bones were measured, and reduced major axis fits were calculated to determine the allometric growth trends. Contrary to expectations based on their robust limbs, Smilodon kittens show the typical pattern of growth found in other large felids (such as the Ice Age lion, Panthera atrox, as well as living tigers, cougars, servals, and wildcats) where the limb grows longer and more slender faster than they grow thick. This adaptation is thought to give felids greater running speed. Smilodon kittens do not grow increasingly more robust with age. Instead, they start out robust and follow the ancestral felid growth pattern, while maintaining their robustness compared to other felids. Apparently, the growth of felid forelimbs is highly canalized and their ontogeny is tightly constrained.

  19. Allometries of maximum growth rate versus body mass at maximum growth indicate that non-avian dinosaurs had growth rates typical of fast growing ectothermic sauropsids.

    Directory of Open Access Journals (Sweden)

    Jan Werner

    Full Text Available We tested if growth rates of recent taxa are unequivocally separated between endotherms and ectotherms, and compared these to dinosaurian growth rates. We therefore performed linear regression analyses on the log-transformed maximum growth rate against log-transformed body mass at maximum growth for extant altricial birds, precocial birds, eutherians, marsupials, reptiles, fishes and dinosaurs. Regression models of precocial birds (and fishes strongly differed from Case's study (1978, which is often used to compare dinosaurian growth rates to those of extant vertebrates. For all taxonomic groups, the slope of 0.75 expected from the Metabolic Theory of Ecology was statistically supported. To compare growth rates between taxonomic groups we therefore used regressions with this fixed slope and group-specific intercepts. On average, maximum growth rates of ectotherms were about 10 (reptiles to 20 (fishes times (in comparison to mammals or even 45 (reptiles to 100 (fishes times (in comparison to birds lower than in endotherms. While on average all taxa were clearly separated from each other, individual growth rates overlapped between several taxa and even between endotherms and ectotherms. Dinosaurs had growth rates intermediate between similar sized/scaled-up reptiles and mammals, but a much lower rate than scaled-up birds. All dinosaurian growth rates were within the range of extant reptiles and mammals, and were lower than those of birds. Under the assumption that growth rate and metabolic rate are indeed linked, our results suggest two alternative interpretations. Compared to other sauropsids, the growth rates of studied dinosaurs clearly indicate that they had an ectothermic rather than an endothermic metabolic rate. Compared to other vertebrate growth rates, the overall high variability in growth rates of extant groups and the high overlap between individual growth rates of endothermic and ectothermic extant species make it impossible to rule out either of the two thermoregulation strategies for studied dinosaurs.

  20. Controversy in the allometric application of fixed- versus varying-exponent models: a statistical and mathematical perspective.

    Science.gov (United States)

    Tang, Huadong; Hussain, Azher; Leal, Mauricio; Fluhler, Eric; Mayersohn, Michael

    2011-02-01

    This commentary is a reply to a recent article by Mahmood commenting on the authors' article on the use of fixed-exponent allometry in predicting human clearance. The commentary discusses eight issues that are related to criticisms made in Mahmood's article and examines the controversies (fixed-exponent vs. varying-exponent allometry) from the perspective of statistics and mathematics. The key conclusion is that any allometric method, which is to establish a power function based on a limited number of animal species and to extrapolate the resulting power function to human values (varying-exponent allometry), is infused with fundamental statistical errors. Copyright © 2010 Wiley-Liss, Inc.

  1. Generations of the polyphenic butterfly Araschnia levana differ in body desing

    Czech Academy of Sciences Publication Activity Database

    Fric, Z.; Konvička, Martin

    2002-01-01

    Roč. 4, - (2002), s. 1017-1032 ISSN 1522-0613 Institutional research plan: CEZ:AV0Z5007907 Keywords : allometry * biomechanical desing * canonical variate analysis Subject RIV: EG - Zoology Impact factor: 1.382, year: 2002

  2. Taylor's law and body size in exploited marine ecosystems.

    Science.gov (United States)

    Cohen, Joel E; Plank, Michael J; Law, Richard

    2012-12-01

    Taylor's law (TL), which states that variance in population density is related to mean density via a power law, and density-mass allometry, which states that mean density is related to body mass via a power law, are two of the most widely observed patterns in ecology. Combining these two laws predicts that the variance in density is related to body mass via a power law (variance-mass allometry). Marine size spectra are known to exhibit density-mass allometry, but variance-mass allometry has not been investigated. We show that variance and body mass in unexploited size spectrum models are related by a power law, and that this leads to TL with an exponent slightly <2. These simulated relationships are disrupted less by balanced harvesting, in which fishing effort is spread across a wide range of body sizes, than by size-at-entry fishing, in which only fish above a certain size may legally be caught.

  3. Many ways to be small: different environmental regulators of size generate distinct scaling relationships in Drosophila melanogaster

    OpenAIRE

    Shingleton, Alexander W.; Estep, Chad M.; Driscoll, Michael V.; Dworkin, Ian

    2009-01-01

    Static allometries, the scaling relationship between body and trait size, describe the shape of animals in a population or species, and are generated in response to variation in genetic or environmental regulators of size. In principle, allometries may vary with the different size regulators that generate them, which can be problematic since allometric differences are also used to infer patterns of selection on morphology. We test this hypothesis by examining the patterns of scaling in Drosop...

  4. Testing the cranial evolutionary allometric 'rule' in Galliformes.

    Science.gov (United States)

    Linde-Medina, M

    2016-09-01

    Recent comparative studies have indicated the existence of a common cranial evolutionary allometric (CREA) pattern in mammals and birds, in which smaller species have relatively smaller faces and bigger braincases than larger species. In these studies, cranial allometry was tested using a multivariate regression between shape (described using landmarks coordinates) and size (i.e. centroid size), after accounting for phylogenetic relatedness. Alternatively, cranial allometry can be determined by comparing the sizes of two anatomical parts using a bivariate regression analysis. In this analysis, a slope higher or lower than one indicates the existence of positive or negative allometry, respectively. Thus, in those species that support the CREA 'rule', positive allometry is expected for the association between face size and braincase size, which would indicate that larger species have disproportionally larger faces. In this study, I applied these two approaches to explore cranial allometry in 83 Galliformes (Aves, Galloanserae), ranging in mean body weight from 30 g to 2.5 kg. The multivariate regression between shape and centroid size revealed the existence of a significant allometric pattern resembling CREA, whereas the second analysis revealed a negative allometry for beak size and braincase size (i.e. contrary to the CREA 'rule', larger galliform species have disproportionally shorter beaks than smaller galliform species). This study suggests that the presence of CREA may be overestimated when using cranium size as the standard measurement. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  5. Evolution of extreme ontogenetic allometric diversity and heterochrony in pythons, a clade of giant and dwarf snakes.

    Science.gov (United States)

    Esquerré, Damien; Sherratt, Emma; Keogh, J Scott

    2017-12-01

    Ontogenetic allometry, how species change with size through their lives, and heterochony, a decoupling between shape, size, and age, are major contributors to biological diversity. However, macroevolutionary allometric and heterochronic trends remain poorly understood because previous studies have focused on small groups of closely related species. Here, we focus on testing hypotheses about the evolution of allometry and how allometry and heterochrony drive morphological diversification at the level of an entire species-rich and diverse clade. Pythons are a useful system due to their remarkably diverse and well-adapted phenotypes and extreme size disparity. We collected detailed phenotype data on 40 of the 44 species of python from 1191 specimens. We used a suite of analyses to test for shifts in allometric trajectories that modify morphological diversity. Heterochrony is the main driver of initial divergence within python clades, and shifts in the slopes of allometric trajectories make exploration of novel phenotypes possible later in divergence history. We found that allometric coefficients are highly evolvable and there is an association between ontogenetic allometry and ecology, suggesting that allometry is both labile and adaptive rather than a constraint on possible phenotypes. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  6. Crescimento relativo do camarão canela Macrobrachium amazonicum (Heller (Crustacea, Decapoda, Palaemonidae em viveiros Relative growth of Amazon river prawn Macrobrachium amazonicum (Heller (Crustacea, Decapoda, Palaemonidae in earthen ponds

    Directory of Open Access Journals (Sweden)

    Patrícia M.C. Moraes-Riodades

    2002-12-01

    Full Text Available Some morphometric relationships in Macrobrachium amazonicum (Heller, 1862 reared in earthen ponds were studied. A total of 239 individuals were collected, sexed and sorted to juvenile or adult. Total length (Lt, post-orbital length (Lpo, carapace length (Lcp and queliped length (Lql were measured. The relationships Lt/Lpo, Lpo/Lcp and Lt/Lcp are the same for juveniles, males and females, indicating unchanged growth pattern during post-larval ontogenetic development. While Lt/Lpo showed isometric growth, Lpo/Lcp and Lt/Lcp showed negative allometry. On the other hand, for the Lql/Lcp relationship, juveniles showed isometric growth, females slight positive allometry and males a strong positive allometry. It suggests that the importance of chelipeds may be different in these groups. Quelipeds play important role on food capture and on agonistic, social and reproductive behavior. Therefore, inter and intraspecific interactions may change during prawn growth, even after morphological

  7. Wind loads and competition for light sculpt trees into self-similar structures.

    Science.gov (United States)

    Eloy, Christophe; Fournier, Meriem; Lacointe, André; Moulia, Bruno

    2017-10-18

    Trees are self-similar structures: their branch lengths and diameters vary allometrically within the tree architecture, with longer and thicker branches near the ground. These tree allometries are often attributed to optimisation of hydraulic sap transport and safety against elastic buckling. Here, we show that these allometries also emerge from a model that includes competition for light, wind biomechanics and no hydraulics. We have developed MECHATREE, a numerical model of trees growing and evolving on a virtual island. With this model, we identify the fittest growth strategy when trees compete for light and allocate their photosynthates to grow seeds, create new branches or reinforce existing ones in response to wind-induced loads. Strikingly, we find that selected trees species are self-similar and follow allometric scalings similar to those observed on dicots and conifers. This result suggests that resistance to wind and competition for light play an essential role in determining tree allometries.

  8. Scaling of Haversian canal surface area to secondary osteon bone volume in ribs and limb bones.

    Science.gov (United States)

    Skedros, John G; Knight, Alex N; Clark, Gunnar C; Crowder, Christian M; Dominguez, Victoria M; Qiu, Shijing; Mulhern, Dawn M; Donahue, Seth W; Busse, Björn; Hulsey, Brannon I; Zedda, Marco; Sorenson, Scott M

    2013-06-01

    Studies of secondary osteons in ribs have provided a great deal of what is known about remodeling dynamics. Compared with limb bones, ribs are metabolically more active and sensitive to hormonal changes, and receive frequent low-strain loading. Optimization for calcium exchange in rib osteons might be achieved without incurring a significant reduction in safety factor by disproportionally increasing central canal size with increased osteon size (positive allometry). By contrast, greater mechanical loads on limb bones might favor reducing deleterious consequences of intracortical porosity by decreasing osteon canal size with increased osteon size (negative allometry). Evidence of this metabolic/mechanical dichotomy between ribs and limb bones was sought by examining relationships between Haversian canal surface area (BS, osteon Haversian canal perimeter, HC.Pm) and bone volume (BV, osteonal wall area, B.Ar) in a broad size range of mature (quiescent) osteons from adult human limb bones and ribs (modern and medieval) and various adult and subadult non-human limb bones and ribs. Reduced major axis (RMA) and least-squares (LS) regressions of HC.Pm/B.Ar data show that rib and limb osteons cannot be distinguished by dimensional allometry of these parameters. Although four of the five rib groups showed positive allometry in terms of the RMA slopes, nearly 50% of the adult limb bone groups also showed positive allometry when negative allometry was expected. Consequently, our results fail to provide clear evidence that BS/BV scaling reflects a rib versus limb bone dichotomy whereby calcium exchange might be preferentially enhanced in rib osteons. Copyright © 2013 Wiley Periodicals, Inc.

  9. An allometric scaling relation based on logistic growth of cities

    International Nuclear Information System (INIS)

    Chen, Yanguang

    2014-01-01

    Highlights: • An allometric scaling based on logistic process can be used to model urban growth. • The traditional allometry is based on exponential growth instead of logistic growth. • The exponential allometry represents a local scaling of urban growth. • The logistic allometry represents a global scaling of urban growth. • The exponential allometry is an approximation relation of the logistic allometry. - Abstract: The relationships between urban area and population size have been empirically demonstrated to follow the scaling law of allometric growth. This allometric scaling is based on exponential growth of city size and can be termed “exponential allometry”, which is associated with the concepts of fractals. However, both city population and urban area comply with the course of logistic growth rather than exponential growth. In this paper, I will present a new allometric scaling based on logistic growth to solve the above mentioned problem. The logistic growth is a process of replacement dynamics. Defining a pair of replacement quotients as new measurements, which are functions of urban area and population, we can derive an allometric scaling relation from the logistic processes of urban growth, which can be termed “logistic allometry”. The exponential allometric relation between urban area and population is the approximate expression of the logistic allometric equation when the city size is not large enough. The proper range of the allometric scaling exponent value is reconsidered through the logistic process. Then, a medium-sized city of Henan Province, China, is employed as an example to validate the new allometric relation. The logistic allometry is helpful for further understanding the fractal property and self-organized process of urban evolution in the right perspective

  10. Does Serranochromis altus (Teleostei: Cichlidae) exist in the ...

    African Journals Online (AJOL)

    Genetic and interspecific divergence in allometry between S. altus and S. angusticeps were non-significant. It was initially thought that these fishes represented different life stages of S. angusticeps. However, we found fish of different sizes, yet with similar ages, representing both species. More accurate age/size and other ...

  11. The three-quarter power scaling of extinction risk in Late Pleistocene mammals, and a new theory of the size selectivity of extinction

    NARCIS (Netherlands)

    Polishchuk, L.

    2010-01-01

    Questions: What is the pattern of body mass versus extinction risk in the Late Pleistocene extinctions of mammals, both qualitatively and quantitatively? Are there patterns that relate extinction risk to the well-known allometries of body mass with population density or population growth rate?

  12. The quarter-power scaling model does not imply size-invariant hydraulic resistance in plants

    Science.gov (United States)

    Annikki Makela; Harry T. Valentine

    2006-01-01

    West, Brown, and Enquist (1997, 1999) propose an integrated model of the structure and allometry of plant vascular systems, which has come to be known as the 'WBE model' (Enquist, 2002). The WBE model weaves together area-preserving branching (Leonardo da Vinci), elastic similarity (Greenhill, 1881), the constant ratio of foliage mass to sapwood area (...

  13. Shape shifting predicts ontogenetic changes in metabolic scaling in diverse aquatic invertebrates

    DEFF Research Database (Denmark)

    Glazier, Douglas S.; Hirst, Andrew G.; Atkinson, D.

    2016-01-01

    in metabolic scaling that deviate from 3/4-power scaling predicted by general models. Here, we show that in diverse aquatic invertebrates, ontogenetic shifts in the scaling of routine metabolic rate from near isometry (bR = scaling exponent approx. 1) to negative allometry (bR

  14. Shrinkage of body size of small insects: A possible link to global warming?

    International Nuclear Information System (INIS)

    He Jihuan

    2007-01-01

    The increase of global mean surface temperature leads to the increase of metabolic rate. This might lead to an unexpected threat from the small insect world. Global warming shrinks cell size, shorten lifespan, and accelerate evolution. The present note speculates on possible connections between allometry and E-infinity theory

  15. Allometric relationship and biomass expansion factors (BEFs) for above- and below-ground biomass prediction and stem volume estimation for ash (Fraxinus excelsior L.) and oak (Quercus robur L.)

    Czech Academy of Sciences Publication Activity Database

    Krejza, Jan; Světlík, J.; Bednář, P.

    2017-01-01

    Roč. 31, č. 4 (2017), s. 1303-1316 ISSN 0931-1890 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : floodplain forest * root biomass * leaf biomass * branch biomass * shoot biomass * Allometry * stem volume * biomass expansion factor Subject RIV: GK - Forestry OBOR OECD: Forestry Impact factor: 1.842, year: 2016

  16. Critical wind speed at which trees break

    Science.gov (United States)

    Virot, E.; Ponomarenko, A.; Dehandschoewercker, É.; Quéré, D.; Clanet, C.

    2016-02-01

    Data from storms suggest that the critical wind speed at which trees break is constant (≃42 m /s ), regardless of tree characteristics. We question the physical origin of this observation both experimentally and theoretically. By combining Hooke's law, Griffith's criterion, and tree allometry, we show that the critical wind speed indeed hardly depends on the height, diameter, and elastic properties of trees.

  17. Allometric relationships for surface area and dry mass of young Norway spruce aboveground organs

    Czech Academy of Sciences Publication Activity Database

    Pokorný, Radek; Tomášková, Ivana

    53 2007, č. 12 (2007), s. 548-554 ISSN 1212-4834 R&D Projects: GA MŽP(CZ) SP/2D1/93/07 Institutional research plan: CEZ:AV0Z60870520 Keywords : allometry * biomass, * Picea abies * sapwood * surface area Subject RIV: GK - Forestry

  18. Skull size and shape variation in Psammomys spp. (Rodentia ...

    African Journals Online (AJOL)

    This finding might explain the uncertainty in classification of these species in the past. The interspecific allometric-free phenotypic differences observed may be associated with adaptive processes linked to the different environmental and trophic preferences of the two species. Keywords: allometry, cranium, geometric ...

  19. Comment on "Evidence for mesothermy in dinosaurs".

    Science.gov (United States)

    Myhrvold, Nathan P

    2015-05-29

    Grady et al. (Reports, 13 June 2014, p. 1268) studied dinosaur metabolism by comparison of maximum somatic growth rate allometry with groups of known metabolism. They concluded that dinosaurs exhibited mesothermy, a metabolic rate intermediate between endothermy and ectothermy. Multiple statistical and methodological issues call into question the evidence for dinosaur mesothermy. Copyright © 2015, American Association for the Advancement of Science.

  20. Strength profile in young male athletes from different sports

    Directory of Open Access Journals (Sweden)

    Buśko Krzysztof

    2013-12-01

    Full Text Available Study aim: The aim of the present study was to determine a strength profile which characterizes young male athletes from different sports and to use the method of allometry to synthetically evaluate the muscular strength with respect to body mass.

  1. Genomewide Association Study of African Children Identifies Association of SCHIP1 and PDE8A with Facial Size and Shape

    Czech Academy of Sciences Publication Activity Database

    Cole, J.B.; Manyama, M.; Kimwaga, E.; Mathayo, J.; Larson, J.R.; Liberton, D.K.; Lukowiak, K.; Ferrara, T.M.; Riccardi, S.L.; Li, M.; Mio, W.; Procházková, Michaela; Williams, T.; Li, H.; Jones, K. L.; Klein, O. D.; Santorico, S.A.; Hallgrimsson, B.; Spritz, R.A.

    2016-01-01

    Roč. 12, č. 8 (2016), č. článku e1006174. ISSN 1553-7404 Institutional support: RVO:68378050 Keywords : cause char-syndrome * wide association * phosphodiesterase 8a * heritability * recognition * mutations * allometry * variants * parents Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.100, year: 2016

  2. Critical wind speed at which trees break.

    Science.gov (United States)

    Virot, E; Ponomarenko, A; Dehandschoewercker, É; Quéré, D; Clanet, C

    2016-02-01

    Data from storms suggest that the critical wind speed at which trees break is constant (≃42m/s), regardless of tree characteristics. We question the physical origin of this observation both experimentally and theoretically. By combining Hooke's law, Griffith's criterion, and tree allometry, we show that the critical wind speed indeed hardly depends on the height, diameter, and elastic properties of trees.

  3. Phenomenological approach to describe logistic growth and ...

    Indian Academy of Sciences (India)

    In this communication, different classes of phenomenological universalities of carrying capacity dependent growth processes have been proposed. The logistic as well as carrying capacity-dependent West-type allometry-based biological growths can be explained in this proposed framework. It is shown that logistic and ...

  4. Modelling dimensional growth of three street tree species in the ...

    African Journals Online (AJOL)

    The results could also be used in the process of modelling energy use reduction, air pollution uptake, rainfall interception, carbon sequestration and microclimate modification of urban forests such as those found in the City of Tshwane. Keywords: allometry; regression; size relationships; tree growth; urban forests. Southern ...

  5. Breaking Haller's rule: brain-body size isometry in a minute parasitic wasp.

    NARCIS (Netherlands)

    Woude, van der E.; Smid, H.M.; Chittka, L.; Huigens, M.E.

    2013-01-01

    Throughout the animal kingdom, Haller's rule holds that smaller individuals have larger brains relative to their body than larger-bodied individuals. Such brain-body size allometry is documented for all animals studied to date, ranging from small ants to the largest mammals. However, through

  6. Scale effects between body size and limb design in quadrupedal mammals.

    Science.gov (United States)

    Kilbourne, Brandon M; Hoffman, Louwrens C

    2013-01-01

    Recently the metabolic cost of swinging the limbs has been found to be much greater than previously thought, raising the possibility that limb rotational inertia influences the energetics of locomotion. Larger mammals have a lower mass-specific cost of transport than smaller mammals. The scaling of the mass-specific cost of transport is partly explained by decreasing stride frequency with increasing body size; however, it is unknown if limb rotational inertia also influences the mass-specific cost of transport. Limb length and inertial properties--limb mass, center of mass (COM) position, moment of inertia, radius of gyration, and natural frequency--were measured in 44 species of terrestrial mammals, spanning eight taxonomic orders. Limb length increases disproportionately with body mass via positive allometry (length ∝ body mass(0.40)); the positive allometry of limb length may help explain the scaling of the metabolic cost of transport. When scaled against body mass, forelimb inertial properties, apart from mass, scale with positive allometry. Fore- and hindlimb mass scale according to geometric similarity (limb mass ∝ body mass(1.0)), as do the remaining hindlimb inertial properties. The positive allometry of limb length is largely the result of absolute differences in limb inertial properties between mammalian subgroups. Though likely detrimental to locomotor costs in large mammals, scale effects in limb inertial properties appear to be concomitant with scale effects in sensorimotor control and locomotor ability in terrestrial mammals. Across mammals, the forelimb's potential for angular acceleration scales according to geometric similarity, whereas the hindlimb's potential for angular acceleration scales with positive allometry.

  7. Improving estimation of tree carbon stocks by harvesting aboveground woody biomass within airborne LiDAR flight areas

    Science.gov (United States)

    Colgan, M.; Asner, G. P.; Swemmer, A. M.

    2011-12-01

    The accurate estimation of carbon stored in a tree is essential to accounting for the carbon emissions due to deforestation and degradation. Airborne LiDAR (Light Detection and Ranging) has been successful in estimating aboveground carbon density (ACD) by correlating airborne metrics, such as canopy height, to field-estimated biomass. This latter step is reliant on field allometry which is applied to forest inventory quantities, such as stem diameter and height, to predict the biomass of a given tree stem. Constructing such allometry is expensive, time consuming, and requires destructive sampling. Consequently, the sample sizes used to construct such allometry are often small, and the largest tree sampled is often much smaller than the largest in the forest population. The uncertainty resulting from these sampling errors can lead to severe biases when the allometry is applied to stems larger than those harvested to construct the allometry, which is then subsequently propagated to airborne ACD estimates. The Kruger National Park (KNP) mission of maintaining biodiversity coincides with preserving ecosystem carbon stocks. However, one hurdle to accurately quantifying carbon density in savannas is that small stems are typically harvested to construct woody biomass allometry, yet they are not representative of Kruger's distribution of biomass. Consequently, these equations inadequately capture large tree variation in sapwood/hardwood composition, root/shoot/leaf allocation, branch fall, and stem rot. This study eliminates the "middleman" of field allometry by directly measuring, or harvesting, tree biomass within the extent of airborne LiDAR. This enables comparisons of field and airborne ACD estimates, and also enables creation of new airborne algorithms to estimate biomass at the scale of individual trees. A field campaign was conducted at Pompey Silica Mine 5km outside Kruger National Park, South Africa, in Mar-Aug 2010 to harvest and weigh tree mass. Since

  8. Sexual differences in size and shape of the Mosor rock lizard [Dinarolacerta mosorensis (Kolombatović, 1886] (squamata: lacertidae: A case study of the Lovćen mountain population (Montenegro

    Directory of Open Access Journals (Sweden)

    Ljubisavljević Katarina

    2008-01-01

    Full Text Available Sexual differences in size and shape of the Mosor rock lizard, Dinarolacerta mosorensis (Kolombatović, 1886, from Lovćen Mountain (Montenegro were examined on the basis of the intersex variation pattern of nine morphometric, eight pholidotic, and four qualitative traits. Sexual dimorphism was apparent for all morphometric characters except snout-vent length, while scalation and dorsal pattern exhibited small differences between sexes. The value of the sexual size difference (SSD index based on snout-vent length was 1.028. The sex-specific allometric slopes for head dimensions and interlimb distance significantly diverged. Head dimensions, especially head height, showed strong positive allometry in males, while interlimb distance was the only character which showed positive allometry in females. Generally, males had significantly greater body size than females. This was true of all body measurements except interlimb distance. The influence of sexual and natural selection on the examined traits is discussed.

  9. Development of allometric models for above and belowground biomass in swidden cultivation fallows of Northern Laos

    DEFF Research Database (Denmark)

    McNicol, Iain M.; Berry, Nicholas J.; Bruun, Thilde Bech

    2015-01-01

    fields and patches of mature forest. Quantifying tree biomass in these landscapes is limited by the availability of reliable allometric models, hindering accurate carbon stock estimation and thus quantification of GHG emission associated with land use transitions. We therefore developed new allometric...... for each tree type. Thus, we suggest that field efforts should be directed towards checking resprouting status over the estimation of tree height. We also found that models fit using non-linear regression provided equally good fits to the data compared to the traditional approach of log......-transforming the data. Our models were subsequently applied to 12 nearby plots spanning a chronosequence of fallows to examine the impact of re-sprouting allometry on biomass estimation. Root biomass stocks were on average 58% higher after accounting for the allometry of resprouting trees, resulting in an average 9...

  10. Ontogenetic body-mass scaling of nitrogen excretion relates to body surface area in diverse pelagic invertebrates

    DEFF Research Database (Denmark)

    Hirst, Andrew G.; Lilley, M.K.S.; Glazier, D.S.

    2017-01-01

    . Among diverse pelagic invertebrates that change shape during ontogeny, recent analysis has demonstrated a significant positive correlation between the body-mass allometry of respiration rates (measured as the ontogenetic body mass-scaling exponent bR) and the allometry of body surface area (b......A, as predicted from body-shape changes using a Euclidean model). As many pelagic invertebrates use a large portion of their external body surface for both resource uptake and waste excretion, we predicted that body-mass scaling exponents for rates of excretion of soluble N (bN) should also then relate...... to the degree of body-shape change during growth. We tested this hypothesis using literature data on bN for 39 species of pelagic invertebrates across five different phyla, and find strong support: bN is significantly positively correlated with predicted bA, whilst also co-varying with bR. Intraspecific...

  11. Mandibular and cranial modularity in the greater horseshoe bat Rhinolophus ferrumequinum (Chiroptera: Rhinolophidae)

    OpenAIRE

    Jojic, Vida; Budinski, Ivana; Blagojevic, Jelena; Vujosevic, Mladen

    2015-01-01

    We report the first evaluation of mandibular and cranial modularity in the greater horseshoe bat (Rhinolophus ferrumequinum). Although some authors found no modular pattern of these morphological structures in mammals, we discovered that traits integration in R. ferrumequinum is not uniform throughout the mandible and cranium, but structured into two distinct modules. Allometry does not affect mandibular and cranial modularity in R. ferrumequinum probably as a result of the low fraction of sh...

  12. Musculoskeletal determinants of pelvic sucker function in Hawaiian stream gobiid fishes: interspecific comparisons and allometric scaling.

    Science.gov (United States)

    Maie, Takashi; Schoenfuss, Heiko L; Blob, Richard W

    2013-07-01

    Gobiid fishes possess a distinctive ventral sucker, formed from fusion of the pelvic fins. This sucker is used to adhere to a wide range of substrates including, in some species, the vertical cliffs of waterfalls that are climbed during upstream migrations. Previous studies of waterfall-climbing goby species have found that pressure differentials and adhesive forces generated by the sucker increase with positive allometry as fish grow in size, despite isometry or negative allometry of sucker area. To produce such scaling patterns for pressure differential and adhesive force, waterfall-climbing gobies might exhibit allometry for other muscular or skeletal components of the pelvic sucker that contribute to its adhesive function. In this study, we used anatomical dissections and modeling to evaluate the potential for allometric growth in the cross-sectional area, effective mechanical advantage (EMA), and force generating capacity of major protractor and retractor muscles of the pelvic sucker (m. protractor ischii and m. retractor ischii) that help to expand the sealed volume of the sucker to produce pressure differentials and adhesive force. We compared patterns for three Hawaiian gobiid species: a nonclimber (Stenogobius hawaiiensis), an ontogenetically limited climber (Awaous guamensis), and a proficient climber (Sicyopterus stimpsoni). Scaling patterns were relatively similar for all three species, typically exhibiting isometric or negatively allometric scaling for the muscles and lever systems examined. Although these scaling patterns do not help to explain the positive allometry of pressure differentials and adhesive force as climbing gobies grow, the best climber among the species we compared, S. stimpsoni, does exhibit the highest calculated estimates of EMA, muscular input force, and output force for pelvic sucker retraction at any body size, potentially facilitating its adhesive ability. Copyright © 2013 Wiley Periodicals, Inc.

  13. Evolution of parental incubation behaviour in dinosaurs cannot be inferred from clutch mass in birds

    OpenAIRE

    Birchard, Geoffrey F.; Ruta, Marcello; Deeming, D. Charles

    2013-01-01

    A recent study proposed that incubation behaviour (i.e. type of parental care) in theropod dinosaurs can be inferred from an allometric analysis of clutch volume in extant birds. However, the study in question failed to account for factors known to affect egg and clutch size in living bird species. A new scaling analysis of avian clutch mass demonstrates that type of parental care cannot be distinguished by conventional allometry because of the confounding effects of phylogeny and hatchling m...

  14. Soil resource supply influences faunal size?specific distributions in natural food webs

    OpenAIRE

    Mulder, Christian; Den Hollander, Henri A.; Vonk, J. Arie; Rossberg, Axel G.; Jagers op Akkerhuis, Gerard A. J. M.; Yeates, Gregor W.

    2009-01-01

    The large range of body-mass values of soil organisms provides a tool to assess the ecological organization of soil communities. The goal of this paper is to identify graphical and quantitative indicators of soil community composition and ecosystem functioning, and to illustrate their application to real soil food webs. The relationships between log-transformed mass and abundance of soil organisms in 20 Dutch meadows and heathlands were investigated. Using principles of allometry, maximal use...

  15. REGULATION OF CARBON SEQUESTRATION AND WATER USE IN A OZARK FOREST: PROPOSING A NEW STRATEGICALLY LOCATED AMERIFLUX TOWER SITE IN MISSOURI

    Energy Technology Data Exchange (ETDEWEB)

    Pallardy, Stephen G

    2013-04-19

    by June 14, 2004, the MOFLUX site was fully instrumented and data streams started to flow. A primary accomplished deliverable for the project period was the data streams of CO{sub 2} and water vapor fluxes and numerous meteorological variables (from which prepared datasets have been submitted to the AmeriFlux data archive for 2004-2006, Additionally, measurements of leaf biochemistry and physiology, biomass inventory, tree allometry, successional trends other variables were obtained.

  16. Bite of the cats: relationships between functional integration and mechanical performance as revealed by mandible geometry.

    Science.gov (United States)

    Piras, Paolo; Maiorino, Leonardo; Teresi, Luciano; Meloro, Carlo; Lucci, Federico; Kotsakis, Tassos; Raia, Pasquale

    2013-11-01

    Cat-like carnivorous mammals represent a relatively homogeneous group of species whose morphology appears constrained by exclusive adaptations for meat eating. We present the most comprehensive data set of extant and extinct cat-like species to test for evolutionary transformations in size, shape and mechanical performance, that is, von Mises stress and surface traction, of the mandible. Size and shape were both quantified by means of geometric morphometrics, whereas mechanical performance was assessed applying finite element models to 2D geometry of the mandible. Additionally, we present the first almost complete composite phylogeny of cat-like carnivorans for which well-preserved mandibles are known, including representatives of 35 extant and 59 extinct species of Felidae, Nimravidae, and Barbourofelidae. This phylogeny was used to test morphological differentiation, allometry, and covariation of mandible parts within and among clades. After taking phylogeny into account, we found that both allometry and mechanical variables exhibit a significant impact on mandible shape. We also tested whether mechanical performance was linked to morphological integration. Mechanical stress at the coronoid process is higher in sabertoothed cats than in any other clade. This is strongly related to the high degree of covariation within modules of sabertooths mandibles. We found significant correlation between integration at the clade level and per-clade averaged stress values, on both original data and by partialling out interclade allometry from shapes when calculating integration. This suggests a strong interaction between natural selection and the evolution of developmental and functional modules at the clade level.

  17. Developmental origin of limb size variation in lizards.

    Science.gov (United States)

    Andrews, Robin M; Skewes, Sable A

    2017-05-01

    In many respects, reptile hatchlings are fully functional, albeit miniature, adults. This means that the adult morphology must emerge during embryonic development. This insight emphasizes the connection between the mechanisms that generate phenotypic variation during embryonic development and the action of selection on post-hatching individuals. To determine when species-specific differences in limb and tail lengths emerge during embryonic development, we compared allometric patterns of early limb growth of four distantly related species of lizards. The major questions addressed were whether early embryonic limb and tail growth is characterized by the gradual (continuous allometry) or by the abrupt emergence (transpositional allometry) of size differences among species. Our observations supported transpositional allometry of both limbs and tails. Species-specific differences in limb and tail length were exhibited when limb and tail buds first protruded from the body wall. Genes known to be associated with early limb development of tetrapods are obvious targets for studies on the genetic mechanisms that determine interspecific differences in relative limb length. Broadly comparative studies of gene regulation would facilitate understanding of the mechanisms underlying adaptive variation in limb size, including limb reduction and loss, of squamate reptiles. © 2017 Wiley Periodicals, Inc.

  18. An allometric scaling relation based on logistic growth of cities

    Science.gov (United States)

    Chen, Yanguang

    2014-08-01

    The relationships between urban area and population size have been empirically demonstrated to follow the scaling law of allometric growth. This allometric scaling is based on exponential growth of city size and can be termed "exponential allometry", which is associated with the concepts of fractals. However, both city population and urban area comply with the course of logistic growth rather than exponential growth. In this paper, I will present a new allometric scaling based on logistic growth to solve the abovementioned problem. The logistic growth is a process of replacement dynamics. Defining a pair of replacement quotients as new measurements, which are functions of urban area and population, we can derive an allometric scaling relation from the logistic processes of urban growth, which can be termed "logistic allometry". The exponential allometric relation between urban area and population is the approximate expression of the logistic allometric equation when the city size is not large enough. The proper range of the allometric scaling exponent value is reconsidered through the logistic process. Then, a medium-sized city of Henan Province, China, is employed as an example to validate the new allometric relation. The logistic allometry is helpful for further understanding the fractal property and self-organized process of urban evolution in the right perspective.

  19. Maintenance cost, toppling risk and size of trees in a self-thinning stand.

    Science.gov (United States)

    Larjavaara, Markku

    2010-07-07

    Wind routinely topples trees during storms, and the likelihood that a tree is toppled depends critically on its allometry. Yet none of the existing theories to explain tree allometry consider wind drag on tree canopies. Since leaf area index in crowded, self-thinning stands is independent of stand density, the drag force per unit land can also be assumed to be independent of stand density, with only canopy height influencing the total toppling moment. Tree stem dimensions and the self-thinning biomass can then be computed by further assuming that the risk of toppling over and stem maintenance per unit land area are independent of stand density, and that stem maintenance cost is a linear function of stem surface area and sapwood volume. These assumptions provide a novel way to understand tree allometry and lead to a self-thinning line relating tree biomass and stand density with a power between -3/2 and -2/3 depending on the ratio of maintenance of sapwood and stem surface. (c) 2010 Elsevier Ltd. All rights reserved.

  20. Interspecific scaling patterns of talar articular surfaces within primates and their closest living relatives

    Science.gov (United States)

    Yapuncich, Gabriel S; Boyer, Doug M

    2014-01-01

    The articular facets of interosseous joints must transmit forces while maintaining relatively low stresses. To prevent overloading, joints that transmit higher forces should therefore have larger facet areas. The relative contributions of body mass and muscle-induced forces to joint stress are unclear, but generate opposing hypotheses. If mass-induced forces dominate, facet area should scale with positive allometry to body mass. Alternatively, muscle-induced forces should cause facets to scale isometrically with body mass. Within primates, both scaling patterns have been reported for articular surfaces of the femoral and humeral heads, but more distal elements are less well studied. Additionally, examination of complex articular surfaces has largely been limited to linear measurements, so that ‘true area' remains poorly assessed. To re-assess these scaling relationships, we examine the relationship between body size and articular surface areas of the talus. Area measurements were taken from microCT scan-generated surfaces of all talar facets from a comprehensive sample of extant euarchontan taxa (primates, treeshrews, and colugos). Log-transformed data were regressed on literature-derived log-body mass using reduced major axis and phylogenetic least squares regressions. We examine the scaling patterns of muscle mass and physiological cross-sectional area (PCSA) to body mass, as these relationships may complicate each model. Finally, we examine the scaling pattern of hindlimb muscle PCSA to talar articular surface area, a direct test of the effect of mass-induced forces on joint surfaces. Among most groups, there is an overall trend toward positive allometry for articular surfaces. The ectal (= posterior calcaneal) facet scales with positive allometry among all groups except ‘sundatherians', strepsirrhines, galagids, and lorisids. The medial tibial facet scales isometrically among all groups except lemuroids. Scaling coefficients are not correlated with sample

  1. Body size-dependent Cd accumulation in the zebra mussel Dreissena polymorpha from different routes.

    Science.gov (United States)

    Tang, Wen-Li; Evans, Douglas; Kraemer, Lisa; Zhong, Huan

    2017-02-01

    Understanding body size-dependent metal accumulation in aquatic organisms (i.e., metal allometry) is critical in interpreting biomonitoring data. While growth has received the most attention, little is known about controls of metal exposure routes on metal allometry. Here, size-dependent Cd accumulation in zebra mussels (Dreissena polymorpha) from different routes were investigated by exposing mussels to A.( 111 Cd spiked algae+ 113 Cd spiked river water) or B.( 111 Cd spiked sediments+ 113 Cd spiked river water). After exposure, 111 Cd or 113 Cd levels in mussel tissue were found to be negatively correlated with tissue weight, while Cd allometry coefficients (b values) were dependent on Cd exposure routes: -0.664 for algae, -0.241 for sediments and -0.379 for river water, compared to -0.582 in un-exposed mussels. By comparing different Cd exposure routes, we found that size-dependent Cd bioaccumulation from algae or river water could be more responsible for the overall size-dependent Cd accumulation in mussels, and the relative importance of the two sources was dependent on mussel size ranges: Cadmium obtained from algae (algae-Cd) was more important in size-dependent Cd accumulation in smaller mussels (tissue dry weight  5 mg). In contrast, sediment-Cd contributed only a small amount to Cd accumulation in zebra mussels and may have little effect on size-dependent Cd bioaccumulation. Our results suggest that size-dependent Cd accumulation in mussels could be largely affected by exposure routes, which should be considered when trying to interpret Cd biomonitoring data of zebra mussels. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Sexual dimorphism and inter-individual variation in the rove beetle, Creophilus maxillosus L. (Col: Staphylinidae

    Directory of Open Access Journals (Sweden)

    Mohammad Shahbaz

    2017-12-01

    Full Text Available Sexual selection is expected to drive phenotypic differences between conspecific male and females, a widespread phenomenon known as sexual dimorphism. At the same time, individuals may exhibit some degree of intra-sexual variation. We examined the sexual dimorphism and inter-individual variation in different body parts of Creophilus maxillosus L. (Col: Staphylinidae, a cosmopolitan rove beetle commonly found on carrion. Male C. maxillosus had significantly wider head and pronotum, longer mandibles, and more distant eyes than females. The head width was positively correlated to mandible length, which may reflect stronger adductor muscles and higher bite force in larger individuals. The allometry of traits can be examined by plotting the logarithms of that specific trait against the logarithm of body size and determining the slope (b of the regression line. Isometry occurs when b=1, i.e. the ratio of given traits to body size remains constant across individuals. Negative allometry occurs when b1, so that larger individuals have disproportionately larger traits. A positive allometry was found in head width (b=1.32, mandible length (b=2.28, and ocular distance (b=1.49 of males. Our results show that, particularly head size, mandible length and ocular distance are probably under sexual selection in males, while traits such as eye size are isometric to body size. The potential role of these traits in male-male combat as well as female attractiveness has been frequently documented in different insect taxa. The striking similarities in patterns of sexual dimorphism among independently evolved insects indicate that common evolutionary force(s are probably at work.

  3. The scaling of tongue projection in the veiled chameleon, Chamaeleo calyptratus.

    Science.gov (United States)

    Herrel, Anthony; Redding, Chrystal L; Meyers, J Jay; Nishikawa, Kiisa C

    2014-08-01

    Within a year of hatching, chameleons can grow by up to two orders of magnitude in body mass. Rapid growth of the feeding mechanism means that bones, muscles, and movements change as chameleons grow while needing to maintain function. A previous morphological study showed that the musculoskeletal components of the feeding apparatus grow with negative allometry relative to snout-vent length (SVL) in chameleons. Here, we investigate the scaling of prey capture kinematics and muscle physiological cross-sectional area in the veiled chameleon, Chamaeleo calyptratus. The chameleons used in this study varied in size from approximately 3 to 18 cm SVL (1-200 g). Feeding sequences of 12 chameleons of different sizes were filmed and the timing of movements and the displacements and velocities of the jaws, tongue, and the hyolingual apparatus were quantified. Our results show that most muscle cross-sectional areas as well as tongue and hyoid mass scaled with isometry relative to mandible length, yet with negative allometry relative to SVL. Durations of movement also scaled with negative allometry relative to SVL and mandible length. Distances and angles generally scaled as predicted under geometric similarity (slopes of 1 and 0, respectively), while velocities generally scaled with slopes greater than 0 relative to SVL and mandible length. These data indicate that the velocity of jaw and tongue movements is generally greater in adults compared to juveniles. The discrepancy between the scaling of cross-sectional areas versus movements suggests changes in the energy storage and release mechanisms implicated in tongue projection. Copyright © 2014 Elsevier GmbH. All rights reserved.

  4. A general model for metabolic scaling in self-similar asymmetric networks.

    Directory of Open Access Journals (Sweden)

    Alexander Byers Brummer

    2017-03-01

    Full Text Available How a particular attribute of an organism changes or scales with its body size is known as an allometry. Biological allometries, such as metabolic scaling, have been hypothesized to result from selection to maximize how vascular networks fill space yet minimize internal transport distances and resistances. The West, Brown, Enquist (WBE model argues that these two principles (space-filling and energy minimization are (i general principles underlying the evolution of the diversity of biological networks across plants and animals and (ii can be used to predict how the resulting geometry of biological networks then governs their allometric scaling. Perhaps the most central biological allometry is how metabolic rate scales with body size. A core assumption of the WBE model is that networks are symmetric with respect to their geometric properties. That is, any two given branches within the same generation in the network are assumed to have identical lengths and radii. However, biological networks are rarely if ever symmetric. An open question is: Does incorporating asymmetric branching change or influence the predictions of the WBE model? We derive a general network model that relaxes the symmetric assumption and define two classes of asymmetrically bifurcating networks. We show that asymmetric branching can be incorporated into the WBE model. This asymmetric version of the WBE model results in several theoretical predictions for the structure, physiology, and metabolism of organisms, specifically in the case for the cardiovascular system. We show how network asymmetry can now be incorporated in the many allometric scaling relationships via total network volume. Most importantly, we show that the 3/4 metabolic scaling exponent from Kleiber's Law can still be attained within many asymmetric networks.

  5. Ontogenetic scaling patterns and functional anatomy of the pelvic limb musculature in emus (Dromaius novaehollandiae

    Directory of Open Access Journals (Sweden)

    Luis P. Lamas

    2014-12-01

    Full Text Available Emus (Dromaius novaehollandiae are exclusively terrestrial, bipedal and cursorial ratites with some similar biomechanical characteristics to humans. Their growth rates are impressive, as their body mass increases eighty-fold from hatching to adulthood whilst maintaining the same mode of locomotion throughout life. These ontogenetic characteristics stimulate biomechanical questions about the strategies that allow emus to cope with their rapid growth and locomotion, which can be partly addressed via scaling (allometric analysis of morphology. In this study we have collected pelvic limb anatomical data (muscle architecture, tendon length, tendon mass and bone lengths and calculated muscle physiological cross sectional area (PCSA and average tendon cross sectional area from emus across three ontogenetic stages (n = 17, body masses from 3.6 to 42 kg. The data were analysed by reduced major axis regression to determine how these biomechanically relevant aspects of morphology scaled with body mass. Muscle mass and PCSA showed a marked trend towards positive allometry (26 and 27 out of 34 muscles respectively and fascicle length showed a more mixed scaling pattern. The long tendons of the main digital flexors scaled with positive allometry for all characteristics whilst other tendons demonstrated a less clear scaling pattern. Finally, the two longer bones of the limb (tibiotarsus and tarsometatarsus also exhibited positive allometry for length, and two others (femur and first phalanx of digit III had trends towards isometry. These results indicate that emus experience a relative increase in their muscle force-generating capacities, as well as potentially increasing the force-sustaining capacities of their tendons, as they grow. Furthermore, we have clarified anatomical descriptions and provided illustrations of the pelvic limb muscle–tendon units in emus.

  6. Intra- and Interspecific Interactions as Proximate Determinants of Sexual Dimorphism and Allometric Trajectories in the Bottlenose Dolphin Tursiops truncatus (Cetacea, Odontoceti, Delphinidae.

    Directory of Open Access Journals (Sweden)

    Maria Carla de Francesco

    Full Text Available Feeding adaptation, social behaviour, and interspecific interactions related to sexual dimorphism and allometric growth are particularly challenging to be investigated in the high sexual monomorphic Delphinidae. We used geometric morphometrics to extensively explore sexual dimorphism and ontogenetic allometry of different projections of the skull and the mandible of the bottlenose dolphin Tursiops truncatus. Two-dimensional landmarks were recorded on the dorsal, ventral, lateral, and occipital views of the skull, and on the lateral view of the left and the right mandible of 104 specimens from the Mediterranean and the North Seas, differing environmental condition and degree of interspecific associations. Landmark configurations were transformed, standardized and superimposed through a Generalized Procrustes Analysis. Size and shape differences between adult males and females were respectively evaluated through ANOVA on centroid size, Procrustes ANOVA on Procrustes distances, and MANOVA on Procrustes coordinates. Ontogenetic allometry was investigated by multivariate regression of shape coordinates on centroid size in the largest homogenous sample from the North Sea. Results evidenced sexual dimorphic asymmetric traits only detected in the adults of the North Sea bottlenose dolphins living in monospecific associations, with females bearing a marked incision of the cavity hosting the left tympanic bulla. These differences were related to a more refined echolocalization system that likely enhances the exploitation of local resources by philopatric females. Distinct shape in immature versus mature stages and asymmetric changes in postnatal allometry of dorsal and occipital traits, suggest that differences between males and females are established early during growth. Allometric growth trajectories differed between males and females for the ventral view of the skull. Allometric trajectories differed among projections of skull and mandible, and were

  7. Sauropod necks: are they really for heat loss?

    Directory of Open Access Journals (Sweden)

    Donald M Henderson

    Full Text Available Three-dimensional digital models of 16 different sauropods were used to examine the scaling relationship between metabolism and surface areas of the whole body, the neck, and the tail in an attempt to see if the necks could have functioned as radiators for the elimination of excess body heat. The sauropod taxa sample ranged in body mass from a 639 kg juvenile Camarasaurus to a 25 t adult Brachiosaurus. Metabolism was assumed to be directly proportional to body mass raised to the ¾ power, and estimates of body mass accounted for the presence of lungs and systems of air sacs in the trunk and neck. Surface areas were determined by decomposing the model surfaces into triangles and their areas being computed by vector methods. It was found that total body surface area was almost isometric with body mass, and that it showed negative allometry when plotted against metabolic rate. In contrast, neck area showed positive allometry when plotted against metabolic rate. Tail area show negative allometry with respect to metabolic rate. The many uncertainties about the biology of sauropods, and the variety of environmental conditions that different species experienced during the groups 150 million years of existence, make it difficult to be absolutely certain about the function of the neck as a radiator. However, the functional combination of the allometric increase of neck area, the systems of air sacs in the neck and trunk, the active control of blood flow between the core and surface of the body, changing skin color, and strategic orientation of the neck with respect to wind, make it plausible that the neck could have functioned as a radiator to avoid over-heating.

  8. Evolution of parental incubation behaviour in dinosaurs cannot be inferred from clutch mass in birds.

    Science.gov (United States)

    Birchard, Geoffrey F; Ruta, Marcello; Deeming, D Charles

    2013-08-23

    A recent study proposed that incubation behaviour (i.e. type of parental care) in theropod dinosaurs can be inferred from an allometric analysis of clutch volume in extant birds. However, the study in question failed to account for factors known to affect egg and clutch size in living bird species. A new scaling analysis of avian clutch mass demonstrates that type of parental care cannot be distinguished by conventional allometry because of the confounding effects of phylogeny and hatchling maturity. Precociality of young but not paternal care in the theropod ancestors of birds is consistent with the available data.

  9. Stochastic ontogenetic growth model

    Science.gov (United States)

    West, B. J.; West, D.

    2012-02-01

    An ontogenetic growth model (OGM) for a thermodynamically closed system is generalized to satisfy both the first and second law of thermodynamics. The hypothesized stochastic ontogenetic growth model (SOGM) is shown to entail the interspecies allometry relation by explicitly averaging the basal metabolic rate and the total body mass over the steady-state probability density for the total body mass (TBM). This is the first derivation of the interspecies metabolic allometric relation from a dynamical model and the asymptotic steady-state distribution of the TBM is fit to data and shown to be inverse power law.

  10. The natural selection of metabolism explains curvature in allometric scaling

    OpenAIRE

    Witting, Lars

    2016-01-01

    I simulate the evolution of metabolism and mass to explain the curvature in the metabolic allometry for placental and marsupial mammals. I assume that the release of inter-specific competition by the extinction of dinosaurs 65 million years ago made it possible for each clade to diversity into a multitude of species across a wide range of niches. The natural selection of metabolism and mass was then fitted to explain the maximum observed body masses over time, as well as the current inter-spe...

  11. An allometric approach of tumor-angiogenesis.

    Science.gov (United States)

    Szasz, Oliver; Vincze, Gyula; Szigeti, Gyula Peter; Benyo, Zoltan; Szasz, Andras

    2018-07-01

    Angiogenesis is one of the main supporting factors of tumor-progression. It is a complex set of interactions together with hypoxia and inflammation, regulating tumor growth. The objective of this study is to examine the effect of angiogenesis with an allometric approach applied to angiogenesis and the regulating factors. The results show that allometry has the potential to describe this aspect, including the sigmoid-like transport function. There are particular conditions under which the complex control maximizes the relative tumor mass. Linear growth of malignancy diameter with an allometric approach was proven. Copyright © 2018. Published by Elsevier Ltd.

  12. Calculating the variance and prediction intervals for estimates obtained from allometric relationships

    CSIR Research Space (South Africa)

    Nickless, A

    2010-09-01

    Full Text Available that across the range of x values, the variability in the error does not change (i.e. no heteroscedasticity). Often the power function in allometry is used: y = axbε This can be converted to: ln(yi) = β0 + β1 ln(xi) + εi The above assumptions now apply... to the regression relationship with the logged variables. Therefore ln(yi) is assumed to be normally distributed with mean µ=β0+β1 ln(xi) and variance σ2*. From regression theory it is known that the expected value (e) and variance (Var) of ln(yi) is given by...

  13. Biomechanics of North Atlantic Right Whale Bone: Mandibular Fracture as a Fatal Endpoint for Blunt Vessel-Whale Collision Modeling

    Science.gov (United States)

    2007-09-01

    considered sexually mature according to their size or age (Kraus, et al., 2007). The number of calves 27 produced in a given year is also highly variable...C~ ~ ~ -~un cz I ~ a -D E -Z Ou = r.. a.) cz toC u n c c E o .) 0 E ’ A u cz r. CA & C.) c.. .. C.) 0 E - " . Wounds or scars from propeller...note is the lower 127 value (21.8%) obtained when a juvenile male was measured. It is unknown if sexual dimorphism or allometry were leading factors

  14. Trilobite spines and beetle horns: sexual selection in the Palaeozoic?

    Science.gov (United States)

    Knell, Robert J; Fortey, Richard A

    2005-06-22

    Raphiophorid trilobites commonly bore median cephalic protuberances such as spines or bulbs, showing a remarkable variety of form. It is unlikely that their primary function was for protection or in hydrodynamics. A case is made that they were secondary sexual features, by comparison with similar morphological structures developed on rhinoceros beetles and other arthropods. This interpretation is supported by four lines of evidence: their ontogeny, their diversity, the existence of plausible examples of sexual dimorphs in some cases and the fact that they show positive allometry.

  15. Body size and allometric variation in facial shape in children.

    Science.gov (United States)

    Larson, Jacinda R; Manyama, Mange F; Cole, Joanne B; Gonzalez, Paula N; Percival, Christopher J; Liberton, Denise K; Ferrara, Tracey M; Riccardi, Sheri L; Kimwaga, Emmanuel A; Mathayo, Joshua; Spitzmacher, Jared A; Rolian, Campbell; Jamniczky, Heather A; Weinberg, Seth M; Roseman, Charles C; Klein, Ophir; Lukowiak, Ken; Spritz, Richard A; Hallgrimsson, Benedikt

    2018-02-01

    Morphological integration, or the tendency for covariation, is commonly seen in complex traits such as the human face. The effects of growth on shape, or allometry, represent a ubiquitous but poorly understood axis of integration. We address the question of to what extent age and measures of size converge on a single pattern of allometry for human facial shape. Our study is based on two large cross-sectional cohorts of children, one from Tanzania and the other from the United States (N = 7,173). We employ 3D facial imaging and geometric morphometrics to relate facial shape to age and anthropometric measures. The two populations differ significantly in facial shape, but the magnitude of this difference is small relative to the variation within each group. Allometric variation for facial shape is similar in both populations, representing a small but significant proportion of total variation in facial shape. Different measures of size are associated with overlapping but statistically distinct aspects of shape variation. Only half of the size-related variation in facial shape can be explained by the first principal component of four size measures and age while the remainder associates distinctly with individual measures. Allometric variation in the human face is complex and should not be regarded as a singular effect. This finding has important implications for how size is treated in studies of human facial shape and for the developmental basis for allometric variation more generally. © 2017 Wiley Periodicals, Inc.

  16. Allometric basis of enrofloxacin scaling in green iguanas.

    Science.gov (United States)

    Maxwell, L K; Jacobson, E R

    2008-02-01

    When body size varies greatly, drug disposition can best be described as an allometric function of body weight. Therefore, the allometry of standard metabolic rate (SMR; 3/4 power) and body surface area (BSA; 2/3 power) have been advocated as surrogate markers for the prediction of key pharmacokinetic parameters. The goal of the present study was to examine the allometric basis of pharmacokinetic scaling within a species, green iguanas. Enrofloxacin was administered intravenously to 20 green iguanas (322-3824 g), and noncompartmental analysis was used to calculate standard pharmacokinetic parameters, which were log(10) transformed and regressed against log(10) body weight. The slopes of significant regressions were compared with the values of unity, 3/4, and 2/3. The slope of enrofloxacin total body clearance (Cl) was also compared with the slopes relating SMR and renal Cl of (99m)Tc-diethylenetriamine penta-acetic acid ((99m)DTPA) to body weight in iguanas. Enrofloxacin Cl depended allometrically on body weight with the power of 0.32. The slope of enrofloxacin Cl was significantly less than those of SMR, Cl of (99m)DTPA, and the 2/3 value. Therefore, the relationship between enrofloxacin Cl and body weight does not directly depend on the allometry of BSA, SMR, or renal Cl of (99m)DTPA in iguanas.

  17. Convergent acoustic field of view in echolocating bats

    DEFF Research Database (Denmark)

    Jakobsen, Lasse; Ratcliffe, John M; Surlykke, Annemarie

    2013-01-01

    Most echolocating bats exhibit a strong correlation between body size and the frequency of maximum energy in their echolocation calls (peak frequency), with smaller species using signals of higher frequency than larger ones. Size-signal allometry or acoustic detection constraints imposed on wavel......Most echolocating bats exhibit a strong correlation between body size and the frequency of maximum energy in their echolocation calls (peak frequency), with smaller species using signals of higher frequency than larger ones. Size-signal allometry or acoustic detection constraints imposed...... on wavelength by preferred prey size have been used to explain this relationship. Here we propose the hypothesis that smaller bats emit higher frequencies to achieve directional sonar beams, and that variable beam width is critical for bats. Shorter wavelengths relative to the size of the emitter translate...... into more directional sound beams. Therefore, bats that emit their calls through their mouths should show a relationship between mouth size and wavelength, driving smaller bats to signals of higher frequency. We found that in a flight room mimicking a closed habitat, six aerial hawking vespertilionid...

  18. Multi-scaling allometric analysis for urban and regional development

    Science.gov (United States)

    Chen, Yanguang

    2017-01-01

    The concept of allometric growth is based on scaling relations, and it has been applied to urban and regional analysis for a long time. However, most allometric analyses were devoted to the single proportional relation between two elements of a geographical system. Few researches focus on the allometric scaling of multielements. In this paper, a process of multiscaling allometric analysis is developed for the studies on spatio-temporal evolution of complex systems. By means of linear algebra, general system theory, and by analogy with the analytical hierarchy process, the concepts of allometric growth can be integrated with the ideas from fractal dimension. Thus a new methodology of geo-spatial analysis and the related theoretical models emerge. Based on the least squares regression and matrix operations, a simple algorithm is proposed to solve the multiscaling allometric equation. Applying the analytical method of multielement allometry to Chinese cities and regions yields satisfying results. A conclusion is reached that the multiscaling allometric analysis can be employed to make a comprehensive evaluation for the relative levels of urban and regional development, and explain spatial heterogeneity. The notion of multiscaling allometry may enrich the current theory and methodology of spatial analyses of urban and regional evolution.

  19. Anatomical and physiological basis for the allometric scaling of cisplatin clearance in dogs.

    Science.gov (United States)

    Achanta, S; Sewell, A; Ritchey, J W; Broaddus, K; Bourne, D W A; Clarke, C R; Maxwell, L K

    2016-06-01

    Cisplatin is a platinum-containing cytotoxic drug indicated for the treatment of solid tumors in veterinary and human patients. Several of the algorithms used to standardize the doses of cytotoxic drugs utilize allometry, or the nonproportional relationships between anatomical and physiological variables, but the underlying basis for these relationships is poorly understood. The objective of this proof of concept study was to determine whether allometric equations explain the relationships between body weight, kidney weight, renal physiology, and clearance of a model, renally cleared anticancer agent in dogs. Postmortem body, kidney, and heart weights were collected from 364 dogs (127 juveniles and 237 adults, including 51 dogs ≥ 8 years of age). Renal physiological and cisplatin pharmacokinetic studies were conducted in ten intact male dogs including two juvenile and eight adult dogs (4-55 kg). Glomerular filtration rate (GFR), effective renal plasma flow, effective renal blood flow, renal cisplatin clearance, and total cisplatin clearance were allometrically related to body weight with powers of 0.75, 0.59, 0.61, 0.71, and 0.70, respectively. The similar values of these diverse mass exponents suggest a common underlying basis for the allometry of kidney size, renal physiology, and renal drug handling. © 2015 John Wiley & Sons Ltd.

  20. Biomass and Volume Yield in Mature Hybrid Poplar Plantations on Temperate Abandoned Farmland

    Directory of Open Access Journals (Sweden)

    Benoit Truax

    2014-12-01

    Full Text Available In this study, we developed clone-specific allometric relationships, with the objective of calculating volume and biomass production after 13 years in 8 poplar plantations, located across an environmental gradient, and composed of 5 unrelated hybrid poplar clones. Allometry was found to be very similar for clones MxB-915311, NxM-3729 and DNxM-915508, all having P. maximoviczii parentage. Clones DxN-3570 and TxD-3230 also had a similar allometry; for a given DBH they have a lower stem volume, stem biomass and branch biomass than P. maximoviczii hybrids. Strong Site × Clone interactions were observed for volume and woody biomass growth, with DxN and TxD hybrids only productive on low elevation fertile sites, whereas P. maximovizcii hybrids were also very productive on higher elevation sites with moderate to high soil fertility. At the site level (5 clones mean, yield reached 27.5 and 22.7 m3/ha/yr. on the two best sites (high fertility and low elevation, confirming the great potential of southern Québec (Canada for poplar culture. The productivity gap between the most and least productive sites has widened from year 8 to year 13, highlighting the need for high quality abandoned farmland site selection in terms of climate and soil fertility. Although clone selection could optimize yield across the studied environmental gradient, it cannot fully compensate for inadequate site selection.

  1. Response to formal comment on Myhrvold (2016) submitted by Griebeler and Werner (2017).

    Science.gov (United States)

    Myhrvold, Nathan P

    2018-01-01

    Griebeler and Werner offer a formal comment on Myhrvold, 2016 defending the conclusions of Werner and Griebeler, 2014. Although the comment criticizes several aspects of methodology in Myhrvold, 2016, all three papers concur on a key conclusion: the metabolism of extant endotherms and ectotherms cannot be reliably classified using growth-rate allometry, because the growth rates of extant endotherms and ectotherms overlap. A key point of disagreement is that the 2014 paper concluded that despite this general case, one can nevertheless classify dinosaurs as ectotherms from their growth rate allometry. The 2014 conclusion is based on two factors: the assertion (made without any supporting arguments) that the comparison with dinosaurs must be restricted only to extant sauropsids, ignoring other vertebrate groups, and that extant sauropsid endotherm and ectotherm growth rates in a data set studied in the 2014 work do not overlap. The Griebeler and Werner formal comment presents their first arguments in support of the restriction proposition. In this response I show that this restriction is unsupported by established principles of phylogenetic comparison. In addition, I show that the data set studied in their 2014 work does show overlap, and that this is visible in one of its figures. I explain how either point effectively invalidates the conclusion of their 2014 paper. I also address the other methodological criticisms of Myhrvold 2016, and find them unsupported.

  2. FITTING AND TESTING ALLOMETRIC EQUATIONS FOR MEXICO’S SINALOAN TROPICAL DRY TREES AND FOREST INVENTORY PLOTS

    Directory of Open Access Journals (Sweden)

    Jose de Jesus Navar Chaidez

    2016-05-01

    Full Text Available Aboveground tree biomass (bole, branches and foliage, M, plays a key role in the conventional and sustainable management of forest communities. The standard approach to assess tree or plot M is harvesting trees, developing and fitting allometric equations to trees or forest inventory plot data. In the absence of local tree allometry, it is usually recommended to fit off site allometric equations to evaluate tree or plot M. This research aims: (a to develop an updated on site allometric equation (b to fit available off site allometric equations to destructively harvested trees and (c to fit available allometric equations to plot M of Mexico’s Sinaloan tropical dry forests to understand sources of inherent tree and plot M variability. Results showed that: (a the improved on site allometric equation increases precision in contrast to the conventional biomass equation previously reported as well as to off site tree M equations, (b off site allometry projects tree and plot M deviates by close to one order of magnitude. Two tested and recommended approaches to increase tree and plot M precision when fitting off site equations are: (i to use all available tree allometric functions to come up with a mean equation or (ii to calibrate off site equations by fitting new, local parameters that can be calculated using statistical programs.These options would eventually increase tree and plot M precision in regional evaluations.

  3. Modeling aboveground tree woody biomass using national-scale allometric methods and airborne lidar

    Science.gov (United States)

    Chen, Qi

    2015-08-01

    Estimating tree aboveground biomass (AGB) and carbon (C) stocks using remote sensing is a critical component for understanding the global C cycle and mitigating climate change. However, the importance of allometry for remote sensing of AGB has not been recognized until recently. The overarching goals of this study are to understand the differences and relationships among three national-scale allometric methods (CRM, Jenkins, and the regional models) of the Forest Inventory and Analysis (FIA) program in the U.S. and to examine the impacts of using alternative allometry on the fitting statistics of remote sensing-based woody AGB models. Airborne lidar data from three study sites in the Pacific Northwest, USA were used to predict woody AGB estimated from the different allometric methods. It was found that the CRM and Jenkins estimates of woody AGB are related via the CRM adjustment factor. In terms of lidar-biomass modeling, CRM had the smallest model errors, while the Jenkins method had the largest ones and the regional method was between. The best model fitting from CRM is attributed to its inclusion of tree height in calculating merchantable stem volume and the strong dependence of non-merchantable stem biomass on merchantable stem biomass. This study also argues that it is important to characterize the allometric model errors for gaining a complete understanding of the remotely-sensed AGB prediction errors.

  4. Genetic parameters for different growth scales in GIFT strain of Nile tilapia (Oreochromis niloticus).

    Science.gov (United States)

    He, J; Gao, H; Xu, P; Yang, R

    2015-12-01

    Body weight, length, width and depth at two growth stages were observed for a total of 5015 individuals of GIFT strain, along with a pedigree including 5588 individuals from 104 sires and 162 dams was collected. Multivariate animal models and a random regression model were used to genetically analyse absolute and relative growth scales of these growth traits. In absolute growth scale, the observed growth traits had moderate heritabilities ranging from 0.321 to 0.576, while pairwise ratios between body length, width and depth were lowly inherited and maximum heritability was only 0.146 for length/depth. All genetic correlations were above 0.5 between pairwise growth traits and genetic correlation between length/width and length/depth varied between both growth stages. Based on those estimates, selection index of multiple traits of interest can be formulated in future breeding program to improve genetically body weight and morphology of the GIFT strain. In relative growth scale, heritabilities in relative growths of body length, width and depth to body weight were 0.257, 0.412 and 0.066, respectively, while genetic correlations among these allometry scalings were above 0.8. Genetic analysis for joint allometries of body weight to body length, width and depth will contribute to genetically regulate the growth rate between body shape and body weight. © 2015 Blackwell Verlag GmbH.

  5. Evolution of male and female genitalia following release from sexual selection.

    Science.gov (United States)

    Cayetano, Luis; Maklakov, Alexei A; Brooks, Robert C; Bonduriansky, Russell

    2011-08-01

    Despite the key functions of the genitalia in sexual interactions and fertilization, the role of sexual selection and conflict in shaping genital traits remains poorly understood. Seed beetle (Callosobruchus maculatus) males possess spines on the intromittent organ, and females possess a thickened reproductive tract wall that also bears spines. We investigated the role of sexual selection and conflict by imposing monogamous mating on eight replicate populations of this naturally polygamous insect, while maintaining eight other populations under polygamy. To establish whether responses to mating system manipulation were robust to ecological context, we simultaneously manipulated life-history selection (early/late reproduction). Over 18-21 generations, male genital spines evolved relatively reduced length in large males (i.e., shallower static allometry) in monogamous populations. Two nonintromittent male genital appendages also evolved in response to the interaction of mating system and ecology. In contrast, no detectable evolution occurred in female genitalia, consistent with the expectation of a delayed response in defensive traits. Our results support a sexually antagonistic role for the male genital spines, and demonstrate the evolution of static allometry in response to variation in sexual selection opportunity. We argue that further advances in the study of genital coevolution will require a much more detailed understanding of the functions of male and female genital traits. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  6. Unifying principles in terrestrial locomotion: do hopping Australian marsupials fit in?

    Science.gov (United States)

    Bennett, M B

    2000-01-01

    Mammalian terrestrial locomotion has many unifying principles. However, the Macropodoidea are a particularly interesting group that exhibit a number of significant deviations from the principles that seem to apply to other mammals. While the properties of materials that comprise the musculoskeletal system of mammals are similar, evidence suggests that tendon properties in macropodoid marsupials may be size or function dependent, in contrast to the situation in placental mammals. Postural differences related to hopping versus running have a dramatic effect on the scaling of the pelvic limb musculoskeletal system. Ratios of muscle fibre to tendon cross-sectional areas for ankle extensors and digital flexors scale with positive allometry in all mammals, but exponents are significantly higher in macropods. Tendon safety factors decline with increasing body mass in mammals, with eutherians at risk of ankle extensor tendon rupture at a body mass of about 150 kg, whereas kangaroos encounter similar problems at a body mass of approximately 35 kg. Tendon strength appears to limit locomotor performance in these animals. Elastic strain energy storage in tendons is mass dependent in all mammals, but exponents are significantly larger in macropodid. Tibial stresses may scale with positive allometry in kangaroos, which result in lower bone safety factors in macropods compared to eutherian mammals.

  7. Craniofacial growth, maturation, and change: teens to midadulthood.

    Science.gov (United States)

    Ross, Ann H; Williams, Shanna E

    2010-03-01

    Despite the attainment of several adult cranial dimensions relatively early in childhood, skeletal maturity and, by consequence, adult form are typically defined by the eruption of the third molars around 17 years of age. This in turn serves as the division between subadults and adults, which is then applied to population studies of biological variation. Specifically, comparative data sets of adult measurements are not directly applied to individuals who do not have complete skeletal growth, as it is believed that the confounding effects of allometry may skew the results. The present study uses geometric morphometrics techniques to investigate the appropriateness of this division with respect to three-dimensional anatomical landmarks. Twenty-six landmarks were collected from a single population of 24 crania partitioned into 4 age groups spanning late adolescence to midadulthood. Generalized Procrustes and multivariate statistical analyses were performed on the landmark data. Results showed no significant morphological differences between the teen and young adult age groups, whereas significant shape and size differences were found in older adults relative to their younger cohorts. Moreover, no growth-related shape variation (ie, allometry) was detected within the sample. These findings suggest that adult form is attained several years earlier than commonly thought and corroborate other research that suggest that subtle changes in cranial morphology continue throughout adulthood.

  8. Secondary osteons scale allometrically in mammalian humerus and femur.

    Science.gov (United States)

    Felder, A A; Phillips, C; Cornish, H; Cooke, M; Hutchinson, J R; Doube, M

    2017-11-01

    Intra-cortical bone remodelling is a cell-driven process that replaces existing bone tissue with new bone tissue in the bone cortex, leaving behind histological features called secondary osteons. While the scaling of bone dimensions on a macroscopic scale is well known, less is known about how the spatial dimensions of secondary osteons vary in relation to the adult body size of the species. We measured the cross-sectional area of individual intact secondary osteons and their central Haversian canals in transverse sections from 40 stylopodal bones of 39 mammalian species (body mass 0.3-21 000 kg). Scaling analysis of our data shows that mean osteonal resorption area (negative allometry, exponent 0.23, R 2  0.54, p <0.005) and Haversian canal area (negative allometry, exponent 0.31, R 2  0.45, p <0.005) are significantly related to body mass, independent of phylogeny. This study is the most comprehensive of its kind to date, and allows us to describe overall trends in the scaling behaviour of secondary osteon dimensions, supporting the inference that the osteonal resorption area may be limited by the need to avoid fracture in smaller mammalian species, but the need to maintain osteocyte viability in larger mammalian species.

  9. Relative growth and sexual maturity of the stone crab Menippe nodifrons Stimpson, 1859 (Brachyura, Xanthoidea in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Giovana Bertini

    2007-03-01

    Full Text Available The relative growth and size at onset of morphological sexual maturity of the stone crab Menippe nodifrons were investigated. A total of 399 crabs was captured on Praia Grande and Tenório beaches at Ubatuba. Carapace width (CW and length, cheliped propodus length and height, abdomen width in females, and gonopod length in males were recorded. In females, the abdominal width showed negative allometry for juveniles and positive allometry for adults; the puberty molt occurred at 31.6 mm CW. In males, the size at onset of morphological sexual maturity was estimated as 29.7 mm CW; the gonopod growth showed positive allometry for juveniles, and an isometric relationship for adults. The gonopod length and the abdominal width were the most appropriate morphometric variables to estimate size at onset of sexual maturity in this stone crab.O objetivo do presente estudo foi determinar o crescimento relativo e a maturidade sexual morfológica de Menippe nodifrons. As coletas foram realizadas na Praia Grande e Tenório, Ubatuba, São Paulo. Os caranguejos foram separados quanto ao sexo e mensurados na região da largura (LC e comprimento da carapaça, comprimento e altura dos própodos quelares direito e esquerdo, largura do abdome (LA nas fêmeas e comprimento do gonopódio (CG nos machos. Obteve-se 399 indivíduos, sendo 195 machos e 204 fêmeas. Os machos atingiram a maturidade sexual com 29,7mm LC e as fêmeas com 31,6mm LC. Para as fêmeas a melhor relação que indicou a muda da puberdade foi LA vs. LC, sendo que o crescimento foi alométrico negativo na fase jovem e alométrico positivo após a muda da puberdade. Para os machos foi CG vs. LC evidenciando crescimento alométrico positivo na fase jovem e isométrico na fase adulta.

  10. Efficacy of generic allometric equations for estimating biomass: a test in Japanese natural forests.

    Science.gov (United States)

    Ishihara, Masae I; Utsugi, Hajime; Tanouchi, Hiroyuki; Aiba, Masahiro; Kurokawa, Hiroko; Onoda, Yusuke; Nagano, Masahiro; Umehara, Toru; Ando, Makoto; Miyata, Rie; Hiura, Tsutom

    2015-07-01

    Accurate estimation of tree and forest biomass is key to evaluating forest ecosystem functions and the global carbon cycle. Allometric equations that estimate tree biomass from a set of predictors, such as stem diameter and tree height, are commonly used. Most allometric equations are site specific, usually developed from a small number of trees harvested in a small area, and are either species specific or ignore interspecific differences in allometry. Due to lack of site-specific allometries, local equations are often applied to sites for which they were not originally developed (foreign sites), sometimes leading to large errors in biomass estimates. In this study, we developed generic allometric equations for aboveground biomass and component (stem, branch, leaf, and root) biomass using large, compiled data sets of 1203 harvested trees belonging to 102 species (60 deciduous angiosperm, 32 evergreen angiosperm, and 10 evergreen gymnosperm species) from 70 boreal, temperate, and subtropical natural forests in Japan. The best generic equations provided better biomass estimates than did local equations that were applied to foreign sites. The best generic equations included explanatory variables that represent interspecific differences in allometry in addition to stem diameter, reducing error by 4-12% compared to the generic equations that did not include the interspecific difference. Different explanatory variables were selected for different components. For aboveground and stem biomass, the best generic equations had species-specific wood specific gravity as an explanatory variable. For branch, leaf, and root biomass, the best equations had functional types (deciduous angiosperm, evergreen angiosperm, and evergreen gymnosperm) instead of functional traits (wood specific gravity or leaf mass per area), suggesting importance of other traits in addition to these traits, such as canopy and root architecture. Inclusion of tree height in addition to stem diameter improved

  11. Prediction of clearance, volume of distribution and half-life by allometric scaling and by use of plasma concentrations predicted from pharmacokinetic constants: a comparative study.

    Science.gov (United States)

    Mahmood, I

    1999-08-01

    Pharmacokinetic parameters (clearance, CL, volume of distribution in the central compartment, VdC, and elimination half-life, t1/2beta) predicted by an empirical allometric approach have been compared with parameters predicted from plasma concentrations calculated by use of the pharmacokinetic constants A, B, alpha and beta, where A and B are the intercepts on the Y axis of the plot of plasma concentration against time and alpha and beta are the rate constants, both pairs of constants being for the distribution and elimination phases, respectively. The pharmacokinetic parameters of cefpiramide, actisomide, troglitazone, procaterol, moxalactam and ciprofloxacin were scaled from animal data obtained from the literature. Three methods were used to generate plots for the prediction of clearance in man: dependence of clearance on body weight (simple allometric equation); dependence of the product of clearance and maximum life-span potential (MLP) on body weight; and dependence of the product of clearance and brain weight on body weight. Plasma concentrations of the drugs were predicted in man by use of A, B, alpha and beta obtained from animal data. The predicted plasma concentrations were then used to calculate CL, VdC and t1/2beta. The pharmacokinetic parameters predicted by use of both approaches were compared with measured values. The results indicate that simple allometry did not predict clearance satisfactorily for actisomide, troglitazone, procaterol and ciprofloxacin. Use of MLP or the product of clearance and brain weight improved the prediction of clearance for these four drugs. Except for troglitazone, VdC and t1/2beta predicted for man by use of the allometric approach were comparable with measured values for the drugs studied. CL, VdC and t1/2beta predicted by use of pharmacokinetic constants were comparable with values predicted by simple allometry. Thus, if simple allometry failed to predict clearance of a drug, so did the pharmacokinetic constant

  12. Brain structure evolution in a basal vertebrate clade: evidence from phylogenetic comparative analysis of cichlid fishes

    Directory of Open Access Journals (Sweden)

    Kolm Niclas

    2009-09-01

    Full Text Available Abstract Background The vertebrate brain is composed of several interconnected, functionally distinct structures and much debate has surrounded the basic question of how these structures evolve. On the one hand, according to the 'mosaic evolution hypothesis', because of the elevated metabolic cost of brain tissue, selection is expected to target specific structures mediating the cognitive abilities which are being favored. On the other hand, the 'concerted evolution hypothesis' argues that developmental constraints limit such mosaic evolution and instead the size of the entire brain varies in response to selection on any of its constituent parts. To date, analyses of these hypotheses of brain evolution have been limited to mammals and birds; excluding Actinopterygii, the basal and most diverse class of vertebrates. Using a combination of recently developed phylogenetic multivariate allometry analyses and comparative methods that can identify distinct rates of evolution, even in highly correlated traits, we studied brain structure evolution in a highly variable clade of ray-finned fishes; the Tanganyikan cichlids. Results Total brain size explained 86% of the variance in brain structure volume in cichlids, a lower proportion than what has previously been reported for mammals. Brain structures showed variation in pair-wise allometry suggesting some degree of independence in evolutionary changes in size. This result is supported by variation among structures on the strength of their loadings on the principal size axis of the allometric analysis. The rate of evolution analyses generally supported the results of the multivariate allometry analyses, showing variation among several structures in their evolutionary patterns. The olfactory bulbs and hypothalamus were found to evolve faster than other structures while the dorsal medulla presented the slowest evolutionary rate. Conclusion Our results favor a mosaic model of brain evolution, as certain

  13. Growth laws for sub-delta crevasses in the Mississippi River Delta

    Science.gov (United States)

    Yocum, T. A.; Georgiou, I. Y.; Straub, K. M.

    2017-12-01

    River deltas are threatened by environmental change, including subsidence, global sea level rise, reduced sediment inputs and other local factors. In the Mississippi River Delta (MRD) these impacts are exemplified, and have led to proposed solutions to build land that include sediment diversions to reinitiate the delta cycle. Deltas were studied extensively using numerical models, theoretical and conceptual frameworks, empirical scaling relationships, laboratory models and field observations. But predicting the future of deltas relies on field observations where for most deltas data are still lacking. Moreover, empirical and theoretical scaling laws may be influenced by the data used to develop them, while laboratory deltas may be influenced by scaling issues. Anthropogenic crevasses in the MRD are large enough to overcome limitations of laboratory deltas, and small enough to allow for rapid channel and wetland development, providing an ideal setting to investigate delta development mechanics. Here we assessed growth laws of sub-delta crevasses (SDC) in the MRD, in two experimental laboratory deltas (LD - weakly and strongly cohesive) and compared them to river dominated deltas worldwide. Channel and delta geometry metrics for each system were obtained using geospatial tools, bathymetric datasets, sediment size, and hydrodynamic observations. Results show that SDC follow growth laws similar to large river dominated deltas, with the exception of some that exhibit anomalous behavior with respect to the frequency and distance to a bifurcation and the fraction of wetted delta shoreline (allometry metrics). Most SDC exhibit a systematic decrease of non-dimensional channel geometries with increased bifurcation order, indicating that channels are adjusting to decreased flow after bifurcations occur, and exhibit linear trends for land allometry and width-depth ratio, although geometries decrease more rapidly per bifurcation order. Measured distance to bifurcations in SDC

  14. Scaling of rotational inertia of primate mandibles.

    Science.gov (United States)

    Ross, Callum F; Iriarte-Diaz, Jose; Platts, Ellen; Walsh, Treva; Heins, Liam; Gerstner, Geoffrey E; Taylor, Andrea B

    2017-05-01

    The relative importance of pendulum mechanics and muscle mechanics in chewing dynamics has implications for understanding the optimality criteria driving the evolution of primate feeding systems. The Spring Model (Ross et al., 2009b), which modeled the primate chewing system as a forced mass-spring system, predicted that chew cycle time would increase faster than was actually observed. We hypothesized that if mandibular momentum plays an important role in chewing dynamics, more accurate estimates of the rotational inertia of the mandible would improve the accuracy with which the Spring Model predicts the scaling of primate chew cycle period. However, if mass-related momentum effects are of negligible importance in the scaling of primate chew cycle period, this hypothesis would be falsified. We also predicted that greater "robusticity" of anthropoid mandibles compared with prosimians would be associated with higher moments of inertia. From computed tomography scans, we estimated the scaling of the moment of inertia (I j ) of the mandibles of thirty-one species of primates, including 22 anthropoid and nine prosimian species, separating I j into the moment about a transverse axis through the center of mass (I xx ) and the moment of the center of mass about plausible axes of rotation. We found that across primates I j increases with positive allometry relative to jaw length, primarily due to positive allometry of jaw mass and I xx , and that anthropoid mandibles have greater rotational inertia compared with prosimian mandibles of similar length. Positive allometry of I j of primate mandibles actually lowers the predictive ability of the Spring Model, suggesting that scaling of primate chew cycle period, and chewing dynamics in general, are more strongly influenced by factors other than scaling of inertial properties of the mandible, such as the dynamic properties of the jaw muscles and neural control. Differences in cycle period scaling between chewing and locomotion

  15. Encyclopedia of distances

    CERN Document Server

    Deza, Michel Marie

    2016-01-01

    This 4th edition of the leading reference volume on distance metrics is characterized by updated and rewritten sections on some items suggested by experts and readers, as well a general streamlining of content and the addition of essential new topics. Though the structure remains unchanged, the new edition also explores recent advances in the use of distances and metrics for e.g. generalized distances, probability theory, graph theory, coding theory, data analysis. New topics in the purely mathematical sections include e.g. the Vitanyi multiset-metric, algebraic point-conic distance, triangular ratio metric, Rossi-Hamming metric, Taneja distance, spectral semimetric between graphs, channel metrization, and Maryland bridge distance. The multidisciplinary sections have also been supplemented with new topics, including: dynamic time wrapping distance, memory distance, allometry, atmospheric depth, elliptic orbit distance, VLBI distance measurements, the astronomical system of units, and walkability distance. Lea...

  16. TREE STEM AND CANOPY BIOMASS ESTIMATES FROM TERRESTRIAL LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    K. Olofsson

    2017-10-01

    Full Text Available In this study an automatic method for estimating both the tree stem and the tree canopy biomass is presented. The point cloud tree extraction techniques operate on TLS data and models the biomass using the estimated stem and canopy volume as independent variables. The regression model fit error is of the order of less than 5 kg, which gives a relative model error of about 5 % for the stem estimate and 10–15 % for the spruce and pine canopy biomass estimates. The canopy biomass estimate was improved by separating the models by tree species which indicates that the method is allometry dependent and that the regression models need to be recomputed for different areas with different climate and different vegetation.

  17. Intrinsic vs. extrinsic influences on life history expression: metabolism and parentally induced temperature influences on embryo development rate

    Science.gov (United States)

    Martin, Thomas E.; Ton, Riccardo; Nikilson, Alina

    2013-01-01

    Intrinsic processes are assumed to underlie life history expression and trade-offs, but extrinsic inputs are theorised to shift trait expression and mask trade-offs within species. Here, we explore application of this theory across species. We do this based on parentally induced embryo temperature as an extrinsic input, and mass-specific embryo metabolism as an intrinsic process, underlying embryonic development rate. We found that embryonic metabolism followed intrinsic allometry rules among 49 songbird species from temperate and tropical sites. Extrinsic inputs via parentally induced temperatures explained the majority of variation in development rates and masked a relationship with metabolism; metabolism explained a minor proportion of the variation in development rates among species, and only after accounting for temperature effects. We discuss evidence that temperature further obscures the expected interspecific trade-off between development rate and offspring quality. These results demonstrate the importance of considering extrinsic inputs to trait expression and trade-offs across species.

  18. Ornament Complexity Is Correlated with Sexual Selection: (A Comment on Raia et al., "Cope's Rule and the Universal Scaling Law of Ornament Complexity").

    Science.gov (United States)

    Holman, Luke; Bro-Jørgensen, Jakob

    2016-08-01

    Raia et al. propose that the evolution of the shape and complexity of animal ornaments (e.g., deer antlers) can be explained by interspecific variation in body size and is not influenced by sexual selection. They claim to show that ornament complexity is related to body size by an 0.25-power law and argue that this finding precludes a role for sexual selection in the evolution of ornament complexity. However, their study does not test alternative hypotheses and mismeasures antler shape allometry by omitting much of the published data. We show that an index of sexual selection (sexual size dimorphism) is positively correlated with size-corrected antler complexity and that the allometric slope of complexity is substantially greater than 0.25, contra Raia et al. We conclude that sexual selection and physical constraints both affect the evolution of antler shape.

  19. Age, growth and mortality of Sciaena umbra (Sciaenidae in the Gulf of Tunis

    Directory of Open Access Journals (Sweden)

    Inès Chater

    2018-03-01

    Full Text Available The growth and mortality of the brown meagre, Sciaena umbra from the Gulf of Tunis, were investigated using a sample of 276 specimens, ranging from 15.3 to 49.2 cm total length and from 43 to 1565 g total weight. Specimens were collected from artisanal fisheries between October 2008 and September 2011. Otoliths were extracted, thin cross-sections were realized and radii were measured. The log-linear morphometric relationships between total length-total weight and total length-otolith radius were significant (p < 0.05, showed positive allometry (b=3.15 and isometry (b=0.90, respectively. The marginal analysis suggested that only one growth increment was deposited per year. The maximum age of the brown meagre was 22 years for males and 31 years for females. The fit of the von Bertalanffy growth function was significantly different between sexes (p

  20. Left Ventricular Hypertrophy: An allometric comparative analysis of different ECG markers

    International Nuclear Information System (INIS)

    Bonomini, MP; Valentinuzzi, M E; Arini, P D; Ingallina, F; Barone, V

    2011-01-01

    Allometry, in general biology, measures the relative growth of a part in relation to the whole living organism. Left ventricular hypertrophy (LVH) is the heart adaptation to excessive load (systolic or diastolic). The increase in left ventricular mass leads to an increase in the electrocardiographic voltages. Based on clinical data, we compared the allometric behavior of three different ECG markers of LVH. To do this, the allometric fit AECG δ + β (VM) relating left ventricular mass (estimated from ecocardiographic data) and ECG amplitudes (expressed as the Cornell-Voltage, Sokolow and the ECG overall voltage indexes) were compared. Besides, sensitivity and specificity for each index were analyzed. The more sensitive the ECG criteria, the better the allometric fit. In conclusion: The allometric paradigm should be regarded as the way to design new and more sensitive ECG-based LVH markers.

  1. Physics of chewing in terrestrial mammals

    Science.gov (United States)

    Virot, Emmanuel; Ma, Grace; Clanet, Christophe; Jung, Sunghwan

    2017-03-01

    Previous studies on chewing frequency across animal species have focused on finding a single universal scaling law. Controversy between the different models has been aroused without elucidating the variations in chewing frequency. In the present study we show that vigorous chewing is limited by the maximum force of muscle, so that the upper chewing frequency scales as the -1/3 power of body mass for large animals and as a constant frequency for small animals. On the other hand, gentle chewing to mix food uniformly without excess of saliva describes the lower limit of chewing frequency, scaling approximately as the -1/6 power of body mass. These physical constraints frame the -1/4 power law classically inferred from allometry of animal metabolic rates. All of our experimental data stay within these physical boundaries over six orders of magnitude of body mass regardless of food types.

  2. Comparative morphometrics of two populations of Mugil curema (Pisces: Mugilidae on the Atlantic and Mexican Pacific coasts

    Directory of Open Access Journals (Sweden)

    Ana Laura Ibáñez-Aguirre

    2006-03-01

    Full Text Available A population of Mugil curema in the Gulf of Mexico was compared with one in the Pacific Ocean using nine morphometric variables. The allometries of each measurement were estimated in relation to total length. Morphometric variations were analyzed using the normalization of the individuals of each group and two multivariate methods: correspondence analysis, used to explore the information, and discriminant analysis. Results indicated that the diameter of the eye differentiated the populations of both coasts, the Atlantic population showed a larger eye diameter. However, other than this and the body width (which can be strongly influenced by sexual maturation there was no difference between the shapes of both populations. We discuss the larger morphometric variability of the Atlantic population which may be due to the presence of more than one population unlike the Pacific population.

  3. Allometric scaling and accidents at work

    Science.gov (United States)

    Cempel, Czesław; Tabaszewski, Maciej; Ordysiński, Szymon

    2016-01-01

    Allometry is the knowledge concerning relations between the features of some beings, like animals, or cities. For example, the daily energy rate is proportional to a mass of mammals rise of 3/4. This way of thinking has spread quickly from biology to many areas of research concerned with sociotechnical systems. It was revealed that the number of innovations, patents or heavy crimes rises as social interaction increases in a bigger city, while other urban indexes such as suicides decrease with social interaction. Enterprise is also a sociotechnical system, where social interaction and accidents at work take place. Therefore, do these interactions increase the number of accidents at work or, on the contrary, are they reduction-driving components? This article tries to catch such links and assess the allometric exponent between the number of accidents at work and the number of employees in an enterprise. PMID:26655044

  4. Sexual selection and the rodent baculum: an intraspecific study in the house mouse (Mus musculus domesticus).

    Science.gov (United States)

    Ramm, Steven A; Khoo, Lin; Stockley, Paula

    2010-01-01

    The rapid divergence of genitalia is a pervasive trend in animal evolution, thought to be due to the action of sexual selection. To test predictions from the sexual selection hypothesis, we here report data on the allometry, variation, plasticity and condition dependence of baculum morphology in the house mouse (Mus musculus domesticus). We find that that baculum size: (a) exhibits no consistent pattern of allometric scaling (baculum size being in most cases unrelated to body size), (b) exhibits low to moderate levels of phenotypic variation, (c) does not exhibit phenotypic plasticity in response to differences in perceived levels of sexual competition and (d) exhibits limited evidence of condition dependence. These patterns provide only limited evidence in support of the sexual selection hypothesis, and no consistent support for any particular sexual selection mechanism; however, more direct measures of how genital morphology influences male fertilization success are required.

  5. Vector field embryogeny.

    Directory of Open Access Journals (Sweden)

    Till Steiner

    Full Text Available We present a novel approach toward evolving artificial embryogenies, which omits the graph representation of gene regulatory networks and directly shapes the dynamics of a system, i.e., its phase space. We show the feasibility of the approach by evolving cellular differentiation, a basic feature of both biological and artificial development. We demonstrate how a spatial hierarchy formulation can be integrated into the framework and investigate the evolution of a hierarchical system. Finally, we show how the framework allows the investigation of allometry, a biological phenomenon, and its role for evolution. We find that direct evolution of allometric change, i.e., the evolutionary adaptation of the speed of system states on transient trajectories in phase space, is advantageous for a cellular differentiation task.

  6. Larval development and shape variation of the kelpfish Myxodes viridis (Teleostei: Clinidae

    Directory of Open Access Journals (Sweden)

    Francisca Zavala-Muñoz

    2016-03-01

    Full Text Available Larval development and shape ontogeny of the kelpfish Myxodes viridis (Clinidae are described for the first time. A total of 214 individuals ranging between 3.51 and 23.09 mm standard length collected off central Chile were assessed employing classic and geometric morphometrics, illustration with camera lucida and a double-staining technique for cartilaginous and bone structure observation. Based on characteristics such as yolk sac presence and fin formation, six stages of larval development were differentiated: yolk sac, preflexion, flexion, early postflexion, late postflexion and juvenile. Shape changes during development are subtle and occur smoothly, being more significant in the head and preanal length, and ontogenetic allometry accounts for almost 15%. Cartilage formation takes place first at the branchial arches and cranium; then hypural, haemal and neural arches are consecutively formed. Bony structure ossification occurs late in the development. Vertebral centra ossify directly, without cartilaginous matrix replacement.

  7. Scale dependence of disease impacts on quaking aspen (Populus tremuloides) mortality in the southwestern United States

    Science.gov (United States)

    Bell, David M.; Bradford, John B.; Lauenroth, William K.

    2015-01-01

    Depending on how disease impacts tree exposure to risk, both the prevalence of disease and disease effects on survival may contribute to patterns of mortality risk across a species' range. Disease may accelerate tree species' declines in response to global change factors, such as drought, biotic interactions, such as competition, or functional traits, such as allometry. To assess the role of disease in mediating mortality risk in quaking aspen (Populus tremuloides), we developed hierarchical Bayesian models for both disease prevalence in live aspen stems and the resulting survival rates of healthy and diseased aspen near the species' southern range limit using 5088 individual trees on 281 United States Forest Service Forest Inventory and Analysis plots in the southwestern United States.

  8. [Life cycle strategies: a synthesis of empirical and theoretical approaches].

    Science.gov (United States)

    Romanovskiĭ, Iu E

    1998-01-01

    A scheme of relationships among life-history characters is developed on assumptions of determinate growth and dependence of juvenile mortality on the specific growth rate. It is shown that constraints on the relative neonate size, (W0/W infinity), and minimum value of the biotic potential, (rmax), lead to "triangular" shape of life history set on the plain defined by juvenile and adult mortality. This completely coincides with the Ramenskiĭ++--Grime (C-S-R) classification of life-history strategies. Phylogenetic constraints can reduce this set to a relatively narŕow r/K-continuum specifically oriented for a certain taxon. Similar restrictions generate models of life history optimization which predict interspecific allometries between life-history traits.

  9. Development of a methodology for assessing the environmental impact of radioactivity in Northern Marine environments

    International Nuclear Information System (INIS)

    Brown, J.E.; Hosseini, A.; Borretzen, P.; Thorring, H. . E-mail havard.thorring@nrpa.no

    2006-01-01

    The requirement to assess the impacts of radioactivity in the environment explicitly and transparently is now generally accepted by the scientific community. A recently developed methodology for achieving this end for marine ecosystems is presented within this paper. With its clear relationship to an overarching system, the marine impact assessment is built around components of environmental transfer, ecodosimetry and radiobiological effects appraisal relying on the use of 'reference organisms'. Concentration factors (CFs), dynamic models and, in cases where parameters are missing, allometry have been employed in the consideration of radionuclide transfer. Dose conversion coefficients (DCCs) have been derived for selected flora and fauna using, inter alia, dose attenuation and chord distribution functions. The calculated dose-rates can be contextualised through comparison with dose-rates arising from natural background and chronic dose-rates at which biological effects have been observed in selected 'umbrella' endpoints

  10. Body size and allometric shape variation in the molly Poecilia vivipara along a gradient of salinity and predation.

    Science.gov (United States)

    Araújo, Márcio S; Perez, S Ivan; Magazoni, Maria Julia C; Petry, Ana C

    2014-12-04

    Phenotypic diversity among populations may result from divergent natural selection acting directly on traits or via correlated responses to changes in other traits. One of the most frequent patterns of correlated response is the proportional change in the dimensions of anatomical traits associated with changes in growth or absolute size, known as allometry. Livebearing fishes subject to predation gradients have been shown to repeatedly evolve larger caudal peduncles and smaller cranial regions under high predation regimes. Poecilia vivipara is a livebearing fish commonly found in coastal lagoons in the north of the state of Rio de Janeiro, Brazil. Similar to what is observed in other predation gradients, lagoons inhabited by P. vivipara vary in the presence of piscivorous fishes; contrary to other poeciliid systems, populations of P. vivipara vary greatly in body size, which opens the possibility of strong allometric effects on shape variation. Here we investigated body shape diversification among six populations of P. vivipara along a predation gradient and its relationship with allometric trajectories within and among populations. We found substantial body size variation and correlated shape changes among populations. Multivariate regression analysis showed that size variation among populations accounted for 66% of shape variation in females and 38% in males, suggesting that size is the most important dimension underlying shape variation among populations of P. vivipara in this system. Changes in the relative sizes of the caudal peduncle and cranial regions were only partly in line with predictions from divergent natural selection associated with predation regime. Our results suggest the possibility that adaptive shape variation among populations has been partly constrained by allometry in P. vivipara. Processes governing body size changes are therefore important in the diversification of this species. We conclude that in species characterized by substantial

  11. Feeding biomechanics and theoretical calculations of bite force in bull sharks (Carcharhinus leucas) during ontogeny.

    Science.gov (United States)

    Habegger, Maria L; Motta, Philip J; Huber, Daniel R; Dean, Mason N

    2012-12-01

    Evaluations of bite force, either measured directly or calculated theoretically, have been used to investigate the maximum feeding performance of a wide variety of vertebrates. However, bite force studies of fishes have focused primarily on small species due to the intractable nature of large apex predators. More massive muscles can generate higher forces and many of these fishes attain immense sizes; it is unclear how much of their biting performance is driven purely by dramatic ontogenetic increases in body size versus size-specific selection for enhanced feeding performance. In this study, we investigated biting performance and feeding biomechanics of immature and mature individuals from an ontogenetic series of an apex predator, the bull shark, Carcharhinus leucas (73-285cm total length). Theoretical bite force ranged from 36 to 2128N at the most anterior bite point, and 170 to 5914N at the most posterior bite point over the ontogenetic series. Scaling patterns differed among the two age groups investigated; immature bull shark bite force scaled with positive allometry, whereas adult bite force scaled isometrically. When the bite force of C. leucas was compared to those of 12 other cartilaginous fishes, bull sharks presented the highest mass-specific bite force, greater than that of the white shark or the great hammerhead shark. A phylogenetic independent contrast analysis of anatomical and dietary variables as determinants of bite force in these 13 species indicated that the evolution of large adult bite forces in cartilaginous fishes is linked predominantly to the evolution of large body size. Multiple regressions based on mass-specific standardized contrasts suggest that the evolution of high bite forces in Chondrichthyes is further correlated with hypertrophication of the jaw adductors, increased leverage for anterior biting, and widening of the head. Lastly, we discuss the ecological significance of positive allometry in bite force as a possible

  12. Geometric morphometric analysis of allometric variation in the mandibular morphology of the hominids of Atapuerca, Sima de los Huesos site.

    Science.gov (United States)

    Rosas, Antonio; Bastir, Markus

    2004-06-01

    Allometry is an important factor of morphological integration that contributes to the organization of the phenotype and its variation. Variation in the allometric shape of the mandible is particularly important in hominid evolution because the mandible carries important taxonomic traits. Some of these traits are known to covary with size, particularly the retromolar space, symphyseal curvature, and position of the mental foramen. The mandible is a well studied system in the context of the evolutionary development of complex morphological structures because it is composed of different developmental units that are integrated within a single bone. In the present study, we investigated the allometric variation of two important developmental units that are separated by the inferior nerve (a branch of CN V3). We tested the null hypothesis that there would be no difference in allometric variation between the two components. Procrustes-based geometric morphometrics of 20 two-dimensional (2D) landmarks were analyzed by multivariate regressions of shape on size in samples from 121 humans, 48 chimpanzees, and 50 gorillas (all recent specimens), eight fossil hominids from Atapuerca, Sima de los Huesos (AT-SH), and 17 Neandertals. The findings show that in all of the examined species, there was significantly greater allometric variation in the supra-nerve unit than in the infra-nerve unit. The formation of the retromolar space exhibited an allometric relationship with the supra-nerve unit in all of the species studied. The formation of the chin-like morphology is an "apodynamic" feature of the infra-nerve unit in the AT-SH hominids. The results of this study support the hypothesis that allometry contributes to the organization of variation in complex morphological structures. Copyright 2004 Wiley-Liss, Inc.

  13. Ontogenetic convergence and evolution of foot morphology in European cave salamanders (Family: Plethodontidae

    Directory of Open Access Journals (Sweden)

    Nistri Annamaria

    2010-07-01

    Full Text Available Abstract Background A major goal in evolutionary biology is to understand the evolution of phenotypic diversity. Both natural and sexual selection play a large role in generating phenotypic adaptations, with biomechanical requirements and developmental mechanisms mediating patterns of phenotypic evolution. For many traits, the relative importance of selective and developmental components remains understudied. Results We investigated ontogenetic trajectories of foot morphology in the eight species of European plethodontid cave salamander to test the hypothesis that adult foot morphology was adapted for climbing. Using geometric morphometrics and other approaches, we found that developmental patterns in five species displayed little morphological change during growth (isometry, where the extensive interdigital webbing in adults was best explained as the retention of the juvenile morphological state. By contrast, three species exhibited significant allometry, with an increase in interdigital webbing during growth. Phylogenetic analyses revealed that multiple evolutionary transitions between isometry and allometry of foot webbing have occurred in this lineage. Allometric parameters of foot growth were most similar to those of a tropical species previously shown to be adapted for climbing. Finally, interspecific variation in adult foot morphology was significantly reduced as compared to variation among juveniles, indicating that ontogenetic convergence had resulted in a common adult foot morphology across species. Conclusions The results presented here provide evidence of a complex history of phenotypic evolution in this clade. The common adult phenotype exhibited among species reveals that selection plays an important part in generating patterns of foot diversity in the group. However, developmental trajectories arriving at this common morphology are distinct; with some species displaying developmental stasis (isometry, while others show an increase

  14. The relationships among jaw-muscle fiber architecture, jaw morphology, and feeding behavior in extant apes and modern humans.

    Science.gov (United States)

    Taylor, Andrea B; Vinyard, Christopher J

    2013-05-01

    The jaw-closing muscles are responsible for generating many of the forces and movements associated with feeding. Muscle physiologic cross-sectional area (PCSA) and fiber length are two architectural parameters that heavily influence muscle function. While there have been numerous comparative studies of hominoid and hominin craniodental and mandibular morphology, little is known about hominoid jaw-muscle fiber architecture. We present novel data on masseter and temporalis internal muscle architecture for small- and large-bodied hominoids. Hominoid scaling patterns are evaluated and compared with representative New- (Cebus) and Old-World (Macaca) monkeys. Variation in hominoid jaw-muscle fiber architecture is related to both absolute size and allometry. PCSAs scale close to isometry relative to jaw length in anthropoids, but likely with positive allometry in hominoids. Thus, large-bodied apes may be capable of generating both absolutely and relatively greater muscle forces compared with smaller-bodied apes and monkeys. Compared with extant apes, modern humans exhibit a reduction in masseter PCSA relative to condyle-M1 length but retain relatively long fibers, suggesting humans may have sacrificed relative masseter muscle force during chewing without appreciably altering muscle excursion/contraction velocity. Lastly, craniometric estimates of PCSAs underestimate hominoid masseter and temporalis PCSAs by more than 50% in gorillas, and overestimate masseter PCSA by as much as 30% in humans. These findings underscore the difficulty of accurately estimating jaw-muscle fiber architecture from craniometric measures and suggest models of fossil hominin and hominoid bite forces will be improved by incorporating architectural data in estimating jaw-muscle forces. Copyright © 2013 Wiley Periodicals, Inc.

  15. Internal dosimetry for [4-{sup 14}C]-cholesterol in humans; Dosimetria interna para o [4-{sup 14}C]-colesterol em humanos

    Energy Technology Data Exchange (ETDEWEB)

    Marcato, Larissa Andreto

    2012-07-01

    The main objective of this work is to provide a biokinetic model in order to estimate the radiometric dose due to intake of [4-{sup 14}C]-cholesterol. The model was validated comparing the values of fecal excretion and absorption described in literature with that predicted by the model. The proposed model achieved good concordance between the results (p = 0.416 for excretion and p = 0.423 for absorption). The coefficients of effective dose (SvBq{sup -1}), equivalent dose (SvBq{sup -1}) and absorbed dose (GyBq{sup -1}) in human organs and tissues were calculated using the MIRD methodology and the compartmental analysis software ANACOMP. The coefficients were estimated for four phantoms: adult with a body mass of 73.3 kg, 15 years old adolescent (56.9 kg), 10 years old child (33.2 kg) and five years old child (19.8 kg). The organ that received the highest absorbed dose for all phantoms was the lower large intestine (LLI). The allometry theory was used to interpolate the coefficient of absorbed dose in the lower large intestine (DLLI) for unknown body mass (m): DLLI (GyBq{sup -1})=161.26 m (kg){sup -1.025}. For the same administered activity, the effective dose coefficient (E) decreases as the body mass increases. On other words, for the same intake activity, individuals with low body mass are exposed to higher doses. The allometry theory was used to interpolate the coefficient effective dose (E) for unknown body mass (m): E(SvB{sup -1})= 171.1 m(kg){sup -1,021}. (author)

  16. A comparative meta-analysis of maximal aerobic metabolism of vertebrates: implications for respiratory and cardiovascular limits to gas exchange.

    Science.gov (United States)

    Hillman, Stanley S; Hancock, Thomas V; Hedrick, Michael S

    2013-02-01

    Maximal aerobic metabolic rates (MMR) in vertebrates are supported by increased conductive and diffusive fluxes of O(2) from the environment to the mitochondria necessitating concomitant increases in CO(2) efflux. A question that has received much attention has been which step, respiratory or cardiovascular, provides the principal rate limitation to gas flux at MMR? Limitation analyses have principally focused on O(2) fluxes, though the excess capacity of the lung for O(2) ventilation and diffusion remains unexplained except as a safety factor. Analyses of MMR normally rely upon allometry and temperature to define these factors, but cannot account for much of the variation and often have narrow phylogenetic breadth. The unique aspect of our comparative approach was to use an interclass meta-analysis to examine cardio-respiratory variables during the increase from resting metabolic rate to MMR among vertebrates from fish to mammals, independent of allometry and phylogeny. Common patterns at MMR indicate universal principles governing O(2) and CO(2) transport in vertebrate cardiovascular and respiratory systems, despite the varied modes of activities (swimming, running, flying), different cardio-respiratory architecture, and vastly different rates of metabolism (endothermy vs. ectothermy). Our meta-analysis supports previous studies indicating a cardiovascular limit to maximal O(2) transport and also implicates a respiratory system limit to maximal CO(2) efflux, especially in ectotherms. Thus, natural selection would operate on the respiratory system to enhance maximal CO(2) excretion and the cardiovascular system to enhance maximal O(2) uptake. This provides a possible evolutionary explanation for the conundrum of why the respiratory system appears functionally over-designed from an O(2) perspective, a unique insight from previous work focused solely on O(2) fluxes. The results suggest a common gas transport blueprint, or Bauplan, in the vertebrate clade.

  17. Domestic chickens defy Rensch's rule: sexual size dimorphism in chicken breeds.

    Science.gov (United States)

    Remeš, V; Székely, T

    2010-12-01

    Sexual size dimorphism (SSD), i.e. the difference in sizes of males and females, is a key evolutionary feature that is related to ecology, behaviour and life histories of organisms. Although the basic patterns of SSD are well documented for several major taxa, the processes generating SSD are poorly understood. Domesticated animals offer excellent opportunities for testing predictions of functional explanations of SSD theory because domestic stocks were often selected by humans for particular desirable traits. Here, we analyse SSD in 139 breeds of domestic chickens Gallus gallus domesticus and compare them to their wild relatives (pheasants, partridges and grouse; Phasianidae, 53 species). SSD was male-biased in all chicken breeds, because males were 21.5 ± 0.55% (mean ± SE) heavier than females. The extent of SSD did not differ among breed categories (cock fighting, ornamental and breeds selected for egg and meat production). SSD of chicken breeds was not different from wild pheasants and allies (23.5 ± 3.43%), although the wild ancestor of chickens, the red jungle fowl G. gallus, had more extreme SSD (male 68.8% heavier) than any domesticated breed. Male mass and female mass exhibited positive allometry among pheasants and allies, consistently with the Rensch's rule reported from various taxa. However, body mass scaled isometrically across chicken breeds. The latter results suggest that sex-specific selection on males vs. females is necessary to generate positive allometry, i.e. the Rensch's rule, in wild populations. © 2010 The Authors. Journal Compilation © 2010 European Society For Evolutionary Biology.

  18. Chewing rates among domestic dog breeds

    Science.gov (United States)

    Gerstner, Geoffrey E.; Cooper, Meghan; Helvie, Peter

    2010-01-01

    The mammalian masticatory rhythm is produced by a brainstem timing network. The rhythm is relatively fixed within individual animals but scales allometrically with body mass (Mb) across species. It has been hypothesized that sensory feedback and feed-forward adjust the rhythm to match the jaw's natural resonance frequency, with allometric scaling being an observable consequence. However, studies performed with adult animals show that the rhythm is not affected by jaw mass manipulations, indicating that either developmental or evolutionary mechanisms are required for allometry to become manifest. The present study was performed to tease out the relative effects of development versus natural selection on chewing rate allometry. Thirty-one dog breeds and 31 mass-matched non-domestic mammalian species with a range in Mb from ∼2 kg to 50 kg were studied. Results demonstrated that the chewing rhythm did not scale with Mb among dog breeds (R=0.299, P>0.10) or with jaw length (Lj) (R=0.328, P>0.05). However, there was a significant relationship between the chewing rhythm and Mb among the non-domestic mammals (R=0.634, Pgeneration but they do not explain the 1/3rd to 1/4th allometric scaling observed among adult mammals. The rhythm of the timing network is either adjusted to the physical parameters of the jaw system during early development only, is genetically determined independently of the jaw system or is uniquely hard-wired among dogs and laboratory rodents. PMID:20543125

  19. Aging, Maturation and Growth of Sauropodomorph Dinosaurs as Deduced from Growth Curves Using Long Bone Histological Data: An Assessment of Methodological Constraints and Solutions.

    Science.gov (United States)

    Griebeler, Eva Maria; Klein, Nicole; Sander, P Martin

    2013-01-01

    Information on aging, maturation, and growth is important for understanding life histories of organisms. In extinct dinosaurs, such information can be derived from the histological growth record preserved in the mid-shaft cortex of long bones. Here, we construct growth models to estimate ages at death, ages at sexual maturity, ages at which individuals were fully-grown, and maximum growth rates from the growth record preserved in long bones of six sauropod dinosaur individuals (one indeterminate mamenchisaurid, two Apatosaurus sp., two indeterminate diplodocids, and one Camarasaurus sp.) and one basal sauropodomorph dinosaur individual (Plateosaurus engelhardti). Using these estimates, we establish allometries between body mass and each of these traits and compare these to extant taxa. Growth models considered for each dinosaur individual were the von Bertalanffy model, the Gompertz model, and the logistic model (LGM), all of which have inherently fixed inflection points, and the Chapman-Richards model in which the point is not fixed. We use the arithmetic mean of the age at the inflection point and of the age at which 90% of asymptotic mass is reached to assess respectively the age at sexual maturity or the age at onset of reproduction, because unambiguous indicators of maturity in Sauropodomorpha are lacking. According to an AIC-based model selection process, the LGM was the best model for our sauropodomorph sample. Allometries established are consistent with literature data on other Sauropodomorpha. All Sauropodomorpha reached full size within a time span similar to scaled-up modern mammalian megaherbivores and had similar maximum growth rates to scaled-up modern megaherbivores and ratites, but growth rates of Sauropodomorpha were lower than of an average mammal. Sauropodomorph ages at death probably were lower than that of average scaled-up ratites and megaherbivores. Sauropodomorpha were older at maturation than scaled-up ratites and average mammals, but

  20. Neighbourhood structure and light availability influence the variations in plant design of shrubs in two cloud forests of different successional status.

    Science.gov (United States)

    Guzmán Q, J Antonio; Cordero, Roberto A

    2016-07-01

    Plant design refers to the construction of the plant body or its constituent parts in terms of form and function. Although neighbourhood structure is recognized as a factor that limits plant survival and species coexistence, its relative importance in plant design is not well understood. We conducted field research to analyse how the surrounding environment of neighbourhood structure and related effects on light availability are associated with changes in plant design in two understorey plants (Palicourea padifolia and Psychotria elata) within two successional stages of a cloud forest in Costa Rica. Features of plant neighbourhood physical structure and light availability, estimated using hemispherical photographs, were used as variables that reflect the surrounding environment. Measures of plant biomechanics, allometry, branching and plant slenderness were used as functional plant attributes that reflect plant design. We propose a framework using a partial least squares path model and used it to test this association. The multidimensional response of plant design of these species suggests that decreases in the height-based factor of safety and increases in mechanical load and developmental stability are influenced by increases in maximum height of neighbours and a distance-dependence interference index more than neighbourhood plant density or neighbour aggregation. Changes in plant branching and slenderness are associated positively with light availability and negatively with canopy cover. Although it has been proposed that plant design varies according to plant density and light availability, we found that neighbour size and distance-dependence interference are associated with changes in biomechanics, allometry and branching, and they must be considered as key factors that contribute to the adaptation and coexistence of these plants in this highly diverse forest community. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany

  1. Allometric and temporal scaling of movement characteristics in Galapagos tortoises

    Science.gov (United States)

    Bastille-Rousseau, Guillaume; Yackulic, Charles B.; Frair, Jacqueline L.; Cabrera, Freddy; Blake, Stephen

    2016-01-01

    Understanding how individual movement scales with body size is of fundamental importance in predicting ecological relationships for diverse species. One-dimensional movement metrics scale consistently with body size yet vary over different temporal scales. Knowing how temporal scale influences the relationship between animal body size and movement would better inform hypotheses about the efficiency of foraging behaviour, the ontogeny of energy budgets, and numerous life-history trade-offs.We investigated how the temporal scaling of allometric patterns in movement varies over the course of a year, specifically during periods of motivated (directional and fast movement) and unmotivated (stationary and tortuous movement) behaviour. We focused on a recently diverged group of species that displays wide variation in movement behaviour – giant Galapagos tortoises (Chelonoidis spp.) – to test how movement metrics estimated on a monthly basis scaled with body size.We used state-space modelling to estimate seven different movement metrics of Galapagos tortoises. We used log-log regression of the power law to evaluate allometric scaling for these movement metrics and contrasted relationships by species and sex.Allometric scaling of movement was more apparent during motivated periods of movement. During this period, allometry was revealed at multiple temporal intervals (hourly, daily and monthly), with values observed at daily and monthly intervals corresponding most closely to the expected one-fourth scaling coefficient, albeit with wide credible intervals. We further detected differences in the magnitude of scaling among taxa uncoupled from observed differences in the temporal structuring of their movement rates.Our results indicate that the definition of temporal scales is fundamental to the detection of allometry of movement and should be given more attention in movement studies. Our approach not only provides new conceptual insights into temporal attributes in one

  2. Aging, Maturation and Growth of Sauropodomorph Dinosaurs as Deduced from Growth Curves Using Long Bone Histological Data: An Assessment of Methodological Constraints and Solutions.

    Directory of Open Access Journals (Sweden)

    Eva Maria Griebeler

    Full Text Available Information on aging, maturation, and growth is important for understanding life histories of organisms. In extinct dinosaurs, such information can be derived from the histological growth record preserved in the mid-shaft cortex of long bones. Here, we construct growth models to estimate ages at death, ages at sexual maturity, ages at which individuals were fully-grown, and maximum growth rates from the growth record preserved in long bones of six sauropod dinosaur individuals (one indeterminate mamenchisaurid, two Apatosaurus sp., two indeterminate diplodocids, and one Camarasaurus sp. and one basal sauropodomorph dinosaur individual (Plateosaurus engelhardti. Using these estimates, we establish allometries between body mass and each of these traits and compare these to extant taxa. Growth models considered for each dinosaur individual were the von Bertalanffy model, the Gompertz model, and the logistic model (LGM, all of which have inherently fixed inflection points, and the Chapman-Richards model in which the point is not fixed. We use the arithmetic mean of the age at the inflection point and of the age at which 90% of asymptotic mass is reached to assess respectively the age at sexual maturity or the age at onset of reproduction, because unambiguous indicators of maturity in Sauropodomorpha are lacking. According to an AIC-based model selection process, the LGM was the best model for our sauropodomorph sample. Allometries established are consistent with literature data on other Sauropodomorpha. All Sauropodomorpha reached full size within a time span similar to scaled-up modern mammalian megaherbivores and had similar maximum growth rates to scaled-up modern megaherbivores and ratites, but growth rates of Sauropodomorpha were lower than of an average mammal. Sauropodomorph ages at death probably were lower than that of average scaled-up ratites and megaherbivores. Sauropodomorpha were older at maturation than scaled-up ratites and average

  3. Scale-Adjusted Metrics for Predicting the Evolution of Urban Indicators and Quantifying the Performance of Cities.

    Directory of Open Access Journals (Sweden)

    Luiz G A Alves

    Full Text Available More than a half of world population is now living in cities and this number is expected to be two-thirds by 2050. Fostered by the relevancy of a scientific characterization of cities and for the availability of an unprecedented amount of data, academics have recently immersed in this topic and one of the most striking and universal finding was the discovery of robust allometric scaling laws between several urban indicators and the population size. Despite that, most governmental reports and several academic works still ignore these nonlinearities by often analyzing the raw or the per capita value of urban indicators, a practice that actually makes the urban metrics biased towards small or large cities depending on whether we have super or sublinear allometries. By following the ideas of Bettencourt et al. [PLoS ONE 5 (2010 e13541], we account for this bias by evaluating the difference between the actual value of an urban indicator and the value expected by the allometry with the population size. We show that this scale-adjusted metric provides a more appropriate/informative summary of the evolution of urban indicators and reveals patterns that do not appear in the evolution of per capita values of indicators obtained from Brazilian cities. We also show that these scale-adjusted metrics are strongly correlated with their past values by a linear correspondence and that they also display crosscorrelations among themselves. Simple linear models account for 31%-97% of the observed variance in data and correctly reproduce the average of the scale-adjusted metric when grouping the cities in above and below the allometric laws. We further employ these models to forecast future values of urban indicators and, by visualizing the predicted changes, we verify the emergence of spatial clusters characterized by regions of the Brazilian territory where we expect an increase or a decrease in the values of urban indicators.

  4. Internal dosimetry for [4-14C]-cholesterol in humans

    International Nuclear Information System (INIS)

    Marcato, Larissa Andreto

    2012-01-01

    The main objective of this work is to provide a biokinetic model in order to estimate the radiometric dose due to intake of [4- 14 C]-cholesterol. The model was validated comparing the values of fecal excretion and absorption described in literature with that predicted by the model. The proposed model achieved good concordance between the results (p = 0.416 for excretion and p = 0.423 for absorption). The coefficients of effective dose (SvBq -1 ), equivalent dose (SvBq -1 ) and absorbed dose (GyBq -1 ) in human organs and tissues were calculated using the MIRD methodology and the compartmental analysis software ANACOMP. The coefficients were estimated for four phantoms: adult with a body mass of 73.3 kg, 15 years old adolescent (56.9 kg), 10 years old child (33.2 kg) and five years old child (19.8 kg). The organ that received the highest absorbed dose for all phantoms was the lower large intestine (LLI). The allometry theory was used to interpolate the coefficient of absorbed dose in the lower large intestine (DLLI) for unknown body mass (m): DLLI (GyBq -1 )=161.26 m (kg) -1.025 . For the same administered activity, the effective dose coefficient (E) decreases as the body mass increases. On other words, for the same intake activity, individuals with low body mass are exposed to higher doses. The allometry theory was used to interpolate the coefficient effective dose (E) for unknown body mass (m): E(SvB -1 )= 171.1 m(kg) -1,021 . (author)

  5. Crescimento alométrico de osso, músculo e gordura em cortes da carcaça de cordeiros Texel segundo os métodos de alimentação e peso de abate Muscle, fat and bone allometric growth in Texel lambs carcasses cuts in relation to the feeding methods and slaughter weight

    Directory of Open Access Journals (Sweden)

    Gilberto Teixeira da Rosa

    2005-08-01

    sexo com coeficientes de alometria variando de 1,80 a 2,12.The experiment aimed at studying the allometric growth of the different tissues of neck, rib, shoulder blade and leg in relation to the cutting weight of male and female lambs. Twenty-two intact Texel males and 23 Texel females were used. Seven of them were slaughtered at the beginning of the experiment and the others at the weight of 25 or 33kg. Sheep and lambs were distributed into three methods of feeding: M1 - Corn silage and concentrate, only to lambs until weaning at 60 days old; M2 - Corn silage and concentrate, only to lambs until weaning at 45 days old and M3 - Corn silage and concentrate to ewe and lamb until weaning at 60 days old. After weaning, lambs were fed with silage plus concentrate. A completely randomized design outlined in a factorial arrangement 3 x 2 x 2 (3 methods, 2 sexes and 2 slaughter weights was used. Determination of growth was obtained through the equation log y = log.a + b log.x, by using the logarithm of bone, muscle and fat weight in function of cutting weight logarithm. It was observed that neck and rib bone was precocious (b1, regardless of sex and feeding method with allometry coefficients varying from 1.78 to 2.15 (neck and 1.51 to 1.65 (rib. In shoulder blade, bone was precocious in both sexes, with allometry coefficients varying from 0.76 to 0.79 and 0.54 to 0.58 for males and females, respectively. Muscle presented isometric growth (b = 1, regardless of sex and slaughter weight. Fat was late (b>1, regardless of slaughter weight and sex, with allometry coefficients varying from 1.80 to 2.12. In leg, bone growth was precocious in females and isometric in males, with allometry coefficients varying from 0.57 to 0.63 and 0.78 to 0.80, respectively, for both sexes. Muscle presented isometric growth (b = 1, regardless of sex and slaughter weight. Fat was late (b>1, regardless of slaughter weight and sex, with allometry coefficients varying from 1.80 to 2.12.

  6. Relative growth and morphological sexual maturity of Chasmagnathus granulatus (Crustacea, Varunidae from a mangrove area in southeastern Brazilian coast Crescimento relativo e maturidade sexual morfológica de Chasmagnathus granulatus (Crustacea, Varunidae de uma área de manguezal no sudeste do Brasil

    Directory of Open Access Journals (Sweden)

    Rafael Augusto Gregati

    Full Text Available The relative growth and morphological sexual maturity of Chasmagnathus granulatus Dana, 1851 are presented for the first time to a mangrove population. The crabs were obtained during low tide periods, in the mangrove of Jabaquara Beach, Paraty, Rio de Janeiro, Brazil. All crabs in intermolt stage were sexed and had their body parts measured as follows: body height (BH, carapace length (CL and width (CW, major cheliped propodus height (PH and length (PL for each sex, gonopod length (GL and abdomen width (AW for males and females, respectively. The relative growth was described using the allometric equation y=ax b and the size at onset sexual maturity was achieved using the software Mature I. The size of specimens ranged from 4.1 mm to 39.5 mm CW. The growth pattern was different between sexes in the cheliped relationships; the relationships BH vs. CW evidenced positive allometry for juveniles; PL vs. CW and PH vs. CW positive allometry for most crabs except juvenile females; AW vs. CW and GL vs. CW evidenced positive allometry for juveniles and isometry for adults. The relationships that best indicated the change from the juvenile to the adult phase were PH vs. CW for males and AW vs. CW for females. The size in which 50% of males from this population are mature is at 19.7 mm of CW (F=144.14; pO crescimento relativo e a maturidade sexual morfológica de Chasmagnathus granulatus Dana, 1851 são apresentados pela primeira vez para uma população de manguezal. Os caranguejos foram obtidos durante os períodos de maré baixa, no manguezal da praia do Jabaquara, Paraty, Rio de Janeiro, Brasil. Todos os caranguejos em estágio de intermuda foram classificados quanto ao sexo e as seguintes medidas lineares foram tomadas: altura do corpo (AC, altura do própodo do quelípodo maior (APQ, comprimento da carapaça (CC, comprimento do própodo do quelípodo maior (CPQ, largura da carapaça (LC, comprimento do gonopódio (CG e largura do abdome (LA para

  7. Estimating mangrove aboveground biomass from airborne LiDAR data: a case study from the Zambezi River delta

    Science.gov (United States)

    Fatoyinbo, Temilola; Feliciano, Emanuelle A.; Lagomasino, David; Kuk Lee, Seung; Trettin, Carl

    2018-02-01

    to predict AGB was based on the East Africa specific allometry and a power-based regression that used Lidar H100 as the height input with an R 2 of 0.85 and an RMSE of 122 Mg ha-1 or 33%. The total AGB of the Lidar inventoried mangrove area (6654 ha) was 1 350 902 Mg with a mean AGB of 203 Mg ha-1 ±166 Mg ha-1. Because the allometry suggested here was developed using standardized height metrics, it is recommended that the models can generate AGB estimates using other remote sensing instruments that are more readily accessible over other mangrove ecosystems on a large scale, and as part of future carbon monitoring efforts in mangroves.

  8. Getting a head in hard soils: Convergent skull evolution and divergent allometric patterns explain shape variation in a highly diverse genus of pocket gophers (Thomomys).

    Science.gov (United States)

    Marcy, Ariel E; Hadly, Elizabeth A; Sherratt, Emma; Garland, Kathleen; Weisbecker, Vera

    2016-10-10

    High morphological diversity can occur in closely related animals when selection favors morphologies that are subject to intrinsic biological constraints. A good example is subterranean rodents of the genus Thomomys, one of the most taxonomically and morphologically diverse mammalian genera. Highly procumbent, tooth-digging rodent skull shapes are often geometric consequences of increased body size. Indeed, larger-bodied Thomomys species tend to inhabit harder soils. We used geometric morphometric analyses to investigate the interplay between soil hardness (the main extrinsic selection pressure on fossorial mammals) and allometry (i.e. shape change due to size change; generally considered the main intrinsic factor) on crania and humeri in this fast-evolving mammalian clade. Larger Thomomys species/subspecies tend to have more procumbent cranial shapes with some exceptions, including a small-bodied species inhabiting hard soils. Counter to earlier suggestions, cranial shape within Thomomys does not follow a genus-wide allometric pattern as even regional subpopulations differ in allometric slopes. In contrast, humeral shape varies less with body size and with soil hardness. Soft-soil taxa have larger humeral muscle attachment sites but retain an orthodont (non-procumbent) cranial morphology. In intermediate soils, two pairs of sister taxa diverge through differential modifications on either the humerus or the cranium. In the hardest soils, both humeral and cranial morphology are derived through large muscle attachment sites and a high degree of procumbency. Our results show that conflict between morphological function and intrinsic allometric patterning can quickly and differentially alter the rodent skeleton, especially the skull. In addition, we found a new case of convergent evolution of incisor procumbency among large-, medium-, and small-sized species inhabiting hard soils. This occurs through different combinations of allometric and non-allometric changes

  9. Do Interspecific Differences in Sapling Growth Traits Contribute to the Co-dominance of Acer saccharum and Fagus grandifolia?

    Science.gov (United States)

    Takahashi, Koichi; Lechowicz, Martin J.

    2008-01-01

    Background and Aims Acer saccharum and Fagus grandifolia are among the most dominant late-successional tree species in North America. The influence of sapling growth responses to canopy gaps on the co-dominance of the two species in an old-growth forest in southern Quebec, Canada was examined. Two predictions were evaluated: (a) F. grandifolia is more shade tolerant than A. saccharum due to greater sapling leaf area and net production per sapling in closed-canopy conditions; and (b) the height growth rate of A. saccharum in canopy gaps is greater than that of F. grandifolia due to increased net production per sapling. Methods Sapling crown allometry, net production and height growth rates were compared between and within the two species in closed canopy vs. canopy gaps. Standardized major axis regression was used to analyse differences in crown allometry. Key Results F. grandifolia had greater crown projection, sapling leaf area and net production rate per sapling than A. saccharum in closed-canopy conditions. In response to canopy gaps, net production per sapling increased to the same degree in both species. The net production per sapling of F. grandifolia thus was much greater than that of A. saccharum in both canopy gap and closed-canopy conditions. The height growth rate of both species increased in canopy gaps, but the degree of increase was greater in F. grandifolia than in A. saccharum. Conclusions F. grandifolia regenerated more successfully than A. saccharum in both closed-canopy conditions and canopy gaps, which indicates that the co-dominance of the two species cannot be maintained simply by interspecific differences in shade tolerance and growth in gaps. Previous research showed that although Fagus and Acer shared dominance at this site, their relative dominance shifted with edaphic conditions. This suggests that the widespread co-dominance of the two species in eastern North American forests is maintained by the joint influence of canopy disturbance

  10. Scale effects and morphological diversification in hindlimb segment mass proportions in neognath birds.

    Science.gov (United States)

    Kilbourne, Brandon M

    2014-01-01

    In spite of considerable work on the linear proportions of limbs in amniotes, it remains unknown whether differences in scale effects between proximal and distal limb segments has the potential to influence locomotor costs in amniote lineages and how changes in the mass proportions of limbs have factored into amniote diversification. To broaden our understanding of how the mass proportions of limbs vary within amniote lineages, I collected data on hindlimb segment masses - thigh, shank, pes, tarsometatarsal segment, and digits - from 38 species of neognath birds, one of the most speciose amniote clades. I scaled each of these traits against measures of body size (body mass) and hindlimb size (hindlimb length) to test for departures from isometry. Additionally, I applied two parameters of trait evolution (Pagel's λ and δ) to understand patterns of diversification in hindlimb segment mass in neognaths. All segment masses are positively allometric with body mass. Segment masses are isometric with hindlimb length. When examining scale effects in the neognath subclade Land Birds, segment masses were again positively allometric with body mass; however, shank, pedal, and tarsometatarsal segment masses were also positively allometric with hindlimb length. Methods of branch length scaling to detect phylogenetic signal (i.e., Pagel's λ) and increasing or decreasing rates of trait change over time (i.e., Pagel's δ) suffer from wide confidence intervals, likely due to small sample size and deep divergence times. The scaling of segment masses appears to be more strongly related to the scaling of limb bone mass as opposed to length, and the scaling of hindlimb mass distribution is more a function of scale effects in limb posture than proximo-distal differences in the scaling of limb segment mass. Though negative allometry of segment masses appears to be precluded by the need for mechanically sound limbs, the positive allometry of segment masses relative to body mass may

  11. Sagittal crest formation in great apes and gibbons.

    Science.gov (United States)

    Balolia, Katharine L; Soligo, Christophe; Wood, Bernard

    2017-06-01

    The frequency of sagittal crest expression and patterns of sagittal crest growth and development have been documented in hominoids, including some extinct hominin taxa, and the more frequent expression of the sagittal crest in males has been traditionally linked with the need for larger-bodied individuals to have enough attachment area for the temporalis muscle. In the present study, we investigate sagittal cresting in a dentally mature sample of four hominoid taxa (Pan troglodytes schweinfurthii, Gorilla gorilla gorilla, Pongo pygmaeus pygmaeus and Hylobates lar). We investigate whether sagittal crest size increases with age beyond dental maturity in males and females of G. g. gorilla and Po. pyg. pygmaeus, and whether these taxa show sex differences in the timing of sagittal crest development. We evaluate the hypothesis that the larger sagittal crest of males may not be solely due to the requirement for a larger surface area than the un-crested cranial vault can provide for the attachment of the temporalis muscle, and present data on sex differences in temporalis muscle attachment area and sagittal crest size relative to cranial size. Gorilla g. gorilla and Po. pyg. pygmaeus males show significant relationships between tooth wear rank and sagittal crest size, and they show sagittal crest size differences between age groups that are not found in females. The sagittal crest emerges in early adulthood in the majority of G. g. gorilla males, whereas the percentage of G. g. gorilla females possessing a sagittal crest increases more gradually. Pongo pyg. pygmaeus males experience a three-fold increase in the number of specimens exhibiting a sagittal crest in mid-adulthood, consistent with a secondary growth spurt. Gorilla g. gorilla and Po. pyg. pygmaeus show significant sex differences in the size of the temporalis muscle attachment area, relative to cranial size, with males of both taxa showing positive allometry not shown in females. Gorilla g

  12. Bat Species Comparisons Based on External Morphology: A Test of Traditional versus Geometric Morphometric Approaches.

    Science.gov (United States)

    Schmieder, Daniela A; Benítez, Hugo A; Borissov, Ivailo M; Fruciano, Carmelo

    2015-01-01

    External morphology is commonly used to identify bats as well as to investigate flight and foraging behavior, typically relying on simple length and area measures or ratios. However, geometric morphometrics is increasingly used in the biological sciences to analyse variation in shape and discriminate among species and populations. Here we compare the ability of traditional versus geometric morphometric methods in discriminating between closely related bat species--in this case European horseshoe bats (Rhinolophidae, Chiroptera)--based on morphology of the wing, body and tail. In addition to comparing morphometric methods, we used geometric morphometrics to detect interspecies differences as shape changes. Geometric morphometrics yielded improved species discrimination relative to traditional methods. The predicted shape for the variation along the between group principal components revealed that the largest differences between species lay in the extent to which the wing reaches in the direction of the head. This strong trend in interspecific shape variation is associated with size, which we interpret as an evolutionary allometry pattern.

  13. Bat Species Comparisons Based on External Morphology: A Test of Traditional versus Geometric Morphometric Approaches.

    Directory of Open Access Journals (Sweden)

    Daniela A Schmieder

    Full Text Available External morphology is commonly used to identify bats as well as to investigate flight and foraging behavior, typically relying on simple length and area measures or ratios. However, geometric morphometrics is increasingly used in the biological sciences to analyse variation in shape and discriminate among species and populations. Here we compare the ability of traditional versus geometric morphometric methods in discriminating between closely related bat species--in this case European horseshoe bats (Rhinolophidae, Chiroptera--based on morphology of the wing, body and tail. In addition to comparing morphometric methods, we used geometric morphometrics to detect interspecies differences as shape changes. Geometric morphometrics yielded improved species discrimination relative to traditional methods. The predicted shape for the variation along the between group principal components revealed that the largest differences between species lay in the extent to which the wing reaches in the direction of the head. This strong trend in interspecific shape variation is associated with size, which we interpret as an evolutionary allometry pattern.

  14. Growing Eremanthus erythropappus in crushed laterite: A promising alternative to topsoil for bauxite-mine revegetation.

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    Machado, Naiara Amaral de Miranda; Leite, Mariangela Garcia Praça; Figueiredo, Maurílio Assis; Kozovits, Alessandra Rodrigues

    2013-11-15

    Topsoil is the preferred substrate for areas requiring rehabilitation after bauxite mining. However, topsoil is sometimes lacking and so there is a need to test the suitability of other, locally available substrates. In an abandoned bauxite mine in Southeastern Brazil, small patches of native vegetation spontaneously established in shallow depressions over weathered laterite, suggesting that granulometric reduction may have facilitated the establishment of plants. To test this hypothesis, blocks of laterite collected in the area were crushed to simulate texture observed in the vegetation patches. Topsoil collected in a preserved ferruginous field near to the extraction area was also used as a substrate in which Eremanthus erythropappus seedlings, a native woody species, were grown. Seedlings were cultivated without fertilizers in these two substrates and also directly over the exposed and uncrushed laterite. The species proved to be very promising for the revegetation, showing a high survival rate in all substrates. Higher annual growth rates and higher final biomass values were observed in topsoil, but the granulometric reduction of laterite doubled plant growth rate in comparison to the exposed laterite. This result was likely due to the increased availability of essential nutrients to plants and to the improvement in physical conditions for root growth and functioning. Moreover, seedling allometry was not altered by the type of substrate, suggesting that the species was highly tolerant to the new substrate conditions, a fundamental characteristic for success of revegetation of bauxite extraction degraded areas. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. An Allometric Algorithm for Fractal-Based Cobb-Douglas Function of Geographical Systems

    Directory of Open Access Journals (Sweden)

    Hongyu Luo

    2014-01-01

    Full Text Available The generalized Cobb-Douglas production function has been derived from a general input-output relation based on fractality assumptions. It was proved to be a useful self-affine model for geographical analysis. However, the ordinary least square calculation is always an ineffectual method for the Cobb-Douglas modeling because of the multicollinearity in the logarithmic linear regression. In this paper, a novel approach is proposed to build the geographical Cobb-Douglas models. Combining the concept of allometric scaling with the linear regression technique, we obtain a simple algorithm that can be employed to estimate the parameters of the Cobb-Douglas function. As a case, the algorithm and models are applied to the public transportation of China’s cities, and the results validate the allometric algorithm. A conclusion can be drawn that the allometric analysis is an effective way of modeling geographical systems with the general Cobb-Douglas function. This study is significant for integrating the notions of allometry, fractals, and scaling into a new framework to form a quantitative methodology of spatial analysis.

  16. Size relationships of different body parts in the three dipteran species Drosophila melanogaster, Ceratitis capitata and Musca domestica.

    Science.gov (United States)

    Siomava, Natalia; Wimmer, Ernst A; Posnien, Nico

    2016-06-01

    Body size is an integral feature of an organism that influences many aspects of life such as fecundity, life span and mating success. Size of individual organs and the entire body size represent quantitative traits with a large reaction norm, which are influenced by various environmental factors. In the model system Drosophila melanogaster, pupal size and adult traits, such as tibia and thorax length or wing size, accurately estimate the overall body size. However, it is unclear whether these traits can be used in other flies. Therefore, we studied changes in size of pupae and adult organs in response to different rearing temperatures and densities for D. melanogaster, Ceratitis capitata and Musca domestica. We confirm a clear sexual size dimorphism (SSD) for Drosophila and show that the SSD is less uniform in the other species. Moreover, the size response to changing growth conditions is sex dependent. Comparison of static and evolutionary allometries of the studied traits revealed that response to the same environmental variable is genotype specific but has similarities between species of the same order. We conclude that the value of adult traits as estimators of the absolute body size may differ among species and the use of a single trait may result in wrong assumptions. Therefore, we suggest using a body size coefficient computed from several individual measurements. Our data is of special importance for monitoring activities of natural populations of the three dipteran flies, since they are harmful species causing economical damage (Drosophila, Ceratitis) or transferring diseases (Musca).

  17. Convergent evolution of vascular optimization in kelp (Laminariales).

    Science.gov (United States)

    Drobnitch, Sarah Tepler; Jensen, Kaare H; Prentice, Paige; Pittermann, Jarmila

    2015-10-07

    Terrestrial plants and mammals, although separated by a great evolutionary distance, have each arrived at a highly conserved body plan in which universal allometric scaling relationships govern the anatomy of vascular networks and key functional metabolic traits. The universality of allometric scaling suggests that these phyla have each evolved an 'optimal' transport strategy that has been overwhelmingly adopted by extant species. To truly evaluate the dominance and universality of vascular optimization, however, it is critical to examine other, lesser-known, vascularized phyla. The brown algae (Phaeophyceae) are one such group--as distantly related to plants as mammals, they have convergently evolved a plant-like body plan and a specialized phloem-like transport network. To evaluate possible scaling and optimization in the kelp vascular system, we developed a model of optimized transport anatomy and tested it with measurements of the giant kelp, Macrocystis pyrifera, which is among the largest and most successful of macroalgae. We also evaluated three classical allometric relationships pertaining to plant vascular tissues with a diverse sampling of kelp species. Macrocystis pyrifera displays strong scaling relationships between all tested vascular parameters and agrees with our model; other species within the Laminariales display weak or inconsistent vascular allometries. The lack of universal scaling in the kelps and the presence of optimized transport anatomy in M. pyrifera raises important questions about the evolution of optimization and the possible competitive advantage conferred by optimized vascular systems to multicellular phyla. © 2015 The Author(s).

  18. Sheldon spectrum and the plankton paradox: two sides of the same coin-a trait-based plankton size-spectrum model.

    Science.gov (United States)

    Cuesta, José A; Delius, Gustav W; Law, Richard

    2018-01-01

    The Sheldon spectrum describes a remarkable regularity in aquatic ecosystems: the biomass density as a function of logarithmic body mass is approximately constant over many orders of magnitude. While size-spectrum models have explained this phenomenon for assemblages of multicellular organisms, this paper introduces a species-resolved size-spectrum model to explain the phenomenon in unicellular plankton. A Sheldon spectrum spanning the cell-size range of unicellular plankton necessarily consists of a large number of coexisting species covering a wide range of characteristic sizes. The coexistence of many phytoplankton species feeding on a small number of resources is known as the Paradox of the Plankton. Our model resolves the paradox by showing that coexistence is facilitated by the allometric scaling of four physiological rates. Two of the allometries have empirical support, the remaining two emerge from predator-prey interactions exactly when the abundances follow a Sheldon spectrum. Our plankton model is a scale-invariant trait-based size-spectrum model: it describes the abundance of phyto- and zooplankton cells as a function of both size and species trait (the maximal size before cell division). It incorporates growth due to resource consumption and predation on smaller cells, death due to predation, and a flexible cell division process. We give analytic solutions at steady state for both the within-species size distributions and the relative abundances across species.

  19. Chewing on the trees: Constraints and adaptation in the evolution of the primate mandible.

    Science.gov (United States)

    Meloro, Carlo; Cáceres, Nilton Carlos; Carotenuto, Francesco; Sponchiado, Jonas; Melo, Geruza Leal; Passaro, Federico; Raia, Pasquale

    2015-07-01

    Chewing on different food types is a demanding biological function. The classic assumption in studying the shape of feeding apparatuses is that animals are what they eat, meaning that adaptation to different food items accounts for most of their interspecific variation. Yet, a growing body of evidence points against this concept. We use the primate mandible as a model structure to investigate the complex interplay among shape, size, diet, and phylogeny. We find a weak but significant impact of diet on mandible shape variation in primates as a whole but not in anthropoids and catarrhines as tested in isolation. These clades mainly exhibit allometric shape changes, which are unrelated to diet. Diet is an important factor in the diversification of strepsirrhines and platyrrhines and a phylogenetic signal is detected in all primate clades. Peaks in morphological disparity occur during the Oligocene (between 37 and 25 Ma) supporting the notion that an adaptive radiation characterized the evolution of South American monkeys. In all primate clades, the evolution of mandible size is faster than its shape pointing to a strong effect of allometry on ecomorphological diversification in this group. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  20. Cope's Rule and the Universal Scaling Law of Ornament Complexity.

    Science.gov (United States)

    Raia, Pasquale; Passaro, Federico; Carotenuto, Francesco; Maiorino, Leonardo; Piras, Paolo; Teresi, Luciano; Meiri, Shai; Itescu, Yuval; Novosolov, Maria; Baiano, Mattia Antonio; Martínez, Ricard; Fortelius, Mikael

    2015-08-01

    Luxuriant, bushy antlers, bizarre crests, and huge, twisting horns and tusks are conventionally understood as products of sexual selection. This view stems from both direct observation and from the empirical finding that the size of these structures grows faster than body size (i.e., ornament size shows positive allometry). We contend that the familiar evolutionary increase in the complexity of ornaments over time in many animal clades is decoupled from ornament size evolution. Increased body size comes with extended growth. Since growth scales to the quarter power of body size, we predicted that ornament complexity should scale according to the quarter power law as well, irrespective of the role of sexual selection in the evolution and function of the ornament. To test this hypothesis, we selected three clades (ammonites, deer, and ceratopsian dinosaurs) whose species bore ornaments that differ in terms of the importance of sexual selection to their evolution. We found that the exponent of the regression of ornament complexity to body size is the same for the three groups and is statistically indistinguishable from 0.25. We suggest that the evolution of ornament complexity is a by-product of Cope's rule. We argue that although sexual selection may control size in most ornaments, it does not influence their shape.

  1. The evolution of cranial base and face in Cercopithecoidea and Hominoidea: Modularity and morphological integration.

    Science.gov (United States)

    Profico, Antonio; Piras, Paolo; Buzi, Costantino; Di Vincenzo, Fabio; Lattarini, Flavio; Melchionna, Marina; Veneziano, Alessio; Raia, Pasquale; Manzi, Giorgio

    2017-12-01

    The evolutionary relationship between the base and face of the cranium is a major topic of interest in primatology. Such areas of the skull possibly respond to different selective pressures. Yet, they are often said to be tightly integrated. In this paper, we analyzed shape variability in the cranial base and the facial complex in Cercopithecoidea and Hominoidea. We used a landmark-based approach to single out the effects of size (evolutionary allometry), morphological integration, modularity, and phylogeny (under Brownian motion) on skull shape variability. Our results demonstrate that the cranial base and the facial complex exhibit different responses to different factors, which produces a little degree of morphological integration between them. Facial shape variation appears primarily influenced by body size and sexual dimorphism, whereas the cranial base is mostly influenced by functional factors. The different adaptations affecting the two modules suggest they are best studied as separate and independent units, and that-at least when dealing with Catarrhines-caution must be posed with the notion of strong cranial integration that is commonly invoked for the evolution of their skull shape. © 2017 Wiley Periodicals, Inc.

  2. A model for allometric scaling of mammalian metabolism with ambient heat loss

    KAUST Repository

    Kwak, Ho Sang

    2016-02-02

    Background Allometric scaling, which represents the dependence of biological trait or process relates on body size, is a long-standing subject in biological science. However, there has been no study to consider heat loss to the ambient and an insulation layer representing mammalian skin and fur for the derivation of the scaling law of metabolism. Methods A simple heat transfer model is proposed to analyze the allometry of mammalian metabolism. The present model extends existing studies by incorporating various external heat transfer parameters and additional insulation layers. The model equations were solved numerically and by an analytic heat balance approach. Results A general observation is that the present heat transfer model predicted the 2/3 surface scaling law, which is primarily attributed to the dependence of the surface area on the body mass. External heat transfer effects introduced deviations in the scaling law, mainly due to natural convection heat transfer which becomes more prominent at smaller mass. These deviations resulted in a slight modification of the scaling exponent to a value smaller than 2/3. Conclusion The finding that additional radiative heat loss and the consideration of an outer insulation fur layer attenuate these deviation effects and render the scaling law closer to 2/3 provides in silico evidence for a functional impact of heat transfer mode on the allometric scaling law in mammalian metabolism.

  3. Phenotypic Plasticity Explains Response Patterns of European Beech (Fagus sylvatica L. Saplings to Nitrogen Fertilization and Drought Events

    Directory of Open Access Journals (Sweden)

    Christoph Dziedek

    2017-03-01

    Full Text Available Abstract: Climate and atmospheric changes affect forest ecosystems worldwide, but little is known about the interactive effects of global change drivers on tree growth. In the present study, we analyzed single and combined effects of nitrogen (N fertilization and drought events (D on the growth of European beech (Fagus sylvatica L. saplings in a greenhouse experiment. We quantified morphological and physiological responses to treatments for one‐ and two‐year‐old plants. N fertilization increased the saplings’ aboveground biomass investments, making them more susceptible to D treatments. This was reflected by the highest tissue dieback in combined N and D treatments and a significant N × D interaction for leaf δ13C signatures. Thus, atmospheric N deposition can strengthen the drought sensitivity of beech saplings. One‐year‐old plants reacted more sensitively to D treatments than two‐year‐old plants (indicated by D‐induced shifts in leaf δ13C signatures of one‐year‐old and two‐year‐old plants by +0.5‰ and −0.2‰, respectively, attributable to their higher shoot:root‐ratios (1.8 and 1.2, respectively. In summary, the saplings’ treatment responses were determined by their phenotypic plasticity (shifts in shoot:root‐ratios, which in turn was a function of both the saplings’ age (effects of allometric growth trajectories = apparent plasticity and environmental impacts (effects of N fertilization = plastic allometry.

  4. Root Systems of Individual Plants, and the Biotic and Abiotic Factors Controlling Their Depth and Distribution: a Synthesis Using a Global Database.

    Science.gov (United States)

    Tumber-Davila, S. J.; Schenk, H. J.; Jackson, R. B.

    2017-12-01

    This synthesis examines plant rooting distributions globally, by doubling the number of entries in the Root Systems of Individual Plants database (RSIP) created by Schenk and Jackson. Root systems influence many processes, including water and nutrient uptake and soil carbon storage. Root systems also mediate vegetation responses to changing climatic and environmental conditions. Therefore, a collective understanding of the importance of rooting systems to carbon sequestration, soil characteristics, hydrology, and climate, is needed. Current global models are limited by a poor understanding of the mechanisms affecting rooting, carbon stocks, and belowground biomass. This improved database contains an extensive bank of records describing the rooting system of individual plants, as well as detailed information on the climate and environment from which the observations are made. The expanded RSIP database will: 1) increase our understanding of rooting depths, lateral root spreads and above and belowground allometry; 2) improve the representation of plant rooting systems in Earth System Models; 3) enable studies of how climate change will alter and interact with plant species and functional groups in the future. We further focus on how plant rooting behavior responds to variations in climate and the environment, and create a model that can predict rooting behavior given a set of environmental conditions. Preliminary results suggest that high potential evapotranspiration and seasonality of precipitation are indicative of deeper rooting after accounting for plant growth form. When mapping predicted deep rooting by climate, we predict deepest rooting to occur in equatorial South America, Africa, and central India.

  5. Nonlinear growth dynamics and the origin of fluctuating asymmetry

    Science.gov (United States)

    Emlen, J.M.; Freeman, D.C.; Graham, J.H.

    1993-01-01

    The nonlinear, complex nature of biosynthesis magnifies the impacts of small, random perturbations on organism growth, leading to distortions in adaptive allometries and, in particular, to fluctuating asymmetry. These distortions can be partly checked by cell-cell and inter-body part feedback during growth and development, though the latter mechanism also may lead to complex patterns in right-left asymmetry. Stress can be expected to increase the degree to which random growth perturbations are magnified and may also result in disruption of the check mechanisms, thus exaggerating fluctuating asymmetry.The processes described not only provide one explanation for the existence of fluctuating asymmetry and its augmentation under stress, but suggest additional effects of stress as well. Specifically, stress is predicted to lead to decreased fractal dimension of bone sutures and branching structures in animals, and in increased dimension of growth trace patterns such as those found in mollusc shells and fish otoliths and scales.A basic yet broad primer on fractals and chaos is provided as background for the theoretical development in this manuscript.

  6. Trait-specific processes of convergence and conservatism shape ecomorphological evolution in ground-dwelling squirrels.

    Science.gov (United States)

    McLean, Bryan S; Helgen, Kristofer M; Goodwin, H Thomas; Cook, Joseph A

    2018-03-01

    Our understanding of mechanisms operating over deep timescales to shape phenotypic diversity often hinges on linking variation in one or few trait(s) to specific evolutionary processes. When distinct processes are capable of similar phenotypic signatures, however, identifying these drivers is difficult. We explored ecomorphological evolution across a radiation of ground-dwelling squirrels whose history includes convergence and constraint, two processes that can yield similar signatures of standing phenotypic diversity. Using four ecologically relevant trait datasets (body size, cranial, mandibular, and molariform tooth shape), we compared and contrasted variation, covariation, and disparity patterns in a new phylogenetic framework. Strong correlations existed between body size and two skull traits (allometry) and among skull traits themselves (integration). Inferred evolutionary modes were also concordant across traits (Ornstein-Uhlenbeck with two adaptive regimes). However, despite these broad similarities, we found divergent dynamics on the macroevolutionary landscape, with phenotypic disparity being differentially shaped by convergence and conservatism. Such among-trait heterogeneity in process (but not always pattern) reiterates the mosaic nature of morphological evolution, and suggests ground squirrel evolution is poorly captured by single process descriptors. Our results also highlight how use of single traits can bias macroevolutionary inference, affirming the importance of broader trait-bases in understanding phenotypic evolutionary dynamics. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  7. Patterns of sexual size dimorphism in horseshoe bats: Testing Rensch's rule and potential causes.

    Science.gov (United States)

    Wu, Hui; Jiang, Tinglei; Huang, Xiaobin; Feng, Jiang

    2018-02-08

    Rensch's rule, stating that sexual size dimorphism (SSD) becomes more evident and male-biased with increasing body size, has been well supported for taxa that exhibit male-biased SSD. Bats, primarily having female-biased SSD, have so far been tested for whether SSD allometry conforms to Rensch's rule in only three studies. However, these studies did not consider phylogeny, and thus the mechanisms underlying SSD variations in bats remain unclear. Thus, the present study reviewed published and original data, including body size, baculum size, and habitat types in 45 bats of the family Rhinolophidae to determine whether horseshoe bats follow Rensch's rule using a phylogenetic comparative framework. We also investigated the potential effect of postcopulatory sexual selection and habitat type on SSD. Our findings indicated that Rensch's rule did not apply to Rhinolophidae, suggesting that SSD did not significantly vary with increasing size. This pattern may be attributable interactions between weak sexual selection to male body size and strong fecundity selection for on female body size. The degree of SSD among horseshoe bats may be attributed to a phylogenetic effect rather than to the intersexual competition for food or to baculum length. Interestingly, we observed that species in open habitats exhibited greater SSD than those in dense forests, suggesting that habitat types may be associated with variations in SSD in horseshoe bats.

  8. POPULATION BIOLOGY OF SEABOB-SHRIMP Xiphopenaeus kroyeri (Heller, 1862 CAPTURED ON THE SOUTH COAST OF PERNAMBUCO STATE, NORTHEASTERN BRAZIL

    Directory of Open Access Journals (Sweden)

    Danilo Francisco Corrêa Lopes

    2014-12-01

    Full Text Available This paper aims to describe the population dynamics and to evaluate the stock of the seabob-shrimp Xiphopenaeus kroyeri on the coast of Pernambuco. Sampling was carried out between August/2011 and July/2012 in Sirinhaém, southern coast of Pernambuco. A total of 1201 individuals were analyzed, 673 females and 528 males. Total length (Lt of females varied from 4.5 to 13.5 cm while the Lt of males ranged between 4.0 and 11.0 cm. The relationship between the Lt and carapace length and Lt and total weight showed negative allometry (males, females and pooled sexes. The slope of the curve "b" was statistically different between males and females for both relationships. Females mature with 8.90 cm. Asymptotic length L∞ was lower for males than for females (12.26 to 14.79 and 10.72 to 11.5 cm, respectively, K was similar between sexes (1.00-2.04 and 1.00-2.63 cm/year-1 respectively as well as the longevity and size at 1st capture (1.50 to 1.97 years and 7.9 to 8.9 cm for males and females, respectively. The results indicate that X. kroyeri in the region is not overexploited for males, however considering females and pooled sexes the stock is near to being fully exploited.

  9. Morphometric relations in the grey eel catfish Plotosus canius in the coastal waters of Port Dickson, Peninsular Malaysia.

    Science.gov (United States)

    Usman, B I; Amin, S M N; Arshad, A; Kamarudin, M S

    2016-07-01

    Samples of grey eel catfish Plotosus canius were collected from the coastal waters of Port Dickson, Malaysia from January to December, 2012. A total of 341 specimens (172 males and 169 females) were used to estimate the length-weight relationship parameters. Mean population size of females were 0.72 cm taller than the males, however difference was not significant (t-test, P > 0.05). The overall relationship equations between total length (TL) and body weight (BW) were established for males as Log TW = 2.71 Log TL - 1.85 (R2 = 0.95) and for females as Log TW = 2.88 Log TL-2.10 (R2 = 0.95). The estimated relative growth co-efficient (b) values were 2.71 for males and 2.88 for females. It is revealed that growth pattern of the species showed negative allometry. In both males and females, relationship between TL and SL gave highest regression coefficient (0.99). While relationship between TL and EL gave lowest regression coefficient in both males and females (0.87 and 0.81 respectively). The findings from this study contributed first information on morphometric relations of the fish from Malaysian coastal waters and could be useful for sustainable management options of P. canius in Malaysia.

  10. Shape shifting predicts ontogenetic changes in metabolic scaling in diverse aquatic invertebrates.

    Science.gov (United States)

    Glazier, Douglas S; Hirst, Andrew G; Atkinson, David

    2015-03-07

    Metabolism fuels all biological activities, and thus understanding its variation is fundamentally important. Much of this variation is related to body size, which is commonly believed to follow a 3/4-power scaling law. However, during ontogeny, many kinds of animals and plants show marked shifts in metabolic scaling that deviate from 3/4-power scaling predicted by general models. Here, we show that in diverse aquatic invertebrates, ontogenetic shifts in the scaling of routine metabolic rate from near isometry (bR = scaling exponent approx. 1) to negative allometry (bR < 1), or the reverse, are associated with significant changes in body shape (indexed by bL = the scaling exponent of the relationship between body mass and body length). The observed inverse correlations between bR and bL are predicted by metabolic scaling theory that emphasizes resource/waste fluxes across external body surfaces, but contradict theory that emphasizes resource transport through internal networks. Geometric estimates of the scaling of surface area (SA) with body mass (bA) further show that ontogenetic shifts in bR and bA are positively correlated. These results support new metabolic scaling theory based on SA influences that may be applied to ontogenetic shifts in bR shown by many kinds of animals and plants. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  11. Observations on the distribution, population structure and biology of Bathypterois mediterraneus Bauchot, 1962 in three areas of the Mediterranean Sea

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    Gianfranco d'Onghia

    2004-12-01

    Full Text Available During the DESEAS cruise Bathypterois mediterraneus specimens were sampled in the Balearic Sea between 1000 and 2800 m as well as in the western and eastern Ionian Sea from 800 to 3300 m and from 800 to 2600 m respectively. The species was found to be more abundant at depths of 1500-2000 m. The size-range was 26-190 mm and the most abundant size class was around 100-120 mm standard length. No significant size-depth trends were shown for either length or weight. Negative allometry was shown in the growth of fishes and otoliths and in the relationship between fish length and otolith size in the samples from the western and eastern Ionian Sea. In these two areas the absolute growth was estimated by adopting the Von Bertalanffy function (western Ionian: SL∞ = 194.3 ± 38.51 mm, k = 0.146 ± 0.061/year, t0 = - 0.921 ± 0.699, ø' = 3.74; eastern Ionian: SL∞ = 180.23 ± 63.36 mm, k = 0.150 ± 0.112/year, t0 = - 0.968 ± 0.868, ø' = 3.70. Although most of the specimens were immature, some ripe gonads were recorded in individuals greater than 104 mm in standard length, confirming the simultaneous hermaphroditism in this fish. The results are discussed in relation to previous observations on the life strategy of B.mediterraneus in the Mediterranean Sea.

  12. Mechanics of evolutionary digit reduction in fossil horses (Equidae).

    Science.gov (United States)

    McHorse, Brianna K; Biewener, Andrew A; Pierce, Stephanie E

    2017-08-30

    Digit reduction is a major trend that characterizes horse evolution, but its causes and consequences have rarely been quantitatively tested. Using beam analysis on fossilized centre metapodials, we tested how locomotor bone stresses changed with digit reduction and increasing body size across the horse lineage. Internal bone geometry was captured from 13 fossil horse genera that covered the breadth of the equid phylogeny and the spectrum of digit reduction and body sizes, from Hyracotherium to Equus To account for the load-bearing role of side digits, a novel, continuous measure of digit reduction was also established-toe reduction index (TRI). Our results show that without accounting for side digits, three-toed horses as late as Parahippus would have experienced physiologically untenable bone stresses. Conversely, when side digits are modelled as load-bearing, species at the base of the horse radiation through Equus probably maintained a similar safety factor to fracture stress. We conclude that the centre metapodial compensated for evolutionary digit reduction and body mass increases by becoming more resistant to bending through substantial positive allometry in internal geometry. These results lend support to two historical hypotheses: that increasing body mass selected for a single, robust metapodial rather than several smaller ones; and that, as horse limbs became elongated, the cost of inertia from the side toes outweighed their utility for stabilization or load-bearing. © 2017 The Author(s).

  13. CHARACTERIZATION OF MORPHOLOGICAL TRAITS OF COMMERCIAL INTEREST IN THE MORELET'S CROCODILE (Crocodylus moreletii

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    Ricardo Serna-Lagunes

    2011-11-01

    Full Text Available Crocodylus moreletii is a species of commercial interest based on its skin. In this study, five morphological traits of commercial interest were characterized in 125 captivity-raised specimens of C. moreletii from four populations (Puente Chilapa, Gutiérrez Zamora, Villa Juárez and Puerto Vallarta. A canonical discriminant analysis (CDA was used to differentiate the populations according to their morphological traits, a cluster analysis (CA was used to infer which populations had the largest total length (TL, and a covariance analysis (ANCOVA was used to assess the allometry and detect which population was different in terms of TL. The CDA showed no significant effects, suggesting that the morphological traits were similar among populations; the CA grouped two populations which had the largest body size; the ANCOVA revealed a significant correlation between morphological traits and detected a TL effect significantly lower in males and females from Puente Chilapa, in comparison with the other three populations. In conclusion, the males from Gutiérrez Zamora and the females from Villa Juárez were morphologically outstanding in terms of TL, and they would be the right crocodiles to establish a breeding nucleus in order to obtain offspring with their phenotypic characteristics.

  14. Final Harvest of Above-Ground Biomass and Allometric Analysis of the Aspen FACE Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mark E. Kubiske

    2013-04-15

    The Aspen FACE experiment, located at the US Forest Service Harshaw Research Facility in Oneida County, Wisconsin, exposes the intact canopies of model trembling aspen forests to increased concentrations of atmospheric CO2 and O3. The first full year of treatments was 1998 and final year of elevated CO2 and O3 treatments is scheduled for 2009. This proposal is to conduct an intensive, analytical harvest of the above-ground parts of 24 trees from each of the 12, 30 m diameter treatment plots (total of 288 trees) during June, July & August 2009. This above-ground harvest will be carefully coordinated with the below-ground harvest proposed by D.F. Karnosky et al. (2008 proposal to DOE). We propose to dissect harvested trees according to annual height growth increment and organ (main stem, branch orders, and leaves) for calculation of above-ground biomass production and allometric comparisons among aspen clones, species, and treatments. Additionally, we will collect fine root samples for DNA fingerprinting to quantify biomass production of individual aspen clones. This work will produce a thorough characterization of above-ground tree and stand growth and allocation above ground, and, in conjunction with the below ground harvest, total tree and stand biomass production, allocation, and allometry.

  15. 14C and tritium dynamics in wild mammals: a metabolic model

    International Nuclear Information System (INIS)

    Galeriu, D.; Beresford, N.A.; Melintescu, A.; Crout, N.M.J.; Takeda, H.

    2004-01-01

    The protection of biota from ionising radiations needs reliable predictions of radionuclide dynamics in wild animals. Data specific for many wild animals radionuclide combinations is lacking and a number of approaches including allometry have been proposed to address this. However, for 14 C and tritium, which are integral components of animals tissues and their diets, a different approach is needed in the absence of experimental data. Here we propose a metabolically based model which can be parameterized predominantly on the basis of published metabolic data. We begin with a metabolic definition of the 14 C and OBT loss rate (assumed to be the same) from the whole body and also specific organs, using available information on field metabolic rate and body composition. The mammalian body is conceptually partitioned into compartments (body water, viscera, adipose, muscle, blood and remainder) and a simple model defined using net maintenance and growth needs of mammals. Intake and excretion, and transfer to body water are modelled using basic metabolic knowledge and published relationships. The model is tested with data from studies using rats and sheep. It provides a reliable prediction for whole body and muscle activity concentrations without the requirement for any calibration specific to 3 H and 14 C. Predictions from the model for representative wild mammals (as selected to be reference organisms within international programmes) are presented. Potential developments of a metabolic model for birds and the application of our work to human food chain modelling are also discussed. (author)

  16. Insights into the development and evolution of exaggerated traits using de novo transcriptomes of two species of horned scarab beetles.

    Directory of Open Access Journals (Sweden)

    Ian A Warren

    Full Text Available Scarab beetles exhibit an astonishing variety of rigid exo-skeletal outgrowths, known as "horns". These traits are often sexually dimorphic and vary dramatically across species in size, shape, location, and allometry with body size. In many species, the horn exhibits disproportionate growth resulting in an exaggerated allometric relationship with body size, as compared to other traits, such as wings, that grow proportionately with body size. Depending on the species, the smallest males either do not produce a horn at all, or they produce a disproportionately small horn for their body size. While the diversity of horn shapes and their behavioural ecology have been reasonably well studied, we know far less about the proximate mechanisms that regulate horn growth. Thus, using 454 pyrosequencing, we generated transcriptome profiles, during horn growth and development, in two different scarab beetle species: the Asian rhinoceros beetle, Trypoxylus dichotomus, and the dung beetle, Onthophagus nigriventris. We obtained over half a million reads for each species that were assembled into over 6,000 and 16,000 contigs respectively. We combined these data with previously published studies to look for signatures of molecular evolution. We found a small subset of genes with horn-biased expression showing evidence for recent positive selection, as is expected with sexual selection on horn size. We also found evidence of relaxed selection present in genes that demonstrated biased expression between horned and horn-less morphs, consistent with the theory of developmental decoupling of phenotypically plastic traits.

  17. δ18O of apatite phosphate in small pelagic fish: insights from wild-caught and tank-grown specimens

    Science.gov (United States)

    Lambert, T.; Javor, B.; Paytan, A.

    2011-12-01

    Oxygen isotope ratios of mineralized structures in fish reflect the temperature and isotopic composition of the water in which they grow. For bulk samples (e.g., whole scales, bones, and otoliths), understanding how this signal is integrated across time and space is critical, especially for organisms exposed to high variability in growth conditions. Here, we assess the response of fish scale δ18O (from apatite phosphate) to experimentally manipulated water conditions. Wild-caught sardines were grown at controlled temperatures (13°C, 17°C, and 21°C) for 11 months. Higher growth temperatures correlated to lower δ18O values, representing a combination of scale apatite deposited before and after the temperature manipulation. Models that account for both biomineral allometry and exposure to varying water properties (e.g., by overlaying migration routes, isoscapes, and temperature maps) have the potential to quantify the varying contributions of minerals grown under different conditions. We use this method to predict δ18O of apatite phosphate for small pelagic fish found in California coastal waters, then compare expected values to those obtained from collected samples. Since phosphate oxygen is relatively resistant to diagenesis, this modern calibration establishes a framework for paleo studies.

  18. Ethnicity and skeletal Class III morphology: a pubertal growth analysis using thin-plate spline analysis.

    Science.gov (United States)

    Alkhamrah, B; Terada, K; Yamaki, M; Ali, I M; Hanada, K

    2001-01-01

    A longitudinal retrospective study using thin-plate spline analysis was used to investigate skeletal Class III etiology in Japanese female adolescents. Headfilms of 40 subjects were chosen from the archives of the Orthodontic department at Niigata University Dental Hospital, and were traced at IIIB and IVA Hellman dental ages. Twenty-eight homologous landmarks, representing hard and soft tissue, were digitized. These were used to reproduce a consensus for the profilogram, craniomaxillary complex, mandible, and soft tissue for each age and skeletal group. Generalized least-square analysis revealed a significant shape difference between age-matched groups (P spline and partial warps (PW)3 and 2 showed a maxillary retrusion at stage IIIB opposite an acute cranial base at stage IVA. Mandibular total spline and PW4, 5 showed changes affecting most landmarks and their spatial interrelationship, especially a stretch along the articulare-pogonion axis. In soft tissue analysis, PW8 showed large and local changes which paralleled the underlying hard tissue components. Allometry of the mandible and anisotropy of the cranial base, the maxilla, and the mandible asserted the complexity of craniofacial growth and the difficulty of predicting its outcome.

  19. Components of soft tissue deformations in subjects with untreated angle's Class III malocclusions: thin-plate spline analysis.

    Science.gov (United States)

    Singh, G D; McNamara, J A; Lozanoff, S

    1998-01-01

    While the dynamics of maxillo-mandibular allometry associated with treatment modalities available for the management of Class III malocclusions currently are under investigation, developmental aberration of the soft tissues in untreated Class III malocclusions requires specification. In this study, lateral cephalographs of 124 prepubertal European-American children (71 with untreated Class III malocclusion; 53 with Class I occlusion) were traced, and 12 soft-tissue landmarks digitized. Resultant geometries were scaled to an equivalent size and mean Class III and Class I configurations compared. Procrustes analysis established statistical difference (P thin-plate spline (TPS) analysis indicated that both affine and non-affine transformations contribute towards the deformation (total spline) of the averaged Class III soft tissue configuration. For non-affine transformations, partial warp 8 had the highest magnitude, indicating large-scale deformations visualized as a combination of columellar retrusion and lower labial protrusion. In addition, partial warp 5 also had a high magnitude, demonstrating upper labial vertical compression with antero-inferior elongation of the lower labio-mental soft tissue complex. Thus, children with Class III malocclusions demonstrate antero-posterior and vertical deformations of the maxillary soft tissue complex in combination with antero-inferior mandibular soft tissue elongation. This pattern of deformations may represent gene-environment interactions, resulting in Class III malocclusions with characteristic phenotypes, that are amenable to orthodontic and dentofacial orthopedic manipulations.

  20. Allometric relationships among body mass, MUZZLE-tail length, and tibia length during the growth of Wistar rats.

    Science.gov (United States)

    Santiago, Hildemberg Agostinho Rocha de; De Pierro, Lucas Rodolfo; Reis, Rafael Menezes; Caluz, Antônio Gabriel Ricardo Engracia; Ribeiro, Victor Barbosa; Volpon, José Batista

    2015-11-01

    To investigate allometric relationships among body mass (BM), muzzle-tail length (MTL), and tibia length (TL) in Wistar rats and establish their growth rate change parameters. Eighteen male and 18 female Wistar rats were studied from the 3rd to the 21st week of age. BM, MTL, and TL were measured daily, and relative growth was compared using allometry. A positive correlation between BM and MTL (p<0.05) and BM and TL (p<0.05) was observed. Males and females showed comparable curves; however, females had turning points at a younger age. The allometric relationship between BM and MTL presented a regular increase until reaching a mass of 351 g (males) and 405 g (females). BM and TL showed an initial increase until 185 g (males) and 182 g (females), and then reached a plateau that finished at 412 g (males) and 334 g (females), to display another increase. The allometric relationship of body mass with animal length and tibia length was comparable for male and female rats, with female rats maturing earlier. Animal longitudinal growth occurred in a single stage. In contrast, tibia length depicted two stages of accelerated growth with an intermediate period of deceleration.

  1. Disproportionate Cochlear Length in Genus Homo Shows a High Phylogenetic Signal during Apes’ Hearing Evolution

    Science.gov (United States)

    Braga, J.; Loubes, J-M.; Descouens, D.; Dumoncel, J.; Thackeray, J. F.; Kahn, J-L.; de Beer, F.; Riberon, A.; Hoffman, K.; Balaresque, P.; Gilissen, E.

    2015-01-01

    Changes in lifestyles and body weight affected mammal life-history evolution but little is known about how they shaped species’ sensory systems. Since auditory sensitivity impacts communication tasks and environmental acoustic awareness, it may have represented a deciding factor during mammal evolution, including apes. Here, we statistically measure the influence of phylogeny and allometry on the variation of five cochlear morphological features associated with hearing capacities across 22 living and 5 fossil catarrhine species. We find high phylogenetic signals for absolute and relative cochlear length only. Comparisons between fossil cochleae and reconstructed ape ancestral morphotypes show that Australopithecus absolute and relative cochlear lengths are explicable by phylogeny and concordant with the hypothetized ((Pan,Homo),Gorilla) and (Pan,Homo) most recent common ancestors. Conversely, deviations of the Paranthropus oval window area from these most recent common ancestors are not explicable by phylogeny and body weight alone, but suggest instead rapid evolutionary changes (directional selection) of its hearing organ. Premodern (Homo erectus) and modern human cochleae set apart from living non-human catarrhines and australopiths. They show cochlear relative lengths and oval window areas larger than expected for their body mass, two features corresponding to increased low-frequency sensitivity more recent than 2 million years ago. The uniqueness of the “hypertrophied” cochlea in the genus Homo (as opposed to the australopiths) and the significantly high phylogenetic signal of this organ among apes indicate its usefulness to identify homologies and monophyletic groups in the hominid fossil record. PMID:26083484

  2. A macroevolutionary explanation for energy equivalence in the scaling of body size and population density.

    Science.gov (United States)

    Damuth, John

    2007-05-01

    Across a wide array of animal species, mean population densities decline with species body mass such that the rate of energy use of local populations is approximately independent of body size. This "energetic equivalence" is particularly evident when ecological population densities are plotted across several or more orders of magnitude in body mass and is supported by a considerable body of evidence. Nevertheless, interpretation of the data has remained controversial, largely because of the difficulty of explaining the origin and maintenance of such a size-abundance relationship in terms of purely ecological processes. Here I describe results of a simulation model suggesting that an extremely simple mechanism operating over evolutionary time can explain the major features of the empirical data. The model specifies only the size scaling of metabolism and a process where randomly chosen species evolve to take resource energy from other species. This process of energy exchange among particular species is distinct from a random walk of species abundances and creates a situation in which species populations using relatively low amounts of energy at any body size have an elevated extinction risk. Selective extinction of such species rapidly drives size-abundance allometry in faunas toward approximate energetic equivalence and maintains it there.

  3. Phylogeny determines flower size-dependent sex allocation at flowering in a hermaphroditic family.

    Science.gov (United States)

    Teixido, A L; Guzmán, B; Staggemeier, V G; Valladares, F

    2017-11-01

    In animal-pollinated hermaphroditic plants, optimal floral allocation determines relative investment into sexes, which is ultimately dependent on flower size. Larger flowers disproportionally increase maleness whereas smaller and less rewarding flowers favour female function. Although floral traits are considered strongly conserved, phylogenetic relationships in the interspecific patterns of resource allocation to floral sex remain overlooked. We investigated these patterns in Cistaceae, a hermaphroditic family. We reconstructed phylogenetic relationships among Cistaceae species and quantified phylogenetic signal for flower size, dry mass and nutrient allocation to floral structures in 23 Mediterranean species using Blomberg's K-statistic. Lastly, phylogenetically-controlled correlational and regression analyses were applied to examine flower size-based allometry in resource allocation to floral structures. Sepals received the highest dry mass allocation, followed by petals, whereas sexual structures increased nutrient allocation. Flower size and resource allocation to floral structures, except for carpels, showed a strong phylogenetic signal. Larger-flowered species allometrically allocated more resources to maleness, by increasing allocation to corollas and stamens. Our results suggest a major role of phylogeny in determining interspecific changes in flower size and subsequent floral sex allocation. This implies that flower size balances the male-female function over the evolutionary history of Cistaceae. While allometric resource investment in maleness is inherited across species diversification, allocation to the female function seems a labile trait that varies among closely related species that have diversified into different ecological niches. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  4. Growth of the silverside Atherinella brasiliensis in a subtropical estuary with some insights concerning the weight-length relationship

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    BARBARA M. DE CARVALHO

    Full Text Available ABSTRACT Specimens of Brazilian silverside (Atherinella brasiliensis, n=9672 with a length range of 1.5 to 14.2 cm were captured in the intertidal areas of the Estuarine Complex of Paranaguá, Brazil, between August 2010 and July 2011. The species’ weight-length relationship was represented by the equation W=0.00533 L3.136 with a slightly positive allometry (b>3 and could be divided into two growth stanzas: W = W1 + W2; Stanza 1: W1= SW. (0.005239 L3.152; Stanza 2: W2= (1 - SW. (0.000699 L3.913; Switch-Function: SW = [1 + e1.204 (L - 11.66]-1. The breakpoint between the first and second stanza (11.66 cm matches published values for the estimated size at first maturity of adult females. Frequency distributions indicate that the species is present in the shallow areas of the Estuarine Complex of Paranaguá during all phases of its ontogenetic development, with the recruitment of juveniles taking place between October and November. Modal displacement was monitored throughout 12 months. The von Bertalanffy growth model and longevity was estimated as follow: asymptotic length (L∞ of 17.5 cm, growth coefficient (K of 0.89 (year-1 and longevity (A95 of 3.33 years. We present some considerations with regard to the general methodology for adjusting weight-length relationships.

  5. Population pharmacokinetics of tamsulosin hydrochloride in paediatric patients with neuropathic and non-neuropathic bladder

    Science.gov (United States)

    Tsuda, Yasuhiro; Tatami, Shinji; Yamamura, Norio; Tadayasu, Yusuke; Sarashina, Akiko; Liesenfeld, Karl-Heinz; Staab, Alexander; Schäfer, Hans-Günter; Ieiri, Ichiro; Higuchi, Shun

    2010-01-01

    AIMS The main objective of this study was to characterize the population pharmacokinetics of tamsulosin hydrochloride (HCl) in paediatric patients with neuropathic and non-neuropathic bladder. A secondary objective was to compare the pharmacokinetics in paediatric patients and adults. METHODS Tamsulosin HCl plasma concentrations in 1082 plasma samples from 189 paediatric patients (age range 2–16 years) were analyzed with NONMEM, applying a one compartment model with first-order absorption. Based on the principles of allometry, body weight was incorporated in the base model, along with fixed allometric exponents. Covariate analysis was performed by means of a stepwise forward inclusion and backward elimination procedure. Simulations based on the final model were used to compare the pharmacokinetics with those in adults. RESULTS Beside the priori-implemented body weight, only α1-acid glycoprotein had an effect on both apparent clearance and apparent volume of distribution. No other investigated covariates, including gender, age, race, patient population and concomitant therapy with anti-cholinergics, significantly affected the pharmacokinetics of tamsulosin HCl (P tamsulosin HCl in paediatric patients was established and it described the data well. There was no major difference in the pharmacokinetics of tamsulosin HCl between paediatric patients (age range 2–16 years) and adults when the effect of body weight was taken into consideration. PMID:20642551

  6. The mechanosensory calcium-selective ion channel: key component of a plasmalemmal control centre?

    Science.gov (United States)

    Pickard, B. G.; Ding, J. P.

    1993-01-01

    Mechanosensory calcium-selective ion channels probably serve to detect not only mechanical stress but also electrical, thermal, and diverse chemical stimuli. Because all stimuli result in a common output, most notably a shift in second messenger calcium concentration, the channels are presumed to serve as signal integrators. Further, insofar as second messenger calcium in turn gives rise to mechanical, electrical, and diverse chemical changes, the channels are postulated to initiate regulatory feedbacks. It is proposed that the channels and the feedback loops play a wide range of roles in regulating normal plant function, as well as in mediating disturbance of normal function by environmental stressors and various pathogens. In developing evidence for the physiological performance of the channel, a model for a cluster of regulatory plasmalemmal proteins and cytoskeletal elements grouped around a set of wall-to-membrane and transmembrane linkers has proved useful. An illustration of how the model might operate is presented. It is founded on the demonstration that several xenobiotics interfere both with normal channel behaviour and with gravitropic reception. Accordingly, the first part of the illustration deals with how the channels and the control system within which they putatively operate might initiate gravitropism. Assuming that gravitropism is an asymmetric expression of growth, the activities of the channels and the plasmalemmal control system are extrapolated to account for regulation of both rate and allometry of cell expansion. Finally, it is discussed how light, hormones, redox agents and herbicides could in principle affect growth via the putative plasmalemmal control cluster or centre.

  7. Differences in mating behavior between two allopatric populations of a Neotropical scorpion.

    Science.gov (United States)

    Olivero, Paola A; Mattoni, Camilo I; Peretti, Alfredo V

    2017-08-01

    Courtship and mating behavior generally evolve rapidly in diverging populations and species. The adaptation to different environments may cause behavioral divergence in characteristics involved in mate choice. Our objective in this study was to compare the sexual behavior of two distant populations of the scorpion Bothriurus bonariensis. This species has a broad distribution in South America, inhabiting Central Argentina, Uruguay and south-eastern Brazil. It is known that in this species there is a divergence in morphological patterns (body size, coloration, allometry and fluctuating asymmetry indexes) among distant populations. Considering the differences in environmental conditions between localities, we compare the sexual behavior in intra-population and inter-population matings from Central Argentina and southern Uruguay populations. We found significant differences in mating patterns, including differences in the frequency and duration of important stimulatory courtship behaviors. In addition, most inter-population matings were unsuccessful. In this framework, the differences in reproductive behavior could indicate reproductive isolation between these populations, which coincides with their already known morphological differences. This is the first study comparing the sexual behavior of allopatric populations of scorpions; it provides new data about the degree of intraspecific geographical divergence in the sexual behavior of B. bonariensis. Copyright © 2017 Elsevier GmbH. All rights reserved.

  8. Trophic divergence despite morphological convergence in a continental radiation of snakes.

    Science.gov (United States)

    Grundler, Michael C; Rabosky, Daniel L

    2014-07-22

    Ecological and phenotypic convergence is a potential outcome of adaptive radiation in response to ecological opportunity. However, a number of factors may limit convergence during evolutionary radiations, including interregional differences in biogeographic history and clade-specific constraints on form and function. Here, we demonstrate that a single clade of terrestrial snakes from Australia--the oxyuranine elapids--exhibits widespread morphological convergence with a phylogenetically diverse and distantly related assemblage of snakes from North America. Australian elapids have evolved nearly the full spectrum of phenotypic modalities that occurs among North American snakes. Much of the convergence appears to involve the recurrent evolution of stereotyped morphologies associated with foraging mode, locomotion and habitat use. By contrast, analysis of snake diets indicates striking divergence in feeding ecology between these faunas, partially reflecting regional differences in ecological allometry between Australia and North America. Widespread phenotypic convergence with the North American snake fauna coupled with divergence in feeding ecology are clear examples of how independent continental radiations may converge along some ecological axes yet differ profoundly along others. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  9. Occurrence of 210Po in periwinkle (Littorina undulata, Gray, 1839) collected from Kudankulam (Gulf of Mannar (GOM), Southeast coast of India)

    International Nuclear Information System (INIS)

    Sunith Shine, S.R.; Feroz Khan, M.; Godwin Wesley, S.

    2013-01-01

    Highlights: • Polonium-210 was quantified in the periwinkle Littorina undulata. • Smaller-sized periwinkles displayed higher Polonium-210. • Marked variation in 210 Po activity between season and sampling site. • The internal dose rate estimated using ERICA Assessment Tool. • The daily intake and committed effective dose estimated. -- Abstract: Polonium-210 activity concentration was analysed in the whole body tissue of periwinkle Littorina undulata collected from intertidal rocky shore along Kudankulam coast. We carried out the study for a period of 12 months (2011–2012) focusing on three seasons. 210 Po was found non-uniformly distributed among the periwinkles depending on the allometry. The 210 Po accumulation showed a significant difference between seasons (p 210 Po compared to larger ones (p 210 Po varied from 13.5 to 58.9 Bq/kg (wet). The activity of 210 Po was also quantified in seawater and intertidal sediments to calculate the biological concentration factor (BCF) and radiation dose rate. The dose rate to the winkles was performed using ERICA Assessment Tool and it was within the prescribed limit. The intake of 210 Po through periwinkles delivered an effective dose in the range of 2.2–9.6 μSv/y to human beings

  10. Development and evaluation of height diameter at breast models for native Chinese Metasequoia.

    Science.gov (United States)

    Liu, Mu; Feng, Zhongke; Zhang, Zhixiang; Ma, Chenghui; Wang, Mingming; Lian, Bo-Ling; Sun, Renjie; Zhang, Li

    2017-01-01

    Accurate tree height and diameter at breast height (dbh) are important input variables for growth and yield models. A total of 5503 Chinese Metasequoia trees were used in this study. We studied 53 fitted models, of which 7 were linear models and 46 were non-linear models. These models were divided into two groups of single models and multivariate models according to the number of independent variables. The results show that the allometry equation of tree height which has diameter at breast height as independent variable can better reflect the change of tree height; in addition the prediction accuracy of the multivariate composite models is higher than that of the single variable models. Although tree age is not the most important variable in the study of the relationship between tree height and dbh, the consideration of tree age when choosing models and parameters in model selection can make the prediction of tree height more accurate. The amount of data is also an important parameter what can improve the reliability of models. Other variables such as tree height, main dbh and altitude, etc can also affect models. In this study, the method of developing the recommended models for predicting the tree height of native Metasequoias aged 50-485 years is statistically reliable and can be used for reference in predicting the growth and production of mature native Metasequoia.

  11. Development and evaluation of height diameter at breast models for native Chinese Metasequoia.

    Directory of Open Access Journals (Sweden)

    Mu Liu

    Full Text Available Accurate tree height and diameter at breast height (dbh are important input variables for growth and yield models. A total of 5503 Chinese Metasequoia trees were used in this study. We studied 53 fitted models, of which 7 were linear models and 46 were non-linear models. These models were divided into two groups of single models and multivariate models according to the number of independent variables. The results show that the allometry equation of tree height which has diameter at breast height as independent variable can better reflect the change of tree height; in addition the prediction accuracy of the multivariate composite models is higher than that of the single variable models. Although tree age is not the most important variable in the study of the relationship between tree height and dbh, the consideration of tree age when choosing models and parameters in model selection can make the prediction of tree height more accurate. The amount of data is also an important parameter what can improve the reliability of models. Other variables such as tree height, main dbh and altitude, etc can also affect models. In this study, the method of developing the recommended models for predicting the tree height of native Metasequoias aged 50-485 years is statistically reliable and can be used for reference in predicting the growth and production of mature native Metasequoia.

  12. Modelling foot height and foot shape-related dimensions.

    Science.gov (United States)

    Xiong, Shuping; Goonetilleke, Ravindra S; Witana, Channa P; Lee Au, Emily Yim

    2008-08-01

    The application of foot anthropometry to design good-fitting footwear has been difficult due to the lack of generalised models. This study seeks to model foot dimensions so that the characteristic shapes of feet, especially in the midfoot region, can be understood. Fifty Hong Kong Chinese adults (26 males and 24 females) participated in this study. Their foot lengths, foot widths, ball girths and foot heights were measured and then evaluated using mathematical models. The results showed that there were no significant allometry (p > 0.05) effects of foot length on ball girth and foot width. Foot height showed no direct relationship with foot length. However, a normalisation with respect to foot length and foot height resulted in a significant relationship for both males and females with R(2) greater than 0.97. Due to the lack of a direct relationship between foot height and foot length, the current practice of grading shoes with a constant increase in height or proportionate scaling in response to foot length is less than ideal. The results when validated with other populations can be a significant way forward in the design of footwear that has an improved fit in the height dimension.

  13. COMPARING 3D FOOT SHAPE MODELS BETWEEN TAIWANESE AND JAPANESE FEMALES.

    Science.gov (United States)

    Lee, Yu-Chi; Kouchi, Makiko; Mochimaru, Masaaki; Wang, Mao-Jiun

    2015-06-01

    This study compares foot shape and foot dimensions between Taiwanese and Japanese females. One hundred Taiwanese and 100 Japanese female 3D foot scanning data were used for comparison. To avoid the allometry effect, data from 23 Taiwanese and 19 Japanese with foot length between 233 to 237 mm were used for shape comparison. Homologous models created for the right feet of the 42 subjects were analyzed by Multidimensional Scaling. The results showed that there were significant differences in the forefoot shape between the two groups, and Taiwanese females had slightly wider feet with straighter big toe than Japanese females. The results of body and foot dimension comparison indicated that Taiwanese females were taller, heavier and had larger feet than Japanese females, while Japanese females had significantly larger toe 1 angle. Since some Taiwanese shoemakers adopt the Japanese shoe sizing system for making shoes, appropriateness of the shoe sizing system was also discussed. The present results provide very useful information for improving shoe last design and footwear fit for Taiwanese females.

  14. Sex-related differences in foot shape.

    Science.gov (United States)

    Krauss, I; Grau, S; Mauch, M; Maiwald, C; Horstmann, T

    2008-11-01

    The purpose of the study was to investigate sex-related differences in foot morphology. In total, 847 subjects were scanned using a 3-D-footscanner. Three different analysis methods were used: (1) comparisons were made for absolute foot measures within 250-270 mm foot length (FL); (2) and for averaged measures (% FL) across all sizes; (3) the feet were then classified using a cluster analysis. Within 250-270 mm FL, male feet were wider and higher (mean differences (MD) 1.3-5.9 mm). No relevant sex-related differences could be found in the comparison of averaged measures (MD 0.3-0.6% FL). Foot types were categorised into voluminous, flat-pointed and slender. Shorter feet were more often voluminous, longer feet were more likely to be narrow and flat. However, the definition of 'short' and 'long' was sex-related; thus, allometry of foot measures was different. For shoe design, measures should be derived for each size and sex separately. Different foot types should be considered to account for the variety in foot shape. Improper footwear can cause foot pain and deformity. Therefore, knowledge of sex-related differences in foot measures is important to assist proper shoe fit in both men and women. The present study supplements the field of knowledge within this context with recommendations for the manufacturing of shoes.

  15. On the Relationships of Postcanine Tooth Size with Dietary Quality and Brain Volume in Primates: Implications for Hominin Evolution

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    Juan Manuel Jiménez-Arenas

    2014-01-01

    Full Text Available Brain volume and cheek-tooth size have traditionally been considered as two traits that show opposite evolutionary trends during the evolution of Homo. As a result, differences in encephalization and molarization among hominins tend to be interpreted in paleobiological grounds, because both traits were presumably linked to the dietary quality of extinct species. Here we show that there is an essential difference between the genus Homo and the living primate species, because postcanine tooth size and brain volume are related to negative allometry in primates and show an inverse relationship in Homo. However, when size effects are removed, the negative relationship between encephalization and molarization holds only for platyrrhines and the genus Homo. In addition, there is no general trend for the relationship between postcanine tooth size and dietary quality among the living primates. If size and phylogeny effects are both removed, this relationship vanishes in many taxonomic groups. As a result, the suggestion that the presence of well-developed postcanine teeth in extinct hominins should be indicative of a poor-quality diet cannot be generalized to all extant and extinct primates.

  16. Density-dependence as a size-independent regulatory mechanism.

    Science.gov (United States)

    de Vladar, Harold P

    2006-01-21

    The growth function of populations is central in biomathematics. The main dogma is the existence of density-dependence mechanisms, which can be modelled with distinct functional forms that depend on the size of the population. One important class of regulatory functions is the theta-logistic, which generalizes the logistic equation. Using this model as a motivation, this paper introduces a simple dynamical reformulation that generalizes many growth functions. The reformulation consists of two equations, one for population size, and one for the growth rate. Furthermore, the model shows that although population is density-dependent, the dynamics of the growth rate does not depend either on population size, nor on the carrying capacity. Actually, the growth equation is uncoupled from the population size equation, and the model has only two parameters, a Malthusian parameter rho and a competition coefficient theta. Distinct sign combinations of these parameters reproduce not only the family of theta-logistics, but also the van Bertalanffy, Gompertz and Potential Growth equations, among other possibilities. It is also shown that, except for two critical points, there is a general size-scaling relation that includes those appearing in the most important allometric theories, including the recently proposed Metabolic Theory of Ecology. With this model, several issues of general interest are discussed such as the growth of animal population, extinctions, cell growth and allometry, and the effect of environment over a population.

  17. Hybridization and adaptation to introduced balloon vines in an Australian soapberry bug.

    Science.gov (United States)

    Andres, J A; Thampy, P R; Mathieson, M T; Loye, J; Zalucki, M P; Dingle, H; Carroll, S P

    2013-12-01

    Contemporary adaptation of plant feeding insects to introduced hosts provides clear cases of ecologically based population divergence. In most cases the mechanisms permitting rapid differentiation are not well known. Here we study morphological and genetic variation associated with recent shifts by the Australian soapberry bug Leptocoris tagalicus onto two naturalized Neotropical balloon vines, Cardiospermum halicacabum and C. grandiflorum that differ in time since introduction. Our results show that these vines have much larger fruits than the native hosts (Whitewood tree -Atalaya hemiglauca- and Woolly Rambutan -Alectryon tomentosus-) and that bugs living on them have evolved significantly longer beaks and new allometries. Genetic analyses of mitochondrial haplotypes and amplified fragment length polymorphic (AFLP) markers indicate that the lineage of bugs on the annual vine C. halicacabum, the older introduction, is intermediate between the two subspecies of L. tagalicus found on native hosts. Moreover, where the annual vine and Whitewood tree co-occur, the morphology and genomic composition of the bugs are similar to those occurring in allopatry. These results show that hybridization provided the genetic elements underlying the strongly differentiated 'Halicacabum bugs'. In contrast, the bugs feeding on the recently introduced perennial balloon vine (C. grandiflorum) showed no evidence of admixture, and are genetically indistinguishable from the nearby populations on a native host. © 2013 John Wiley & Sons Ltd.

  18. Postlarval development of Halicarcinus planatus females (Crustacea, Decapoda, Hymenosomatidae in the estuary of the Deseado River, Argentina

    Directory of Open Access Journals (Sweden)

    Julio H. Vinuesa

    2008-03-01

    Full Text Available This study analyses morphology and morphometric growth changes of Halicarcinus planatus females until their terminal moult, and characterises new juvenile stages. Monthly samples were collected in the estuary of the Deseado River, Santa Cruz Province, Argentina. Crabs were sampled between the mid-intertidal and upper subtidal levels. Intermoult stages were analysed in sub-samples of adolescents and adults, and the presence of epizoic organisms was registered. Juveniles and adults were reared at the laboratory and examined for moult changes. All 3376 crabs caught were females, indicating a clear spatial segregation between sexes. Five juvenile stages (immature 1, 2, 3, 4 and adolescent and a mature one were recognised on the basis of morphology and morphometry. All immature stages differed in cephalothorax width (CW and abdomen width (AW. Positive allometry was observed in some juvenile stages and isometry in an immature stage and in mature females. Adolescents and adults encompassed a wide range of sizes, and the considerable size overlap between them suggests an anomalous growth process. Moult staging analysis indicated that adolescents have a high incidence of pre-moult stages in winter, when the terminal moult occurs. The measurements performed in laboratory-reared females indicated no abnormal increases during the moult. The terminal moult occurs within a wide size range, perhaps in association with mating.

  19. Lessons in modularity: the evolutionary ecology of colonial invertebrates

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    Roger N. Hughes

    2005-06-01

    Full Text Available Benthic colonial invertebrates share with higher plants a modular construction and a sessile adult life. Both types of organism show parallel evolutionary responses to common selective forces, but in contrast to the long-established focus on plants, comparable study of colonial invertebrates has developed relatively recently, largely owing to the application of new techniques in image processing and molecular biology. Species whose life cycles are readily completed under laboratory conditions and whose colonies are easily propagated from cuttings provide powerful models for experimentally investigating fundamental evolutionary problems, including metabolic allometry, the manifestation of ageing and the origin of allorecognition systems. Free of the confounding influences of behavioural manipulation and costs of copulation, colonial invertebrates whose water-borne sperm fertilize retained eggs lend themselves well to the experimental study of cryptic female choice, sperm competition and sexual conflict. In these respects, it will be productive to adopt and extend theoretical frameworks developed for flowering plants to guide experimental investigation of modular animals. Since mate choice occurs at the cellular level in modular animals, reproductive isolation is uncorrelated with morphology and cryptic speciation is likely to be widespread.

  20. Condition dependence of male and female genital structures in the seed beetle Callosobruchus maculatus (Coleoptera: Bruchidae).

    Science.gov (United States)

    Cayetano, L; Bonduriansky, R

    2015-07-01

    Theory predicts that costly secondary sexual traits will evolve heightened condition dependence, and many studies have reported strong condition dependence of signal and weapon traits in a variety of species. However, although genital structures often play key roles in intersexual interactions and appear to be subject to sexual or sexually antagonistic selection, few studies have examined the condition dependence of genital structures, especially in both sexes simultaneously. We investigated the responses of male and female genital structures to manipulation of larval diet quality (new versus once-used mung beans) in the bruchid seed beetle Callosobruchus maculatus. We quantified effects on mean relative size and static allometry of the male aedeagus, aedeagal spines, flap and paramere and the female reproductive tract and bursal spines. None of the male traits showed a significant effect of diet quality. In females, we found that longer bursal spines (relative to body size) were expressed on low-quality diet. Although the function of bursal spines is poorly understood, we suggest that greater bursal spine length in low-condition females may represent a sexually antagonistic adaptation. Overall, we found no evidence that genital traits in C. maculatus are expressed to a greater extent when nutrients are more abundant. This suggests that, even though some genital traits appear to function as secondary sexual traits, genital traits do not exhibit heightened condition dependence in this species. We discuss possible reasons for this finding. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  1. A general model for the scaling of offspring size and adult size.

    Science.gov (United States)

    Falster, Daniel S; Moles, Angela T; Westoby, Mark

    2008-09-01

    Understanding evolutionary coordination among different life-history traits is a key challenge for ecology and evolution. Here we develop a general quantitative model predicting how offspring size should scale with adult size by combining a simple model for life-history evolution with a frequency-dependent survivorship model. The key innovation is that larger offspring are afforded three different advantages during ontogeny: higher survivorship per time, a shortened juvenile phase, and advantage during size-competitive growth. In this model, it turns out that size-asymmetric advantage during competition is the factor driving evolution toward larger offspring sizes. For simplified and limiting cases, the model is shown to produce the same predictions as the previously existing theory on which it is founded. The explicit treatment of different survival advantages has biologically important new effects, mainly through an interaction between total maternal investment in reproduction and the duration of competitive growth. This goes on to explain alternative allometries between log offspring size and log adult size, as observed in mammals (slope = 0.95) and plants (slope = 0.54). Further, it suggests how these differences relate quantitatively to specific biological processes during recruitment. In these ways, the model generalizes across previous theory and provides explanations for some differences between major taxa.

  2. Patterns of morphological variation of extant sloth skulls and their implication for future conservation efforts.

    Science.gov (United States)

    Hautier, Lionel; Billet, Guillaume; Eastwood, Bethany; Lane, Jemima

    2014-06-01

    Several studies have shown an increased morphological variability of sloths from mammalian norms, affecting varied phenotypic traits from skeletal parts to soft tissues. We present here the first descriptive comparison of the whole skull morphology within the two extant sloth genera, combining geometric morphometric approaches with comparative anatomy. We used these methods to explore the patterns of the intra- and interspecific morphological variation of the skull with regard to several factors such as phylogeny, geography, allometry, or sexual dimorphism. Our study first revealed strong phylogenetic and geographical imprints on the cranial and mandibular morphological traits. This result demonstrates the importance of accurate knowledge of species and their geographical distributions; here we show from an example pertaining to Bradypus variegatus populations the implications this has on conservation management. Moreover, in order to control the amount of this detected variation, we tentatively compared sloths to a wide range of mammalian species. Our analysis found no significant increase in the average deviation of skull shape within each investigated sloth species compared to other mammals. This suggests that the intraspecific cranial variation in sloths does not depart significantly from the variation observed in other mammals. This result has positive implications for the demarcation of anatomical regions that maintain high levels of morphological variation in sloths. Copyright © 2014 Wiley Periodicals, Inc.

  3. Energetic benefits and adaptations in mammalian limbs: Scale effects and selective pressures.

    Science.gov (United States)

    Kilbourne, Brandon M; Hoffman, Louwrens C

    2015-06-01

    Differences in limb size and shape are fundamental to mammalian morphological diversity; however, their relevance to locomotor costs has long been subject to debate. In particular, it remains unknown if scale effects in whole limb morphology could partially underlie decreasing mass-specific locomotor costs with increasing limb length. Whole fore- and hindlimb inertial properties reflecting limb size and shape-moment of inertia (MOI), mass, mass distribution, and natural frequency-were regressed against limb length for 44 species of quadrupedal mammals. Limb mass, MOI, and center of mass position are negatively allometric, having a strong potential for lowering mass-specific locomotor costs in large terrestrial mammals. Negative allometry of limb MOI results in a 40% reduction in MOI relative to isometry's prediction for our largest sampled taxa. However, fitting regression residuals to adaptive diversification models reveals that codiversification of limb mass, limb length, and body mass likely results from selection for differing locomotor modes of running, climbing, digging, and swimming. The observed allometric scaling does not result from selection for energetically beneficial whole limb morphology with increasing size. Instead, our data suggest that it is a consequence of differing morphological adaptations and body size distributions among quadrupedal mammals, highlighting the role of differing limb functions in mammalian evolution. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  4. Diversity among African pygmies.

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    Fernando V Ramírez Rozzi

    Full Text Available Although dissimilarities in cranial and post-cranial morphology among African pygmies groups have been recognized, comparative studies on skull morphology usually pull all pygmies together assuming that morphological characters are similar among them and different with respect to other populations. The main aim of this study is to compare cranial morphology between African pygmies and non-pygmies populations from Equatorial Africa derived from both the Eastern and the Western regions in order to test if the greatest morphological difference is obtained in the comparison between pygmies and non-pygmies. Thirty three-dimensional (3D landmarks registered with Microscribe in four cranial samples (Western and Eastern pygmies and non-pygmies were obtained. Multivariate analysis (generalized Procrustes analysis, Mahalanobis distances, multivariate regression and complementary dimensions of size were evaluated with ANOVA and post hoc LSD. Results suggest that important cranial shape differentiation does occur between pygmies and non-pygmies but also between Eastern and Western populations and that size changes and allometries do not affect similarly Eastern and Western pygmies. Therefore, our findings raise serious doubt about the fact to consider African pygmies as a homogenous group in studies on skull morphology. Differences in cranial morphology among pygmies would suggest differentiation after divergence. Although not directly related to skull differentiation, the diversity among pygmies would probably suggest that the process responsible for reduced stature occurred after the split of the ancestors of modern Eastern and Western pygmies.

  5. Distilling allometric and environmental information from time series of conduit size: the standardization issue and its relationship to tree hydraulic architecture.

    Science.gov (United States)

    Carrer, Marco; von Arx, Georg; Castagneri, Daniele; Petit, Giai

    2015-01-01

    Trees are among the best natural archives of past environmental information. Xylem anatomy preserves information related to tree allometry and ecophysiological performance, which is not available from the more customary ring-width or wood-density proxy parameters. Recent technological advances make tree-ring anatomy very attractive because time frames of many centuries can now be covered. This calls for the proper treatment of time series of xylem anatomical attributes. In this article, we synthesize current knowledge on the biophysical and physiological mechanisms influencing the short- to long-term variation in the most widely used wood-anatomical feature, namely conduit size. We also clarify the strong mechanistic link between conduit-lumen size, tree hydraulic architecture and height growth. Among the key consequences of these biophysical constraints is the pervasive, increasing trend of conduit size during ontogeny. Such knowledge is required to process time series of anatomical parameters correctly in order to obtain the information of interest. An appropriate standardization procedure is fundamental when analysing long tree-ring-related chronologies. When dealing with wood-anatomical parameters, this is even more critical. Only an interdisciplinary approach involving ecophysiology, wood anatomy and dendrochronology will help to distill the valuable information about tree height growth and past environmental variability correctly. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Estimating the biological half-life for radionuclides in homoeothermic vertebrates: a simplified allometric approach

    Energy Technology Data Exchange (ETDEWEB)

    Beresford, N.A. [Lancaster Environment Centre, NERC Centre for Ecology and Hydrology, Lancaster (United Kingdom); Vives i Batlle, J. [Belgian Nuclear Research Centre, Mol (Belgium)

    2013-11-15

    The application of allometric, or mass-dependent, relationships within radioecology has increased with the evolution of models to predict the exposure of organisms other than man. Allometry presents a method of addressing the lack of empirical data on radionuclide transfer and metabolism for the many radionuclide-species combinations which may need to be considered. However, sufficient data across a range of species with different masses are required to establish allometric relationships and this is not always available. Here, an alternative allometric approach to predict the biological half-life of radionuclides in homoeothermic vertebrates which does not require such data is derived. Biological half-life values are predicted for four radionuclides and compared to available data for a range of species. All predictions were within a factor of five of the observed values when the model was parameterised appropriate to the feeding strategy of each species. This is an encouraging level of agreement given that the allometric models are intended to provide broad approximations rather than exact values. However, reasons why some radionuclides deviate from what would be anticipated from Kleiber's law need to be determined to allow a more complete exploitation of the potential of allometric extrapolation within radioecological models. (orig.)

  7. Reconsidering the evolution of brain, cognition and behaviour in birds and mammals

    Directory of Open Access Journals (Sweden)

    Romain eWillemet

    2013-07-01

    Full Text Available Despite decades of research, some of the most basic issues concerning the extraordinarily complex brains and behaviour of birds and mammals, such as the factors responsible for the diversity of brain size and composition, are still unclear. This is partly due to a number of conceptual and methodological issues. Determining species and group differences in brain composition requires accounting for the presence of taxon-cerebrotypes and the use of precise statistical methods. The role of allometry in determining brain variables should be revised. In particular, bird and mammalian brains appear to have evolved in response to a variety of selective pressures influencing both brain size and composition. Brain and cognition are indeed meta-variables, made up of the variables that are ecologically relevant and evolutionarily selected. External indicators of species differences in cognition and behaviour are limited by the complexity of these differences. Indeed, behavioural differences between species and individuals are caused by cognitive and affective components. Although intra-species variability forms the basis of species evolution, some of the mechanisms underlying individual differences in brain and behaviour appear to differ from those between species. While many issues have persisted over the years because of a lack of appropriate data or methods to test them; several fallacies, particularly those related to the human brain, reflect scientists’ preconceptions. The theoretical framework on the evolution of brain, cognition and behaviour in birds and mammals should be reconsidered with these biases in mind.

  8. How sexual selection can drive the evolution of costly sperm ornamentation

    Science.gov (United States)

    Lüpold, Stefan; Manier, Mollie K.; Puniamoorthy, Nalini; Schoff, Christopher; Starmer, William T.; Luepold, Shannon H. Buckley; Belote, John M.; Pitnick, Scott

    2016-05-01

    Post-copulatory sexual selection (PSS), fuelled by female promiscuity, is credited with the rapid evolution of sperm quality traits across diverse taxa. Yet, our understanding of the adaptive significance of sperm ornaments and the cryptic female preferences driving their evolution is extremely limited. Here we review the evolutionary allometry of exaggerated sexual traits (for example, antlers, horns, tail feathers, mandibles and dewlaps), show that the giant sperm of some Drosophila species are possibly the most extreme ornaments in all of nature and demonstrate how their existence challenges theories explaining the intensity of sexual selection, mating-system evolution and the fundamental nature of sex differences. We also combine quantitative genetic analyses of interacting sex-specific traits in D. melanogaster with comparative analyses of the condition dependence of male and female reproductive potential across species with varying ornament size to reveal complex dynamics that may underlie sperm-length evolution. Our results suggest that producing few gigantic sperm evolved by (1) Fisherian runaway selection mediated by genetic correlations between sperm length, the female preference for long sperm and female mating frequency, and (2) longer sperm increasing the indirect benefits to females. Our results also suggest that the developmental integration of sperm quality and quantity renders post-copulatory sexual selection on ejaculates unlikely to treat male-male competition and female choice as discrete processes.

  9. Individual-Based Allometric Equations Accurately Measure Carbon Storage and Sequestration in Shrublands

    Directory of Open Access Journals (Sweden)

    Norman W.H. Mason

    2014-02-01

    Full Text Available Many studies have quantified uncertainty in forest carbon (C storage estimation, but there is little work examining the degree of uncertainty in shrubland C storage estimates. We used field data to simulate uncertainty in carbon storage estimates from three error sources: (1 allometric biomass equations; (2 measurement errors of shrubs harvested for the allometry; and (3 measurement errors of shrubs in survey plots. We also assessed uncertainty for all possible combinations of these error sources. Allometric uncertainty had the greatest independent effect on C storage estimates for individual plots. The largest error arose when all three error sources were included in simulations (where the 95% confidence interval spanned a range equivalent to 40% of mean C storage. Mean C sequestration (1.73 Mg C ha–1 year–1 exceeded the margin of error produced by the simulated sources of uncertainty. This demonstrates that, even when the major sources of uncertainty were accounted for, we were able to detect relatively modest gains in shrubland C storage.

  10. A mathematical model for pressure-based organs behaving as biological pressure vessels.

    Science.gov (United States)

    Casha, Aaron R; Camilleri, Liberato; Gauci, Marilyn; Gatt, Ruben; Sladden, David; Chetcuti, Stanley; Grima, Joseph N

    2018-04-26

    We introduce a mathematical model that describes the allometry of physical characteristics of hollow organs behaving as pressure vessels based on the physics of ideal pressure vessels. The model was validated by studying parameters such as body and organ mass, systolic and diastolic pressures, internal and external dimensions, pressurization energy and organ energy output measurements of pressure-based organs in a wide range of mammals and birds. Seven rules were derived that govern amongst others, lack of size efficiency on scaling to larger organ sizes, matching organ size in the same species, equal relative efficiency in pressurization energy across species and direct size matching between organ mass and mass of contents. The lung, heart and bladder follow these predicted theoretical relationships with a similar relative efficiency across various mammalian and avian species; an exception is cardiac output in mammals with a mass exceeding 10kg. This may limit massive body size in mammals, breaking Cope's rule that populations evolve to increase in body size over time. Such a limit was not found in large flightless birds exceeding 100kg, leading to speculation about unlimited dinosaur size should dinosaurs carry avian-like cardiac characteristics. Copyright © 2018. Published by Elsevier Ltd.

  11. An online database for informing ecological network models: http://kelpforest.ucsc.edu.

    Science.gov (United States)

    Beas-Luna, Rodrigo; Novak, Mark; Carr, Mark H; Tinker, Martin T; Black, August; Caselle, Jennifer E; Hoban, Michael; Malone, Dan; Iles, Alison

    2014-01-01

    Ecological network models and analyses are recognized as valuable tools for understanding the dynamics and resiliency of ecosystems, and for informing ecosystem-based approaches to management. However, few databases exist that can provide the life history, demographic and species interaction information necessary to parameterize ecological network models. Faced with the difficulty of synthesizing the information required to construct models for kelp forest ecosystems along the West Coast of North America, we developed an online database (http://kelpforest.ucsc.edu/) to facilitate the collation and dissemination of such information. Many of the database's attributes are novel yet the structure is applicable and adaptable to other ecosystem modeling efforts. Information for each taxonomic unit includes stage-specific life history, demography, and body-size allometries. Species interactions include trophic, competitive, facilitative, and parasitic forms. Each data entry is temporally and spatially explicit. The online data entry interface allows researchers anywhere to contribute and access information. Quality control is facilitated by attributing each entry to unique contributor identities and source citations. The database has proven useful as an archive of species and ecosystem-specific information in the development of several ecological network models, for informing management actions, and for education purposes (e.g., undergraduate and graduate training). To facilitate adaptation of the database by other researches for other ecosystems, the code and technical details on how to customize this database and apply it to other ecosystems are freely available and located at the following link (https://github.com/kelpforest-cameo/databaseui).

  12. A potential mechanism for allometric trabecular bone scaling in terrestrial mammals.

    Science.gov (United States)

    Christen, Patrik; Ito, Keita; van Rietbergen, Bert

    2015-03-01

    Trabecular bone microstructural parameters, including trabecular thickness, spacing, and number, have been reported to scale with animal size with negative allometry, whereas bone volume fraction is animal size-invariant in terrestrial mammals. As for the majority of scaling patterns described in animals, its underlying mechanism is unknown. However, it has also been found that osteocyte density is inversely related to animal size, possibly adapted to metabolic rate, which shows a negative relationship as well. In addition, the signalling reach of osteocytes is limited by the extent of the lacuno-canalicular network, depending on trabecular dimensions and thus also on animal size. Here we propose animal size-dependent variations in osteocyte density and their signalling influence distance as a potential mechanism for negative allometric trabecular bone scaling in terrestrial mammals. Using an established and tested computational model of bone modelling and remodelling, we run simulations with different osteocyte densities and influence distances mimicking six terrestrial mammals covering a large range of body masses. Simulated trabecular structures revealed negative allometric scaling for trabecular thickness, spacing, and number, constant bone volume fraction, and bone turnover rates inversely related to animal size. These results are in agreement with previous observations supporting our proposal of osteocyte density and influence distance variation as a potential mechanism for negative allometric trabecular bone scaling in terrestrial mammals. The inverse relationship between bone turnover rates and animal size further indicates that trabecular bone scaling may be linked to metabolic rather than mechanical adaptations. © 2015 Anatomical Society.

  13. Morphological and phenological shoot plasticity in a Mediterranean evergreen oak facing long-term increased drought.

    Science.gov (United States)

    Limousin, Jean-Marc; Rambal, Serge; Ourcival, Jean-Marc; Rodríguez-Calcerrada, Jesus; Pérez-Ramos, Ignacio M; Rodríguez-Cortina, Raquel; Misson, Laurent; Joffre, Richard

    2012-06-01

    Mediterranean trees must adjust their canopy leaf area to the unpredictable timing and severity of summer drought. The impact of increased drought on the canopy dynamics of the evergreen Quercus ilex was studied by measuring shoot growth, leaf production, litterfall, leafing phenology and leaf demography in a mature forest stand submitted to partial throughfall exclusion for 7 years. The leaf area index rapidly declined in the throughfall-exclusion plot and was 19% lower than in the control plot after 7 years of treatment. Consequently, leaf litterfall was significantly lower in the dry treatment. Such a decline in leaf area occurred through a change in branch allometry with a decreased number of ramifications produced and a reduction of the leaf area supported per unit sapwood area of the shoot (LA/SA). The leafing phenology was slightly delayed and the median leaf life span was slightly longer in the dry treatment. The canopy dynamics in both treatments were driven by water availability with a 1-year lag: leaf shedding and production were reduced following dry years; in contrast, leaf turnover was increased following wet years. The drought-induced decrease in leaf area, resulting from both plasticity in shoot development and slower leaf turnover, appeared to be a hydraulic adjustment to limit canopy transpiration and maintain leaf-specific hydraulic conductivity under drier conditions.

  14. Environmental drivers of sapwood and heartwood proportions

    Science.gov (United States)

    Thurner, Martin; Beer, Christian

    2017-04-01

    Recent advances combining information on stem volume from remote sensing with allometric relationships derived from forest inventory databases have led to spatially continuous estimates of stem, branch, root and foliage biomass in northern boreal and temperate forests. However, a separation of stem biomass into sapwood and heartwood mass has remained unsolved, despite their important differences in biogeochemical function, for instance concerning their contribution to tree respiratory costs. Although relationships between sapwood cross-sectional area and supported leaf area are well established, less is known about relations between sapwood or heartwood mass and other traits (e.g. stem mass), since these biomass compartments are more difficult to measure in practice. Here we investigate the variability in sapwood and heartwood proportions and determining environmental factors. For this task we explore an available biomass and allometry database (BAAD) and study relative sapwood and heartwood area, volume, mass and density in dependence of tree species, age and climate. First, a theoretical framework on how to estimate sap- and heartwood mass from stem mass is developed. Subsequently, the underlying assumptions and relationships are explored with the help of the BAAD. The established relationships can be used to derive spatially continuous sapwood and heartwood mass estimates by applying them to remote sensing based stem volume products. This would be a fundamental step forward to a data-driven estimate of autotrophic respiration.

  15. Diet and body shape changes of pāroko Kelloggella disalvoi (Gobiidae) from intertidal pools of Easter Island.

    Science.gov (United States)

    Vera-Duarte, J; Bustos, C A; Landaeta, M F

    2017-11-01

    This study assesses seasonal variation in the morphology and diet of juveniles and adults of the Easter Island endemic goby Kelloggella disalvoi from intertidal pools during September-October 2015 (spring) and June-July 2016 (winter), utilizing geometric morphometric and gut-content analyses. A set of 16 landmarks was digitized in 128 individuals. Shape changes related to size changes (i.e. allometry) were low (18·6%) and were seasonally similar. Body shape changes were mainly dorsoventral (44·2% of variance) and comprised posteroventral displacement of the premaxilla and bending of the body. The latter included vertical displacement of the anterior portion of the first and second dorsal fins and the entire base of the caudal fin. Diets mainly comprised developmental stages of harpacticoid copepods (from eggs to adults), ostracods, isopods, gastropods and bivalves. Also, trophic niche breadth remained constant throughout development and did not vary between seasons. Nonetheless, significant dietary differences were detected in specimens collected during spring (main prey items: harpacticoid copepods and copepod eggs) and winter (harpacticoid copepods and copepod nauplii). Finally, there was weak but significant covariation between diet and morphology: molluscivores were characterized by having an inferior mouth gape, whereas planktivores had an anteriorly directed premaxilla. © 2017 The Fisheries Society of the British Isles.

  16. The brain sizes of living elasmobranchii as their organization level indicator. I. General analysis.

    Science.gov (United States)

    Myagkov, N A

    1991-01-01

    The relationship between brain and body masses of 64 species and subspecies of modern sharks and skates was investigated. It was established that the level of their encephalization in terms of the polygons of encephalization and the allometry coefficient (alpha), shows quite obviously the general organization level of one or another taxon of sharks and skates. Alpha = 0.56 for the class of cartilaginous fishes, and for the superorder of sharks and skates alpha = 0.54 and 0.61, accordingly. For several orders alpha constitutes: sharks--common for relict Hexanchiformes and Heterodontiformes 0.44, Squaliformes 0.43 and Carcharhiniformes 0.52 and skates--Rajiformes 0.44 and Dasyatiformes 0.52. All values are similar to those of other vertebrates and the theoretically calculated value of alpha (0.67). It was established the "place" of present-day Elasmobranchii and all cartilaginous fishes in the evolutionary row of Gnathostomata and Craniata on the developing and relative sizes of CNS, and the corrected alpha value for this particular vertebrate class was specified which was found to be sensationally high also in the works of foreign and native authors (Bauchot et al., 1976; Northcutt, 1978; Ebbesson, 1980; Kreps, 1980).

  17. Geographic differences in the carapace shape of the crab Cyrtograpsus affinis (Decapoda: Varunidae and its taxonomic implications

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    Aníbal H. Lezcano

    2011-11-01

    Full Text Available Cyrtograpsus genus was traditionally considered to be composed of three species: C. angulatus, C. altimanus and C. affinis. However, recent studies have found solid evidence suggesting that C. affinis and C. altimanus belong to a single species and hypothesize that the morphological differences which caused this misclassification could be related to different ecophenotypes or life stages. Here we report a geometric morphometrics study on the carapace shape of Cyrtograpsus specimens from the Río de la Plata estuary (36°S and the Nuevo Gulf (42.75°S, testing for shape differences between different sizes (allometry in the two environments. We found that previous morphological descriptions of the two species were associated with different sizes of a continuous, statistically significant allometric shape variation, concluding that C. affinis is a junior synonym of C. altimanus. We also found significant differences in the carapace shape between estuarine and marine environments, suggesting an effect of the environmental variables on carapace shape and a potential adaptive value of this trait.

  18. Differential scaling patterns of vertebrae and the evolution of neck length in mammals.

    Science.gov (United States)

    Arnold, Patrick; Amson, Eli; Fischer, Martin S

    2017-06-01

    Almost all mammals have seven vertebrae in their cervical spines. This consistency represents one of the most prominent examples of morphological stasis in vertebrae evolution. Hence, the requirements associated with evolutionary modifications of neck length have to be met with a fixed number of vertebrae. It has not been clear whether body size influences the overall length of the cervical spine and its inner organization (i.e., if the mammalian neck is subject to allometry). Here, we provide the first large-scale analysis of the scaling patterns of the cervical spine and its constituting cervical vertebrae. Our findings reveal that the opposite allometric scaling of C1 and C2-C7 accommodate the increase of neck bending moment with body size. The internal organization of the neck skeleton exhibits surprisingly uniformity in the vast majority of mammals. Deviations from this general pattern only occur under extreme loading regimes associated with particular functional and allometric demands. Our results indicate that the main source of variation in the mammalian neck stems from the disparity of overall cervical spine length. The mammalian neck reveals how evolutionary disparity manifests itself in a structure that is otherwise highly restricted by meristic constraints. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  19. A morphological and life history comparison between desert populations of a sit-and-pursue antlion, in reference to a co-occurring pit-building antlion.

    Science.gov (United States)

    Scharf, Inon; Filin, Ido; Subach, Aziz; Ovadia, Ofer

    2009-10-01

    Although most antlion species do not construct pits, the vast majority of studies on antlions focused on pit-building species. We report here on a transplant experiment aiming to test for morphological and life history differences between two desert populations of a sit-and-pursue antlion species, Lopezus fedtschenkoi (Neuroptera: Myrmeleontidae), originating from habitats, which mainly differ in plant cover and productivity. We raised the antlion larvae in environmental chambers simulating either hyper-arid or Mediterranean climate. We found significant differences in the morphology and life history of L. fedtschenkoi larvae between the two populations. For example, the larvae originating from the more productive habitat pupated faster and had a higher growth rate. In agreement with the temperature-size rule, antlions reached higher final mass in the colder Mediterranean climate and exhibited a higher growth rate, but there was no difference in their developmental time. Observed differences in morphology between populations as well as those triggered by climate growing conditions could be explained by differences in size allometry. We also provide a quantitative description of the allometric growth axis, based on 12 morphological traits. Comparing the responses of L. fedtschenkoi with those observed in a co-occurring pit-building antlion indicated that there were neither shape differences that are independent of size nor was there a difference in the plasticity level between the two species.

  20. Insights into the development and evolution of exaggerated traits using de novo transcriptomes of two species of horned scarab beetles.

    Science.gov (United States)

    Warren, Ian A; Vera, J Cristobal; Johns, Annika; Zinna, Robert; Marden, James H; Emlen, Douglas J; Dworkin, Ian; Lavine, Laura C

    2014-01-01

    Scarab beetles exhibit an astonishing variety of rigid exo-skeletal outgrowths, known as "horns". These traits are often sexually dimorphic and vary dramatically across species in size, shape, location, and allometry with body size. In many species, the horn exhibits disproportionate growth resulting in an exaggerated allometric relationship with body size, as compared to other traits, such as wings, that grow proportionately with body size. Depending on the species, the smallest males either do not produce a horn at all, or they produce a disproportionately small horn for their body size. While the diversity of horn shapes and their behavioural ecology have been reasonably well studied, we know far less about the proximate mechanisms that regulate horn growth. Thus, using 454 pyrosequencing, we generated transcriptome profiles, during horn growth and development, in two different scarab beetle species: the Asian rhinoceros beetle, Trypoxylus dichotomus, and the dung beetle, Onthophagus nigriventris. We obtained over half a million reads for each species that were assembled into over 6,000 and 16,000 contigs respectively. We combined these data with previously published studies to look for signatures of molecular evolution. We found a small subset of genes with horn-biased expression showing evidence for recent positive selection, as is expected with sexual selection on horn size. We also found evidence of relaxed selection present in genes that demonstrated biased expression between horned and horn-less morphs, consistent with the theory of developmental decoupling of phenotypically plastic traits.

  1. Optimal allocation of leaf epidermal area for gas exchange.

    Science.gov (United States)

    de Boer, Hugo J; Price, Charles A; Wagner-Cremer, Friederike; Dekker, Stefan C; Franks, Peter J; Veneklaas, Erik J

    2016-06-01

    A long-standing research focus in phytology has been to understand how plants allocate leaf epidermal space to stomata in order to achieve an economic balance between the plant's carbon needs and water use. Here, we present a quantitative theoretical framework to predict allometric relationships between morphological stomatal traits in relation to leaf gas exchange and the required allocation of epidermal area to stomata. Our theoretical framework was derived from first principles of diffusion and geometry based on the hypothesis that selection for higher anatomical maximum stomatal conductance (gsmax ) involves a trade-off to minimize the fraction of the epidermis that is allocated to stomata. Predicted allometric relationships between stomatal traits were tested with a comprehensive compilation of published and unpublished data on 1057 species from all major clades. In support of our theoretical framework, stomatal traits of this phylogenetically diverse sample reflect spatially optimal allometry that minimizes investment in the allocation of epidermal area when plants evolve towards higher gsmax . Our results specifically highlight that the stomatal morphology of angiosperms evolved along spatially optimal allometric relationships. We propose that the resulting wide range of viable stomatal trait combinations equips angiosperms with developmental and evolutionary flexibility in leaf gas exchange unrivalled by gymnosperms and pteridophytes. © 2016 The Authors New Phytologist © 2016 New Phytologist Trust.

  2. Sexual Dimorphism and Allometric Effects Associated With the Wing Shape of Seven Moth Species of Sphingidae (Lepidoptera: Bombycoidea).

    Science.gov (United States)

    de Camargo, Willian Rogers Ferreira; de Camargo, Nícholas Ferreira; Corrêa, Danilo do Carmo Vieira; de Camargo, Amabílio J Aires; Diniz, Ivone Rezende

    2015-01-01

    Sexual dimorphism is a pronounced pattern of intraspecific variation in Lepidoptera. However, moths of the family Sphingidae (Lepidoptera: Bombycoidea) are considered exceptions to this rule. We used geometric morphometric techniques to detect shape and size sexual dimorphism in the fore and hindwings of seven hawkmoth species. The shape variables produced were then subjected to a discriminant analysis. The allometric effects were measured with a simple regression between the canonical variables and the centroid size. We also used the normalized residuals to assess the nonallometric component of shape variation with a t-test. The deformations in wing shape between sexes per species were assessed with a regression between the nonreduced shape variables and the residuals. We found sexual dimorphism in both wings in all analyzed species, and that the allometric effects were responsible for much of the wing shape variation between the sexes. However, when we removed the size effects, we observed shape sexual dimorphism. It is very common for females to be larger than males in Lepidoptera, so it is expected that the shape of structures such as wings suffers deformations in order to preserve their function. However, sources of variation other than allometry could be a reflection of different reproductive flight behavior (long flights in search for sexual mates in males, and flight in search for host plants in females). © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  3. Demography of the endangered tree species Ocotea porosa (Lauraceae along a gradient of forest disturbance in southern Brazil

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    Cibele Amato Munhoz

    2014-12-01

    Full Text Available Ocotea porosa (Ness Barroso (Lauraceae, a typical tree of the southern Atlantic Forest in Brazil, was heavily exploited for timber in the last century. With the aim of examining the status of the remaining populations, we surveyed five forest fragments in the state of Paraná, in southern Brazil, and evaluated whether disturbances caused by selective logging and fragmentation were related to population structure of O. porosa. We assessed demographic aspects related to tree density, size hierarchy and individual allometry, correlating those parameters with fragment structure variables (fragment size, isolation and logging level. We found that, although all populations occurred in low densities (60-440 individuals ha−¹, the number of adults was significantly lower in the smaller and most disturbed fragments (13 and 35 individuals ha−¹, respectively. We did not detect changes in allometric relationships among individuals in the five populations studied. However, we found that populations in more heavily disturbed areas presented lower size hierarchy (i.e., less dominance of larger trees than did those in undisturbed areas, suggesting that selective logging affects the population structure of O. porosa, possibly affecting the rates of reproduction and fecundity, which may ultimately increase the probability of local extinction.

  4. Influence of planting methods on root development, crop productivity and water use efficiency in maize hybrids Influencia de métodos de siembra sobre el desarrollo radical, productividad y eficiencia del uso del agua en híbridos de maíz

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    Muhammad B. Khan

    2012-12-01

    Full Text Available Optimum planting methods better ensure water and nutrient supply through improved root development resulting in better crop growth and productivity. This study was conducted to evaluate the effects of planting methods on root development, crop allometry, water use efficiency (WUE, productivity and economic returns of different maize (Zea mays L. hybrids. Maize hybrids NK-6621, Pioneer-30Y87, and Pioneer-30Y58 were sown on beds, ridges, and flat surface. Ridge sowing was better followed by bed sowing; while amongst the hybrids, 'Pioneer-30Y87' performed the best. Well-developed root system, with longer primary root, more number of lateral roots and higher root growth rate, was observed in 'Pioneer-30Y87' planted on ridges, which led to higher WUE, grain yield and its related traits. The same hybrid exhibited higher leaf area index and crop growth rate, and maximum net return and benefit:cost ratio sowed on ridges. Overall, the ridge sowing improved root development resulting in better allometry, productivity (5.45 t ha-1, and WUE (1.345 kg m-3, in all the maize hybrids. Although maize hybrids exhibited different response to different planting methods; maximum grain yield (5.63 t ha-1, WUE (1.41 kg m-3, and net economic returns were observed from hybrid Pioneer-30Y87.Métodos óptimos de siembra aseguran mejor suministro de agua y nutrientes a través del mejorado desarrollo de raíces que resulta en mejor crecimiento y productividad de los cultivos. Este estudio se realizó para evaluar los efectos de los métodos de siembra en el desarrollo de las raíces, alometría de cultivos, uso eficiente del agua (WUE, productividad y rentabilidad económica de diferentes híbridos de maíz (Zea mays L.. Híbridos de maíz NK-6621, Pioneer 30Y87, y 30Y58-Pioneer se sembraron en camas, surcos, y superficie plana. La siembra en surco fue mejor, seguida por siembra en cama, mientras entre los híbridos, 'Pioneer 30Y87' tuvo los mejores resultados. Se observ

  5. Size Scaling in Western North Atlantic Loggerhead Turtles Permits Extrapolation between Regions, but Not Life Stages.

    Science.gov (United States)

    Marn, Nina; Klanjscek, Tin; Stokes, Lesley; Jusup, Marko

    2015-01-01

    Sea turtles face threats globally and are protected by national and international laws. Allometry and scaling models greatly aid sea turtle conservation and research, and help to better understand the biology of sea turtles. Scaling, however, may differ between regions and/or life stages. We analyze differences between (i) two different regional subsets and (ii) three different life stage subsets of the western North Atlantic loggerhead turtles by comparing the relative growth of body width and depth in relation to body length, and discuss the implications. Results suggest that the differences between scaling relationships of different regional subsets are negligible, and models fitted on data from one region of the western North Atlantic can safely be used on data for the same life stage from another North Atlantic region. On the other hand, using models fitted on data for one life stage to describe other life stages is not recommended if accuracy is of paramount importance. In particular, young loggerhead turtles that have not recruited to neritic habitats should be studied and modeled separately whenever practical, while neritic juveniles and adults can be modeled together as one group. Even though morphometric scaling varies among life stages, a common model for all life stages can be used as a general description of scaling, and assuming isometric growth as a simplification is justified. In addition to linear models traditionally used for scaling on log-log axes, we test the performance of a saturating (curvilinear) model. The saturating model is statistically preferred in some cases, but the accuracy gained by the saturating model is marginal.

  6. Plasticity in reproduction and growth among 52 range-wide populations of a Mediterranean conifer: adaptive responses to environmental stress.

    Science.gov (United States)

    Santos-Del-Blanco, L; Bonser, S P; Valladares, F; Chambel, M R; Climent, J

    2013-09-01

    A plastic response towards enhanced reproduction is expected in stressful environments, but it is assumed to trade off against vegetative growth and efficiency in the use of available resources deployed in reproduction [reproductive efficiency (RE)]. Evidence supporting this expectation is scarce for plants, particularly for long-lived species. Forest trees such as Mediterranean pines provide ideal models to study the adaptive value of allocation to reproduction vs. vegetative growth given their among-population differentiation for adaptive traits and their remarkable capacity to cope with dry and low-fertility environments. We studied 52 range-wide Pinus halepensis populations planted into two environmentally contrasting sites during their initial reproductive stage. We investigated the effect of site, population and their interaction on vegetative growth, threshold size for female reproduction, reproductive-vegetative size relationships and RE. We quantified correlations among traits and environmental variables to identify allocation trade-offs and ecotypic trends. Genetic variation for plasticity was high for vegetative growth, whereas it was nonsignificant for reproduction. Size-corrected reproduction was enhanced in the more stressful site supporting the expectation for adverse conditions to elicit plastic responses in reproductive allometry. However, RE was unrelated with early reproductive investment. Our results followed theoretical predictions and support that phenotypic plasticity for reproduction is adaptive under stressful environments. Considering expectations of increased drought in the Mediterranean, we hypothesize that phenotypic plasticity together with natural selection on reproductive traits will play a relevant role in the future adaptation of forest tree species. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  7. Reducing Uncertainty in Mapping of Mangrove Aboveground Biomass Using Airborne Discrete Return Lidar Data

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    Francisca Rocha de Souza Pereira

    2018-04-01

    Full Text Available Remote sensing techniques offer useful tools for estimating forest biomass to large extent, thereby contributing to the monitoring of land use and landcover dynamics and the effectiveness of environmental policies. The main goal of this study was to investigate the potential use of discrete return light detection and ranging (lidar data to produce accurate aboveground biomass (AGB maps of mangrove forests. AGB was estimated in 34 small plots scatted over a 50 km2 mangrove forest in Rio de Janeiro, Brazil. Plot AGB was computed using either species-specific or non-species-specific allometric models. A total of 26 descriptive lidar metrics were extracted from the normalized height of the lidar point cloud data, and various model forms (random forest and partial least squares regression with backward selection of predictors (Auto-PLS were tested to predict the recorded AGB. The models developed using species-specific allometric models were distinctly more accurate (R2(calibration = 0.89, R2(validation = 0.80, root-mean-square error (RMSE, calibration = 11.20 t·ha−1, and RMSE(validation = 14.80 t·ha−1. The use of non-species-specific allometric models yielded large errors on a landscape scale (+14% or −18% bias depending on the allometry considered, indicating that using poor quality training data not only results in low precision but inaccuracy at all scales. It was concluded that under suitable sampling pattern and provided that accurate field data are used, discrete return lidar can accurately estimate and map the AGB in mangrove forests. Conversely this study underlines the potential bias affecting the estimates of AGB in other forested landscapes where only non-species-specific allometric equations are available.

  8. Contrasting trait syndromes in angiosperms and conifers are associated with different responses of tree growth to temperature on a large scale.

    Science.gov (United States)

    Carnicer, Jofre; Barbeta, Adrià; Sperlich, Dominik; Coll, Marta; Peñuelas, Josep

    2013-01-01

    Recent large-scale studies of tree growth in the Iberian Peninsula reported contrasting positive and negative effects of temperature in Mediterranean angiosperms and conifers. Here we review the different hypotheses that may explain these trends and propose that the observed contrasting responses of tree growth to temperature in this region could be associated with a continuum of trait differences between angiosperms and conifers. Angiosperm and conifer trees differ in the effects of phenology in their productivity, in their growth allometry, and in their sensitivity to competition. Moreover, angiosperms and conifers significantly differ in hydraulic safety margins, sensitivity of stomatal conductance to vapor-pressure deficit (VPD), xylem recovery capacity or the rate of carbon transfer. These differences could be explained by key features of the xylem such as non-structural carbohydrate content (NSC), wood parenchymal fraction or wood capacitance. We suggest that the reviewed trait differences define two contrasting ecophysiological strategies that may determine qualitatively different growth responses to increased temperature and drought. Improved reciprocal common garden experiments along altitudinal or latitudinal gradients would be key to quantify the relative importance of the different hypotheses reviewed. Finally, we show that warming impacts in this area occur in an ecological context characterized by the advance of forest succession and increased dominance of angiosperm trees over extensive areas. In this context, we examined the empirical relationships between the responses of tree growth to temperature and hydraulic safety margins in angiosperm and coniferous trees. Our findings suggest a future scenario in Mediterranean forests characterized by contrasting demographic responses in conifer and angiosperm trees to both temperature and forest succession, with increased dominance of angiosperm trees, and particularly negative impacts in pines.

  9. Contrasting trait syndromes in angiosperms and conifers are associated with different responses of tree growth to temperature on a large scale.

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    Jofre eCarnicer

    2013-10-01

    Full Text Available Recent large-scale studies of tree growth in the Iberian Peninsula reported contrasting positive and negative effects of temperature in Mediterranean angiosperms and conifers. Here we review the different hypotheses that may explain these trends and propose that the observed contrasting responses of tree growth to temperature in this region could be associated with a continuum of trait differences between angiosperms and conifers. Angiosperm and conifer trees differ in the effects of phenology in their productivity, in their growth allometry, and in their sensitivity to competition. Moreover, angiosperms and conifers significantly differ in hydraulic safety margins, sensitivity of stomatal conductance to vapor-pressure deficit, xylem recovery capacity or the rate of carbon transfer. These differences could be explained by key features of the xylem such as non-structural carbohydrate content (NSC, wood parenchymal fraction or wood capacitance. We suggest that the reviewed trait differences define two contrasting ecophysiological strategies that may determine qualitatively different growth responses to increased temperature and drought. Improved reciprocal common garden experiments along altitudinal or latitudinal gradients would be key to quantify the relative importance of the different hypotheses reviewed. Finally, we show that warming impacts in this area occur in an ecological context characterized by the advance of forest succession and increased dominance of angiosperm trees over extensive areas. In this context, we examined the empirical relationships between the responses of tree growth to temperature and hydraulic safety margins in angiosperm and coniferous trees. Our findings suggest a future scenario in Mediterranean forests characterized by contrasting demographic responses in conifer and angiosperm trees to both temperature and forest succession, with increased dominance of angiosperm trees, and particularly negative impacts in pines.

  10. The influence of feeding on the evolution of sensory signals: a comparative test of an evolutionary trade-off between masticatory and sensory functions of skulls in southern African horseshoe bats (Rhinolophidae).

    Science.gov (United States)

    Jacobs, D S; Bastian, A; Bam, L

    2014-12-01

    The skulls of animals have to perform many functions. Optimization for one function may mean another function is less optimized, resulting in evolutionary trade-offs. Here, we investigate whether a trade-off exists between the masticatory and sensory functions of animal skulls using echolocating bats as model species. Several species of rhinolophid bats deviate from the allometric relationship between body size and echolocation frequency. Such deviation may be the result of selection for increased bite force, resulting in a decrease in snout length which could in turn lead to higher echolocation frequencies. If so, there should be a positive relationship between bite force and echolocation frequency. We investigated this relationship in several species of southern African rhinolophids using phylogenetically informed analyses of the allometry of their bite force and echolocation frequency and of the three-dimensional shape of their skulls. As predicted, echolocation frequency was positively correlated with bite force, suggesting that its evolution is influenced by a trade-off between the masticatory and sensory functions of the skull. In support of this, variation in skull shape was explained by both echolocation frequency (80%) and bite force (20%). Furthermore, it appears that selection has acted on the nasal capsules, which have a frequency-specific impedance matching function during vocalization. There was a negative correlation between echolocation frequency and capsule volume across species. Optimization of the masticatory function of the skull may have been achieved through changes in the shape of the mandible and associated musculature, elements not considered in this study. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  11. Limb-bone scaling indicates diverse stance and gait in quadrupedal ornithischian dinosaurs.

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    Susannah C R Maidment

    Full Text Available BACKGROUND: The most primitive ornithischian dinosaurs were small bipeds, but quadrupedality evolved three times independently in the clade. The transition to quadrupedality from bipedal ancestors is rare in the history of terrestrial vertebrate evolution, and extant analogues do not exist. Constraints imposed on quadrupedal ornithischians by their ancestral bipedal bauplan remain unexplored, and consequently, debate continues about their stance and gait. For example, it has been proposed that some ornithischians could run, while others consider that none were cursorial. METHODOLOGY/PRINCIPAL FINDINGS: Drawing on biomechanical concepts of limb bone scaling and locomotor theory developed for extant taxa, we use the largest dataset of ornithischian postcranial measurements so far compiled to examine stance and gait in quadrupedal ornithischians. Differences in femoral midshaft eccentricity in hadrosaurs and ceratopsids may indicate that hadrosaurs placed their feet on the midline during locomotion, while ceratopsids placed their feet more laterally, under the hips. More robust humeri in the largest ceratopsids relative to smaller taxa may be due to positive allometry in skull size with body mass in ceratopsids, while slender humeri in the largest stegosaurs may be the result of differences in dermal armor distribution within the clade. Hadrosaurs are found to display the most cursorial morphologies of the quadrupedal ornithischian cades, indicating higher locomotor performance than in ceratopsids and thyreophorans. CONCLUSIONS/SIGNIFICANCE: Limb bone scaling indicates that a previously unrealised diversity of stances and gaits were employed by quadrupedal ornithischians despite apparent convergence in limb morphology. Grouping quadrupedal ornithischians together as a single functional group hides this disparity. Differences in limb proportions and scaling are likely due to the possession of display structures such as horns, frills and dermal armor

  12. Forest disturbance spurs growth of modeling and technology

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    Bohrer, G.; Matheny, A. M.; Mirfenderesgi, G.; Morin, T. H.; Rey Sanchez, A. C.; Gough, C. M.; Vogel, C. S.; Nadelhoffer, K. J.; Curtis, P.

    2016-12-01

    As new opportunities for scientific exploration open, needs for data generate a drive for innovative developments of new research tools. The Forest Accelerated Succession ExperimenT (FASET) was enacted in 2007, continuous flux observations at the University of Michigan Biological Station (UMBS) since 2000. FASET is a large-scale ecological experiment testing the immediate and intermediate term effects of disturbance, and eventually, the role of succession and community composition on forest flux dynamics. Decades-long tree-level observations in the UMBS forest, combined with the long term flux observations allowed us to match the bottom-up accumulated response of individual trees with the top-down whole-plot response measured from the flux tower. However, data describing tree-level canopy structure and hydrological response over an entire plot were not readily available. Unintentionally, FASET became both a motivation and a test-bed for new research tools and approaches. We expanded the operation and analysis approach for a portable canopy LiDARfor 3-D measurements meter-scale canopy structure. We matched canopy LiDAR measurements with root measurements from ground penetrating radar. To study the hydrological effects of the disturbance, we instrumented a large number of trees with Granier-style sap flux sensors. We further developed an approach to use frequency domain reflectometry sensors for continuous measurements of tree water content. We developed an approach to combine plot census, allometry and sap-flux observations in a bottom-up fashion to compare with plot-level EC transpiration rates. We found that while the transpirational water demand in the disturbance plot increased, overall evapotranspiration decreased. This decrease, however, is not uniform across species. A new individual-plant to ecosystem scale hydrodynamic model (FETCH2) demonstrates how specific traits translate to intra-daily differences in plot-level transpiration dynamics.

  13. The soil water balance in a mosaic of clumped vegetation

    Science.gov (United States)

    Pizzolla, Teresa; Manfreda, Salvatore; Caylor, Kelly; Gioia, Andrea; Iacobellis, Vito

    2014-05-01

    The spatio-temporal distribution of soil moisture influences the plant growth and the distribution of terrestrial vegetation. This effect is more evident in arid and semiarid ecosystems where the interaction between individuals and the water limited conditions play a fundamental role, providing environmental conditions which drive a variety of non-linear ecohydrological response functions (such as transpiration, photosynthesis, leakage). In this context, modeling vegetation patterns at multiple spatial aggregation scales is important to understand how different vegetation structures can modify the soil water distribution and the exchanged fluxes between soil and atmosphere. In the present paper, the effect of different spatial vegetation patterns, under different climatic scenarios, is investigated in a patchy vegetation mosaic generated by a random process of individual tree canopies and their accompanying root system. Vegetation pattern are generated using the mathematical framework proposed by Caylor et al. (2006) characterized by a three dimensional stochastic vegetation structure, based on the density, dispersion, size distribution, and allometry of individuals within a landscape. A Poisson distribution is applied to generate different distribution of individuals paying particular attention on the role of clumping on water distribution dynamics. The soil water balance is evaluated using the analytical expression proposed by Laio et al. (2001) to explore the influence of climate and vegetation patterns on soil water balance steady-state components (such as the average rates of evaporation, the root water uptake and leakage) and on the stress-weighted plant water uptake. Results of numerical simulations show that clumping may be beneficial for water use efficiency at the landscape scale. References Caylor, Kelly K., P. D'Odorico and I. Rodriguez Iturbe: On the ecohydrology of structurally heterogeneous semiarid landscape. Water Resour. Res., 28, W07424, 2006

  14. Parameterisation of Biome BGC to assess forest ecosystems in Africa

    Science.gov (United States)

    Gautam, Sishir; Pietsch, Stephan A.

    2010-05-01

    African forest ecosystems are an important environmental and economic resource. Several studies show that tropical forests are critical to society as economic, environmental and societal resources. Tropical forests are carbon dense and thus play a key role in climate change mitigation. Unfortunately, the response of tropical forests to environmental change is largely unknown owing to insufficient spatially extensive observations. Developing regions like Africa where records of forest management for long periods are unavailable the process-based ecosystem simulation model - BIOME BGC could be a suitable tool to explain forest ecosystem dynamics. This ecosystem simulation model uses descriptive input parameters to establish the physiology, biochemistry, structure, and allocation patterns within vegetation functional types, or biomes. Undocumented parameters for larger-resolution simulations are currently the major limitations to regional modelling in African forest ecosystems. This study was conducted to document input parameters for BIOME-BGC for major natural tropical forests in the Congo basin. Based on available literature and field measurements updated values for turnover and mortality, allometry, carbon to nitrogen ratios, allocation of plant material to labile, cellulose, and lignin pools, tree morphology and other relevant factors were assigned. Daily climate input data for the model applications were generated using the statistical weather generator MarkSim. The forest was inventoried at various sites and soil samples of corresponding stands across Gabon were collected. Carbon and nitrogen in the collected soil samples were determined from soil analysis. The observed tree volume, soil carbon and soil nitrogen were then compared with the simulated model outputs to evaluate the model performance. Furthermore, the simulation using Congo Basin specific parameters and generalised BIOME BGC parameters for tropical evergreen broadleaved tree species were also

  15. Additive genetic variation in the craniofacial skeleton of baboons (genus Papio) and its relationship to body and cranial size.

    Science.gov (United States)

    Joganic, Jessica L; Willmore, Katherine E; Richtsmeier, Joan T; Weiss, Kenneth M; Mahaney, Michael C; Rogers, Jeffrey; Cheverud, James M

    2018-02-01

    Determining the genetic architecture of quantitative traits and genetic correlations among them is important for understanding morphological evolution patterns. We address two questions regarding papionin evolution: (1) what effect do body and cranial size, age, and sex have on phenotypic (V P ) and additive genetic (V A ) variation in baboon crania, and (2) how might additive genetic correlations between craniofacial traits and body mass affect morphological evolution? We use a large captive pedigreed baboon sample to estimate quantitative genetic parameters for craniofacial dimensions (EIDs). Our models include nested combinations of the covariates listed above. We also simulate the correlated response of a given EID due to selection on body mass alone. Covariates account for 1.2-91% of craniofacial V P . EID V A decreases across models as more covariates are included. The median genetic correlation estimate between each EID and body mass is 0.33. Analysis of the multivariate response to selection reveals that observed patterns of craniofacial variation in extant baboons cannot be attributed solely to correlated response to selection on body mass, particularly in males. Because a relatively large proportion of EID V A is shared with body mass variation, different methods of correcting for allometry by statistically controlling for size can alter residual V P patterns. This may conflate direct selection effects on craniofacial variation with those resulting from a correlated response to body mass selection. This shared genetic variation may partially explain how selection for increased body mass in two different papionin lineages produced remarkably similar craniofacial phenotypes. © 2017 Wiley Periodicals, Inc.

  16. Within-species patterns challenge our understanding of the causes and consequences of trait variation with implications for trait-based models

    Science.gov (United States)

    Anderegg, L. D.; Berner, L. T.; Badgley, G.; Hillerislambers, J.; Law, B. E.

    2017-12-01

    Functional traits could facilitate ecological prediction by provide scale-free tools for modeling ecosystem function. Yet much of their utility lies in three key assumptions: 1) that global patterns of trait covariation are the result of universal trade-offs independent of taxonomic scale, so empirical trait-trait relationships can be used to constrain vegetation models 2) that traits respond predictably to environmental gradients and can therefore be reliably quantified to parameterize models and 3) that well sampled traits influence productivity. We use an extensive dataset of within-species leaf trait variation in North American conifers combined with global leaf trait datasets to test these assumptions. We examine traits central to the `leaf economics spectrum', and quantify patterns of trait variation at multiple taxonomic scales. We also test whether site environment explains geographic trait variation within conifers, and ask whether foliar traits explain geographic variation in relative growth rates. We find that most leaf traits vary primarily between rather than within species globally, but that a large fraction of within-PFT trait variation is within-species. We also find that some leaf economics spectrum relationships differ in sign within versus between species, particularly the relationship between leaf lifespan and LMA. In conifers, we find weak and inconsistent relationships between site environment and leaf traits, making it difficult capture within-species leaf trait variation for regional model parameterization. Finally, we find limited relationships between tree relative growth rate and any foliar trait other than leaf lifespan, with leaf traits jointly explaining 42% of within-species growth variation but environmental factors explaining 77% of variation. We suggest that additional traits, particularly whole plant allometry/allocation traits may be better than leaf traits for improving vegetation model performance at smaller taxonomic and

  17. Variability in echolocation call intensity in a community of horseshoe bats: a role for resource partitioning or communication?

    Science.gov (United States)

    Schuchmann, Maike; Siemers, Björn M

    2010-09-17

    Only recently data on bat echolocation call intensities is starting to accumulate. Yet, intensity is an ecologically crucial parameter, as it determines the extent of the bats' perceptual space and, specifically, prey detection distance. Interspecifically, we thus asked whether sympatric, congeneric bat species differ in call intensities and whether differences play a role for niche differentiation. Specifically, we investigated whether R. mehelyi that calls at a frequency clearly above what is predicted by allometry, compensates for frequency-dependent loss in detection distance by using elevated call intensity. Maximum echolocation call intensities might depend on body size or condition and thus be used as an honest signal of quality for intraspecific communication. We for the first time investigated whether a size-intensity relation is present in echolocating bats. We measured maximum call intensities and frequencies for all five European horseshoe bat species. Maximum intensity differed among species largely due to R. euryale. Furthermore, we found no compensation for frequency-dependent loss in detection distance in R. mehelyi. Intraspecifically, there is a negative correlation between forearm lengths and intensity in R. euryale and a trend for a negative correlation between body condition index and intensity in R. ferrumequinum. In R. hipposideros, females had 8 dB higher intensities than males. There were no correlations with body size or sex differences and intensity for the other species. Based on call intensity and frequency measurements, we estimated echolocation ranges for our study community. These suggest that intensity differences result in different prey detection distances and thus likely play some role for resource access. It is interesting and at first glance counter-intuitive that, where a correlation was found, smaller bats called louder than large individuals. Such negative relationship between size or condition and vocal amplitude may

  18. Aboveground and belowground biomass allocation in native Prosopis caldenia Burkart secondaries woodlands in the semi-arid Argentinean pampas

    International Nuclear Information System (INIS)

    Risio, Lucia; Herrero, Celia; Bogino, Stella M.; Bravo, Felipe

    2014-01-01

    The woodlands in the south-west of the Argentinean pampas are dominated by Prosopis Caldenia Burkart (calden). The current deforestation rate of this woodlands is 0.82% per year. Different compensation initiatives have begun that recognize the role of forests as environmental service providers. The financial incentives they offer make it necessary to quantify the amount of carbon stored in the forest biomass. A model for estimating calden biomass was developed. Thirty-eight trees were selected, felled and divided into sections. An equation system was fitted using joint generalized regression to ensure the additivity property. A weighted regression was used to avoid heteroscedasticity. In these woodlands fire is the main disturbance and it can modify tree allometry, due this all models included the area of the base of the stem and tree height as independent variables since it indirectly collects this variability. Total biomass and the stem fraction had the highest R2 A dj. values (0.75), while branches with a diameter less than 7 cm had the lowest (0.58). Tree biomass was also analyzed by partitioning into the basic fractions of stem, crown, roots, and the root/shoot ratio. Biomass allocation was greatest in the crown fraction and the mean root/shoot ratio was 0.58. The carbon stock of the caldenales considering only calden tree biomass is 20.2 Mg ha −1 . While the overall carbon balance of the region is negative (deforestation and biomass burning, the remnant forested area has increased their calden density and in an indirect way his carbon sequestration capacity could also be increased. - Highlights: • A model for estimating aboveground and belowground Prosopis caldenia biomass was developed. • Biomass allocation into the tree and the root/shoot ratio were analyzed. • The equation systems presented had made it possible to more accurately estimate the biomass stored in calden woodlands

  19. Modelling Variable Fire Severity in Boreal Forests: Effects of Fire Intensity and Stand Structure.

    Science.gov (United States)

    Miquelajauregui, Yosune; Cumming, Steven G; Gauthier, Sylvie

    2016-01-01

    It is becoming clear that fires in boreal forests are not uniformly stand-replacing. On the contrary, marked variation in fire severity, measured as tree mortality, has been found both within and among individual fires. It is important to understand the conditions under which this variation can arise. We integrated forest sample plot data, tree allometries and historical forest fire records within a diameter class-structured model of 1.0 ha patches of mono-specific black spruce and jack pine stands in northern Québec, Canada. The model accounts for crown fire initiation and vertical spread into the canopy. It uses empirical relations between fire intensity, scorch height, the percent of crown scorched and tree mortality to simulate fire severity, specifically the percent reduction in patch basal area due to fire-caused mortality. A random forest and a regression tree analysis of a large random sample of simulated fires were used to test for an effect of fireline intensity, stand structure, species composition and pyrogeographic regions on resultant severity. Severity increased with intensity and was lower for jack pine stands. The proportion of simulated fires that burned at high severity (e.g. >75% reduction in patch basal area) was 0.80 for black spruce and 0.11 for jack pine. We identified thresholds in intensity below which there was a marked sensitivity of simulated fire severity to stand structure, and to interactions between intensity and structure. We found no evidence for a residual effect of pyrogeographic region on simulated severity, after the effects of stand structure and species composition were accounted for. The model presented here was able to produce variation in fire severity under a range of fire intensity conditions. This suggests that variation in stand structure is one of the factors causing the observed variation in boreal fire severity.

  20. Temporal Variation of Wood Density and Carbon in Two Elevational Sites of Pinus cooperi in Relation to Climate Response in Northern Mexico

    Science.gov (United States)

    Pompa-García, Marín; Venegas-González, Alejandro

    2016-01-01

    Forest ecosystems play an important role in the global carbon cycle. Therefore, understanding the dynamics of carbon uptake in forest ecosystems is much needed. Pinus cooperi is a widely distributed species in the Sierra Madre Occidental in northern Mexico and future climatic variations could impact these ecosystems. Here, we analyze the variations of trunk carbon in two populations of P. cooperi situated at different elevational gradients, combining dendrochronological techniques and allometry. Carbon sequestration (50% biomass) was estimated from a specific allometric equation for this species based on: (i) variation of intra-annual wood density and (ii) diameter reconstruction. The results show that the population at a higher elevation had greater wood density, basal area, and hence, carbon accumulation. This finding can be explained by an ecological response of trees to adverse weather conditions, which would cause a change in the cellular structure affecting the within-ring wood density profile. The influence of variations in climate on the maximum density of chronologies showed a positive correlation with precipitation and the Multivariate El Niño Southern Oscillation Index during the winter season, and a negative correlation with maximum temperature during the spring season. Monitoring previous conditions to growth is crucial due to the increased vulnerability to extreme climatic variations on higher elevational sites. We concluded that temporal variability of wood density contributes to a better understanding of environmental historical changes and forest carbon dynamics in Northern Mexico, representing a significant improvement over previous studies on carbon sequestration. Assuming a uniform density according to tree age is incorrect, so this method can be used for environmental mitigation strategies, such as for managing P. cooperi, a dominant species of great ecological amplitude and widely used in forest industries. PMID:27272519

  1. Growth but not photosynthesis response of a host plant to infection by a holoparasitic plant depends on nitrogen supply.

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    Hao Shen

    Full Text Available Parasitic plants can adversely influence the growth of their hosts by removing resources and by affecting photosynthesis. Such negative effects depend on resource availability. However, at varied resource levels, to what extent the negative effects on growth are attributed to the effects on photosynthesis has not been well elucidated. Here, we examined the influence of nitrogen supply on the growth and photosynthesis responses of the host plant Mikania micrantha to infection by the holoparasite Cuscuta campestris by focusing on the interaction of nitrogen and infection. Mikania micrantha plants fertilized at 0.2, 1 and 5 mM nitrate were grown with and without C. campestris infection. We observed that the infection significantly reduced M. micrantha growth at each nitrate fertilization and more severely at low than at high nitrate. Such alleviation at high nitrate was largely attributed to a stronger influence of infection on root biomass at low than at high nitrate fertilization. However, although C. campestris altered allometry and inhibited host photosynthesis, the magnitude of the effects was independent of nitrate fertilizations. The infection reduced light saturation point, net photosynthesis at saturating irradiances, apparent quantum yield, CO2 saturated rate of photosynthesis, carboxylation efficiency, the maximum carboxylation rate of Rubisco, and maximum light-saturated rate of electron transport, and increased light compensation point in host leaves similarly across nitrate levels, corresponding to a similar magnitude of negative effects of the parasite on host leaf soluble protein and Rubisco concentrations, photosynthetic nitrogen use efficiency and stomatal conductance across nitrate concentrations. Thus, the more severe inhibition in host growth at low than at high nitrate supplies cannot be attributed to a greater parasite-induced reduction in host photosynthesis, but the result of a higher proportion of host resources

  2. Growth but Not Photosynthesis Response of a Host Plant to Infection by a Holoparasitic Plant Depends on Nitrogen Supply

    Science.gov (United States)

    Shen, Hao; Xu, Shu-Jun; Hong, Lan; Wang, Zhang-Ming; Ye, Wan-Hui

    2013-01-01

    Parasitic plants can adversely influence the growth of their hosts by removing resources and by affecting photosynthesis. Such negative effects depend on resource availability. However, at varied resource levels, to what extent the negative effects on growth are attributed to the effects on photosynthesis has not been well elucidated. Here, we examined the influence of nitrogen supply on the growth and photosynthesis responses of the host plant Mikania micrantha to infection by the holoparasite Cuscuta campestris by focusing on the interaction of nitrogen and infection. Mikania micrantha plants fertilized at 0.2, 1 and 5 mM nitrate were grown with and without C. campestris infection. We observed that the infection significantly reduced M. micrantha growth at each nitrate fertilization and more severely at low than at high nitrate. Such alleviation at high nitrate was largely attributed to a stronger influence of infection on root biomass at low than at high nitrate fertilization. However, although C. campestris altered allometry and inhibited host photosynthesis, the magnitude of the effects was independent of nitrate fertilizations. The infection reduced light saturation point, net photosynthesis at saturating irradiances, apparent quantum yield, CO2 saturated rate of photosynthesis, carboxylation efficiency, the maximum carboxylation rate of Rubisco, and maximum light-saturated rate of electron transport, and increased light compensation point in host leaves similarly across nitrate levels, corresponding to a similar magnitude of negative effects of the parasite on host leaf soluble protein and Rubisco concentrations, photosynthetic nitrogen use efficiency and stomatal conductance across nitrate concentrations. Thus, the more severe inhibition in host growth at low than at high nitrate supplies cannot be attributed to a greater parasite-induced reduction in host photosynthesis, but the result of a higher proportion of host resources transferred to the parasite at

  3. Leaf morphology, taxonomy and geometric morphometrics: a simplified protocol for beginners.

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    Vincenzo Viscosi

    Full Text Available Taxonomy relies greatly on morphology to discriminate groups. Computerized geometric morphometric methods for quantitative shape analysis measure, test and visualize differences in form in a highly effective, reproducible, accurate and statistically powerful way. Plant leaves are commonly used in taxonomic analyses and are particularly suitable to landmark based geometric morphometrics. However, botanists do not yet seem to have taken advantage of this set of methods in their studies as much as zoologists have done. Using free software and an example dataset from two geographical populations of sessile oak leaves, we describe in detailed but simple terms how to: a compute size and shape variables using Procrustes methods; b test measurement error and the main levels of variation (population and trees using a hierachical design; c estimate the accuracy of group discrimination; d repeat this estimate after controlling for the effect of size differences on shape (i.e., allometry. Measurement error was completely negligible; individual variation in leaf morphology was large and differences between trees were generally bigger than within trees; differences between the two geographic populations were small in both size and shape; despite a weak allometric trend, controlling for the effect of size on shape slighly increased discrimination accuracy. Procrustes based methods for the analysis of landmarks were highly efficient in measuring the hierarchical structure of differences in leaves and in revealing very small-scale variation. In taxonomy and many other fields of botany and biology, the application of geometric morphometrics contributes to increase scientific rigour in the description of important aspects of the phenotypic dimension of biodiversity. Easy to follow but detailed step by step example studies can promote a more extensive use of these numerical methods, as they provide an introduction to the discipline which, for many biologists, is

  4. Peatland Woody Plant Growth Responses to Warming and Elevated CO2 in a Southern-boreal Raised Bog Ecosystem

    Science.gov (United States)

    Phillips, J. R.; Hanson, P. J.; Warren, J.; Ward, E. J.; Brice, D. J.; Graham, J.

    2017-12-01

    Spruce and Peatland Responses Under Changing Environments (SPRUCE) is an in situ warming by elevated CO2 manipulation located in a high-carbon, spruce peatland in northern Minnesota. Warming treatments combined a 12-m diameter open topped chamber with internally recirculating warm air and soil deep heating to simulate a broad range of future warming treatments. Deep below ground soil warming rates are 0, +2.25, +4.5, +6.75, and +9 °C. Deep belowground warming was initiated in June 2014 followed by air warming in August 2015. In June 2016, elevated CO2 atmospheres (eCO2 at + 500 ppm) were added to half of the warming treatments in a regression design. Our objective was to track long-term vegetation responses to warming and eCO2. Annual tree growth is based on winter measurement of circumference of all Picea mariana and Larix laricina trees within each 113 m2 plot, automated dendrometers, terrestrial LIDAR scanning of tree heights and canopy volumes, and destructive allometry. Annual shrub growth is measured in late summer by destructive clipping in two 0.25 m2 sub-plots and separation of the current year tissues. During the first year of warming, tree basal area growth was reduced for Picea, but not Larix trees. Growth responses for the woody shrub vegetation remains highly variable with a trend towards increasing growth with warming. Elevated CO2 enhancements of growth are not yet evident in the data. Second-year results will also be reported. Long-term hypotheses for increased woody plant growth under warming include potential enhancements driven by increased nutrient availability from warming induced decomposition of surface peats.

  5. Bipartite life cycle of coral reef fishes promotes increasing shape disparity of the head skeleton during ontogeny: an example from damselfishes (Pomacentridae

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    Vandewalle Pierre

    2011-03-01

    Full Text Available Abstract Background Quantitative studies of the variation of disparity during ontogeny exhibited by the radiation of coral reef fishes are lacking. Such studies dealing with the variation of disparity, i.e. the diversity of organic form, over ontogeny could be a first step in detecting evolutionary mechanisms in these fishes. The damselfishes (Pomacentridae have a bipartite life-cycle, as do the majority of demersal coral reef fishes. During their pelagic dispersion phase, all larvae feed on planktonic prey. On the other hand, juveniles and adults associated with the coral reef environment show a higher diversity of diets. Using geometric morphometrics, we study the ontogenetic dynamic of shape disparity of different head skeletal units (neurocranium, suspensorium and opercle, mandible and premaxilla in this fish family. We expected that larvae of different species might be relatively similar in shapes. Alternatively, specialization may become notable even in the juvenile and adult phase. Results The disparity levels increase significantly throughout ontogeny for each skeletal unit. At settlement, all larval shapes are already species-specific. Damselfishes show high levels of ontogenetic allometry during their post-settlement growth. The divergence of allometric patterns largely explains the changes in patterns and levels of shape disparity over ontogeny. The rate of shape change and the length of ontogenetic trajectories seem to be less variable among species. We also show that the high levels of shape disparity at the adult stage are correlated to a higher level of ecological and functional diversity in this stage. Conclusion Diversification throughout ontogeny of damselfishes results from the interaction among several developmental novelties enhancing disparity. The bipartite life-cycle of damselfishes exemplifies a case where the variation of environmental factors, i.e. the transition from the more homogeneous oceanic environment to the

  6. Bipartite life cycle of coral reef fishes promotes increasing shape disparity of the head skeleton during ontogeny: an example from damselfishes (Pomacentridae)

    Science.gov (United States)

    2011-01-01

    Background Quantitative studies of the variation of disparity during ontogeny exhibited by the radiation of coral reef fishes are lacking. Such studies dealing with the variation of disparity, i.e. the diversity of organic form, over ontogeny could be a first step in detecting evolutionary mechanisms in these fishes. The damselfishes (Pomacentridae) have a bipartite life-cycle, as do the majority of demersal coral reef fishes. During their pelagic dispersion phase, all larvae feed on planktonic prey. On the other hand, juveniles and adults associated with the coral reef environment show a higher diversity of diets. Using geometric morphometrics, we study the ontogenetic dynamic of shape disparity of different head skeletal units (neurocranium, suspensorium and opercle, mandible and premaxilla) in this fish family. We expected that larvae of different species might be relatively similar in shapes. Alternatively, specialization may become notable even in the juvenile and adult phase. Results The disparity levels increase significantly throughout ontogeny for each skeletal unit. At settlement, all larval shapes are already species-specific. Damselfishes show high levels of ontogenetic allometry during their post-settlement growth. The divergence of allometric patterns largely explains the changes in patterns and levels of shape disparity over ontogeny. The rate of shape change and the length of ontogenetic trajectories seem to be less variable among species. We also show that the high levels of shape disparity at the adult stage are correlated to a higher level of ecological and functional diversity in this stage. Conclusion Diversification throughout ontogeny of damselfishes results from the interaction among several developmental novelties enhancing disparity. The bipartite life-cycle of damselfishes exemplifies a case where the variation of environmental factors, i.e. the transition from the more homogeneous oceanic environment to the coral reef offering a wide

  7. Forearm articular proportions and the antebrachial index in Homo sapiens, Australopithecus afarensis and the great apes.

    Science.gov (United States)

    Williams, Frank L'Engle; Cunningham, Deborah L; Amaral, Lia Q

    2015-12-01

    When hominin bipedality evolved, the forearms were free to adopt nonlocomotor tasks which may have resulted in changes to the articular surfaces of the ulna and the relative lengths of the forearm bones. Similarly, sex differences in forearm proportions may be more likely to emerge in bipeds than in the great apes given the locomotor constraints in Gorilla, Pan and Pongo. To test these assumptions, ulnar articular proportions and the antebrachial index (radius length/ulna length) in Homo sapiens (n=51), Gorilla gorilla (n=88), Pan troglodytes (n=49), Pongo pygmaeus (n=36) and Australopithecus afarensis A.L. 288-1 and A.L. 438-1 are compared. Intercept-adjusted ratios are used to control for size and minimize the effects of allometry. Canonical scores axes show that the proximally broad and elongated trochlear notch with respect to size in H. sapiens and A. afarensis is largely distinct from G. gorilla, P. troglodytes and P. pygmaeus. A cluster analysis of scaled ulnar articular dimensions groups H. sapiens males with A.L. 438-1 ulna length estimates, while one A.L. 288-1 ulna length estimate groups with Pan and another clusters most closely with H. sapiens, G. gorilla and A.L. 438-1. The relatively low antebrachial index characterizing H. sapiens and non-outlier estimates of A.L. 288-1 and A.L. 438-1 differs from those of the great apes. Unique sex differences in H. sapiens suggest a link between bipedality and forearm functional morphology. Copyright © 2015 Elsevier GmbH. All rights reserved.

  8. Size Scaling in Western North Atlantic Loggerhead Turtles Permits Extrapolation between Regions, but Not Life Stages.

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    Nina Marn

    Full Text Available Sea turtles face threats globally and are protected by national and international laws. Allometry and scaling models greatly aid sea turtle conservation and research, and help to better understand the biology of sea turtles. Scaling, however, may differ between regions and/or life stages. We analyze differences between (i two different regional subsets and (ii three different life stage subsets of the western North Atlantic loggerhead turtles by comparing the relative growth of body width and depth in relation to body length, and discuss the implications.Results suggest that the differences between scaling relationships of different regional subsets are negligible, and models fitted on data from one region of the western North Atlantic can safely be used on data for the same life stage from another North Atlantic region. On the other hand, using models fitted on data for one life stage to describe other life stages is not recommended if accuracy is of paramount importance. In particular, young loggerhead turtles that have not recruited to neritic habitats should be studied and modeled separately whenever practical, while neritic juveniles and adults can be modeled together as one group. Even though morphometric scaling varies among life stages, a common model for all life stages can be used as a general description of scaling, and assuming isometric growth as a simplification is justified. In addition to linear models traditionally used for scaling on log-log axes, we test the performance of a saturating (curvilinear model. The saturating model is statistically preferred in some cases, but the accuracy gained by the saturating model is marginal.

  9. Mexorchestia: a new genus of talitrid amphipod (Crustacea, Amphipoda, Talitridae) from the Gulf of Mexico and Caribbean Sea, with the description of a new species and two new subspecies.

    Science.gov (United States)

    Wildish, David J; Lecroy, Sara E

    2014-08-26

    Two species of supralittoral Tethorchestia were reported by Bousfield (1984) to occur on the shores of the Gulf of Mexico and closely adjacent waters: T. antillensis Bousfield, 1984 from Quintana Roo, Mexico and an undescribed species, Tethorchestia sp. B of Bousfield (1984), from Florida and the U.S. Gulf coast. In this paper, we rediagnose and illustrate the former taxon based on material from Goodland Bay, Florida, which represents a range extension for that species. We examined the latter taxon from many locations throughout the Gulf of Mexico using classical morphology, epidermal pigment pattern recognition and allometry, reinforced by molecular markers (mitochondrial cytochrome oxidase I, Radulovici 2012), determining that Tethorchestia sp. B represents a new genus and species, comprising two subspecies. The nominate subspecies, Mexorchestia carpenteri carpenteri n. gen., sp. and subsp., is described from Tiger Tail Beach, Florida, based on conventional morphological criteria and its distinctive epidermal pigment patterns. The Tiger Tail Beach ecotope of M. c. carpenteri n. gen., sp. and subsp. was distinct from that of other locations examined in Florida and was associated with epidermal pigment pattern polymorphism, absent at other locations. A second subspecies, distinguished by differences in size, number of articles in the flagellum of antenna 2, the number of marginal setae on oostegite 2 of the female and the number of distal dorsolateral robust setae on the telson, was found in samples from Belize and Mexico. This subspecies is described from material collected at Turneffe Island, Belize, as Mexorchestia carpenteri raduloviciae n. gen., sp. and subsp. Like M. c. carpenteri n. gen., sp. and subsp., this taxon is also associated with epidermal pigment pattern polymorphism. A key is provided for the three currently described species of Tethorchestia (two extant) and two new subspecies of Mexorchestia n.gen. 

  10. Sexual dimorphism in shells of Cochlostoma septemspirale (Caenogastropoda, Cyclophoroidea, Diplommatinidae, Cochlostomatinae

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    Fabian Reichenbach

    2012-07-01

    Full Text Available Sexual dimorphisms in shell-bearing snails expressed by characteristic traits of their respective shells would offer the possibility for a lot of studies about gender distribution in populations, species, etc. In this study, the seven main shell characters of the snail Cochlostoma septemspirale were measured in both sexes: (1 height and (2 width of the shell, (3 height and (4 width of the aperture, (5 width of the last whorl, (6 rib density on the last whorl, and (7 intensity of the reddish or brown pigments forming three bands over the shell. The variation of size and shape was explored with statistical methods adapted to principal components analysis (PCA and linear discriminant analysis (LDA. In particular, we applied some multivariate morphometric tools for the analysis of ratios that have been developed only recently, that is, the PCA ratio spectrum, allometry ratio spectrum, and LDA ratio extractor. The overall separation of the two sexes was tested with LDA cross validation.The results show that there is a sexual dimorphism in the size and shape of shells. Females are more slender than males and are characterised by larger size, a slightly reduced aperture height but larger shell height and whorl width. Therefore they have a considerable larger shell volume (about one fifth in the part above the aperture. Furthermore, the last whorl of females is slightly less strongly pigmented and mean rib density slightly higher. All characters overlap quite considerably between sexes. However, by using cross validation based on the 5 continuous shell characters more than 90% of the shells can be correctly assigned to each sex.

  11. Evolutionary morphology in shape and size of haptoral anchors in 14 Ligophorus spp. (Monogenea: Dactylogyridae).

    Science.gov (United States)

    Rodríguez-González, Abril; Sarabeev, Volodimir; Balbuena, Juan Antonio

    2017-01-01

    The search for phylogenetic signal in morphological traits using geometric morphometrics represents a powerful approach to estimate the relative weights of convergence and shared evolutionary history in shaping organismal form. We assessed phylogenetic signal in the form of ventral and dorsal haptoral anchors of 14 species of Ligophorus occurring on grey mullets (Osteichthyes: Mugilidae) from the Mediterranean, the Black Sea and the Sea of Azov. The phylogenetic relationships among these species were mapped onto the morphospaces of shape and size of dorsal and ventral anchors and two different tests were applied to establish whether the spatial positions in the morphospace were dictated by chance. Overall significant phylogenetic signal was found in the data. Allometric effects on anchor shape were moderate or non-significant in the case of evolutionary allometry. Relatively phylogenetically distant species occurring on the same host differed markedly in anchor morphology indicating little influence of host species on anchor form. Our results suggest that common descent and shared evolutionary history play a major role in determining the shape and, to a lesser degree in the size of haptoral anchors in Ligophorus spp. The present approach allowed tracing paths of morphological evolution in anchor shape. Species with narrow anchors and long shafts were associated predominately with Liza saliens. This morphology was considered to be ancestral relative to anchors of species occurring on Liza haematocheila and M. cephalus possessing shorter shafts and longer roots. Evidence for phylogenetic signal was more compelling for the ventral anchors, than for the dorsal ones, which could reflect different functional roles in attachment to the gills. Although phylogeny and homoplasy may act differently in other monogeneans, the present study delivers a common framework to address effectively the relationships among morphology, phylogeny and other traits, such as host specificity

  12. Evolutionary morphology in shape and size of haptoral anchors in 14 Ligophorus spp. (Monogenea: Dactylogyridae.

    Directory of Open Access Journals (Sweden)

    Abril Rodríguez-González

    Full Text Available The search for phylogenetic signal in morphological traits using geometric morphometrics represents a powerful approach to estimate the relative weights of convergence and shared evolutionary history in shaping organismal form. We assessed phylogenetic signal in the form of ventral and dorsal haptoral anchors of 14 species of Ligophorus occurring on grey mullets (Osteichthyes: Mugilidae from the Mediterranean, the Black Sea and the Sea of Azov. The phylogenetic relationships among these species were mapped onto the morphospaces of shape and size of dorsal and ventral anchors and two different tests were applied to establish whether the spatial positions in the morphospace were dictated by chance. Overall significant phylogenetic signal was found in the data. Allometric effects on anchor shape were moderate or non-significant in the case of evolutionary allometry. Relatively phylogenetically distant species occurring on the same host differed markedly in anchor morphology indicating little influence of host species on anchor form. Our results suggest that common descent and shared evolutionary history play a major role in determining the shape and, to a lesser degree in the size of haptoral anchors in Ligophorus spp. The present approach allowed tracing paths of morphological evolution in anchor shape. Species with narrow anchors and long shafts were associated predominately with Liza saliens. This morphology was considered to be ancestral relative to anchors of species occurring on Liza haematocheila and M. cephalus possessing shorter shafts and longer roots. Evidence for phylogenetic signal was more compelling for the ventral anchors, than for the dorsal ones, which could reflect different functional roles in attachment to the gills. Although phylogeny and homoplasy may act differently in other monogeneans, the present study delivers a common framework to address effectively the relationships among morphology, phylogeny and other traits, such

  13. Relative crystallinity of plant biomass: studies on assembly, adaptation and acclimation.

    Directory of Open Access Journals (Sweden)

    Darby Harris

    Full Text Available Plant biomechanical design is central to cell shape, morphogenesis, reproductive performance and protection against environmental and mechanical stress. The cell wall forms the central load bearing support structure for plant design, yet a mechanistic understanding of its synthesis is incomplete. A key tool for studying the structure of cellulose polymorphs has been x-ray diffraction and fourier transform infrared spectroscopy (FTIR. Relative crystallinity index (RCI is based on the x-ray diffraction characteristics of two signature peaks and we used this technique to probe plant assembly, adaptation and acclimation. Confocal microscopy was used to visualize the dynamics of cellulose synthase in transgenic Arabidopsis plants expressing a homozygous YFP::CESA6. Assembly: RCI values for stems and roots were indistinguishable but leaves had 23.4 and 21.6% lower RCI than stems and roots respectively. Adaptation: over 3-fold variability in RCI was apparent in leaves from 35 plant species spanning Ordovician to Cretaceous periods. Within this study, RCI correlated positively with leaf geometric constraints and with mass per unit area, suggestive of allometry. Acclimation: biomass crystallinity was found to decrease under conditions of thigmomorphogenesis in Arabidopsis. Further, in etiolated pea hypocotyls, RCI values also decreased compared to plants that were grown in light, consistent with alterations in FTIR cellulose fingerprint peaks and live cell imaging experiments revealing rapid orientation of the YFP::cellulose synthase-6 array in response to light. Herein, results and technical challenges associated with the structure of the cell wall that gives rise to sample crystallinity are presented and examined with respect to adaptation, acclimation and assembly in ecosystem-level processes.

  14. A macroecological analysis of SERA derived forest heights and implications for forest volume remote sensing.

    Science.gov (United States)

    Brolly, Matthew; Woodhouse, Iain H; Niklas, Karl J; Hammond, Sean T

    2012-01-01

    Individual trees have been shown to exhibit strong relationships between DBH, height and volume. Often such studies are cited as justification for forest volume or standing biomass estimation through remote sensing. With resolution of common satellite remote sensing systems generally too low to resolve individuals, and a need for larger coverage, these systems rely on descriptive heights, which account for tree collections in forests. For remote sensing and allometric applications, this height is not entirely understood in terms of its location. Here, a forest growth model (SERA) analyzes forest canopy height relationships with forest wood volume. Maximum height, mean, H₁₀₀, and Lorey's height are examined for variability under plant number density, resource and species. Our findings, shown to be allometrically consistent with empirical measurements for forested communities world-wide, are analyzed for implications to forest remote sensing techniques such as LiDAR and RADAR. Traditional forestry measures of maximum height, and to a lesser extent H₁₀₀ and Lorey's, exhibit little consistent correlation with forest volume across modeled conditions. The implication is that using forest height to infer volume or biomass from remote sensing requires species and community behavioral information to infer accurate estimates using height alone. SERA predicts mean height to provide the most consistent relationship with volume of the height classifications studied and overall across forest variations. This prediction agrees with empirical data collected from conifer and angiosperm forests with plant densities ranging between 10²-10⁶ plants/hectare and heights 6-49 m. Height classifications investigated are potentially linked to radar scattering centers with implications for allometry. These findings may be used to advance forest biomass estimation accuracy through remote sensing. Furthermore, Lorey's height with its specific relationship to remote sensing

  15. Support for maternal manipulation of developmental nutrition in a facultatively eusocial bee, Megalopta genalis (Halictidae).

    Science.gov (United States)

    Kapheim, Karen M; Bernal, Sandra P; Smith, Adam R; Nonacs, Peter; Wcislo, William T

    2011-06-01

    Developmental maternal effects are a potentially important source of phenotypic variation, but they can be difficult to distinguish from other environmental factors. This is an important distinction within the context of social evolution, because if variation in offspring helping behavior is due to maternal manipulation, social selection may act on maternal phenotypes, as well as those of offspring. Factors correlated with social castes have been linked to variation in developmental nutrition, which might provide opportunity for females to manipulate the social behavior of their offspring. Megalopta genalis is a mass-provisioning facultatively eusocial sweat bee for which production of males and females in social and solitary nests is concurrent and asynchronous. Female offspring may become either gynes (reproductive dispersers) or workers (non-reproductive helpers). We predicted that if maternal manipulation plays a role in M. genalis caste determination, investment in daughters should vary more than for sons. The mass and protein content of pollen stores provided to female offspring varied significantly more than those of males, but volume and sugar content did not. Sugar content varied more among female eggs in social nests than in solitary nests. Provisions were larger, with higher nutrient content, for female eggs and in social nests. Adult females and males show different patterns of allometry, and their investment ratio ranged from 1.23 to 1.69. Adult body weight varied more for females than males, possibly reflecting increased variation in maternal investment in female offspring. These differences are consistent with a role for maternal manipulation in the social plasticity observed in M. genalis.

  16. The 'temporal effect' in hominids: Reinvestigating the nature of support for a chimp-human clade in bone morphology.

    Science.gov (United States)

    Pearson, Alannah; Groves, Colin; Cardini, Andrea

    2015-11-01

    In 2004, an analysis by Lockwood and colleagues of hard-tissue morphology, using geometric morphometrics on the temporal bone, succeeded in recovering the correct phylogeny of living hominids without resorting to potentially problematic methods for transforming continuous shape variables into meristic characters. That work has increased hope that by using modern analytical methods and phylogenetically informative anatomical data we might one day be able to accurately infer the relationships of hominins, including the closest extinct relatives of modern humans. In the present study, using 3D virtually generated models of the hominid temporal bone and a larger suite of geometric morphometric and comparative techniques, we have re-examined the evidence for a Pan-Homo clade. Despite differences in samples, as well as the type of raw data, the effect of measurement error (and especially landmark digitization by a different operator), but also a broader perspective brought in by our diverse set of approaches, our reanalysis largely supports Lockwood and colleagues' original results. However, by focusing not only mainly on shape (as in the original 2004 analysis) but also on size and 'size-corrected' (non-allometric) shape, we demonstrate that the strong phylogenetic signal in the temporal bone is largely related to similarities in size. Thus, with this study, we are not suggesting the use of a single 'character', such as size, for phylogenetic inference, but we do challenge the common view that shape, with its highly complex and multivariate nature, is necessarily more phylogenetically informative than size and that actually size and size-related shape variation (i.e., allometry) confound phylogenetic inference based on morphology. This perspective may in fact be less generalizable than often believed. Thus, while we confirm the original findings by Lockwood et al., we provide a deep reinterpretation of their nature and potential implications for hominid phylogenetics

  17. The effects of replacing Dichantium hay with banana (Musa paradisiaca) leaves and pseudo-stem on carcass traits of Ovin Martinik sheep.

    Science.gov (United States)

    Marie-Magdeleine, Carine; Liméa, Léticia; Etienne, Tatiana; Lallo, Cicero H O; Archimède, Harry; Alexandre, Gisele

    2009-10-01

    A study was done to evaluate banana (Musa paradisiaca) as a forage (leaves and pseudo-stems) for feeding Ovin Martinik lambs (OMK), with the aim to test its impact on carcass quality. Forty four intact OMK male were used after weaning with an initial mean live weight of 14.4 (+/- 3.3) kg, reared in individual pens. Animals were offered either Dichantium hay (control diet, Dh) or cut chopped leaves and pseudo-stems of banana (experimental diet, Blps). They were fed 200-250 g x d(-1) of commercial concentrate. Lambs were slaughtered according to 3 classes of slaughter weight (SW): SW20, SW23 and SW26. Growth and carcass performances of both groups were not significantly different, 77 vs. 81 g x d(-1) and 42% vs. 43% hot carcass yield, for Dh vs. Blps, respectively. There was a significant (P < 0.05) decrease (31.0 vs. 29.7%) for the dry matter content of the shoulder for lambs fed the banana diet. However, there was no effect observed for the other chemical component (CP, lipid and mineral 585, 317 and 95 g x kg(-1) DM, respectively). The shoulder (20% of the carcass whatever the SW) was precocious as demonstrated by the allometry coefficient relative to carcass weight (0.894) significantly (P < 0.01) less than 1. It was concluded that, the use of Blps had no significant effect on growth, carcass weights and yields of the OMK lambs, irrespective of the class of the slaughter weight. From these initial results, the use of banana foliages and pseudo-stems could be recommended as sources of forages.

  18. Phylogenetic and functional implications of the ear region anatomy of Glossotherium robustum (Xenarthra, Mylodontidae) from the Late Pleistocene of Argentina

    Science.gov (United States)

    Boscaini, Alberto; Iurino, Dawid A.; Billet, Guillaume; Hautier, Lionel; Sardella, Raffaele; Tirao, German; Gaudin, Timothy J.; Pujos, François

    2018-04-01

    Several detailed studies of the external morphology of the ear region in extinct sloths have been published in the past few decades, and this anatomical region has proved extremely helpful in elucidating the phylogenetic relationships among the members of this mammalian clade. Few studies of the inner ear anatomy in these peculiar animals were conducted historically, but these are increasing in number in recent years, in both the extinct and extant representatives, due to wider access to CT-scanning facilities, which allow non-destructive access to internal morphologies. In the present study, we analyze the extinct ground sloth Glossotherium robustum and provide a description of the external features of the ear region and the endocranial side of the petrosal bone, coupled with the first data on the anatomy of the bony labyrinth. Some features observable in the ear region of G. robustum (e.g., the shape and size of the entotympanic bone and the morphology of the posteromedial surface of the petrosal) are highly variable, both intraspecifically and intraindividually. The form of the bony labyrinth of G. robustum is also described, providing the first data from this anatomical region for the family Mylodontidae. The anatomy of the bony labyrinth of the genus Glossotherium is here compared at the level of the superorder Xenarthra, including all available extant and extinct representatives, using geometric morphometric methods. In light of the new data, we discuss the evolution of inner ear anatomy in the xenarthran clade, and most particularly in sloths, considering the influence of phylogeny, allometry, and physiology on the shape of this highly informative region of the skull. These analyses show that the inner ear of Glossotherium more closely resembles that of the extant anteaters, and to a lesser extent those of the giant ground sloth Megatherium and euphractine armadillos, than those of the extant sloths Bradypus and Choloepus, further demonstrating the striking

  19. Is BMR repeatable in deer mice? Organ mass correlates and the effects of cold acclimation and natal altitude.

    Science.gov (United States)

    Russell, G A; Chappell, M A

    2007-01-01

    Basal metabolic rate (BMR) is probably the most studied aspect of energy metabolism in vertebrate endotherms. Numerous papers have explored its mass allometry, phylogenetic and ecological relationships, and ontogeny. Implicit in many of these studies (and explicit in some) is the view that BMR responds to selection, which requires repeatability and heritability. However, BMR is highly plastic in response to numerous behavioral and environmental factors and there are surprisingly few data on its repeatability. Moreover, the mechanistic underpinnings of variation in BMR are unclear, despite considerable research. We studied BMR repeatability in deer mice (Peromyscus maniculatus) across intervals of 30-60 days, and also examined the influence of birth altitude (3,800 m versus 340 m) and temperature acclimation (to approximately 5 or approximately 20 degrees C) on BMR, and the relationship between BMR and organ size. Neither acclimation temperature nor natal altitude alone influenced BMR, but the combination of birth at high altitude and cold acclimation significantly increased BMR. Few visceral organ masses were correlated to BMR and most were inconsistent across natal altitudes and acclimation temperatures, indicating that no single organ 'controls' variation in BMR. In several treatment groups, the mass of the 'running motor' (combined musculoskeletal mass) was negatively correlated to BMR and the summed mass of visceral organs was positively correlated to BMR. We found no repeatability of BMR in any treatment group. That finding-in sharp contrast to high repeatability of BMR in several other small endotherms-suggests little potential for direct selection to drive BMR evolution in deer mice.

  20. Sexual dimorphism in sister species of Leucoraja skate and its relationship to reproductive strategy and life history.

    Science.gov (United States)

    Martinez, Christopher M; Rohlf, F James; Frisk, Michael G

    2016-01-01

    Instances of sexual dimorphism occur in a great variety of forms and manifestations. Most skates (Batoidea: Rajoidei) display some level of body shape dimorphism in which the pectoral fins of mature males develop to create a distinct bell-shaped body not found in females. This particular form of dimorphism is present in each of the sister species Leucoraja erinacea and Leucoraja ocellata, but differences between sexes are much greater in the former. In order to understand the nature and potential causes of pectoral dimorphism, we used geometric morphometrics to investigate allometry of fin shape in L. erinacea and L. ocellata and its relationship to the development of reproductive organs, based on previous work on the bonnethead shark, Sphyrna tiburo. We found that allometric trajectories of overall pectoral shape were different in both species of skate, but only L. erinacea varied significantly with respect to endoskeleton development. Male maturation was characterized by a number of sex-specific morphological changes, which appeared concurrently in developmental timing with elongation of cartilage-supported claspers. We suggest that external sexual dimorphism of pectoral fins in skates is a byproduct of skeletal growth needed for clasper development. Further, the magnitude of male shape change appears to be linked to the differential life histories of species. This work reports for the first time that pectoral dimorphism is a persistent feature in rajoid fishes, occurring in varying degrees across several genera. Lastly, our results suggest that pectoral morphology may be useful as a relative indicator of reproductive strategy in some species. © 2016 Wiley Periodicals, Inc.

  1. The role of extrahepatic metabolism in the pharmacokinetics of the targeted covalent inhibitors afatinib, ibrutinib, and neratinib.

    Science.gov (United States)

    Shibata, Yoshihiro; Chiba, Masato

    2015-03-01

    Despite the fact that much progress has been made recently in the development of targeted covalent inhibitors (TCIs), their pharmacokinetics (PK) have not been well characterized in the light of extrahepatic clearance (CLextH) by glutathione (GSH)/glutathione S-transferase (GST)-dependent conjugation attributable to the unique electrophilic structure (e.g., acrylamide moiety) of TCI compounds. In the present study, CLextH values were examined in rat, dog, and monkey to predict the contribution of CLextH to the PK of the TCIs afatinib, ibrutinib, and neratinib in humans. Afatinib and neratinib both underwent extensive conjugation with GSH in buffer and cytosol fractions of liver and kidney, whereas ibrutinib showed much lower reactivity/susceptibility to GSH/GST-dependent conjugation. The CLextH in each species was calculated from the difference between observed total body clearance and predicted hepatic clearance (CLH) in cryopreserved hepatocytes suspended in 100% serum of the corresponding species. The power-based simple allometry relating the CLextH for the unbound compound to animal body weight was applicable across species for afatinib and neratinib (R(2) ≥ 0.9) but not for ibrutinib (R(2) = 0.04). The predicted AUC after oral administration of afatinib and neratinib agreed reasonably closely with reported values in phase I dose-escalation studies. Comparisons of CLextH and CLH predicted that CLextH largely determined the PK of afatinib (>90% as a proportion of total body clearance) and neratinib (∼34%) in humans. The present method can serve as one of the tools for the optimization of PK in humans at the discovery stage for the development of TCI candidates. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  2. Differential investment in pre- vs. post-copulatory sexual selection reinforces a cross-continental reversal of sexual size dimorphism in Sepsis punctum (Diptera: Sepsidae).

    Science.gov (United States)

    Puniamoorthy, Nalini; Blanckenhorn, W U; Schäfer, M A

    2012-11-01

    Theory predicts that males have a limited amount of resources to invest in reproduction, suggesting a trade-off between traits that enhance mate acquisition and those that enhance fertilization success. Here, we investigate the relationship between pre- and post-copulatory investment by comparing the mating behaviour and reproductive morphology of four European and five North American populations of the dung fly Sepsis punctum (Diptera) that display a reversal of sexual size dimorphism (SSD). We show that the geographic reversal in SSD between the continents (male biased in Europe, female biased in North America) is accompanied by differential investment in pre- vs. post-copulatory traits. We find higher remating rates in European populations, where larger males acquire more matings and consequently have evolved relatively larger testes and steeper hyper-allometry with body size. American populations, in sharp contrast, display much reduced, if any, effect of body size on those traits. Instead, North American males demonstrate an increased investment in mate acquisition prior to copulation, with more mounting attempts and a distinctive abdominal courtship display that is completely absent in Europe. When controlling for body size, relative female spermathecal size is similar on both continents, so we find no direct evidence for the co-evolution of male and female internal reproductive morphology. By comparing allopatric populations of the same species that apparently have evolved different mating systems and consequently SSD, we thus indirectly demonstrate differential investment in pre- vs. post-copulatory mechanisms increasing reproductive success. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

  3. Why allometric variation in mammalian metabolism is curvilinear on the logarithmic scale.

    Science.gov (United States)

    Packard, Gary C

    2017-11-01

    Studies performed over the last 20 years have repeatedly documented a slight convex curvature (relative to the x-axis) in double-logarithmic plots of basal metabolic rate (BMR) versus body mass in mammals. This curvilinear pattern has usually been interpreted in the context of a simple, two-parameter power function on the arithmetic scale, y  =  a  ×  x b , with the exponent in the equation supposedly increasing systematically with body size. An equation of this form has caused concern among ecologists because a variable exponent is inconsistent with an assumption underlying the metabolic theory of ecology (MTE). However, the appearance of an exponent that varies with body size is an artifact resulting from the widespread use of logarithmic transformations in allometric analyses. Curvature in the distribution on the logarithmic scale actually is caused by a requirement for an explicit, non-zero intercept-and not a variable exponent-in the model describing the distribution on the arithmetic scale. Thus, the MTE need not be revised to accommodate an exponent that varies with body size in the scaling of mammalian BMR, but the theory may need to be tweaked to accommodate an intercept in the allometric equation. In general, any bivariate dataset that is well described by a three-parameter power equation on the arithmetic scale will follow a curvilinear path when displayed on the logarithmic scale. Consequently, reports of curvilinearity in log domain (i.e., "complex allometry") need to be revisited because conclusions from those investigations are likely to be flawed. © 2018 Wiley Periodicals, Inc.

  4. Macroevolutionary patterns of sexual size dimorphism in copepods

    Science.gov (United States)

    Hirst, Andrew G.; Kiørboe, Thomas

    2014-01-01

    Major theories compete to explain the macroevolutionary trends observed in sexual size dimorphism (SSD) in animals. Quantitative genetic theory suggests that the sex under historically stronger directional selection will exhibit greater interspecific variance in size, with covariation between allometric slopes (male to female size) and the strength of SSD across clades. Rensch's rule (RR) also suggests a correlation, but one in which males are always the more size variant sex. Examining free-living pelagic and parasitic Copepoda, we test these competing predictions. Females are commonly the larger sex in copepod species. Comparing clades that vary by four orders of magnitude in their degree of dimorphism, we show that isometry is widespread. As such we find no support for either RR or for covariation between allometry and SSD. Our results suggest that selection on both sexes has been equally important. We next test the prediction that variation in the degree of SSD is related to the adult sex ratio. As males become relatively less abundant, it has been hypothesized that this will lead to a reduction in both inter-male competition and male size. However, the lack of such a correlation across diverse free-living pelagic families of copepods provides no support for this hypothesis. By comparison, in sea lice of the family Caligidae, there is some qualitative support of the hypothesis, males may suffer elevated mortality when they leave the host and rove for sedentary females, and their female-biased SSD is greater than in many free-living families. However, other parasitic copepods which do not appear to have obvious differences in sex-based mate searching risks also show similar or even more extreme SSD, therefore suggesting other factors can drive the observed extremes. PMID:25100692

  5. Unusual ratio between free thyroxine and free triiodothyronine in a long-lived mole-rat species with bimodal ageing.

    Science.gov (United States)

    Henning, Yoshiyuki; Vole, Christiane; Begall, Sabine; Bens, Martin; Broecker-Preuss, Martina; Sahm, Arne; Szafranski, Karol; Burda, Hynek; Dammann, Philip

    2014-01-01

    Ansell's mole-rats (Fukomys anselli) are subterranean, long-lived rodents, which live in eusocial families, where the maximum lifespan of breeders is twice as long as that of non-breeders. Their metabolic rate is significantly lower than expected based on allometry, and their retinae show a high density of S-cone opsins. Both features may indicate naturally low thyroid hormone levels. In the present study, we sequenced several major components of the thyroid hormone pathways and analyzed free and total thyroxine and triiodothyronine in serum samples of breeding and non-breeding F. anselli to examine whether a) their thyroid hormone system shows any peculiarities on the genetic level, b) these animals have lower hormone levels compared to euthyroid rodents (rats and guinea pigs), and c) reproductive status, lifespan and free hormone levels are correlated. Genetic analyses confirmed that Ansell's mole-rats have a conserved thyroid hormone system as known from other mammalian species. Interspecific comparisons revealed that free thyroxine levels of F. anselli were about ten times lower than of guinea pigs and rats, whereas the free triiodothyronine levels, the main biologically active form, did not differ significantly amongst species. The resulting fT4:fT3 ratio is unusual for a mammal and potentially represents a case of natural hypothyroxinemia. Comparisons with total thyroxine levels suggest that mole-rats seem to possess two distinct mechanisms that work hand in hand to downregulate fT4 levels reliably. We could not find any correlation between free hormone levels and reproductive status, gender or weight. Free thyroxine may slightly increase with age, based on sub-significant evidence. Hence, thyroid hormones do not seem to explain the different ageing rates of breeders and non-breeders. Further research is required to investigate the regulatory mechanisms responsible for the unusual proportion of free thyroxine and free triiodothyronine.

  6. A structural equation model to integrate changes in functional strategies during old-field succession.

    Science.gov (United States)

    Vile, Denis; Shipley, Bill; Garnier, Eric

    2006-02-01

    From a functional perspective, changes in abundance, and ultimately species replacement, during succession are a consequence of integrated suites of traits conferring different relative ecological advantages as the environment changes over time. Here we use structural equations to model the interspecific relationships between these integrated functional traits using 34 herbaceous species from a Mediterranean old-field succession and thus quantify the notion of a plant strategy. We measured plant traits related to plant vegetative and reproductive size, leaf functioning, reproductive phenology, seed mass, and production on 15 individuals per species monitored during one growing season. The resulting structural equation model successfully accounts for the pattern of trait covariation during the first 45 years post-abandonment using just two forcing variables: time since site abandonment and seed mass; no association between time since field abandonment and seed mass was observed over these herbaceous stages of secondary succession. All other predicted traits values are determined by these two variables and the cause-effect linkage between them. Adding pre-reproductive vegetative mass as a third forcing variable noticeably increased the predictive power of the model. Increasing the time after abandonment favors species with increasing life span and pre-reproductive biomass and decreasing specific leaf area. Allometric coefficients relating vegetative and reproductive components of plant size were in accordance with allometry theory. The model confirmed the trade-off between seed mass and seed number. Maximum plant height and seed mass were major determinants of reproductive phenology. Our results show that beyond verbal conceptualization, plant ecological strategies can be quantified and modeled.

  7. Unusual ratio between free thyroxine and free triiodothyronine in a long-lived mole-rat species with bimodal ageing.

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Henning

    Full Text Available Ansell's mole-rats (Fukomys anselli are subterranean, long-lived rodents, which live in eusocial families, where the maximum lifespan of breeders is twice as long as that of non-breeders. Their metabolic rate is significantly lower than expected based on allometry, and their retinae show a high density of S-cone opsins. Both features may indicate naturally low thyroid hormone levels. In the present study, we sequenced several major components of the thyroid hormone pathways and analyzed free and total thyroxine and triiodothyronine in serum samples of breeding and non-breeding F. anselli to examine whether a their thyroid hormone system shows any peculiarities on the genetic level, b these animals have lower hormone levels compared to euthyroid rodents (rats and guinea pigs, and c reproductive status, lifespan and free hormone levels are correlated. Genetic analyses confirmed that Ansell's mole-rats have a conserved thyroid hormone system as known from other mammalian species. Interspecific comparisons revealed that free thyroxine levels of F. anselli were about ten times lower than of guinea pigs and rats, whereas the free triiodothyronine levels, the main biologically active form, did not differ significantly amongst species. The resulting fT4:fT3 ratio is unusual for a mammal and potentially represents a case of natural hypothyroxinemia. Comparisons with total thyroxine levels suggest that mole-rats seem to possess two distinct mechanisms that work hand in hand to downregulate fT4 levels reliably. We could not find any correlation between free hormone levels and reproductive status, gender or weight. Free thyroxine may slightly increase with age, based on sub-significant evidence. Hence, thyroid hormones do not seem to explain the different ageing rates of breeders and non-breeders. Further research is required to investigate the regulatory mechanisms responsible for the unusual proportion of free thyroxine and free triiodothyronine.

  8. Evolution of sexual dimorphism and Rensch’s rule in the beetle genus Limnebius (Hydraenidae: is sexual selection opportunistic?

    Directory of Open Access Journals (Sweden)

    Andrey Rudoy

    2017-03-01

    Full Text Available Sexual size dimorphism (SSD is widespread among animals, with larger females usually attributed to an optimization of resources in reproduction and larger males to sexual selection. A general pattern in the evolution of SSD is Rensch’s rule, which states that SSD increases with body size in species with larger males but decreases when females are larger. We studied the evolution of SSD in the genus Limnebius (Coleoptera, Hydraenidae, measuring SSD and male genital size and complexity of ca. 80% of its 150 species and reconstructing its evolution in a molecular phylogeny with 71 species. We found strong support for a higher evolutionary lability of male body size, which had an overall positive allometry with respect to females and higher evolutionary rates measured over the individual branches of the phylogeny. Increases in SSD were associated to increases in body size, but there were some exceptions with an increase associated to changes in only one sex. Secondary sexual characters (SSC in the external morphology of males appeared several times independently, generally on species that had already increased their size. There was an overall significant correlation between SSD, male body size and male genital size and complexity, although some lineages with complex genitalia had low SSD, and some small species with complex genitalia had no SSD. Our results suggest that the origin of the higher evolutionary variance of male body size may be due to lack of constraints rather than to sexual selection, that may start to act in species with already larger males due to random variation.

  9. Ontogenetic scaling of locomotor kinetics and kinematics of the ostrich (Struthio camelus).

    Science.gov (United States)

    Smith, Nicola C; Jespers, Karin J; Wilson, Alan M

    2010-04-01

    Kinematic and kinetic parameters of running gait were investigated through growth in the ostrich, from two weeks up to 10 months of age, in order to investigate the effects of increasing body size. Ontogenetic scaling relationships were compared with published scaling relationships found to exist with increasing body size between species to determine whether dynamic similarity is maintained during growth. During the study, ostrich mass (M(b)) ranged from 0.7 kg to 108.8 kg. Morphological measurements showed that lengths scaled with positive allometry during growth (hip height proportional to M(b)(0.40); foot segment length proportional to M(b)(0.40); tarsometatarsus length proportional to M(b)(0.41); tibiotarsus length proportional to M(b)(0.38); femur length proportional to M(b)(0.37)), significantly exceeding the close to geometric scaling observed between mammalian and avian species of increasing body size. Scaling of kinematic variables largely agreed with predicted scaling for increasing size and demonstrated relationships close to dynamic similarity and, as such, ontogenetic scaling of locomotor parameters was similar to that observed with increasing body mass between species. However, the ways in which these scaling trends were achieved were very different, with ontogenetic scaling of locomotor mechanics largely resulting from simple scaling of the limb segments rather than postural changes, likely to be due to developmental constraints. Small deviations from dynamic similarity of kinematic parameters and a reduction in the predicted scaling of limb stiffness (proportional to M(b)(0.59)) were found to be accounted for by the positive allometric scaling of the limb during growth.

  10. Interaction between Orobanche crenata and its host legumes: unsuccessful haustorial penetration and necrosis of the developing parasite.

    Science.gov (United States)

    Pérez-DE-Luque, A; Rubiales, D; Cubero, J I; Press, M C; Scholes, J; Yoneyama, K; Takeuchi, Y; Plakhine, D; Joel, D M

    2005-05-01

    Orobanche species represent major constraints to crop production in many parts of the world as they reduce yield and alter root/shoot allometry. Although much is known about the histology and effect of Orobanche spp. on susceptible hosts, less is known about the basis of host resistance to these parasites. In this work, histological aspects related to the resistance of some legumes to Orobanche crenata have been investigated in order to determine which types of resistance responses are involved in the unsuccessful penetration of O. crenata. Samples of resistance reactions against O. crenata on different genotypes of resistant legumes were collected. The samples were fixed, sectioned and stained using different procedures. Sections were observed using a transmission light microscope and by epi-fluorescence. Lignification of endodermal and pericycle host cells seems to prevent parasite intrusion into the root vascular cylinder at early infection stages. But in other cases, established tubercles became necrotic and died. Contrary to some previous studies, it was found that darkening at the infection site in these latter cases does not correspond to death of host tissues, but to the secretion of substances that fill the apoplast in the host-parasite interface and in much of the infected host tissues. The secretions block neighbouring host vessels. This may interfere with the nutrient flux between host and parasite, and may lead to necrosis and death of the developing parasite. The unsuccessful penetration of O. crenata seedlings into legume roots cannot be attributed to cell death in the host. It seems to be associated with lignification of host endodermis and pericycle cells at the penetration site. The accumulation of secretions at the infection site, may lead to the activation of xylem occlusion, another defence mechanism, which may cause further necrosis of established tubercles.

  11. Histomorphometry and cortical robusticity of the adult human femur.

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    Miszkiewicz, Justyna Jolanta; Mahoney, Patrick

    2018-01-13

    Recent quantitative analyses of human bone microanatomy, as well as theoretical models that propose bone microstructure and gross anatomical associations, have started to reveal insights into biological links that may facilitate remodeling processes. However, relationships between bone size and the underlying cortical bone histology remain largely unexplored. The goal of this study is to determine the extent to which static indicators of bone remodeling and vascularity, measured using histomorphometric techniques, relate to femoral midshaft cortical width and robusticity. Using previously published and new quantitative data from 450 adult human male (n = 233) and female (n = 217) femora, we determine if these aspects of femoral size relate to bone microanatomy. Scaling relationships are explored and interpreted within the context of tissue form and function. Analyses revealed that the area and diameter of Haversian canals and secondary osteons, and densities of secondary osteons and osteocyte lacunae from the sub-periosteal region of the posterior midshaft femur cortex were significantly, but not consistently, associated with femoral size. Cortical width and bone robusticity were correlated with osteocyte lacunae density and scaled with positive allometry. Diameter and area of osteons and Haversian canals decreased as the width of cortex and bone robusticity increased, revealing a negative allometric relationship. These results indicate that microscopic products of cortical bone remodeling and vascularity are linked to femur size. Allometric relationships between more robust human femora with thicker cortical bone and histological products of bone remodeling correspond with principles of bone functional adaptation. Future studies may benefit from exploring scaling relationships between bone histomorphometric data and measurements of bone macrostructure.

  12. A new approach for the analysis of facial growth and age estimation: Iris ratio.

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    Carlos Eduardo Palhares Machado

    Full Text Available The study of facial growth is explored in many fields of science, including anatomy, genetics, and forensics. In the field of forensics, it acts as a valuable tool for combating child pornography. The present research proposes a new method, based on relative measurements and fixed references of the human face-specifically considering measurements of the diameter of the iris (iris ratio-for the analysis of facial growth in association with age in children and sub-adults. The experimental sample consisted of digital photographs of 1000 Brazilian subjects, aged between 6 and 22 years, distributed equally by sex and divided into five specific age groups (6, 10, 14, 18, and 22 year olds ± one month. The software package SAFF-2D® (Forensic Facial Analysis System, Brazilian Federal Police, Brazil was used for positioning 11 landmarks on the images. Ten measurements were calculated and used as fixed references to evaluate the growth of the other measurements for each age group, as well the accumulated growth (6-22 years old. The Intraclass Correlation Coefficient (ICC was applied for the evaluation of intra-examiner and inter-examiner reliability within a specific set of images. Pearson's Correlation Coefficient was used to assess the association between each measurement taken and the respective age groups. ANOVA and Post-hoc Tukey tests were used to search for statistical differences between the age groups. The outcomes indicated that facial structures grow with different timing in children and adolescents. Moreover, the growth allometry expressed in this study may be used to understand what structures have more or less proportional variation in function for the age ranges studied. The diameter of the iris was found to be the most stable measurement compared to the others and represented the best cephalometric measurement as a fixed reference for facial growth ratios (or indices. The method described shows promising potential for forensic

  13. Conarticular congruence of the hominoid subtalar joint complex with implications for joint function in Plio-Pleistocene hominins.

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    Prang, Thomas C

    2016-07-01

    The purpose of this study is to test the hypothesis that conarticular surfaces areas and curvatures are correlates of mobility at the hominoid talocalcaneal and talonavicular joints. Articular surface areas and curvatures of the talonavicular, anterior talocalcaneal, and posterior talocalcaneal joints were quantified using a total of 425 three-dimensional surface models of extant hominoid and fossil hominin tali, calcanei, and naviculars. Quadric surface fitting was used to calculate curvatures, pairwise comparisons were used to evaluate statistical differences between taxa, and regression was used to test for the effects of allometry. Pairwise comparisons show that the distributions of values for joint curvature indices follow the predicted arboreal-terrestrial morphocline in hominoid primates with no effect of body mass (PGLS p > 0.05). OH 8 (Homo habilis) and LB 1 (Homo floresiensis) can be accommodated within the range of human variation for the talonavicular joint, whereas MH2 (Australopithecus sediba) falls within the ranges of variation for Pan troglodytes and Gorilla gorilla in measures of posterior talocalcaneal joint congruity. Joint curvature indices are better discriminators than joint surface area indices, which may reflect a greater contribution of rotation, rather than translation, to joint movement in plantigrade taxa due to discrepancies in conarticular congruence and the "convex-concave" rule. The pattern of joint congruence in Au. sediba contributes to other data on the foot and ankle suggesting that the lateral side of the foot was more mobile than the medial side, which is consistent with suggestions of increased medial weight transfer associated with hyperpronation. Am J Phys Anthropol 160:446-457, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  14. Temporal Variation of Wood Density and Carbon in Two Elevational Sites of Pinus cooperi in Relation to Climate Response in Northern Mexico.

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    Marín Pompa-García

    Full Text Available Forest ecosystems play an important role in the global carbon cycle. Therefore, understanding the dynamics of carbon uptake in forest ecosystems is much needed. Pinus cooperi is a widely distributed species in the Sierra Madre Occidental in northern Mexico and future climatic variations could impact these ecosystems. Here, we analyze the variations of trunk carbon in two populations of P. cooperi situated at different elevational gradients, combining dendrochronological techniques and allometry. Carbon sequestration (50% biomass was estimated from a specific allometric equation for this species based on: (i variation of intra-annual wood density and (ii diameter reconstruction. The results show that the population at a higher elevation had greater wood density, basal area, and hence, carbon accumulation. This finding can be explained by an ecological response of trees to adverse weather conditions, which would cause a change in the cellular structure affecting the within-ring wood density profile. The influence of variations in climate on the maximum density of chronologies showed a positive correlation with precipitation and the Multivariate El Niño Southern Oscillation Index during the winter season, and a negative correlation with maximum temperature during the spring season. Monitoring previous conditions to growth is crucial due to the increased vulnerability to extreme climatic variations on higher elevational sites. We concluded that temporal variability of wood density contributes to a better understanding of environmental historical changes and forest carbon dynamics in Northern Mexico, representing a significant improvement over previous studies on carbon sequestration. Assuming a uniform density according to tree age is incorrect, so this method can be used for environmental mitigation strategies, such as for managing P. cooperi, a dominant species of great ecological amplitude and widely used in forest industries.

  15. Confronting remote sensing product with ground base measurements across time and scale

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    Pourmokhtarian, A.; Dietze, M.

    2015-12-01

    Ecosystem models are essential tools in forecasting ecosystem responses to global climate change. One of the most challenging issues in ecosystem modeling is scaling while preserving landscape characteristics and minimizing loss of information, when moving from point observation to regional scale. There is a keen interest in providing accurate inputs for ecosystem models which represent ecosystem initial state conditions. Remote sensing land cover products, such as Landsat NLCD and MODIS MCD12Q1, provide extensive spatio-temporal coverage but do not capture forest composition and structure. Lidar and hyperspectral have the potential to meet this need but lack sufficient spatial and historical coverage. Forest inventory measurements provide detailed information on the landscape but in a very small footprint. Combining inventory and land cover could improve estimates of ecosystem state and characteristic across time and space. This study focuses on the challenges associated with fusing and scaling the US Forest Service FIA database and NLCD across regional scales to quantify ecosystem characteristics and reduce associated uncertainties. Across Southeast of U.S. 400 stratified random samples of 10x10 km2 landscapes were selected. Data on plant density, species, age, and DBH of trees in FIA plots within each site were extracted. Using allometry equations, the canopy cover of different plant functional types (PFTs) was estimated using a PPA-style canopy model and used to assign each inventory plot to a land cover class. Inventory and land cover were fused in a Bayesian model that adjusts the fractional coverage of inventory plots while accounting for multiple sources of uncertainty. Results were compared to estimates derived from inventory alone, land cover alone, and model spin-up alone. Our findings create a framework of data assimilation to better interpret remote sensing data using ground-based measurements.

  16. Diet Switching by Mammalian Herbivores in Response to Exotic Grass Invasion.

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    Carolina Bremm

    Full Text Available Invasion by exotic grasses is a severe threat to the integrity of grassland ecosystems all over the world. Because grasslands are typically grazed by livestock and wildlife, the invasion is a community process modulated by herbivory. We hypothesized that the invasion of native South American grasslands by Eragrostis plana Nees, an exotic tussock-forming grass from Africa, could be deterred by grazing if grazers switched dietary preferences and included the invasive grass as a large proportion of their diets. Bos taurus (heifers and Ovis aries (ewes grazed plots with varying degrees of invasion by E. plana in a replicated manipulative experiment. Animal positions and species grazed were observed every minute in 45-min grazing session. Proportion of bites and steps in and out of E. plana tussocks were measured and used to calculate several indices of selectivity. Both heifers and ewes exhibited increasing probability of grazing E. plana as the proportion of area covered by tussocks increased, but they behaved differently. In agreement with expectations based on the allometry of dietary preferences and morphology, ewes consumed a low proportion of E. plana, except in areas that had more than 90% E. plana cover. Heifers consumed proportionally more E. plana than ewes. Contrary to our hypothesis, herbivores did not exhibit dietary switching towards the invasive grass. Moreover, they exhibited avoidance of the invasive grass and preference for short-statured native species, both of which should tend to enhance invasion. Unless invasive plants are highly palatable to livestock, the effect of grazing to deter the invasion is limited, due to the inherent avoidance of the invasive grass by the main grazers in the ecosystem, particularly sheep.

  17. Biological parameters and feeding behaviour of invasive whelk Rapana venosa Valenciennes, 1846 in the south-eastern Black Sea of Turkey

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    Hacer Saglam

    2014-06-01

    Full Text Available Objective: To determine length-weight relationships, growth type and feeding behavior of the benthic predator Rapa whelk at the coast of Camburnu, south-eastern Black Sea. Methods: Rapa whelk was monthly collected by dredge sampling on the south-eastern Black Sea at 20 m depth. The relationships between morphometric parameters of Rapa whelk were described by linear and exponential models. The allometric growth of each variable relative to shell length (SL was calculated from the function Y=aSLb or logY=loga+blogSL. The functional regression b values were tested by t-test at the 0.05 significance level if it was significantly different from isometric growth. The total time spent on feeding either on mussel tissue or live mussels was recorded for each individual under controlled conditions in laboratory. Results: The length-weight relationships showed positive allometric growth and no inter-sex variability. Body size in the male population was significantly higher than in the individuals of the female. All characters in males and females showed a trend towards allometry rather than isometry. While the total time spent feeding increased with increasing prey size the total time that Rapana venosa spent feeding decreased with increasing Rapa whelk size. The total average feeding time needed by Rapa whelks was 160 min. But they took 310 min on live mussels in 27-28 °C in the laboratory conditions. Conclusions: Length and weight relationships, growth type, total time spent feeding of this species were explained in details for this region. It would be useful to sustainable management in the south-eastern Black Sea of Turkey. The results about the feeding behaviour of this species will contribute to the understanding of the role of this species within the ecosystem.

  18. Scaling of Primate Forearm Muscle Architecture as It Relates to Locomotion and Posture.

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    Leischner, Carissa L; Crouch, Michael; Allen, Kari L; Marchi, Damiano; Pastor, Francisco; Hartstone-Rose, Adam

    2018-03-01

    It has been previously proposed that distal humerus morphology may reflect the locomotor pattern and substrate preferred by different primates. However, relationships between these behaviors and the morphological capabilities of muscles originating on these osteological structures have not been fully explored. Here, we present data about forearm muscle architecture in a sample of 44 primate species (N = 55 specimens): 9 strepsirrhines, 15 platyrrhines, and 20 catarrhines. The sample includes all major locomotor and substrate use groups. We isolated each antebrachial muscle and categorized them into functional groups: wrist and digital extensors and flexors, antebrachial mm. that do not cross the wrist, and functional combinations thereof. Muscle mass, physiological cross-sectional area (PCSA), reduced PCSA (RPCSA), and fiber length (FL) are examined in the context of higher taxonomic group, as well as locomotor/postural and substrate preferences. Results show that muscle masses, PCSA, and RPCSA scale with positive allometry while FL scales with isometry indicating that larger primates have relatively stronger, but neither faster nor more flexible, forearms across the sample. When accounting for variation in body size, we found no statistically significant difference in architecture among higher taxonomic groups or locomotor/postural groups. However, we found that arboreal primates have significantly greater FL than terrestrial ones, suggesting that these species are adapted for greater speed and/or flexibility in the trees. These data may affect our interpretation of the mechanisms for variation in humeral morphology and provide information for refining biomechanical models of joint stress and movement in extant and fossil primates. Anat Rec, 301:484-495, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  19. Cranial shape variation in adult howler monkeys (Alouatta seniculus).

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    Fiorenza, Luca; Bruner, Emiliano

    2018-01-01

    Howler monkeys (genus Alouatta) display a distinctive cranial architecture characterized by airorhynchy (or retroflexion of the facial skeleton on the cranial base), a small braincase, and a posteriorly oriented foramen magnum. This configuration has been associated with distinct factors including a high folivory diet, locomotion, and the presence of a specialized vocal tract characterized by large hyoid bone. However, the morphological relationships between the facial and neurocranial blocks in Alouatta have been scarcely investigated. In this study we quantitatively analyzed the cranial shape variation in Alouatta seniculus, to evaluate possible influences and constraints in face and braincase associated with airorhynchy. We also considered the structural role of the pteric area within the cranial functional matrix. We applied landmark-based analysis and multivariate statistics to 31 adult crania, computing shape analyses based on 3D coordinates registration as well as the analysis of the Euclidean distance matrix to investigate patterns of intraspecific morphological variability. Our results suggest that allometry is the main source of variation involved in shaping cranial morphology in howlers, influencing the degree of facial proportions and braincase flattening, and generating the main sexual differences. Larger individuals are characterized by a higher degree of airorhynchy, neurocranial flattening, and expansion of the zygomatic arch. Allometric variations influence the skull as a whole, without distinct patterns for face and braincase, which behave as an integrated morphological unit. A preliminary survey on the pteric pattern suggests that the morphology of this area may be the result of variations in the vertical growth rates between face and braincase. Future studies should be dedicated to the ontogenetic series and focus on airorhynchy in terms of differential growth among distinct cranial districts. © 2017 Wiley Periodicals, Inc.

  20. Cortical surface area and cortical thickness in the precuneus of adult humans.

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    Bruner, E; Román, F J; de la Cuétara, J M; Martin-Loeches, M; Colom, R

    2015-02-12

    The precuneus has received considerable attention in the last decade, because of its cognitive functions, its role as a central node of the brain networks, and its involvement in neurodegenerative processes. Paleoneurological studies suggested that form changes in the deep parietal areas represent a major character associated with the origin of the modern human brain morphology. A recent neuroanatomical survey based on shape analysis suggests that the proportions of the precuneus are also a determinant source of overall brain geometrical differences among adult individuals, influencing the brain spatial organization. Here, we evaluate the variation of cortical thickness and cortical surface area of the precuneus in a sample of adult humans, and their relation with geometry and cognition. Precuneal thickness and surface area are not correlated. There is a marked individual variation. The right precuneus is thinner and larger than the left one, but there are relevant fluctuating asymmetries, with only a modest correlation between the hemispheres. Males have a thicker cortex but differences in cortical area are not significant between sexes. The surface area of the precuneus shows a positive allometry with the brain surface area, although the correlation is modest. The dilation/contraction of the precuneus, described as a major factor of variability within adult humans, is associated with absolute increase/decrease of its surface, but not with variation in thickness. Precuneal thickness, precuneal surface area and precuneal morphology are not correlated with psychological factors such as intelligence, working memory, attention control, and processing speed, stressing further possible roles of this area in supporting default mode functions. Beyond gross morphology, the processes underlying the large phenotypic variation of the precuneus must be further investigated through specific cellular analyses, aimed at considering differences in cellular size, density

  1. Osmo and hydro priming improvement germination characteristics and enzyme activity of Mountain Rye (Secale montanum seeds under drought stress

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    Ansari O.

    2012-11-01

    Full Text Available Impacts of various concentrations of polyetylenglycol 6000 (PEG 6000(0, -9, -11, -13 and -15 bar and hydro priming on Mountain Rye (secale montanum germination characteristic and enzyme activity were evaluated under drought stress in the seed laboratory of Natural Resources Faculty, University of Tehran, Karaj, Iran. Analyze of variance for hydro priming showed that temperature × time of priming interaction was significantly for germination percentage (GP, normal seedling percentage (NSP, coefficient of velocity of germination (CVG, seedling vigor index (SVI, coefficient of allometry (AC and seedling length (SL under drought stress and for osmo priming showed that Concentration of PEG × Temperature × Time of priming interaction was significantly for all traits under drought stress. Results of interaction effects for hydro priming showed that the highest GP (53% and NSP (23.5% were attained from hydro priming for 16h at 15 ◦C and the highest CVG (0.21 and AC (0.49 were attained from hydro priming for 8h at 10 ◦C, also hydro priming for 8h at 15 ◦C increased SL (3.15 as compared to the unprimed.Osmo priming with concentration of -15 bar PEG for 24h at 15 ◦C increased GP (80.5 %, GI (17.9, NSP (45 %, SVI (257.85 and SL (5.73 cm and decreased MTG as compared to the unprimed and other treatments of osmo priming. The highest CVG was attained from concentration of -9 bar PEG for 24h at 10 ◦C. the highest AC was attained from concentration of -9 bar PEG for 12h at 15 ◦C. Also osmo and hydro priming increased catalase (CAT and ascorbate peroxidase (APX as compared to the unprimed.

  2. Are tree ontogenetic structure and allometric relationship independent of vegetation formation type? A case study with Cordia oncocalyx in the Brazilian caatinga

    Science.gov (United States)

    Silveira, Andréa P.; Martins, Fernando R.; Araújo, Francisca S.

    2012-08-01

    In temperate and tropical rainforests, ontogenetic structure and allometry during tree ontogeny are often associated with light gradients. Light is not considered a limiting resource in deciduous thorny woodland (DTW), but establishment and growth occur during a short rainy period, when the canopy is fully leaved and light in the understory may be modified. Our aim was to investigate whether the light gradient in DTW and the biomechanical limitations of tree growth would be enough to produce an ontogenetic structure and allometric growth similar to rainforest canopy trees. We investigated the ontogenetic stages and diameter-height relationship of Cordia oncocalyx (Boraginaceae), a dominant canopy tree of the DTW of semiarid northeastern Brazil. We tagged, measured and classified the ontogenetic stages of 2.895 individuals in a 1 ha area (5°6'58.1″S and 40°52'19.4″W). In the rainy season only 4.7% of the light falling on the canopy reached the ground. Initial ontogenetic stages, mainly infant (50.9%) and seedling (42.1%), were predominant in the population, with the remaining 7% distributed among juvenile, immature, virginile and reproductive. The ontogenetic structure was similar to that of rainforest tree species, but the population formed both permanent seed and infant banks in response to long dry periods and erratic rainy spells. Like many other Boraginaceae tree species in tropical rainforests, C. oncocalyx has a Prévost architectural model, but allometric growth was quite different from rainforest trees. C. oncocalyx invested slightly more in diameter at first, then in height and finally invested greatly in diameter and attained an asymptotic height. The continued high investment in diameter growth at late stages and the asymptotic height point to low tree density and more frequent xylem embolism as the main drivers of tree allometric shape in DTW. This indicates that tree ontogenetic structure and allometric relationships depend on vegetation

  3. Evolutionary morphology of the rabbit skull

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    Brian Kraatz

    2016-09-01

    Full Text Available The skull of leporids (rabbits and hares is highly transformed, typified by pronounced arching of the dorsal skull and ventral flexion of the facial region (i.e., facial tilt. Previous studies show that locomotor behavior influences aspects of cranial shape in leporids, and here we use an extensive 3D geometric morphometrics dataset to further explore what influences leporid cranial diversity. Facial tilt angle, a trait that strongly correlates with locomotor mode, significantly predicts the cranial shape variation captured by the primary axis of cranial shape space, and describes a small proportion (13.2% of overall cranial shape variation in the clade. However, locomotor mode does not correlate with overall cranial shape variation in the clade, because there are two district morphologies of generalist species, and saltators and cursorial species have similar morphologies. Cranial shape changes due to phyletic size change (evolutionary allometry also describes a small proportion (12.5% of cranial shape variation in the clade, but this is largely driven by the smallest living leporid, the pygmy rabbit (Brachylagus idahoensis. By integrating phylogenetic history with our geometric morphometric data, we show that the leporid cranium exhibits weak phylogenetic signal and substantial homoplasy. Though these results make it difficult to reconstruct what the ‘ancestral’ leporid skull looked like, the fossil records suggest that dorsal arching and facial tilt could have occurred before the origin of the crown group. Lastly, our study highlights the diversity of cranial variation in crown leporids, and highlights a need for additional phylogenetic work that includes stem (fossil leporids and includes morphological data that captures the transformed morphology of rabbits and hares.

  4. Growth laws for delta crevasses in the Mississippi River Delta: observations and modeling

    Science.gov (United States)

    Yocum, T. A.; Georgiou, I. Y.

    2016-02-01

    River deltas are accumulations of sedimentary deposits delivered by rivers via a network of distributary channels. Worldwide they are threatened by environmental changes, including subsidence, global sea level rise and a suite of other local factors. In the Mississippi River Delta (MRD) these impacts are exemplified, and have led to proposed solutions to build land that include sediment diversions, thereby reinitiating the delta cycle. While economically efficient, there are too few analogs of small deltas aside from laboratory studies, numerical modeling studies, theoretical approaches, and limited field driven observations. Anthropogenic crevasses in the modern delta are large enough to overcome limitations of laboratory deltas, and small enough to allow for "rapid" channel and wetland development, providing an ideal setting to investigate delta development mechanics. Crevasse metrics were obtained using a combination of geospatial tools, extracting key parameters (bifurcation length and width, channel order and depth) that were non-dimensionalized and compared to river-dominated delta networks previously studied. Analysis showed that most crevasses in the MRD appear to obey delta growth laws and delta allometry relationships, suggesting that crevasses do exhibit similar planform metrics to larger Deltas; the distance to mouth bar versus bifurcation order demonstrated to be a very reasonable first order estimate of delta-top footprint. However, some crevasses exhibited different growth metrics. To better understand the hydrodynamic and geomorphic controls governing crevasse evolution in the MRD, we assess delta dynamics via a suite of field observations and numerical modeling in both well-established and newly constructed crevasses. Our analysis suggests that delta development is affected by the relative influence of external (upstream and downstream) and internal controls on the hydrodynamic and sediment transport patterns in these systems.

  5. Spatial and Temporal Evolution of Urban Systems in China during Rapid Urbanization

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    Huan Li

    2016-07-01

    Full Text Available The structure of urban hierarchy and the role of cities of different sizes have drawn considerable scholarly interests and societal concerns. This paper analyzes the evolution and underlying mechanisms of urban hierarchy in China during the recent period of rapid urbanization. By comparing scale changes of seven types of cities (megacity, large city, Type I big city, Type II big city, medium-sized city, type I small city and type II small city, we find that allometry is the main characteristic of urban hierarchical evolution in China. We also test the validity of Zipf’s law and Gibrat’s law, which broaden the scope of existing studies by including county-level cities. We find that urban hierarchical distribution is lognormal, rather than Pareto. The result also shows that city size growth rates are constant across cities of different types. For better understanding of the mechanisms of urban hierarchical formation, we measure the optimal city size and resource allocation by the Pareto optimality criterion and non-parametric frontier method. The main findings are as follows: (1 scale efficiency is still at a relatively low level among the seven types of cities; (2 the economic efficiency of megacities and large cities is overestimated when compared to economic-environmental efficiency. Hence, this paper has two policy implications: (1 to correct factor market (land, labor and infrastructure investment distortions among different types of cities for the improvement of efficiency; (2 to strengthen rural property rights to improve social equity, as well as land use intensity.

  6. Global patterns and clines in the growth of common carp Cyprinus carpio.

    Science.gov (United States)

    Vilizzi, L; Copp, G H

    2017-07-01

    This review provides a meta-analytical assessment of the global patterns and clines in the growth of Cyprinus carpio as measured by length-at-age (L t ) or von Bertalanffy growth function (VBGF) parameters, mass-length relationship (W-L t ) and condition factor, based on literature data. In total, 284 studies were retrieved spanning 91 years of research and carried out on 381 waterbodies-locations in 50 countries in all five continents. Although native C. carpio achieved larger (asymptotic) size relative to its non-native counterpart, the latter grew faster during the first 7 years of life. Lentic populations (especially in natural lakes) also achieved larger sizes relative to lotic ones and the same was true for populations in cold and temperate v. arid climates. Unlike previous studies (on much more restricted datasets), only weak latitudinal clines in instantaneous growth rate, L t at age 3 and mortality were observed globally and this was probably due to the presence of counter-gradient growth variation at all representative age classes (i.e. 1-10 years). Slightly negative allometry was revealed by the W-L t and the related form factor tended to distinguish the more elongated and torpedo-shaped body typical of the wild form from the deeper body of feral-domesticated C. carpio. Existing population dynamics models for C. carpio will benefit from the comprehensive range of waterbody type × climate class-specific VBGF parameters provided in the present study; whereas, more studies are needed on the species' growth in tropical regions and to unravel the possibility of confounding effects on age estimation due to both historical and methodological reasons. © 2017 The Fisheries Society of the British Isles.

  7. Assessing allometric models to predict vegetative growth of mango (Mangifera indica; Anacardiaceae) at the current-year branch scale.

    Science.gov (United States)

    Normand, Frédéric; Lauri, Pierre-Éric

    2012-03-01

    Accurate and reliable predictive models are necessary to estimate nondestructively key variables for plant growth studies such as leaf area and leaf, stem, and total biomass. Predictive models are lacking at the current-year branch scale despite the importance of this scale in plant science. We calibrated allometric models to estimate leaf area and stem and branch (leaves + stem) mass of current-year branches, i.e., branches several months old studied at the end of the vegetative growth season, of four mango cultivars on the basis of their basal cross-sectional area. The effects of year, site, and cultivar were tested. Models were validated with independent data and prediction accuracy was evaluated with the appropriate statistics. Models revealed a positive allometry between dependent and independent variables, whose y-intercept but not the slope, was affected by the cultivar. The effects of year and site were negligible. For each branch characteristic, cultivar-specific models were more accurate than common models built with pooled data from the four cultivars. Prediction quality was satisfactory but with data dispersion around the models, particularly for large values. Leaf area and stem and branch mass of mango current-year branches could be satisfactorily estimated on the basis of branch basal cross-sectional area with cultivar-specific allometric models. The results suggested that, in addition to the heteroscedastic behavior of the variables studied, model accuracy was probably related to the functional plasticity of branches in relation to the light environment and/or to the number of growth units composing the branches.

  8. Size-mediated tree transpiration along soil drainage gradients in a boreal black spruce forest wildfire chronosequence.

    Science.gov (United States)

    Angstmann, J L; Ewers, B E; Kwon, H

    2012-05-01

    Boreal forests are crucial to climate change predictions because of their large land area and ability to sequester and store carbon, which is controlled by water availability. Heterogeneity of these forests is predicted to increase with climate change through more frequent wildfires, warmer, longer growing seasons and potential drainage of forested wetlands. This study aims at quantifying controls over tree transpiration with drainage condition, stand age and species in a central Canadian black spruce boreal forest. Heat dissipation sensors were installed in 2007 and data were collected through 2008 on 118 trees (69 Picea mariana (Mill.) Britton, Sterns & Poggenb. (black spruce), 25 Populus tremuloides Michx. (trembling aspen), 19 Pinus banksiana Lamb. (jack pine), 3 Larix laricina (Du Roi) K. Koch (tamarack) and 2 Salix spp. (willow)) at four stand ages (18, 43, 77 and 157 years old) each containing a well- and poorly-drained stand. Transpiration estimates from sap flux were expressed per unit xylem area, J(S), per unit ground area, E(C) and per unit leaf area, E(L), using sapwood (A(S)) and leaf (A(L)) area calculated from stand- and species-specific allometry. Soil drainage differences in transpiration were variable; only the 43- and 157-year-old poorly-drained stands had ∼ 50% higher total stand E(C) than well-drained locations. Total stand E(C) tended to decrease with stand age after an initial increase between the 18- and 43-year-old stands. Soil drainage differences in transpiration were controlled primarily by short-term physiological drivers such as vapor pressure deficit and soil moisture whereas stand age differences were controlled by successional species shifts and changes in tree size (i.e., A(S)). Future predictions of boreal climate change must include stand age, species and soil drainage heterogeneity to avoid biased estimates of forest water loss and latent energy exchanges.

  9. Stomatal conductance at Duke FACE: Leveraging the lessons from 11 years of scaled sap flux measurements for region-wide analyses

    Science.gov (United States)

    Ward, E. J.; Bell, D.; Clark, J. S.; McCarthy, H. R.; Kim, H.; domec, J.; Noormets, A.; McNulty, D.; Sun, G.; Oren, R.

    2013-12-01

    A network of thermal dissipation probes (TDPs) monitoring sap flux density was used to estimate leaf-specific transpiration (EL) and canopy-averaged stomatal conductance (GS) in Pinus taeda (L.) exposed to +200 ppm atmospheric CO2 levels (eCO2) and nitrogen fertilization as part of the Duke FACE study. Data from scaling half-hourly measurements from hundreds of sensors over 11 years indicated that P. taeda in eCO2 intermittently (49% of monthly values) decreased stomatal conductance relative to the control, with a mean reduction of 13% in both total EL and mean daytime GS. This intermittent response was related to changes in a hydraulic allometry index (AH), defined as sapwood area per unit leaf area per unit canopy height, which was linearly related to GS at reference conditions (GSR) during the growing season across years (R2=0.67). Overall, AH decreased a mean of 15% with eCO2 over the course of the study, due mostly to a mean 19% increase in leaf area. Throughout the southeastern U.S., other P. taeda stands have been monitored with TDPs, such as the US-NC2 Ameriflux site and four fertilizer × throughfall displacement studies recently begun as part of the PINEMAP research network in VA, GA, FL and OK. We will also discuss the challenges and benefits of using a common modeling platform to combine FACE TDP data with that from a diversity of sites and treatments to draw inferences about EL and GS responses to environmental drivers and climate change, as well as their relation to AH, across the range of P. taeda.

  10. The temporal response to drought in a Mediterranean evergreen tree: comparing a regional precipitation gradient and a throughfall exclusion experiment.

    Science.gov (United States)

    Martin-Stpaul, Nicolas K; Limousin, Jean-Marc; Vogt-Schilb, Hélène; Rodríguez-Calcerrada, Jesus; Rambal, Serge; Longepierre, Damien; Misson, Laurent

    2013-08-01

    Like many midlatitude ecosystems, Mediterranean forests will suffer longer and more intense droughts with the ongoing climate change. The responses to drought in long-lived trees differ depending on the time scale considered, and short-term responses are currently better understood than longer term acclimation. We assessed the temporal changes in trees facing a chronic reduction in water availability by comparing leaf-scale physiological traits, branch-scale hydraulic traits, and stand-scale biomass partitioning in the evergreen Quercus ilex across a regional precipitation gradient (long-term changes) and in a partial throughfall exclusion experiment (TEE, medium term changes). At the leaf scale, gas exchange, mass per unit area and nitrogen concentration showed homeostatic responses to drought as they did not change among the sites of the precipitation gradient or in the experimental treatments of the TEE. A similar homeostatic response was observed for the xylem vulnerability to cavitation at the branch scale. In contrast, the ratio of leaf area over sapwood area (LA/SA) in young branches exhibited a transient response to drought because it decreased in response to the TEE the first 4 years of treatment, but did not change among the sites of the gradient. At the stand scale, leaf area index (LAI) decreased, and the ratios of stem SA to LAI and of fine root area to LAI both increased in trees subjected to throughfall exclusion and from the wettest to the driest site of the gradient. Taken together, these results suggest that acclimation to chronic drought in long-lived Q. ilex is mediated by changes in hydraulic allometry that shift progressively from low (branch) to high (stand) organizational levels, and act to maintain the leaf water potential within the range of xylem hydraulic function and leaf photosynthetic assimilation. © 2013 John Wiley & Sons Ltd.

  11. Sex differences in gait utilization and energy metabolism during terrestrial locomotion in two varieties of chicken (Gallus gallus domesticus selected for different body size

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    Kayleigh A. Rose

    2015-10-01

    Full Text Available In leghorn chickens (Gallus gallus domesticus of standard breed (large and bantam (small varieties, artificial selection has led to females being permanently gravid and sexual selection has led to male-biased size dimorphism. Using respirometry, videography and morphological measurements, sex and variety differences in metabolic cost of locomotion, gait utilisation and maximum sustainable speed (Umax were investigated during treadmill locomotion. Males were capable of greater Umax than females and used a grounded running gait at high speeds, which was only observed in a few bantam females and no standard breed females. Body mass accounted for variation in the incremental increase in metabolic power with speed between the varieties, but not the sexes. For the first time in an avian species, a greater mass-specific incremental cost of locomotion, and minimum measured cost of transport (CoTmin were found in males than in females. Furthermore, in both varieties, the female CoTmin was lower than predicted from interspecific allometry. Even when compared at equivalent speeds (using Froude number, CoT decreased more rapidly in females than in males. These trends were common to both varieties despite a more upright limb in females than in males in the standard breed, and a lack of dimorphism in posture in the bantam variety. Females may possess compensatory adaptations for metabolic efficiency during gravidity (e.g. in muscle specialization/posture/kinematics. Furthermore, the elevated power at faster speeds in males may be linked to their muscle properties being suited to inter-male aggressive combat.

  12. The role of cross-sectional geometry, curvature, and limb posture in maintaining equal safety factors: a computed tomography study.

    Science.gov (United States)

    Brassey, Charlotte A; Kitchener, Andrew C; Withers, Philip J; Manning, Phillip L; Sellers, William I

    2013-03-01

    The limb bones of an elephant are considered to experience similar peak locomotory stresses as a shrew. "Safety factors" are maintained across the entire range of body masses through a combination of robusticity of long bones, postural variation, and modification of gait. The relative contributions of these variables remain uncertain. To test the role of shape change, we undertook X-ray tomographic scans of the leg bones of 60 species of mammals and birds, and extracted geometric properties. The maximum resistible forces the bones could withstand before yield under compressive, bending, and torsional loads were calculated using standard engineering equations incorporating curvature. Positive allometric scaling of cross-sectional properties with body mass was insufficient to prevent negative allometry of bending (F(b) ) and torsional maximum force (F(t) ) (and hence decreasing safety factors) in mammalian (femur F(b) ∞M(b) (0.76) , F(t) ∞M(b) (0.80) ; tibia F(b) ∞M(b) (0.80) , F(t) ∞M(b) (0.76) ) and avian hindlimbs (tibiotarsus F(b) ∞M(b) (0.88) , F(t) ∞M(b) (0.89) ) with the exception of avian femoral F(b) and F(t) . The minimum angle from horizontal a bone must be held while maintaining a given safety factor under combined compressive and bending loads increases with M(b) , with the exception of the avian femur. Postural erectness is shown as an effective means of achieving stress similarity in mammals. The scaling behavior of the avian femur is discussed in light of unusual posture and kinematics. Copyright © 2013 Wiley Periodicals, Inc.

  13. Performance comparison of resistance-trained subjects by different methods of adjusting for body mass. DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n3p313

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    Wladymir Külkamp

    2012-05-01

    Full Text Available The aim of this study was to compare the performance (1RM of resistance-trained subjects, using different methods of adjusting for body mass (BM: ratio standard, theoretical allometric exponent (0.67, and specific allometric exponents. The study included 11 male and 11 female healthy non-athletes (mean age = 22 years engaged in regular resistance training for at least 6 months. Bench press (BP, 45° leg press (LP and arm curl (AC exercises were performed, and the participants were ranked (in descending order according to each method. The specific allometric exponents for each exercise were: for men – BP (0.73, LP (0.35, and AC (0.71; and for women – BP (1.22, LP (1.02, and AC (0.85. The Kruskal-Wallis test revealed no differences between the rankings. However, visual inspection indicated that the participants were often classified differently in relation to performance by the methods used. Furthermore, no adjusted strength score was equal to the absolute strength values (1RM. The results suggest that there is a range of values in which the differences between exponents do not reflect different rankings (below 0.07 points and a range in which rankings can be fundamentally different (above 0.14 points. This may be important in long-term selection of universally accepted allometric exponents, considering the range of values found in different studies. The standardization of exponents may allow the use of allometry as an additional tool in the prescription of resistance training.

  14. Allometric convergence in savanna trees and implications for the use of plant scaling models in variable ecosystems.

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    Andrew T Tredennick

    Full Text Available Theoretical models of allometric scaling provide frameworks for understanding and predicting how and why the morphology and function of organisms vary with scale. It remains unclear, however, if the predictions of 'universal' scaling models for vascular plants hold across diverse species in variable environments. Phenomena such as competition and disturbance may drive allometric scaling relationships away from theoretical predictions based on an optimized tree. Here, we use a hierarchical Bayesian approach to calculate tree-specific, species-specific, and 'global' (i.e. interspecific scaling exponents for several allometric relationships using tree- and branch-level data harvested from three savanna sites across a rainfall gradient in Mali, West Africa. We use these exponents to provide a rigorous test of three plant scaling models (Metabolic Scaling Theory (MST, Geometric Similarity, and Stress Similarity in savanna systems. For the allometric relationships we evaluated (diameter vs. length, aboveground mass, stem mass, and leaf mass the empirically calculated exponents broadly overlapped among species from diverse environments, except for the scaling exponents for length, which increased with tree cover and density. When we compare empirical scaling exponents to the theoretical predictions from the three models we find MST predictions are most consistent with our observed allometries. In those situations where observations are inconsistent with MST we find that departure from theory corresponds with expected tradeoffs related to disturbance and competitive interactions. We hypothesize savanna trees have greater length-scaling exponents than predicted by MST due to an evolutionary tradeoff between fire escape and optimization of mechanical stability and internal resource transport. Future research on the drivers of systematic allometric variation could reconcile the differences between observed scaling relationships in variable ecosystems and

  15. Kleiber's Law: How the Fire of Life ignited debate, fueled theory, and neglected plants as model organisms.

    Science.gov (United States)

    Niklas, Karl J; Kutschera, Ulrich

    2015-01-01

    Size is a key feature of any organism since it influences the rate at which resources are consumed and thus affects metabolic rates. In the 1930s, size-dependent relationships were codified as "allometry" and it was shown that most of these could be quantified using the slopes of log-log plots of any 2 variables of interest. During the decades that followed, physiologists explored how animal respiration rates varied as a function of body size across taxa. The expectation was that rates would scale as the 2/3 power of body size as a reflection of the Euclidean relationship between surface area and volume. However, the work of Max Kleiber (1893-1976) and others revealed that animal respiration rates apparently scale more closely as the 3/4 power of body size. This phenomenology, which is called "Kleiber's Law," has been described for a broad range of organisms, including some algae and plants. It has also been severely criticized on theoretical and empirical grounds. Here, we review the history of the analysis of metabolism, which originated with the works of Antoine L. Lavoisier (1743-1794) and Julius Sachs (1832-1897), and culminated in Kleiber's book The Fire of Life (1961; 2. ed. 1975). We then evaluate some of the criticisms that have been leveled against Kleiber's Law and some examples of the theories that have tried to explain it. We revive the speculation that intracellular exo- and endocytotic processes are resource delivery-systems, analogous to the supercellular systems in multicellular organisms. Finally, we present data that cast doubt on the existence of a single scaling relationship between growth and body size in plants.

  16. Can foraging ecology drive the evolution of body size in a diving endotherm?

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    Timothée R Cook

    Full Text Available Within a single animal species, different morphs can allow for differential exploitation of foraging niches between populations, while sexual size dimorphism can provide each sex with access to different resources. Despite being potentially important agents of evolution, resource polymorphisms, and the way they operate in wild populations, remain poorly understood. In this study, we examine how trophic factors can select for different body sizes between populations and sexes in a diving endotherm. Dive depth and duration are positively related to body size in diving birds and mammals, a relationship explained by a lower mass-specific metabolic rate and greater oxygen stores in larger individuals. Based on this allometry, we predict that selection for exploiting resources situated at different depths can drive the evolution of body size in species of diving endotherms at the population and sexual level. To test this prediction, we studied the foraging ecology of Blue-eyed Shags, a group of cormorants with male-biased sexual size dimorphism from across the Southern Ocean. We found that mean body mass and relative difference in body mass between sexes varied by up to 77% and 107% between neighbouring colonies, respectively. Birds from colonies with larger individuals dived deeper than birds from colonies with smaller individuals, when accounting for sex. In parallel, males dived further offshore and deeper than females and the sexual difference in dive depth reflected the level of sexual size dimorphism at each colony. We argue that body size in this group of birds is under intense selection for diving to depths of profitable benthic prey patches and that, locally, sexual niche divergence selection can exaggerate the sexual size dimorphism of Blue-eyed Shags initially set up by sexual selection. Our findings suggest that trophic resources can select for important geographic micro-variability in body size between populations and sexes.

  17. Ontogenetic shifts of heart position in snakes.

    Science.gov (United States)

    Lillywhite, Harvey B; Lillywhite, Steven M

    2017-08-01

    Heart position relative to total body length (TL) varies among snakes, with anterior hearts in arboreal species and more centrally located hearts in aquatic or ground-dwelling species. Anterior hearts decrease the cardiac work associated with cranial blood flow and minimize drops in cranial pressure and flow during head-up climbing. Here, we investigate whether heart position shifts intraspecifically during ontogenetic increases in TL. Insular Florida cottonmouth snakes, Agkistrodon conanti, are entirely ground-dwelling and have a mean heart position that is 33.32% TL from the head. In contrast, arboreal rat snakes, Pantherophis obsoleta, of similar lengths have a mean heart position that is 17.35% TL from the head. In both species, relative heart position shifts craniad during ontogeny, with negative slopes = -.035 and -.021% TL/cm TL in Agkistrodon and Pantherophis, respectively. Using a large morphometric data set available for Agkistrodon (N = 192 individuals, 23-140 cm TL), we demonstrate there is an anterior ontogenetic shift of the heart position within the trunk (= 4.56% trunk length from base of head to cloacal vent), independent of head and tail allometry which are both negative. However, in longer snakes > 100 cm, the heart position reverses and shifts caudally in longer Agkistrodon but continues toward the head in longer individuals of Pantherophis. Examination of data sets for two independent lineages of fully marine snakes (Acrochordus granulatus and Hydrophis platurus), which do not naturally experience postural gravity stress, demonstrate both ontogenetic patterns for heart position that are seen in the terrestrial snakes. The anterior migration of the heart is greater in the terrestrial species, even if TL is standardized to that of the longer P. obsoleta, and compensates for about 5 mmHg gravitational pressure head if they are fully upright. © 2017 Wiley Periodicals, Inc.

  18. Blue Carbon distribution in mangrove forests of the Americas

    Science.gov (United States)

    Simard, M.; Rivera-Monroy, V.; Fatoyinbo, T. E.; Roy Chowdhury, R.

    2013-12-01

    Globally, coastal ecosystems are critical to maintaining human livelihood and biodiversity. These ecosystems including mangroves, salt marshes, and sea grasses provide essential ecosystem services, such as supporting fisheries by providing important spawning grounds, filtering pollutants and contaminants from coastal waters, and protecting coastal development and communities against storms, floods and erosion. Additionally, recent research indicates that these vegetated coastal ecosystems are highly efficient carbon sinks (i.e. 'Blue Carbon') and can potentially play a significant role in ameliorating the effect of increasing global climate change by capturing significant amounts of carbon into sediments and plant biomass. The term blue carbon indicates the carbon stored in coastal vegetated wetlands (i.e., mangroves, intertidal marshes, and seagrass meadows). As a result of rapid global changes in coastal regions, it is crucial that we improve our understanding of the current and future state of the remaining coastal ecosystems and associated ecosystem services and their vulnerability to global climate change. In this study, we present a continental scale study of mangrove distribution and assess patterns of forest structural development associated to latitude and geomorphological setting. We produced a baseline map of mangrove canopy height and biomass for all mangrove forests of the Americas using data from the Shuttle Radar Topography Mission (SRTM) and publicly available land cover maps (Figure 1). The resulting canopy height map was calibrated using ICEsat/Geoscience Laser Altimeter system (GLAS). Biomass was derived from field data and allometry. The maps were validated with field data and results in accuracies that vary spatially around 2 to 3m in height and 20% in biomass. Figure 1: Global distribution of mangrove forests (green) and SRTM elevation data. These data were used to produce large scale maps of mangrove canopy height and biomass.

  19. Slice-push, formation of grooves and the scale effect in cutting.

    Science.gov (United States)

    Atkins, A G

    2016-06-06

    Three separate aspects of cutting are investigated which complement other papers on the mechanics of separation processes presented at this interdisciplinary Theo Murphy meeting. They apply in all types of cutting whether blades are sharp or blunt, and whether the material being cut is 'hard, stiff and strong' or 'soft, compliant and weak'. The first topic discusses why it is easier to cut when there is motion along (parallel to) the blade as well motion across (perpendicular to) the cutting edge, and the analysis is applied to optimization of blade geometries to produce minimum cutting forces and hence minimum damage to cut surfaces. The second topic concerns cutting with more than one edge with particular application to the formation of grooves in surfaces by hard pointed tools. The mechanics are investigated and applied to the topic of abrasive wear by hard particles. Traditional analyses say that abrasive wear resistance increases monotonically with the hardness of the workpiece, but we show that the fracture toughness of the surface material is also important, and that behaviour is determined by the toughness-to-hardness ratio rather than hardness alone. Scaling forms the third subject. As cutting is a branch of elasto-plastic fracture mechanics, cube-square energy scaling applies in which the important length scale is (ER/k (2)), where E is Young's modulus, R is the fracture toughness and k is the shear yield strength. Whether, in cutting, material is removed as ductile ribbons, as semi-ductile discontinuous chips, or by brittle 'knocking lumps out' is shown to depend on the depth of cut relative to this characteristic length parameter. Scaling in biology is called allometry and its relationship with engineering scaling is discussed. Some speculative predictions are made in relation to the action of teeth on food.

  20. Emergence, development, and maturity of the gonad of two species of chitons "sea cockroach" (Mollusca: Polyplacophora) through the early life stages.

    Science.gov (United States)

    Avila-Poveda, Omar Hernando; Abadia-Chanona, Quetzalli Yasú

    2013-01-01

    This study describes and recognises, using histological and microscopical examinations on a morphometrical basis, several gonad traits through the early life stages of Chiton articulatus and C. albolineatus. Gonadal ontogenesis, gonad development stages, sexual differentiation, onset of the first sexual maturity, and growth sequences or "early life stages" were determined. In addition, allometry between lengths and body weight pooled for both sexes per each chiton were calculated using equation Y = aX(b) . A total of 125 chitons (4≤TL≤40 mm, in total length "TL") were used. All allometric relations showed a strong positive correlation (r), close to 1, with b-values above three, indicating an isometric growth. Gonadal ontogenesis and gonad development stages were categorised into three periods ("Pw" without gonad, "Pe" gonad emergence, and "Pf" gonadal sac formed) and four stages ("S0" gametocytogenesis, "S1" gametogenesis, "S2" mature, and "S3" spawning), respectively. Compound digital images were attained for each process. Periods and stages are overlapped among them and between species, with the following overall confidence intervals in TL: Pw 6.13-14.32 mm, Pe 10.32-16.93 mm, Pf 12.99-25.01 mm, S0 16.08-24.34 mm (females) and 19.51-26.60 mm (males), S1 27.15-35.63 mm (females) and 23.45-32.27 mm (males), S2 24.48-40.24 mm (females) and 25.45-32.87 mm (males). Sexual differentiation (in S0) of both chitons occurs first as a female then as a male; although, males reach the onset of the first sexual maturity earlier than females, thus for C. articulatus males at 17 mm and females at 32 mm, and for C. albolineatus males at 23.5 mm and females at 28 mm, all in TL. Four early life stages (i.e., subjuvenile, juvenile, subadult, and adult) are described and proposed to distinguish growth sequences. Our results may be useful to diverse disciplines, from developmental biology to fisheries management.

  1. Characteristics of non-cerebral coenurosis in tropical goats.

    Science.gov (United States)

    Christodoulopoulos, G; Kassab, A; Theodoropoulos, G

    2015-07-30

    observed allometries is not known, but perhaps for evolutionary reasons the parasite is investing its resources more on the growth of scoleces, less on the growth of cyst volume, and even less on the number of clusters. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Final Report: Archiving Data to Support Data Synthesis of DOE Sponsored Elevated CO2 Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Megonigal, James [Smithsonian Environmental Research Center, Edgewater, MD (United States); Lu, Meng [Smithsonian Environmental Research Center, Edgewater, MD (United States)

    2017-09-05

    Over the last three decades DOE made a large investment in field-scale experiments in order to understand the role of terrestrial ecosystems in the global carbon cycle, and forecast how carbon cycling will change over the next century. The Smithsonian Environmental Research Center received one of the first awards in this program and managed two long-term studies (25 years and 10 years) with a total of approximately $10 million of support from DOE, and many more millions leveraged from the Smithsonian Institution and agencies such as NSF. The present DOE grant was based on the premise that such a large investment demands a proper synthesis effort so that the full potential of these experiments are realized through data analysis and modeling. The goal of the this grant was to archive legacy data from two major elevated carbon dioxide experiments in DOE databases, and to engage in synthesis activities using these data. Both goals were met. All datasets deemed a high priority for data synthesis and modeling were prepared for archiving and analysis. Many of these datasets were deposited in DOE’s CDIAC, while others are being held at the Oak Ridge National Lab and the Smithsonian Institution until they can be received by DOE’s new ESS-DIVE system at Berkeley Lab. Most of the effort was invested in researching and re-constituting high-quality data sets from a 30-year elevated CO2 experiment. Using these data, the grant produced products that are already benefiting climate change science, including the publication of new coastal wetland allometry equations based on 9,771 observations, public posting of dozens of datasets, metadata and supporting codes from long-term experiments at the Global Change Research Wetland, and publication of two synthetic data papers on scrub oak forest responses to elevated CO2. In addition, three papers are in review or nearing submission reporting unexpected long-term patterns in ecosystem responses to elevated CO

  3. Assessment of Aboveground Woody Biomass Dynamics Using Terrestrial Laser Scanner and L-Band ALOS PALSAR Data in South African Savanna

    Directory of Open Access Journals (Sweden)

    Victor Onyango Odipo

    2016-11-01

    Full Text Available The use of optical remote sensing data for savanna vegetation structure mapping is hindered by sparse and heterogeneous distribution of vegetation canopy, leading to near-similar spectral signatures among lifeforms. An additional challenge to optical sensors is the high cloud cover and unpredictable weather conditions. Longwave microwave data, with its low sensitivity to clouds addresses some of these problems, but many space borne studies are still limited by low quality structural reference data. Terrestrial laser scanning (TLS derived canopy cover and height metrics can improve aboveground biomass (AGB prediction at both plot and landscape level. To date, few studies have explored the strength of TLS for vegetation structural mapping, and particularly few focusing on savannas. In this study, we evaluate the potential of high resolution TLS-derived canopy cover and height metrics to estimate plot-level aboveground biomass, and to extrapolate to a landscape-wide biomass estimation using multi-temporal L-band Synthetic Aperture Radar (SAR within a 9 km2 area savanna in Kruger National Park (KNP. We inventoried 42 field plots in the wet season and computed AGB for each plot using site-specific allometry. Canopy cover, canopy height, and their product were regressed with plot-level AGB over the TLS-footprint, while SAR backscatter was used to model dry season biomass for the years 2007, 2008, 2009, and 2010 for the study area. The results from model validation showed a significant linear relationship between TLS-derived predictors with field biomass, p < 0.05 and adjusted R2 ranging between 0.56 for SAR to 0.93 for the TLS-derived canopy cover and height. Log-transformed AGB yielded lower errors with TLS metrics compared with non-transformed AGB. An assessment of the backscatter based on root mean square error (RMSE showed better AGB prediction with cross-polarized (RMSE = 6.6 t/ha as opposed to co-polarized data (RMSE = 6.7 t/ha, attributed to

  4. Comparative analysis of vestibular ecomorphology in birds.

    Science.gov (United States)

    Benson, Roger B J; Starmer-Jones, Ethan; Close, Roger A; Walsh, Stig A

    2017-12-01

    The bony labyrinth of vertebrates houses the semicircular canals. These sense rotational accelerations of the head and play an essential role in gaze stabilisation during locomotion. The sizes and shapes of the semicircular canals have hypothesised relationships to agility and locomotory modes in many groups, including birds, and a burgeoning palaeontological literature seeks to make ecological interpretations from the morphology of the labyrinth in extinct species. Rigorous tests of form-function relationships for the vestibular system are required to support these interpretations. We test the hypothesis that the lengths, streamlines and angles between the semicircular canals are related to body size, wing kinematics and flying style in birds. To do this, we applied geometric morphometrics and multivariate phylogenetic comparative methods to a dataset of 64 three-dimensional reconstructions of the endosseous labyrinth obtained using micro-computed tomography scanning of bird crania. A strong relationship between centroid size of the semicircular canals and body size indicates that larger birds have longer semicircular canals compared with their evolutionary relatives. Wing kinematics related to manoeuvrability (and quantified using the brachial index) explain a small additional portion of the variance in labyrinth size. We also find strong evidence for allometric shape change in the semicircular canals of birds, indicating that major aspects of the shape of the avian labyrinth are determined by spatial constraints. The avian braincase accommodates a large brain, a large eye and large semicircular canals compared with other tetrapods. Negative allometry of these structures means that the restriction of space within the braincase is intense in small birds. This may explain our observation that the angles between planes of the semicircular canals of birds deviate more strongly from orthogonality than those of mammals, and especially from agile, gliding and flying

  5. Ecomorphological inferences in early vertebrates: reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi) caudal fin from palaeoecological data.

    Science.gov (United States)

    Ferrón, Humberto G; Martínez-Pérez, Carlos; Botella, Héctor

    2017-01-01

    Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well-ossified endoskeleton in a large number of groups hinder the preservation of complete specimens. Previous reconstructions of most early vertebrates known from partial remains have been wholly based on phylogenetically closely related taxa. However, body design of fishes is determined, to a large extent, by their swimming mode and feeding niche, making it possible to recognise different morphological traits that have evolved several times in non-closely related groups with similar lifestyles. Based on this well-known ecomorphological correlation, here we propose a useful comparative framework established on extant taxa for predicting some anatomical aspects in extinct aquatic vertebrates from palaeoecological data and vice versa. For this, we have assessed the relationship between the locomotory patterns and the morphological variability of the caudal region in extant sharks by means of geometric morphometrics and allometric regression analysis. Multivariate analyses reveal a strong morphological convergence in non-closely related shark species that share similar modes of life, enabling the characterization of the caudal fin morphology of different ecological subgroups. In addition, interspecific positive allometry, affecting mainly the caudal fin span, has been detected. This phenomenon seems to be stronger in sharks with more pelagic habits, supporting its role as a compensation mechanism for the loss of hydrodynamic lift associated with the increase in body size, as previously suggested for many other living and extinct aquatic vertebrates. The quantification of shape change per unit size in each ecological subgroup has allowed us to establish a basis for inferring not only qualitative aspects of the caudal fin

  6. Ecomorphological inferences in early vertebrates: reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi caudal fin from palaeoecological data

    Directory of Open Access Journals (Sweden)

    Humberto G. Ferrón

    2017-12-01

    Full Text Available Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well-ossified endoskeleton in a large number of groups hinder the preservation of complete specimens. Previous reconstructions of most early vertebrates known from partial remains have been wholly based on phylogenetically closely related taxa. However, body design of fishes is determined, to a large extent, by their swimming mode and feeding niche, making it possible to recognise different morphological traits that have evolved several times in non-closely related groups with similar lifestyles. Based on this well-known ecomorphological correlation, here we propose a useful comparative framework established on extant taxa for predicting some anatomical aspects in extinct aquatic vertebrates from palaeoecological data and vice versa. For this, we have assessed the relationship between the locomotory patterns and the morphological variability of the caudal region in extant sharks by means of geometric morphometrics and allometric regression analysis. Multivariate analyses reveal a strong morphological convergence in non-closely related shark species that share similar modes of life, enabling the characterization of the caudal fin morphology of different ecological subgroups. In addition, interspecific positive allometry, affecting mainly the caudal fin span, has been detected. This phenomenon seems to be stronger in sharks with more pelagic habits, supporting its role as a compensation mechanism for the loss of hydrodynamic lift associated with the increase in body size, as previously suggested for many other living and extinct aquatic vertebrates. The quantification of shape change per unit size in each ecological subgroup has allowed us to establish a basis for inferring not only qualitative aspects of

  7. Improving dynamic global vegetation model (DGVM) simulation of western U.S. rangelands vegetation seasonal phenology and productivity

    Science.gov (United States)

    Kerns, B. K.; Kim, J. B.; Day, M. A.; Pitts, B.; Drapek, R. J.

    2017-12-01

    of temperature and precipitation. The algorithm also does not accurately translate simulated carbon stocks into the canopy allometry of woodland tree species that dominate the BME, thereby inaccurately shading out the grasses in the understory. We are devising improvements to these shortcomings in the model architecture.

  8. Illustrating ontogenetic change in the dentition of the Nile monitor lizard, Varanus niloticus: a case study in the application of geometric morphometric methods for the quantification of shape-size heterodonty.

    Science.gov (United States)

    D'Amore, Domenic C

    2015-05-01

    Many recent attempts have been made to quantify heterodonty in non-mammalian vertebrates, but the majority of these are limited to Euclidian measurements. One taxon frequently investigated is Varanus niloticus, the Nile monitor. Juveniles possess elongate, pointed teeth (caniniform) along the entirety of the dental arcade, whereas adults develop large, bulbous distal teeth (molariform). The purpose of this study was to present a geometric morphometric method to quantify V. niloticus heterodonty through ontogeny that may be applied to other non-mammalian taxa. Data were collected from the entire tooth row of 19 dry skull specimens. A semilandmark analysis was conducted on the outline of the photographed teeth, and size and shape were derived. Width was also measured with calipers. From these measures, sample ranges and allometric functions were created using multivariate statistical analyses for each tooth position separately, as well as overall measures of heterodonty for each specimen based on morphological disparity. The results confirm and expand upon previous studies, showing measurable shape-size heterodonty in the species with significant differences at each tooth position. Tooth size increases with body size at most positions, and the allometric coefficient increases at more distal positions. Width shows a dramatic increase at the distal positions with ontogeny, often displaying pronounced positive allometry. Dental shape varied in two noticeable ways, with the first composing the vast majority of shape variance: (i) caniniformy vs. molariformy and (ii) mesially leaning, 'rounded' apices vs. distally leaning, 'pointed' apices. The latter was twice as influential in the mandible, a consequence of host bone shape. Mesial teeth show no significant shape change with growth, whereas distal teeth change significantly due primarily to an increase in molariformy. Overall, heterodonty increases with body size concerning both tooth size and shape, but shape

  9. How much Carbon is Stored in Deserts? AN Approach for the Chilean Atacama Desert Using LANDSAT-8 Products

    Science.gov (United States)

    Hernández, H. J.; Acuña, T.; Reyes, P.; Torres, M.; Figueroa, E.

    2016-06-01

    The Atacama Desert in northern Chile is known as the driest place on Earth, with an average rainfall of about 15 mm per year. Despite these conditions, it contains a rich variety of flora with hundreds of species characterised by their extraordinary ability to adapt to this extreme environment. These biotic components have a direct link to important ecosystem services, especially those related to carbon storage and sequestration. No quantitative assessment is currently available for these services and the role of the desert in this matter remains unclear. We propose an approach to estimate above-ground biomass (AGB) using Landsat-8 data, which we tested in the Taparacá region, located in the northern section of the desert. To calibrate and validate the models, we used field data from 86 plots and several spectral indexes (NDVI, EVI and SAVI) obtained from the provisional Landsat-8 Surface-reflectance products. We applied randomised branch sampling and allometry principles (non-destructive methods) to collect biomass samples for all plant biological types: wetlands, steppes, shrubs and trees. All samples were dried in an oven until they reached constant weight and the final values were used to extrapolate dry matter content (AGB) to each plot in terms of kg m-2. We used all available scenes from September 2014 to August 2015 to calculate the maximum, minimum and average value for each index in each pixel within this period. For modeling, we used the method based on classification and regression trees called random forest (RF), available in the statistical software R-Project. The explained variance obtained by the RF algorithm was around 80-85%, and it improved when a wetland vector layer was used as the predictive factor in the model to reach the range 85-90%. The mean error was 1.45 kg m-2 of dry matter. The best model was obtained using the maximum and mean values of SAVI and EVI indexes. We were able to estimate total biomass storage of around 8 million tons

  10. Making the most of what we have: application of extrapolation approaches in radioecological wildlife transfer models

    International Nuclear Information System (INIS)

    Beresford, Nicholas A.; Wood, Michael D.; Vives i Batlle, Jordi; Yankovich, Tamara L.; Bradshaw, Clare; Willey, Neil

    2016-01-01

    We will never have data to populate all of the potential radioecological modelling parameters required for wildlife assessments. Therefore, we need robust extrapolation approaches which allow us to make best use of our available knowledge. This paper reviews and, in some cases, develops, tests and validates some of the suggested extrapolation approaches. The concentration ratio (CR_p_r_o_d_u_c_t_-_d_i_e_t or CR_w_o_-_d_i_e_t) is shown to be a generic (trans-species) parameter which should enable the more abundant data for farm animals to be applied to wild species. An allometric model for predicting the biological half-life of radionuclides in vertebrates is further tested and generally shown to perform acceptably. However, to fully exploit allometry we need to understand why some elements do not scale to expected values. For aquatic ecosystems, the relationship between log_1_0(a) (a parameter from the allometric relationship for the organism-water concentration ratio) and log(K_d) presents a potential opportunity to estimate concentration ratios using K_d values. An alternative approach to the CR_w_o_-_m_e_d_i_a model proposed for estimating the transfer of radionuclides to freshwater fish is used to satisfactorily predict activity concentrations in fish of different species from three lakes. We recommend that this approach (REML modelling) be further investigated and developed for other radionuclides and across a wider range of organisms and ecosystems. Ecological stoichiometry shows potential as an extrapolation method in radioecology, either from one element to another or from one species to another. Although some of the approaches considered require further development and testing, we demonstrate the potential to significantly improve predictions of radionuclide transfer to wildlife by making better use of available data. - Highlights: • Robust extrapolation approaches allowing best use of available knowledge are needed. • Extrapolation approaches are

  11. Quantifying Biomass from Point Clouds by Connecting Representations of Ecosystem Structure

    Science.gov (United States)

    Hendryx, S. M.; Barron-Gafford, G.

    2017-12-01

    one out cross validation, by 40.6% from deterministic mesquite allometry and 35.9% from the inferred ecosystem-state allometric function. Our framework should allow for the inference of biomass more efficiently than common subplot methods and more accurately than individual tree segmentation methods in densely vegetated environments.

  12. HOW MUCH CARBON IS STORED IN DESERTS? AN APPROACH FOR THE CHILEAN ATACAMA DESERT USING LANDSAT-8 PRODUCTS

    Directory of Open Access Journals (Sweden)

    H. J. Hernández

    2016-06-01

    Full Text Available The Atacama Desert in northern Chile is known as the driest place on Earth, with an average rainfall of about 15 mm per year. Despite these conditions, it contains a rich variety of flora with hundreds of species characterised by their extraordinary ability to adapt to this extreme environment. These biotic components have a direct link to important ecosystem services, especially those related to carbon storage and sequestration. No quantitative assessment is currently available for these services and the role of the desert in this matter remains unclear. We propose an approach to estimate above-ground biomass (AGB using Landsat-8 data, which we tested in the Taparacá region, located in the northern section of the desert. To calibrate and validate the models, we used field data from 86 plots and several spectral indexes (NDVI, EVI and SAVI obtained from the provisional Landsat-8 Surface-reflectance products. We applied randomised branch sampling and allometry principles (non-destructive methods to collect biomass samples for all plant biological types: wetlands, steppes, shrubs and trees. All samples were dried in an oven until they reached constant weight and the final values were used to extrapolate dry matter content (AGB to each plot in terms of kg m-2. We used all available scenes from September 2014 to August 2015 to calculate the maximum, minimum and average value for each index in each pixel within this period. For modeling, we used the method based on classification and regression trees called random forest (RF, available in the statistical software R-Project. The explained variance obtained by the RF algorithm was around 80-85%, and it improved when a wetland vector layer was used as the predictive factor in the model to reach the range 85-90%. The mean error was 1.45 kg m-2 of dry matter. The best model was obtained using the maximum and mean values of SAVI and EVI indexes. We were able to estimate total biomass storage of around 8

  13. Population biology of the mangrove crab Ucides cordatus (Decapoda: Ucididae) in an estuary from semiarid northeastern Brazil.

    Science.gov (United States)

    Leite, Marcos de Miranda Leão; Rezende, Carla Ferreira; Silva, José Roberto Feitosa

    2013-12-01

    The mangrove crab Ucides cordatus is an important resource of estuarine regions along the Brazilian coast. U. cordatus is distributed from Florida, U.S.A., to the coast of Santa Catarina, Brazil. The species plays an important role in processing leaf litter in the mangroves, which optimizes the processes of energy transfer and nutrient cycling, and is considered a keystone species in the ecosystem. Population declines have been reported in different parts of the Brazilian coast. In the present study we evaluated aspects of the population structure, sex ratio and size at morphological sexual maturity. We analyzed 977 specimens collected monthly over 24 months (2010-2012), in a mangrove of the Jaguaribe River, in the municipality of Aracati on the East coast of Ceará state, Northeastern Brazil. The study area has a mild semiarid tropical climate, with mean temperatures between 26 and 28 degrees C. The area is located within the eco-region of the semiarid Northeast coast, where mangroves occur in small areas and estuaries are affected by mesomareal regimes. The population structure was evaluated by the frequency distribution of size classes in each month, and the overall sex ratio was analyzed using the chi-square test. Size at morphological sexual maturity was estimated based on the allometry of the cheliped of the males and the abdomen width of the females, using the program REGRANS. The size-frequency distribution was unimodal in both sexes. The overall sex ratio (M:F) (1:0.6) was significantly different from 1:1. Analysis of the sex ratio by size class showed that the proportion of males increased significantly from size class 55-60 mm upward, and this pattern persisted in the larger size classes. In the smaller size classes the sex ratio did not differ from 1:1. The size at morphological sexual maturity was estimated at a carapace width (CW) of 52 mm and 45 mm for males and females, respectively. Analysis of the population parameters indicated that the

  14. The relationship between body mass and field metabolic rate among individual birds and mammals.

    Science.gov (United States)

    Hudson, Lawrence N; Isaac, Nick J B; Reuman, Daniel C

    2013-09-01

    are consistent with the heat dissipation theory of Speakman & Król (2010) and provided some support for the metabolic levels boundary hypothesis of Glazier (2010). 5. Our analysis provides the first comprehensive empirical analysis of the scaling relationship between field metabolic rate and body mass in individual birds and mammals. Our data set is a valuable contribution to those interested in theories of the allometry of metabolic rates. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

  15. Plant hydraulic controls over ecosystem responses to climate-enhanced disturbances

    Science.gov (United States)

    Mackay, D. S.; Ewers, B. E.; Reed, D. E.; Pendall, E.; McDowell, N. G.

    2012-12-01

    Climate-enhanced disturbances such as drought and insect infestation range in severity, contributing minor to severe stress to forests including forest mortality. While neither form of disturbance has been unambiguously implicated as a mechanism of mortality, both induce changes in water, carbon, and nutrient cycling that are key to understanding forest ecosystem response to, and recovery from, disturbance. Each disturbance type has different biophysical, ecohydrological, and biogeochemical signatures that potentially complicate interpretation and development of theory. Plant hydraulic function is arguably a unifying control over these responses to disturbance because it regulates stomatal conductance, leaf biochemistry, carbon (C) uptake and utilization, and nutrient cycling. We demonstrated this idea by focusing on water and C, including non-structural (NSC), resources, and nitrogen (N) uptake across a spectrum of forest ecosystems (e.g., northern temperate mixed forests, lodgepole pine forests in the Rocky Mountains, and pinon pine - juniper woodlands in New Mexico) using the Terrestrial Regional Ecosystem Exchange Simulator (TREES). TREES is grounded in the biophysics of water movement through soil and plants, respectively via hydraulic conductivity of the soil and cavitation of xylem. It combines this dynamic plant hydraulic conductance with canopy biochemical controls over photosynthesis, and the dynamics of structural and non-structural carbon through a carbon budget that responds to plant hydraulic status. As such, the model can be used to develop testable hypotheses on a multitude of disturbance and recovery responses including xylem dysfunction, stomatal and non-stomatal controls on photosynthesis and carbon allocation, respiration, and allocation to defense compounds. For each of the ecosystems we constrained and evaluated the model with allometry, sap flux and/or eddy covariance data, leaf gas exchange measurements, and vulnerability to cavitation data

  16. [Effects of selective cutting on the carbon density and net primary productivity of a mixed broadleaved-Korean pine forest in Northeast China].

    Science.gov (United States)

    Liu, Qi; Cai, Hui-Ying; Jin, Guang-Ze

    2013-10-01

    To accurately quantify forest carbon density and net primary productivity (NPP) is of great significance in estimating the role of forest ecosystems in global carbon cycle. By using the forest inventory and allometry approaches, this paper measured the carbon density and NPP of the virgin broadleaved-Korean pine (Pinus koraiensis) forest and of the broadleaved-Korean pine forest after 34 years selective-cutting (the cutting intensity was 30%, and the cutting trees were in large diameter class). The total carbon density of the virgin and selective-cutting broadleaved-Korean pine forests was (397.95 +/- 93.82) and (355.61 +/- 59.37) t C x hm(-2), respectively. In the virgin forest, the carbon density of the vegetation, debris, and soil accounted for 31.0%, 3.1%, and 65.9% of the total carbon pool, respectively; in the selective-cutting forest, the corresponding values were 31.7%, 2.9%, and 65.4%, respectively. No significant differences were observed in the total carbon density and the carbon density of each component between the two forests. The total NPP of the virgin and selective-cutting forests was (36.27 +/- 0.36) and (6.35 +/- 0.70) t C x hm(-2) x a(-1), among which, the NPP of overstory, understory, and fine roots in virgin forest and selective-cutting forest accounted for 60.3%, 2.0%, and 37.7%, and 66.1%, 2.0%, and 31.2%, respectively. No significant differences were observed in the total NPP and the contribution rate of each component between the two forests. However, the ratios of the needle and broadleaf NPPs of the virgin and selective-cutting forests were 47.24:52.76 and 20.48:79.52, respectively, with a significant difference. The results indicated that the carbon density and NPP of the broadleaved-Korean pine forest after 34 years selective-cutting recovered to the levels of the virgin broadleaved-Korean pine forest.

  17. Masticatory form and function in the African apes.

    Science.gov (United States)

    Taylor, Andrea B

    2002-02-01

    This study examines variability in masticatory morphology as a function of dietary preference among the African apes. The African apes differ in the degree to which they consume leaves and other fibrous vegetation. Gorilla gorilla beringei, the eastern mountain gorilla, consumes the most restricted diet comprised of mechanically resistant foods such as leaves, pith, bark, and bamboo. Gorilla gorilla gorilla, the western lowland gorilla subspecies, consumes leaves and other terrestrial herbaceous vegetation (THV) but also consumes a fair amount of ripe, fleshy fruit. In contrast to gorillas, chimpanzees are frugivores and rely on vegetation primarily as fallback foods. However, there has been a long-standing debate regarding whether Pan paniscus, the pygmy chimpanzee (or bonobo), consumes greater quantities of THV as compared to Pan troglodytes, the common chimpanzee. Because consumption of resistant foods involves more daily chewing cycles and may require larger average bite force, the mechanical demands placed on the masticatory system are expected to be greater in folivores as compared to primates that consume large quantities of fleshy fruit. Therefore, more folivorous taxa are predicted to exhibit features that improve load-resistance capabilities and increase force production. To test this hypothesis, jaw and skull dimensions were compared in ontogenetic series of G. g. beringei, G. g. gorilla, P. t. troglodytes, and P. paniscus. Controlling for the influence of allometry, results show that compared to both chimpanzees and bonobos, gorillas exhibit some features of the jaw complex that are suggestive of improved masticatory efficiency. For example, compared to all other taxa, G. g. beringei has a significantly wider mandibular corpus and symphysis, larger area for the masseter muscle, higher mandibular ramus, and higher mandibular condyle relative to the occlusal plane of the mandible. However, the significantly wider mandibular symphysis may be an

  18. The bony labyrinth of the middle Pleistocene Sima de los Huesos hominins (Sierra de Atapuerca, Spain).

    Science.gov (United States)

    Quam, Rolf; Lorenzo, Carlos; Martínez, Ignacio; Gracia-Téllez, Ana; Arsuaga, Juan Luis

    2016-01-01

    fully resolved, the low placement of the posterior canal in Neandertals may be related to some combination of absolutely large brain size, a wide cranial base, and an archaic pattern of brain allometry. This more general explanation would not necessarily follow taxonomic lines, even though this morphology of the bony labyrinth occurs at high frequencies among Neandertals. While a functional interpretation of the relatively small vertical canals in the Neandertal clade remains elusive, the relative proportions of the semicircular canals is one of several derived Neandertal features in the Atapuerca (SH) crania. Examination of additional European middle Pleistocene specimens suggests that the full suite of Neandertal features in the bony labyrinth did not emerge in Europe until perhaps <200 kya. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Preclinical pharmacokinetics, interspecies scaling, and pharmacokinetics of a Phase I clinical trial of TTAC-0001, a fully human monoclonal antibody against vascular endothelial growth factor 2

    Directory of Open Access Journals (Sweden)

    Lee WS

    2018-03-01

    , allometry, clearance, biodistribution

  20. Making the most of what we have: application of extrapolation approaches in wildlife transfer models

    Energy Technology Data Exchange (ETDEWEB)

    Beresford, Nicholas A.; Barnett, Catherine L.; Wells, Claire [NERC Centre for Ecology and Hydrology, Lancaster Environment Center, Library Av., Bailrigg, Lancaster, LA1 4AP (United Kingdom); School of Environment and Life Sciences, University of Salford, Manchester, M4 4WT (United Kingdom); Wood, Michael D. [School of Environment and Life Sciences, University of Salford, Manchester, M4 4WT (United Kingdom); Vives i Batlle, Jordi [Belgian Nuclear Research Centre, Boeretang 200, 2400 Mol (Belgium); Brown, Justin E.; Hosseini, Ali [Norwegian Radiation Protection Authority, P.O. Box 55, N-1332 Oesteraas (Norway); Yankovich, Tamara L. [International Atomic Energy Agency, Vienna International Centre, 1400, Vienna (Austria); Bradshaw, Clare [Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-10691 (Sweden); Willey, Neil [Centre for Research in Biosciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY (United Kingdom)

    2014-07-01

    Radiological environmental protection models need to predict the transfer of many radionuclides to a large number of organisms. There has been considerable development of transfer (predominantly concentration ratio) databases over the last decade. However, in reality it is unlikely we will ever have empirical data for all the species-radionuclide combinations which may need to be included in assessments. To provide default values for a number of existing models/frameworks various extrapolation approaches have been suggested (e.g. using data for a similar organism or element). This paper presents recent developments in two such extrapolation approaches, namely phylogeny and allometry. An evaluation of how extrapolation approaches have performed and the potential application of Bayesian statistics to make best use of available data will also be given. Using a Residual Maximum Likelihood (REML) mixed-model regression we initially analysed a dataset comprising 597 entries for 53 freshwater fish species from 67 sites to investigate if phylogenetic variation in transfer could be identified. The REML analysis generated an estimated mean value for each species on a common scale after taking account of the effect of the inter-site variation. Using an independent dataset, we tested the hypothesis that the REML model outputs could be used to predict radionuclide activity concentrations in other species from the results of a species which had been sampled at a specific site. The outputs of the REML analysis accurately predicted {sup 137}Cs activity concentrations in different species of fish from 27 lakes. Although initially investigated as an extrapolation approach the output of this work is a potential alternative to the highly site dependent concentration ratio model. We are currently applying this approach to a wider range of organism types and different ecosystems. An initial analysis of these results will be presented. The application of allometric, or mass

  1. Life-history and ecological correlates of geographic variation in egg and clutch mass among passerine species

    Science.gov (United States)

    Martin, T.E.; Bassar, R.D.; Bassar, S.K.; Fontaine, J.J.; Lloyd, P.; Mathewson, Heather A.; Niklison, Alina M.; Chalfoun, A.

    2006-01-01

    Broad geographic patterns in egg and clutch mass are poorly described, and potential causes of variation remain largely unexamined. We describe interspecific variation in avian egg and clutch mass within and among diverse geographic regions and explore hypotheses related to allometry, clutch size, nest predation, adult mortality, and parental care as correlates and possible explanations of variation. We studied 74 species of Passeriformes at four latitudes on three continents: the north temperate United States, tropical Venezuela, subtropical Argentina, and south temperate South Africa. Egg and clutch mass increased with adult body mass in all locations, but differed among locations for the same body mass, demonstrating that egg and clutch mass have evolved to some extent independent of body mass among regions. A major portion of egg mass variation was explained by an inverse relationship with clutch size within and among regions, as predicted by life-history theory. However, clutch size did not explain all geographic differences in egg mass; eggs were smallest in South Africa despite small clutch sizes. These small eggs might be explained by high nest predation rates in South Africa; life-history theory predicts reduced reproductive effort under high risk of offspring mortality. This prediction was supported for clutch mass, which was inversely related to nest predation but not for egg mass. Nevertheless, clutch mass variation was not fully explained by nest predation, possibly reflecting interacting effects of adult mortality. Tests of the possible effects of nest predation on egg mass were compromised by limited power and by counterposing direct and indirect effects. Finally, components of parental investment, defined as effort per offspring, might be expected to positively coevolve. Indeed, egg mass, but not clutch mass, was greater in species that shared incubation by males and females compared with species in which only females incubate eggs. However, egg and

  2. Body mass and body weight: a dual reference system in biology Masa y peso corporales: un sistema dual de referencia en biología

    Directory of Open Access Journals (Sweden)

    BRUNO GÜNTHER

    2003-03-01

    Full Text Available ABSTRACT The aim of the present study was to compare two different biological similarity criteria, one was based on body mass (M as a theoretical reference system in accordance with the MLT-system of physics, while the other utilized the body weight (W for the same purpose. The mass-dependent allometry should be applied during space flights as well as during fetal and newborn conditions of life, whereas the weight-dependence should prevail in earth-bound physiology. The above mentioned distinctions are relevant not only for the specific metabolic rates but also for numerous biological time functions, as for instance for the heart and respiratory rates of all mammals, whose allometric exponent is b = - 0.09 during fetal life, and b = - 0.25 in all adult specimens.El objetivo del presente trabajo fue la comparación de dos diferentes criterios de similitud, uno basado en la masa corporal (M como sistema teórico de referencia de acuerdo con el sistema MLT de la Física, en tanto que el otro utilizó el peso corporal (W con este mismo propósito. La alometría dependiente de la masa debería aplicarse durante los vuelos espaciales así como durante la vida fetal y la condición de recién nacido, en tanto que la dependencia del peso debe prevalecer en la fisiología terrestre. La distinción antes mencionada es relevante, no sólo para el metabolismo específico y también para numerosas funciones biológicas en relación con funciones de tiempo, como ser con las frecuencias cardiaca y respiratoria de todos los mamíferos cuyo exponente alométrico es b = - 0,09 durante la vida fetal, y b = - 0,25 en todos los especimenes adultos.

  3. An Allometric Analysis of Sex and Sex Chromosome Dosage Effects on Subcortical Anatomy in Humans

    Science.gov (United States)

    Clasen, Liv; Giedd, Jay N.; Blumenthal, Jonathan; Lerch, Jason P.; Chakravarty, M. Mallar; Raznahan, Armin

    2016-01-01

    , regional brain allometry (nonlinear scaling) poses largely unaddressed methodological and theoretical challenges for such research. We build the first set of allometric norms for global and regional subcortical anatomy, and use these to dissect out the complex, distributed and topologically organized patterns of areal contraction and expansion, which characterize sex and SCD effects on subcortical anatomy. Our data inform basic research into the patterning of neuroanatomical variation, and the clinical neuroscience of sex-chromosome aneuploidy. PMID:26911691

  4. A new approach for the analysis of facial growth and age estimation: Iris ratio

    Science.gov (United States)

    Machado, Carlos Eduardo Palhares; Flores, Marta Regina Pinheiro; Lima, Laíse Nascimento Correia; Tinoco, Rachel Lima Ribeiro; Bezerra, Ana Cristina Barreto; Evison, Martin Paul; Guimarães, Marco Aurélio

    2017-01-01

    The study of facial growth is explored in many fields of science, including anatomy, genetics, and forensics. In the field of forensics, it acts as a valuable tool for combating child pornography. The present research proposes a new method, based on relative measurements and fixed references of the human face—specifically considering measurements of the diameter of the iris (iris ratio)—for the analysis of facial growth in association with age in children and sub-adults. The experimental sample consisted of digital photographs of 1000 Brazilian subjects, aged between 6 and 22 years, distributed equally by sex and divided into five specific age groups (6, 10, 14, 18, and 22 year olds ± one month). The software package SAFF-2D® (Forensic Facial Analysis System, Brazilian Federal Police, Brazil) was used for positioning 11 landmarks on the images. Ten measurements were calculated and used as fixed references to evaluate the growth of the other measurements for each age group, as well the accumulated growth (6–22 years old). The Intraclass Correlation Coefficient (ICC) was applied for the evaluation of intra-examiner and inter-examiner reliability within a specific set of images. Pearson’s Correlation Coefficient was used to assess the association between each measurement taken and the respective age groups. ANOVA and Post-hoc Tukey tests were used to search for statistical differences between the age groups. The outcomes indicated that facial structures grow with different timing in children and adolescents. Moreover, the growth allometry expressed in this study may be used to understand what structures have more or less proportional variation in function for the age ranges studied. The diameter of the iris was found to be the most stable measurement compared to the others and represented the best cephalometric measurement as a fixed reference for facial growth ratios (or indices). The method described shows promising potential for forensic applications

  5. Emergence, development, and maturity of the gonad of two species of chitons "sea cockroach" (Mollusca: Polyplacophora through the early life stages.

    Directory of Open Access Journals (Sweden)

    Omar Hernando Avila-Poveda

    Full Text Available This study describes and recognises, using histological and microscopical examinations on a morphometrical basis, several gonad traits through the early life stages of Chiton articulatus and C. albolineatus. Gonadal ontogenesis, gonad development stages, sexual differentiation, onset of the first sexual maturity, and growth sequences or "early life stages" were determined. In addition, allometry between lengths and body weight pooled for both sexes per each chiton were calculated using equation Y = aX(b . A total of 125 chitons (4≤TL≤40 mm, in total length "TL" were used. All allometric relations showed a strong positive correlation (r, close to 1, with b-values above three, indicating an isometric growth. Gonadal ontogenesis and gonad development stages were categorised into three periods ("Pw" without gonad, "Pe" gonad emergence, and "Pf" gonadal sac formed and four stages ("S0" gametocytogenesis, "S1" gametogenesis, "S2" mature, and "S3" spawning, respectively. Compound digital images were attained for each process. Periods and stages are overlapped among them and between species, with the following overall confidence intervals in TL: Pw 6.13-14.32 mm, Pe 10.32-16.93 mm, Pf 12.99-25.01 mm, S0 16.08-24.34 mm (females and 19.51-26.60 mm (males, S1 27.15-35.63 mm (females and 23.45-32.27 mm (males, S2 24.48-40.24 mm (females and 25.45-32.87 mm (males. Sexual differentiation (in S0 of both chitons occurs first as a female then as a male; although, males reach the onset of the first sexual maturity earlier than females, thus for C. articulatus males at 17 mm and females at 32 mm, and for C. albolineatus males at 23.5 mm and females at 28 mm, all in TL. Four early life stages (i.e., subjuvenile, juvenile, subadult, and adult are described and proposed to distinguish growth sequences. Our results may be useful to diverse disciplines, from developmental biology to fisheries management.

  6. Root biomechanics in Rhizophora mangle: anatomy, morphology and ecology of mangrove’s flying buttresses

    Science.gov (United States)

    Méndez-Alonzo, Rodrigo; Moctezuma, Coral; Ordoñez, Víctor R.; Angeles, Guillermo; Martínez, Armando J.; López-Portillo, Jorge

    2015-01-01

    Background and Aims Rhizophora species of mangroves have a conspicuous system of stilt-like roots (rhizophores) that grow from the main stem and resemble flying buttresses. As such, the development of rhizophores can be predicted to be important for the effective transmission of dynamic loads from the top of the tree to the ground, especially where the substrate is unstable, as is often the case in the habitats where Rhizophora species typically grow. This study tests the hypothesis that rhizophore architecture in R. mangle co-varies with their proximity to the main stem, and with stem size and crown position. Methods The allometry and wood mechanical properties of R. mangle (red mangrove) trees growing in a mangrove basin forest within a coastal lagoon in Mexico were compared with those of coexisting, non-buttressed mangrove trees of Avicennia germinans. The anatomy of rhizophores was related to mechanical stress due to crown orientation (static load) and to prevailing winds (dynamic load) at the study site. Key Results Rhizophores buttressed between 10 and 33 % of tree height. There were significant and direct scaling relationships between the number, height and length of rhizophores vs. basal area, tree height and crown area. Wood mechanical resistance was significantly higher in the buttressed R. mangle (modulus of elasticity, MOE = 18·1 ± 2 GPa) than in A. germinans (MOE = 12·1 ± 0·5 GPa). Slenderness ratios (total height/stem diameter) were higher in R. mangle, but there were no interspecies differences in critical buckling height. When in proximity to the main stem, rhizophores had a lower length/height ratio, higher eccentricity and higher xylem/bark and pith proportions. However, there were no directional trends with regard to prevailing winds or tree leaning. Conclusions In comparison with A. germinans, a tree species with wide girth and flare at the base, R. mangle supports a thinner stem of higher mechanical resistance that is

  7. A comparative analysis of temporomandibular joint morphology in the African apes.

    Science.gov (United States)

    Taylor, Andrea B

    2005-06-01

    ramal and condylar heights do not result from the simple extrapolation of common growth allometries relative to jaw length. As such, they are suggestive of an adaptive shift towards a tougher, more folivorous diet. However, the allometric patterning for condylar area and condylar width does not systematically conform to predictions based on dietary specialization. Thus, while differences in condylar shapes may confer functional advantages both during growth and as adults, there is no evidence to suggest selection for altered condylar proportions, independent of the effects of changes in jaw size.

  8. Below-ground biomass production and allometric relationships of eucalyptus coppice plantation in the central highlands of Madagascar

    International Nuclear Information System (INIS)

    Razakamanarivo, Ramarson H.; Razakavololona, Ando; Razafindrakoto, Marie-Antoinette; Vieilledent, Ghislain; Albrecht, Alain

    2012-01-01

    Short rotations of Eucalyptus plantations under coppice regime are extensively managed for wood production in Madagascar. Nevertheless, little is known about their biomass production and partitioning and their potential in terms of carbon sequestration. If above-ground biomass (AGB) can be estimated based on established allometric relations, below-ground (BGB) estimates are much less common. The aim of this work was to develop allometric equations to estimate biomass of these plantations, mainly for the root components. Data from 9 Eucalyptus robusta stands (47–87 years of plantation age, 3–5 years of coppice-shoot age) were collected and analyzed. Biomass of 3 sampled trees per stand was determined destructively. Dry weight of AGB components (leaves, branches and stems) were estimated as a function of basal area of all shoots per stump and dry weight for BGB components (mainly stump, coarse root (CR) and medium root (MR)) were estimated as a function of stump circumference. Biomass was then computed using allometric equations from stand inventory data. Stand biomass ranged from 102 to 130 Mg ha −1 with more than 77% contained in the BGB components. The highest dry weight was allocated in the stump and in the CR (51% and 42% respectively) for BGB parts and in the stem (69%) for AGB part. Allometric relationships developed herein could be applied to other Eucalyptus plantations which present similar stand density and growing conditions; anyhow, more is needed to be investigated in understanding biomass production and partitioning over time for this kind of forest ecosystem. -- Highlights: ► We studied the potential of old eucalyptus coppices in Madagascar to mitigate global warming. ► Biomass measurement, mainly for below-ground BGB (stump, coarse-medium-and fine roots) was provided. ► BGB allometry relationships for short rotation forestry under coppice were established. ► BGB were found to be important with their 102-130MgC ha -1 (<77% of the C in

  9. Extensive Sampling of Forest Carbon using High Density Power Line Lidar

    Science.gov (United States)

    Hampton, H. M.; Chen, Q.; Dye, D. G.; Hungate, B. A.

    2013-12-01

    unmanaged areas, using high point density lidar collected over transmission line corridors. The lidar metric of quadratic mean height guided our selection of field plots spanning the full range from low to high levels of aboveground biomass across the study region. Before model selection, we minimized two of the major sources of errors in lidar calibration: variance in tree allometry across landscapes and plot edge effects (spatial mismatch between field measurements and lidar points). We tested an assortment of model selection techniques and goodness of fit measures for deriving forest structural metrics of interest. For example, we obtained an R-squared value for aboveground biomass (Mg/ha) of 0.9 using stepwise regression. The forest metrics obtained are being used in the next stage of the project to parameterize biogeochemical models linking terrestrial carbon pools and atmospheric greenhouse gas exchanges.

  10. Anatomy, feeding ecology, and ontogeny of a transitional baleen whale: a new genus and species of Eomysticetidae (Mammalia: Cetacea) from the Oligocene of New Zealand

    Science.gov (United States)

    Fordyce, R. Ewan

    2015-01-01

    The Eocene history of cetacean evolution is now represented by the expansive fossil record of archaeocetes elucidating major morphofunctional shifts relating to the land to sea transition, but the change from archaeocetes to modern cetaceans is poorly established. New fossil material of the recently recognized family Eomysticetidae from the upper Oligocene Otekaike Limestone includes a new genus and species, Waharoa ruwhenua, represented by skulls and partial skeletons of an adult, juvenile, and a smaller juvenile. Ontogenetic status is confirmed by osteohistology of ribs. Waharoa ruwhenua is characterized by an elongate and narrow rostrum which retains vestigial alveoli and alveolar grooves. Palatal foramina and sulci are present only on the posterior half of the palate. The nasals are elongate, and the bony nares are positioned far anteriorly. Enormous temporal fossae are present adjacent to an elongate and narrow intertemporal region with a sharp sagittal crest. The earbones are characterized by retaining inner and outer posterior pedicles, lacking fused posterior processes, and retaining a separate accessory ossicle. Phylogenetic analysis supports inclusion of Waharoa ruwhenua within a monophyletic Eomysticetidae as the earliest diverging clade of toothless mysticetes. This eomysticetid clade also included Eomysticetus whitmorei, Micromysticetus rothauseni, Tohoraata raekohao, Tokarahia kauaeroa, Tokarahia lophocephalus, and Yamatocetus canaliculatus. Detailed study of ontogenetic change demonstrates postnatal elaboration of the sagittal and nuchal crests, elongation of the intertemporal region, inflation of the zygomatic processes, and an extreme proportional increase in rostral length. Tympanic bullae are nearly full sized during early postnatal ontogeny indicating precocial development of auditory structures, but do increase slightly in size. Positive allometry of the rostrum suggests an ontogenetic change in feeding ecology, from neonatal suckling to a more

  11. Allometric Scaling and Resource Limitations Model of Total Aboveground Biomass in Forest Stands: Site-scale Test of Model

    Science.gov (United States)

    CHOI, S.; Shi, Y.; Ni, X.; Simard, M.; Myneni, R. B.

    2013-12-01

    Sparseness in in-situ observations has precluded the spatially explicit and accurate mapping of forest biomass. The need for large-scale maps has raised various approaches implementing conjugations between forest biomass and geospatial predictors such as climate, forest type, soil property, and topography. Despite the improved modeling techniques (e.g., machine learning and spatial statistics), a common limitation is that biophysical mechanisms governing tree growth are neglected in these black-box type models. The absence of a priori knowledge may lead to false interpretation of modeled results or unexplainable shifts in outputs due to the inconsistent training samples or study sites. Here, we present a gray-box approach combining known biophysical processes and geospatial predictors through parametric optimizations (inversion of reference measures). Total aboveground biomass in forest stands is estimated by incorporating the Forest Inventory and Analysis (FIA) and Parameter-elevation Regressions on Independent Slopes Model (PRISM). Two main premises of this research are: (a) The Allometric Scaling and Resource Limitations (ASRL) theory can provide a relationship between tree geometry and local resource availability constrained by environmental conditions; and (b) The zeroth order theory (size-frequency distribution) can expand individual tree allometry into total aboveground biomass at the forest stand level. In addition to the FIA estimates, two reference maps from the National Biomass and Carbon Dataset (NBCD) and U.S. Forest Service (USFS) were produced to evaluate the model. This research focuses on a site-scale test of the biomass model to explore the robustness of predictors, and to potentially improve models using additional geospatial predictors such as climatic variables, vegetation indices, soil properties, and lidar-/radar-derived altimetry products (or existing forest canopy height maps). As results, the optimized ASRL estimates satisfactorily

  12. Macromorfometría de juveniles de Geochelone sulcata (Testudines: Testudinidaeen Costa Rica

    Directory of Open Access Journals (Sweden)

    Manuel Merchán

    2005-06-01

    Full Text Available Se midieron 31 ejemplares de tortuga africana de espolones Geochelone sulcata para la realización de un estudio biométrico. Se consideraron 26 medidas morfológicas para cada individuo. Las tortugas tenían una edad de entre 5 y 34 meses, y ninguna había alcanzado la madurez sexual. Todas ellas habían nacido en cautiverio en La Garita de Alajuela, Costa Rica, donde son una especie introducida. La longitud recta del espaldar fue de 83.1 mm, la anchura recta del espaldar de 68.3 mm y la altura máxima media de 46.2 mm. Todas las medidas estaban correlacionadas entre sí, salvo la longitud de la cola y la distancia cloacal. El mayor coeficiente de alometría positiva correspondió a la variable Peso. El mayor coeficiente de alometría negativa correspondió a la anchura a nivel de los escudos gulares. Todas las variables se agruparon en dos componentes principales, la longitud de la cola y la distancia cloacal en el Factor 2 y el resto en el Factor 1. La falta de correlación de las medidas de la cola así como su inclusión en un factor aparte al resto de la muestra podría responder a un proceso incipiente de diferenciación sexualGross morphometry of young Geochelone sulcata (Testudines: Testudinidae in Costa Rica. The African Spur tortoise, Geochelone sulcata, has been introduced to Costa Rica. A total of 31 tortoises were measured for 26 gross morphometry parameters. All individuals measured were inmature, aged from 5 to 34 months, and were born in captivity in La Garita de Alajuela, Costa Rica. Mean straight carapace length was 83.1 mm, mean straight plastron length was 68.3 mm and mean maximum height was 46.2 mm. All the measurements were correlated, except tail length and cloacal distance. Weight had the highest positive allometry coefficient. All the variables were joined in two Principal Components; tail length and cloacal distance in Factor 2 and the rest of them in Factor 1. Lack of correlation among tail measures and the other

  13. Comparative cranial ontogeny of Tapirus (Mammalia: Perissodactyla: Tapiridae).

    Science.gov (United States)

    Moyano, S Rocio; Giannini, Norberto P

    2017-11-01

    dentition, and correlated changes in diastemata, mandibular body, and sagittal and nuchal crests. In the nasal region, ontogenetic remodeling affected the space for the meatal diverticulum and the surfaces for the origin of the proboscis musculature. Overall, ontogenetic trajectories exhibited more negative allometric components in T. indicus than in T. terrestris, and they shared 47.83% of allometric trends. Tapirus indicus differed most significantly from T. terrestris in the allometry of postcanine toothrows, diastemata and mandibular body. Thus, some allometric trends seem to be highly conserved among the species studied, and the changes observed showed a strong functional and likely adaptive basis in this lineage of ungulates. © 2017 Anatomical Society.

  14. Toward Understanding the Mammalian Zygoma: Insights From Comparative Anatomy, Growth and Development, and Morphometric Analysis.

    Science.gov (United States)

    Márquez, Samuel; Pagano, Anthony S; Schwartz, Jeffrey H; Curtis, Abigail; Delman, Bradley N; Lawson, William; Laitman, Jeffrey T

    2017-01-01

    The zygoma, or jugum, is a cranial element that was present in Mesozoic tetrapods, well before the appearance of mammals. Although as an entity the zygoma is a primitive retention among mammals, it has assumed myriad configurations as this group diversified. As the zygoma is located at the intersection of the visual, respiratory, and masticatory apparatuses, it is potentially of great importance in systematic, phylogenetic, and functional studies focused on this region. For example, the facial component of the zygoma and its contribution to a postorbital bar (POB) appear to be relevant to the systematics of a number of mammalian subclades, and the formation of a bony postorbital septum (POS) that separates the orbit from the infratemporal fossa is unique to, and thus potentially phylogenetically significant for uniting anthropoid primates, while the zygoma itself appears to serve to resist tension and bending forces during mastication. In order to better understand the zygoma in the context of its contributions to the circumorbital region, we documented its morphological expression in specimens representing 10 orders of mammals. Since the presence of a POB and of a POS has long been used to justify uniting extant primates and anthropoid primates as respective clades, and because postorbital closure (POC) is morphologically more complex than a POB, we provide detail necessary to address these claims. Our taxically broad overview also allowed us to provide for the first time definitions of configurations that can be applied to future studies. Using a different, but also taxically broad sample of mammals, and of primates in particular, we performed two geometric morphometric analyses that were geared toward testing long-held interpretations of the functional role of the zygoma, especially with regard to mastication and in the context of orbital frontation (to which the zygoma contributes). Further, overall, zygomatic morphology tends not to scale with allometry

  15. Above-ground woody biomass allocation and within tree carbon and nutrient distribution of wild cherry (Prunus avium L. – a case study

    Directory of Open Access Journals (Sweden)

    Christopher Morhart

    2016-02-01

    strongly supports the idea of the inclusion of wild cherry within agroforestry systems as an option for carbon sequestration. Keywords: Carbon sequestration, Biomass, Bark, Branch, Stem, Nutrient content, Allometry, Agroforestry

  16. Alligators and Crocodiles Have High Paracellular Absorption of Nutrients, But Differ in Digestive Morphology and Physiology.

    Science.gov (United States)

    Tracy, Christopher R; McWhorter, Todd J; Gienger, C M; Starck, J Matthias; Medley, Peter; Manolis, S Charlie; Webb, Grahame J W; Christian, Keith A

    2015-12-01

    Much of what is known about crocodilian nutrition and growth has come from animals propagated in captivity, but captive animals from the families Crocodilidae and Alligatoridae respond differently to similar diets. Since there are few comparative studies of crocodilian digestive physiology to help explain these differences, we investigated young Alligator mississippiensis and Crocodylus porosus in terms of (1) gross and microscopic morphology of the intestine, (2) activity of the membrane-bound digestive enzymes aminopeptidase-N, maltase, and sucrase, and (3) nutrient absorption by carrier-mediated and paracellular pathways. We also measured gut morphology of animals over a larger range of body sizes. The two species showed different allometry of length and mass of the gut, with A. mississippiensis having a steeper increase in intestinal mass with body size, and C. porosus having a steeper increase in intestinal length with body size. Both species showed similar patterns of magnification of the intestinal surface area, with decreasing magnification from the proximal to distal ends of the intestine. Although A. mississippiensis had significantly greater surface-area magnification overall, a compensating significant difference in gut length between species meant that total surface area of the intestine was not significantly different from that of C. porosus. The species differed in enzyme activities, with A. mississippiensis having significantly greater ability to digest carbohydrates relative to protein than did C. porosus. These differences in enzyme activity may help explain the differences in performance between the crocodilian families when on artificial diets. Both A. mississippiensis and C. porosus showed high absorption of 3-O methyl d-glucose (absorbed via both carrier-mediated and paracellular transport), as expected. Both species also showed surprisingly high levels of l-glucose-uptake (absorbed paracellularly), with fractional absorptions as high as those

  17. Root biomechanics in Rhizophora mangle: anatomy, morphology and ecology of mangrove's flying buttresses.

    Science.gov (United States)

    Méndez-Alonzo, Rodrigo; Moctezuma, Coral; Ordoñez, Víctor R; Angeles, Guillermo; Martínez, Armando J; López-Portillo, Jorge

    2015-04-01

    Rhizophora species of mangroves have a conspicuous system of stilt-like roots (rhizophores) that grow from the main stem and resemble flying buttresses. As such, the development of rhizophores can be predicted to be important for the effective transmission of dynamic loads from the top of the tree to the ground, especially where the substrate is unstable, as is often the case in the habitats where Rhizophora species typically grow. This study tests the hypothesis that rhizophore architecture in R. mangle co-varies with their proximity to the main stem, and with stem size and crown position. The allometry and wood mechanical properties of R. mangle (red mangrove) trees growing in a mangrove basin forest within a coastal lagoon in Mexico were compared with those of coexisting, non-buttressed mangrove trees of Avicennia germinans. The anatomy of rhizophores was related to mechanical stress due to crown orientation (static load) and to prevailing winds (dynamic load) at the study site. Rhizophores buttressed between 10 and 33 % of tree height. There were significant and direct scaling relationships between the number, height and length of rhizophores vs. basal area, tree height and crown area. Wood mechanical resistance was significantly higher in the buttressed R. mangle (modulus of elasticity, MOE = 18·1 ± 2 GPa) than in A. germinans (MOE = 12·1 ± 0·5 GPa). Slenderness ratios (total height/stem diameter) were higher in R. mangle, but there were no interspecies differences in critical buckling height. When in proximity to the main stem, rhizophores had a lower length/height ratio, higher eccentricity and higher xylem/bark and pith proportions. However, there were no directional trends with regard to prevailing winds or tree leaning. In comparison with A. germinans, a tree species with wide girth and flare at the base, R. mangle supports a thinner stem of higher mechanical resistance that is stabilized by rhizophores resembling flying

  18. An allometric approach to quantify the extinction vulnerability of birds and mammals.

    Science.gov (United States)

    Hilbers, J P; Schipper, A M; Hendriks, A J; Verones, F; Pereira, H M; Huijbregts, M A J

    2016-03-01

    Methods to quantify the vulnerability of species to extinction are typically limited by the availability of species-specific input data pertaining to life-history characteristics and population dynamics. This lack of data hampers global biodiversity assessments and conservation planning. Here, we developed a new framework that systematically quantifies extinction risk based on allometric relationships between various wildlife demographic parameters and body size. These allometric relationships have a solid theoretical and ecological foundation. Extinction risk indicators included are (1) the probability of extinction, (2) the mean time to extinction, and (3) the critical patch size. We applied our framework to assess the global extinction vulnerability of terrestrial carnivorous and non-carnivorous birds and mammals. Irrespective of the indicator used, large-bodied species were found to be more vulnerable to extinction than their smaller counterparts. The patterns with body size were confirmed for all species groups by a comparison with IUCN data on the proportion of extant threatened species: the models correctly predicted a multimodal distribution with body size for carnivorous birds and a monotonic distribution for mammals and non-carnivorous birds. Carnivorous mammals were found to have higher extinction risks than non-carnivores, while birds were more prone to extinction than mammals. These results are explained by the allometric relationships, predicting the vulnerable species groups to have lower intrinsic population growth rates, smaller population sizes, lower carrying capacities, or larger dispersal distances, which, in turn, increase the importance of losses due to environmental stochastic effects and dispersal activities. Our study is the first to integrate population viability analysis and allometry into a novel, process-based framework that is able to quantify extinction risk of a large number of species without requiring data-intensive, species

  19. The effects of elevated CO2 and nitrogen fertilization on stomatal conductance estimated from 11 years of scaled sap flux measurements at Duke FACE.

    Science.gov (United States)

    Ward, Eric J; Oren, Ram; Bell, David M; Clark, James S; McCarthy, Heather R; Kim, Hyun-Seok; Domec, Jean-Christophe

    2013-02-01

    In this study, we employ a network of thermal dissipation probes (TDPs) monitoring sap flux density to estimate leaf-specific transpiration (E(L)) and stomatal conductance (G(S)) in Pinus taeda (L.) and Liquidambar styraciflua L. exposed to +200 ppm atmospheric CO(2) levels (eCO(2)) and nitrogen fertilization. Scaling half-hourly measurements from hundreds of sensors over 11 years, we found that P. taeda in eCO(2) intermittently (49% of monthly values) decreased stomatal conductance (G(S)) relative to the control, with a mean reduction of 13% in both total E(L) and mean daytime G(S). This intermittent response was related to changes in a hydraulic allometry index (A(H)), defined as sapwood area per unit leaf area per unit canopy height, which decreased a mean of 15% with eCO(2) over the course of the study, due mostly to a mean 19% increase in leaf area (A(L)). In contrast, L. styraciflua showed a consistent (76% of monthly values) reduction in G(S) with eCO(2) with a total reduction of 32% E(L), 31% G(S) and 23% A(H) (due to increased A(L) per sapwood area). For L. styraciflua, like P. taeda, the relationship between A(H) and G(S) at reference conditions suggested a decrease in G(S) across the range of A(H). Our findings suggest an indirect structural effect of eCO(2) on G(S) in P. taeda and a direct leaf level effect in L. styraciflua. In the initial year of fertilization, P. taeda in both CO(2) treatments, as well as L. styraciflua in eCO(2), exhibited higher G(S) with N(F) than expected from shifts in A(H), suggesting a transient direct effect on G(S). Whether treatment effects on mean leaf-specific G(S) are direct or indirect, this paper highlights that long-term treatment effects on G(S) are generally reflected in A(H) as well.

  20. Effects of warming on the structure and function of a boreal black spruce forest

    Energy Technology Data Exchange (ETDEWEB)

    Stith T.Gower

    2010-03-03

    net primary production (NPP) budgets. Autotrophic respiration budgets will be constructed using chamber measurements for each tissue and NPP and standard allometry techniques (Gower et al. 1999). (4) Compare microbial and root dynamics, and net soil surface CO2 flux, of control and warmed soils to identify causes that may explain the hypothesized minimal effect of soil warming on soil surface CO2 flux. Fine root production and turnover will be quantified using minirhizotrons, and microbial dynamics will be determined using laboratory mineralization incubations. Soil surface CO2 flux will be measured using automated soil surface CO2 flux systems and portable CO2 analyzers. The proposed study builds on the existing research programs Gower has in northern Manitoba and would not be possible without in-kind services and financial support from Manitoba Hydro and University of Wisconsin.

  1. Correlation between investment in sexual traits and valve sexual dimorphism in Cyprideis species (Ostracoda.

    Directory of Open Access Journals (Sweden)

    Maria João Fernandes Martins

    Full Text Available Assessing the long-term macroevolutionary consequences of sexual selection has been hampered by the difficulty of studying this process in the fossil record. Cytheroid ostracodes offer an excellent system to explore sexual selection in the fossil record because their readily fossilized carapaces are sexually dimorphic. Specifically, males are relatively more elongate than females in this superfamily. This sexual shape difference is thought to arise so that males carapaces can accommodate their very large copulatory apparatus, which can account for up to one-third of body volume. Here we test this widely held explanation for sexual dimorphism in cytheroid ostracodes by correlating investment in male genitalia, a trait in which sexual selection is seen as the main evolutionary driver, with sexual dimorphism of carapace in the genus Cyprideis. We analyzed specimens collected in the field (C. salebrosa, USA; C. torosa, UK and from collections of the National Museum of Natural History, Washington, DC (C. mexicana. We digitized valve outlines in lateral view to obtain measures of size (valve area and shape (elongation, measured as length to height ratio, and obtained several dimensions from two components of the hemipenis: the muscular basal capsule, which functions as a sperm pump, and the section that includes the intromittent organ (terminal extension. In addition to the assessment of this primary sexual trait, we also quantified two dimensions of the male secondary sexual trait-where the transformed right walking leg functions as a clasping organ during mating. We also measured linear dimensions from four limbs as indicators of overall (soft-part body size, and assessed allometry of the soft anatomy. We observed significant correlations in males between valve size, but not elongation, and distinct structural parts of the hemipenis, even after accounting for their shared correlation with overall body size. We also found weak but significant

  2. Carbon stocks and dynamics at different successional stages in an Afromontane tropical forest

    Science.gov (United States)

    Nyirambangutse, Brigitte; Zibera, Etienne; Uwizeye, Félicien K.; Nsabimana, Donat; Bizuru, Elias; Pleijel, Håkan; Uddling, Johan; Wallin, Göran

    2017-03-01

    As a result of different types of disturbance, forests are a mixture of stands at different stages of ecological succession. Successional stage is likely to influence forest productivity and carbon storage, linking the degree of forest disturbance to the global carbon cycle and climate. Although tropical montane forests are an important part of tropical forest ecosystems (ca. 8 %, elevation > 1000 m a.s.l.), there are still significant knowledge gaps regarding the carbon dynamics and stocks of these forests, and how these differ between early (ES) and late successional (LS) stages. This study examines the carbon (C) stock, relative growth rate (RGR) and net primary production (NPP) of ES and LS forest stands in an Afromontane tropical rainforest using data from inventories of quantitatively important ecosystem compartments in fifteen 0.5 ha plots in Nyungwe National Park in Rwanda. The total C stock was 35 % larger in LS compared to ES plots due to significantly larger above-ground biomass (AGB; 185 and 76 Mg C ha-1 in LS and ES plots), while the soil and root C stock (down to 45 cm depth in the mineral soil) did not significantly differ between the two successional stages (178 and 204 Mg C ha-1 in LS and ES plots). The main reasons for the difference in AGB were that ES trees had significantly lower stature and wood density compared to LS trees. However, ES and LS stands had similar total NPP (canopy, wood and roots of all plots ˜ 9.4 Mg C ha-1) due to counterbalancing effects of differences in AGB (higher in LS stands) and RGR (higher in ES stands). The AGB in the LS plots was considerably higher than the average value reported for old-growth tropical montane forest of south-east Asia and Central and South America at similar elevations and temperatures, and of the same magnitude as in tropical lowland forest of these regions. The results of this study highlight the importance of accounting for disturbance regimes and differences in wood density and allometry of

  3. Assessment of oxytetracycline baths as therapeutic treatment for the control of the agent of withering syndrome (WS) in red abalone (Haliotis rufescens).

    Science.gov (United States)

    Winkler, Federico M; García, Ricardo; Valdivia, María Vicenta; Lohrmann, Karin B

    2018-03-01

    Withering Syndrome (WS) is a lethal disease that affects abalone species in both wild and farmed populations. This infection, caused by the rickettsial-like intracellular organism (RLO) Candidatus Xenohaliotis californiensis, can severely impair the normal development of affected animals, and ultimately, their survival. The most common line of action against the WS has been the use of antibiotics, specifically oxytetracycline (OTC), administered via intramuscular injection and per os via medicated feed. In the present study, we have assessed the effectiveness of OTC baths as therapeutic treatment for the control of the WS agent in H. rufescens. Clinical signs of infection were monitored for 11 months in treated juveniles, in addition to feed consumption rate, growth patterns and gonad development. Abalones were asymptomatic until the end of the experiment, when a small number of non-treated animals exhibited clinical signs of infection. Gonad maturity was not observed. OTC treated animals grew significantly less than their non-treated counterparts, being 4.3% shorter and 13.6% lighter at the end of the experiment. They also displayed negative allometry, i.e. for the same shell length, they were lighter than non-treated groups. Furthermore, the weight of muscle and soft tissues in OTC treated animals was lighter than in the other groups, while no differences were found in shell weight. The feed consumption rate was the same for all groups, thus the observed growth patterns cannot be attributed to a decreased feed intake. One possible explanation is that antibiotic treatment may have impacted gut microflora, thus preventing efficient nutrient digestion and absorption and, indirectly, reducing growth. Prevalence of RLOs causing WS (WS-RLO) and the variant form (RLOv), infected with a bacteriophague and non virulent, were significantly lower in the OTC-treated group than in the other groups. Similar results were observed for the mean intensity of RLOv, while for WS

  4. Crescimento alométrico, morfologia e uso do habitat em cinco espécies de Mabuya Fitzinger (Reptilia, Scincidae Allometric growth, morphology and habitat use in five species of Mabuya Fitzinger (Reptilia, Scincidae

    Directory of Open Access Journals (Sweden)

    Gabriel Silva Pinto

    2004-06-01

    allometry, while remaining segments were variable. Some hypothesis relating body form and habitat in these species have been raised, which need to be tested.

  5. Desarrollo larvario de algunas especies del género Bregmaceros (Pisces: Bregmacerotidae del sureste del Golfo de México

    Directory of Open Access Journals (Sweden)

    Jorge Blas-Cabrera

    2006-06-01

    . houdei (six, 1.5-1.9 mm and B. macclellandi (three, 2.4, 3.4 and 5.4 mm. All specimens were collected in the southern Gulf of Mexico from November 27 through December 6, 1998. Larvae were identified to species, and descriptions were made based on pigmentation, and morphometric and meristic characteristics. We defined five development stages: preflexion, flexion, postflexion, transformation and juvenile. In the preflexion stage B. cantori displayed a greater growth in mouth size and head length relative to SL (positive allometry; there was negative allometry from the flexion to juvenile stage. B. cantori have the shortest body height and head length, thus being the thinnest; whereas B. macclellandi larvae are the most robust ones. From the four species reported from the southern Gulf of Mexico, B. atlanticus larvae are the most pigmented in both head and body, with an homogeneous pattern; B. macclellandi presents a different pigmentation pattern consisting in large melanophore groups with a body arrangement that changes from one stage to the next; additionally, from the preflexion stage it develops both the occipital radius and pelvic fins. B. houdei larvae measuring 1.5 to 1.9 mm have melanophores at the tip of the lower jaw and the head, as well as at the pectoral fin base. Larval development was more pronounced in this B. cantori and B. atlanticus than in specimens from higher latitudes. Rev. Biol. Trop. 54(2: 561-575. Epub 2006 Jun 01.

  6. Climate-dependent evolution of Antarctic ectotherms: An integrative analysis

    Science.gov (United States)

    Pörtner, Hans O.

    2006-04-01

    , and the use of lipid body stores for neutral buoyancy. Important trade-offs result from obligatory energy savings in the permanent cold: low metabolic rates support cold-compensated growth but imply narrow windows of thermal tolerance and reduced scopes for activity. The degree of thermal specialization is not uniformly defined by cold temperature but varies with life style characteristics and activity levels and associated aerobic scope. Trade-offs for the sake of cold compensated growth parallel reduced capacities for exercise performance, exacerbated by the effect of high haemolymph magnesium levels in crustaceans and, possibly, other invertebrates. High magnesium levels likely exclude the group of reptant decapod crustaceans from Antarctic waters below 0 °C. The hypothesis is developed that energy savings imposed by the permanent cold bear specific life history consequences. Due to effects of allometry, energy savings are exacerbated at small body size, favouring passive lecithotrophic larvae. At all stages of life history, reduced energy turnover for the sake of growth causes delays and low rates in other higher functions, with the result of late maturity, fecundity and offspring release, as well as extended development. As a consequence, extended life spans evolved due to life history requirements. At the same time, polar gigantism is enabled by a combination of elevated oxygen levels in cold waters, of reduced metabolism and of extended periods of growth at slow developmental rates.

  7. Le mythe du microcèbe primitif The myth of the primitive mouse lemur

    Directory of Open Access Journals (Sweden)

    Fabien Génin

    2011-10-01

    criticise this almost mythical view, which is neither supported by the fossil record nor by the most recent phylogenies. We propose the alternative hypothesis of a reduction of body size, or dwarfism, a phenomenon known to occur frequently on islands, and in isolated regions subject to El Niño-related unpredictable droughts. We confirm Gould’s model of progenesis, which explains dwarfism by hypervariability leading to acceleration of life history. Cheirogaleids appear as paedomorphic dwarfs compared to their sister-taxon, the Lepilemuridae (Lepilemur. They probably experienced at least 3 independent events of dwarfing which lead to parallel changes in the proportions of the head and limbs (allometry. The first one (dwarfing has led to a decrease in the size of body and limbs, without any significant change in cranial form (with the exception of teeth in the largest forms Phaner, Mirza, and the largest forms of the genus Cheirogaleus. The second (hyper-dwarfing has led to parallel changes in cranial form in the smallest taxa (Allocebus, Microcebus and the smaller forms of the genus Cheirogaleus, associated with typical paedomorphic traits (large eyes and small, pointed snout. This new interpretation explains many unique characteristics of this group of lemurs, in particular their rapid life histories.

  8. Ground measured evapotranspiration scaled to stand level using MODIS and Landsat sensors to study Tamarix spp.response to repeated defoliation by the Tamarix leaf beetle at two sites

    Science.gov (United States)

    Pearlstein, S.; Nagler, P. L.; Glenn, E. P.; Hultine, K. R.

    2012-12-01

    The Dolores River in Southern Utah and the Virgin River in Southern Nevada are ecosystems under pressure from increased groundwater withdrawal due to growing populations and introduced riparian species. We studied the impact of the biocontrol Tamarix leaf beetles (Dirohabda carinulata and D. elongata) on the introduced riparian species, Tamarix spp., phenology and water use over multiple cycles of annual defoliation. Heat balance sap flow measurements, leaf area index (LAI), well data, allometry and satellite imagery from Landsat Thematic Mapper 5 and EOS-1 Moderate Resolution Imaging Spectrometer (MODIS) sensors were used to assess the distribution of beetle defoliation and its effect on evapotranspiration (ET). Study objectives for the Virgin River were to measure pre-beetle arrival ET, while the Dolores River site has had defoliation since 2004 and is a site of long-term beetle effect monitoring. This study focuses on measurements conducted over two seasons, 2010 and 2011. At the Dolores River site, results from 2010 were inconclusive due to sensor malfunctions but plant ET by sap flow in 2011 averaged 1.02 mm/m^2 leaf area/day before beetle arrival, dropping to an average of 0.75 mm/m^2 leaf area/day after beetle arrival. Stand level estimations from May - December, 2010 by MODIS were about 0.63 mm/ day, results from Landsat were 0.51 mm/day in June and 0.78 in August. For January -September, 2011, MODIS values were about 0.6 mm/day, and Landsat was 0.57 mm/day in June and 0.62 mm/day in August. These values are lower than previously reported ET values for this site meaning that repeated defoliation does diminish stand level water use. The Virgin River site showed plant ET from sap flow averaged about 3.9-4 mm/m^2 leaf area/day from mid-May - September, 2010. In 2011, ET from sap flow averaged 3.83 mm/m^2 leaf area/day during June - July, but dropped to 3.73 mm/ m^2 leaf area/day after beetle arrival in August. The slight drop in plant ET is not significant

  9. Evaluating the coupled vegetation-fire model, LPJ-GUESS-SPITFIRE, against observed tropical forest biomass

    Science.gov (United States)

    Spessa, Allan; Forrest, Matthew; Werner, Christian; Steinkamp, Joerg; Hickler, Thomas

    2013-04-01

    disturbance such as fire. SPITFIRE (SPread and InTensity of FIRe and Emissions) mechanistically simulates the number of fires, area burnt, fire intensity, crown fires, fire-induced plant mortality, and emissions of carbon, trace gases and aerosols from biomass burning. Originally developed as an embedded model within LPJ-DGVM, SPITFIRE has since been coupled to LPJ-GUESS. However, neither LPJ-DGVM-SPITFIRE nor LPJ-GUESS-SPITFIRE has been fully benchmarked, especially in terms of how well each model simulates vegetation patterns and biomass in areas where fire is known to be important. This information is crucial if we are to have confidence in the models in forecasting fire, emissions from biomass burning and fire-climate impacts on ecosystems. Here we report on the benchmarking of the LPJ-GUESS-SPITFIRE model. We benchmarked LPJ-GUESS-SPITFIRE driven by a combination of daily reanalysis climate data (Sheffield 2012), monthly GFEDv3 burnt area data (1997-2009) (van der Werf et al. 2010) and long-term annual fire statistics (1901 to 2000) (Mouillot and Field 2005) against new Lidar-based biomass data for tropical forests and savannas (Saatchi et al. 2011; Baccini et al., 2012). Our new work has focused on revising the way GUESS simulates tree allometry, light penetration through the tree canopy and sapling recruitment, and how GUESS-SPITFIRE simulates fire-induced mortality, all based on recent literature, as well as a more explicit accounting of land cover change (JRC's GLC 2009). We present how these combined changes result in a much improved simulation of tree carbon across the tropics, including the Americas, Africa, Asia and Australia. Our results are compared with respect to more empirical-based approaches to calculating emissions from biomass burning. We discuss our findings in terms of improved forecasting of fire, emissions from biomass burning and fire-climate impacts on ecosystems.

  10. Ontogenetic study of the skull in modern humans and the common chimpanzees: neotenic hypothesis reconsidered with a tridimensional Procrustes analysis.

    Science.gov (United States)

    Penin, Xavier; Berge, Christine; Baylac, Michel

    2002-05-01

    Heterochronic studies compare ontogenetic trajectories of an organ in different species: here, the skulls of common chimpanzees and modern humans. A growth trajectory requires three parameters: size, shape, and ontogenetic age. One of the great advantages of the Procrustes method is the precise definition of size and shape for whole organs such as the skull. The estimated ontogenetic age (dental stages) is added to the plot to give a graphical representation to compare growth trajectories. We used the skulls of 41 Homo sapiens and 50 Pan troglodytes at various stages of growth. The Procrustes superimposition of all specimens was completed by statistical procedures (principal component analysis, multivariate regression, and discriminant function) to calculate separately size-related shape changes (allometry common to chimpanzees and humans), and interspecific shape differences (discriminant function). The results confirm the neotenic theory of the human skull (sensu Gould [1977] Ontogeny and Phylogeny, Cambridge: Harvard University Press; Alberch et al. [1979] Paleobiology 5:296-317), but modify it slightly. Human growth is clearly retarded in terms of both the magnitude of changes (size-shape covariation) and shape alone (size-shape dissociation) with respect to the chimpanzees. At the end of growth, the adult skull in humans reaches an allometric shape (size-related shape) which is equivalent to that of juvenile chimpanzees with no permanent teeth, and a size which is equivalent to that of adult chimpanzees. Our results show that human neoteny involves not only shape retardation (paedomorphosis), but also changes in relative growth velocity. Before the eruption of the first molar, human growth is accelerated, and then strongly decelerated, relative to the growth of the chimpanzee as a reference. This entails a complex process, which explains why these species reach the same overall (i.e., brain + face) size in adult stage. The neotenic traits seem to concern

  11. Literacy in Action: A Carbon-Neutral Field Program at Cornell University

    Science.gov (United States)

    Moore, A.; Derry, L.

    2010-12-01

    added value by gathering data for and modeling the resulting carbon sequestration. The data include species composition and allometry, outplanting numbers, survivorship, and annual growth increment. Modeling elements include allometric equations, growth trajectories, mortality, and an economic discount rate. Although the project is young, initial estimates indicate that the CO2 offset from outplanting several hundred trees per year significantly exceeds (>3X) the CO2 footprint of the program, including all air travel. The project allows students to gain first hand experience with quantifying multiple aspects of CO2 generation and offsets, and with the rate and scale of transfer and sequestration processes - with which are important and which are not - resulting in valuable and sometimes surprising insights. We view this project as a win-win scenario for all participants.

  12. G-LiHT: Goddard's LiDAR, Hyperspectral and Thermal Airborne Imager

    Science.gov (United States)

    Cook, Bruce; Corp, Lawrence; Nelson, Ross; Morton, Douglas; Ranson, Kenneth J.; Masek, Jeffrey; Middleton, Elizabeth

    2012-01-01

    Scientists at NASA's Goddard Space Flight Center have developed an ultra-portable, low-cost, multi-sensor remote sensing system for studying the form and function of terrestrial ecosystems. G-LiHT integrates two LIDARs, a 905 nanometer single beam profiler and 1550 nm scanner, with a narrowband (1.5 nanometers) VNIR imaging spectrometer and a broadband (8-14 micrometers) thermal imager. The small footprint (approximately 12 centimeters) LIDAR data and approximately 1 meter ground resolution imagery are advantageous for high resolution applications such as the delineation of canopy crowns, characterization of canopy gaps, and the identification of sparse, low-stature vegetation, which is difficult to detect from space-based instruments and large-footprint LiDAR. The hyperspectral and thermal imagery can be used to characterize species composition, variations in biophysical variables (e.g., photosynthetic pigments), surface temperature, and responses to environmental stressors (e.g., heat, moisture loss). Additionally, the combination of LIDAR optical, and thermal data from G-LiHT is being used to assess forest health by sensing differences in foliage density, photosynthetic pigments, and transpiration. Low operating costs (approximately $1 ha) have allowed us to evaluate seasonal differences in LiDAR, passive optical and thermal data, which provides insight into year-round observations from space. Canopy characteristics and tree allometry (e.g., crown height:width, canopy:ground reflectance) derived from G-LiHT data are being used to generate realistic scenes for radiative transfer models, which in turn are being used to improve instrument design and ensure continuity between LiDAR instruments. G-LiHT has been installed and tested in aircraft with fuselage viewports and in a custom wing-mounted pod that allows G-LiHT to be flown on any Cessna 206, a common aircraft in use throughout the world. G-LiHT is currently being used for forest biomass and growth estimation

  13. COMPARISON OF THREE METHODS TO PROJECT FUTURE BASELINE CARBON EMISSIONS IN TEMPERATE RAINFOREST, CURINANCO, CHILE

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Gonzalez; Antonio Lara; Jorge Gayoso; Eduardo Neira; Patricio Romero; Leonardo Sotomayor

    2005-07-14

    Deforestation of temperate rainforests in Chile has decreased the provision of ecosystem services, including watershed protection, biodiversity conservation, and carbon sequestration. Forest conservation can restore those ecosystem services. Greenhouse gas policies that offer financing for the carbon emissions avoided by preventing deforestation require a projection of future baseline carbon emissions for an area if no forest conservation occurs. For a proposed 570 km{sup 2} conservation area in temperate rainforest around the rural community of Curinanco, Chile, we compared three methods to project future baseline carbon emissions: extrapolation from Landsat observations, Geomod, and Forest Restoration Carbon Analysis (FRCA). Analyses of forest inventory and Landsat remote sensing data show 1986-1999 net deforestation of 1900 ha in the analysis area, proceeding at a rate of 0.0003 y{sup -1}. The gross rate of loss of closed natural forest was 0.042 y{sup -1}. In the period 1986-1999, closed natural forest decreased from 20,000 ha to 11,000 ha, with timber companies clearing natural forest to establish plantations of non-native species. Analyses of previous field measurements of species-specific forest biomass, tree allometry, and the carbon content of vegetation show that the dominant native forest type, broadleaf evergreen (bosque siempreverde), contains 370 {+-} 170 t ha{sup -1} carbon, compared to the carbon density of non-native Pinus radiata plantations of 240 {+-} 60 t ha{sup -1}. The 1986-1999 conversion of closed broadleaf evergreen forest to open broadleaf evergreen forest, Pinus radiata plantations, shrublands, grasslands, urban areas, and bare ground decreased the carbon density from 370 {+-} 170 t ha{sup -1} carbon to an average of 100 t ha{sup -1} (maximum 160 t ha{sup -1}, minimum 50 t ha{sup -1}). Consequently, the conversion released 1.1 million t carbon. These analyses of forest inventory and Landsat remote sensing data provided the data to

  14. Carbon sequestration by young Norway spruce monoculture

    Science.gov (United States)

    Pokorny, R.; Rajsnerova, P.; Kubásek, J.

    2012-04-01

    Many studies have been focused on allometry, wood-mass inventory, carbon (C) sequestration, and biomass expansion factors as the first step for the evaluation of C sinks of different plant ecosystems. To identify and quantify these terrestrial C sinks, and evaluate CO2 human-induced emissions on the other hand, information for C balance accounting (for impletion of commitment to Kyoto protocol) are currently highly needed. Temperate forest ecosystems have recently been identified as important C sink. Carbon sink might be associated with environmental changes (elevated [CO2], air temperature, N deposition etc.) and large areas of managed fast-growing young forests. Norway spruce (Pice abies L. Karst) is the dominant tree species (35%) in Central European forests. It covers 55 % of the total forested area in the Czech Republic, mostly at high altitudes. In this contribution we present C sequestration by young (30-35 year-old) Norway spruce monocultures in highland (650-700 m a.s.l., AT- mean annual temperature: 6.9 ° C; P- annual amount of precipitation: 700 mm; GL- growing season duration: 150 days) and mountain (850-900 m a.s.l.; AT of 5.5 ° C; P of 1300 mm; and GL of 120 days) areas and an effect of a different type of thinning. However, the similar stem diameter at the breast height and biomass proportions among above-ground tree organs were obtained in the both localities; the trees highly differ in their height, above-ground organ's biomass values and total above ground biomass, particularly in stem. On the total mean tree biomass needle, branch and stem biomass participated by 22 %, 24 % and 54 % in highland, and by 19 %, 23 % and 58 % in mountain area, respectively. Silvicultural management affects mainly structure, density, and tree species composition of the stand. Therefore, dendrometric parameters of a tree resulted from genotype, growth conditions and from management history as well. Low type of thinning (LT; common in highland) stimulates rather tree

  15. Space-borne polarimetric SAR sensors or the golden age of radar polarimetry

    Directory of Open Access Journals (Sweden)

    Pottier E.

    2010-06-01

    Full Text Available SAR Polarimetry represents an active area of research in Active Earth Remote Sensing. This interest is clearly supported by the fact that nowadays there exists, or there will exist in a very next future, a non negligible quantity of launched Polarimetric SAR Spaceborne sensors. The ENVISAT satellite, developed by ESA, was launched on March 2002, and was the first Spaceborne sensor offering an innovative dualpolarization Advanced Synthetic Aperture Radar (ASAR system operating at C-band. The second Polarimetric Spaceborne sensor is ALOS, a Japanese Earth-Observation satellite, developed by JAXA and was launched in January 2006. This mission includes an active L-band polarimetric radar sensor (PALSAR whose highresolution data may be used for environmental and hazard monitoring. The third Polarimetric Spaceborne sensor is TerraSAR-X, a new German radar satellite, developed by DLR, EADS-Astrium and Infoterra GmbH, was launched on June 2007. This sensor carries a dual-polarimetric and high frequency X-Band SAR sensor that can be operated in different modes and offers features that were not available from space before. At least, the Polarimetric Spaceborne sensor, developed by CSA and MDA, and named RADARSAT-2 was launched in December 2007 The Radarsat program was born out the need for effective monitoring of Canada’s icy waters, and some Radarsat-2 capabilities that benefit sea- and river ice applications are the multi-polarization options that will improve ice-edge detection, ice-type discrimination and structure information. The many advances in these different Polarimetric Spaceborne platforms were developed to respond to specific needs for radar data in environmental monitoring applications around the world, like : sea- and river-ice monitoring, marine surveillance, disaster management, oil spill detection, snow monitoring, hydrology, mapping, geology, agriculture, soil characterisation, forestry applications (biomass, allometry, height

  16. Root phenology at Harvard Forest and beyond

    Science.gov (United States)

    Abramoff, R. Z.; Finzi, A.

    2013-12-01

    Roots are hidden from view and heterogeneously distributed making them difficult to study in situ. As a result, the causes and timing of root production are not well understood. Researchers have long assumed that above and belowground phenology is synchronous; for example, most parameterizations of belowground carbon allocation in terrestrial biosphere models are based on allometry and represent a fixed fraction of net C uptake. However, using results from metaanalysis as well as empirical data from oak and hemlock stands at Harvard Forest, we show that synchronous root and shoot growth is the exception rather than the rule. We collected root and shoot phenology measurements from studies across four biomes (boreal, temperate, Mediterranean, and subtropical). General patterns of root phenology varied widely with 1-5 production peaks in a growing season. Surprisingly, in 9 out of the 15 studies, the first root production peak was not the largest peak. In the majority of cases maximum shoot production occurred before root production (Offset>0 in 32 out of 47 plant sample means). The number of days offset between maximum root and shoot growth was negatively correlated with median annual temperature and therefore differs significantly across biomes (ANOVA, F3,43=9.47, pGrowth form (woody or herbaceous) also influenced the relative timing of root and shoot growth. Woody plants had a larger range of days between root and shoot growth peaks as well as a greater number of growth peaks. To explore the range of phenological relationships within woody plants in the temperate biome, we focused on above and belowground phenology in two common northeastern tree species, Quercus rubra and Tsuga canadensis. Greenness index, rate of stem growth, root production and nonstructural carbohydrate content were measured beginning in April 2012 through August 2013 at the Harvard Forest in Petersham, MA, USA. Greenness and stem growth were highest in late May and early June with one clear

  17. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2004

    Energy Technology Data Exchange (ETDEWEB)

    Diefenderfer, Heida L.; Roegner, Curtis; Thom, Ronald M.; Dawley, Earl M.; Whiting, Allan H.; Johnson, Gary E.; Sobocinski, Kathryn L.; Anderson, Michael G.; Ebberts, Blaine

    2005-12-15

    indicators for detecting a signal in the estuarine system resulting from the multiple projects were also reviewed, i.e. organic matter production, nutrient cycling, sedimentation, food webs, biodiversity, salmon habitat usage, habitat opportunity, and allometry. In subsequent work, this information will be used to calculate the over net effect on the ecosystem. To evaluate the effectiveness of habitat restoration actions in the lower Columbia River and estuary, a priority of this study has been to develop a set of minimum ecosystem monitoring protocols based on metrics important for the CRE. The metrics include a suite of physical measurements designed to evaluate changes in hydrological and topographic features, as well as biological metrics that will quantify vegetation and fish community structure. These basic measurements, intended to be conducted at all restoration sites in the CRE, will be used to (1) evaluate the effectiveness of various restoration procedures on target metrics, and (2) provide the data to determine the cumulative effects of many restoration projects on the overall system. A protocol manual is being developed for managers, professional researchers, and informed volunteers, and is intended to be a practical technical guide for the design and implementation of monitoring for the effects of restoration activities. The guidelines are intended to standardize the collection of data critical for analyzing the anticipated ecological change resulting from restoration treatments. Field studies in 2005 are planned to initiate the testing and evaluation of these monitoring metrics and protocols and initiate the evaluation of higher order metrics for cumulative effects.

  18. Drivers of variability in tree transpiration in a Boreal Black Spruce Forest Chronosequence

    Science.gov (United States)

    Angstmann, J. L.; Ewers, B. E.; Kwon, H.

    2009-12-01

    Boreal forests are of particular interest in climate change studies because of their large land area and ability to sequester and store carbon, which is controlled by water availability. Heterogeneity of these forests is predicted to increase with climate change through the impact of more frequent wildfires, warmer, longer growing seasons, and potential drainage of forested wetlands. This study aims to quantify the influence of stand age, drainage condition, and species on tree transpiration and its drivers in a central Canadian black spruce boreal forest. Heat dissipation sensors were installed in 113 trees (69 Picea mariana (black spruce), 25 Populus tremuloides (trembling aspen), and 19 Pinus banksiana (jack pine) at four stand ages, each containing a well- and poorly-drained site over three growing seasons (2006-2008). Sap flux per unit xylem area, JS, was expressed as transpiration per unit ground area, EC, and transpiration per unit leaf area, EL, using site- and species-specific allometry to obtain sapwood area (AS)and leaf area(AL)per unit ground area. Well-drained, younger Picea mariana daily JS was 47-64% greater than the older well-drained burn ages and younger poorly-drained stands were 64-68% greater than the two oldest poorly-drained stands. Daily EL in the well-drained Picea mariana stands was on average 12-33% higher in younger stand than in the two oldest stands whereas young, poorly-drained Picea mariana had 71% greater daily EL than the older stands. Well-drained Picea mariana trees had 52% higher daily EC than older trees and poorly-drained Picea mariana in the 1964 burn had 42-81% higher daily EC than the oldest stands. Populus tremuloides located in the two youngest stands had daily JS 38-58% greater rates than the 1930 burn, whereas daily EL and EC had no distint differences due to high interannual variability. Pinus banksiana experienced 21-33% greater daily JS in the 1989 burn than in the older 1964 burn for well- and poorly-drained sites

  19. Associação de cetamina S(+ e midazolam pelo método convencional de cálculo e pela extrapolação alométrica em bugios-ruivo (Alouatta guariba clamitans: resposta clínica e cardiorrespiratória S(+ ketamine and midazolam association by the conventional method of calculation and allometric extrapolation in red howler monkeys (Alouatta guariba clamitans: clinical and cardiopulmonary response

    Directory of Open Access Journals (Sweden)

    Joana Aurora Braun Chagas

    2010-02-01

    calculation (weight dose and allometric extrapolation. Twelve healthy red howler monkeys (Alouatta guariba clamitans, average weight 4.84±0.97kg, male and female, were used for this study. After a 12-hour period of food restriction and 6 hours of water restriction, the animals were physically restraint and the following parameters were measured: heart rate (HR, respiratory rate (RR, capillary refill time (CRT, rectal temperature (RT, non invasive systolic arterial pressure (NISAP and arterial blood gases analysis. The animals were distributed into two groups: CG (Conventional Group, n=6, in which the animals received S(+ ketamine (5mg kg-1 and midazolam (0.5mg kg-1, by intramuscular (IM injection; and AG (Allometry Group, n=6, in which the animals also received S(+ ketamine and midazolan IM, but the doses were calculated by allometric extrapolation. Parameters were evaluated at the following moments: M5, M10, M20 and M30 (5, 10, 20 and 30 minutes after IM injection, respectively. Muscle relaxation, pedal and caudal reflexes, interdigital pinch, recumbency time, sedation's quality and duration, and recovery time and its quality were also evaluated. The AG had a faster time for recumbency, higher period and quality of sedation, and a significantly reduction on HR and SAP from M5 to M30 when compared to CG. It was concluded that allometric extrapolation presented a better muscle relaxation and sedation without significant cardiorespiratory depression.

  20. Ontogenetic variation in light interception, self-shading and biomass distribution of seedlings of the conifer Araucaria araucana (Molina K. Koch Variación ontogenética en la intercepción lumínica, autosombramiento y distribución de biomasa en plántulas de la conífera Araucaria araucana (Molina K. Koch

    Directory of Open Access Journals (Sweden)

    CHRISTOPHER H LUSK

    2006-09-01

    Full Text Available One of the factors thought to contribute to ontogenetic declines in plant growth rates is diminishing light interception efficiency, as a result of the difficulties of avoiding self-shading among a growing number of leaves, and by stems. The effects of plant size on self-shading and light interception have rarely been quantified, however. We used a three-dimensional digitising system to construct virtual models of the architecture of Araucaria araucana seedlings 71 to 358 mm tall, and modelled their light interception in the forest understorey using the program YPLANT. We also analyzed seedling allometry, to determine the combined effects of biomass distribution and self-shading on total light interception. Average light interception efficiencies calculated for A. araucana (29 % were the lowest reported for rainforest tree seedlings, reflecting the limitations imposed by short leaves, lack of petioles and an inability to develop planar foliage geometry on branches. Total light interception was related to seedling leaf area by an exponent of 0.735, reflecting increasing self-shading as seedlings grew bigger. However, because leaf area was related to seedling mass by an exponent of 1.24, light interception scaled nearly isometrically (0.91 power with seedling mass. This resulted from taller plants having proportionally thinner stems, and a smaller fraction of their biomass in roots. Thus, an ontogenetic increase in self-shading in A. araucana is largely offset by allocation changes which increase leaf area ratio as seedlings grow bigger. These mechanisms conserving the relationship of light interception with plant mass seem likely to be restricted to species with long-lived leaves, growing in humid situations protected from wind stress. In open habitats, where wind and drought stress likely make such allocation patterns less feasible, the role of self-shading in ontogenetic declines in relative growth rate may be more evidentLa caída en la

  1. Amphibian fertilization and development in microgravity

    Science.gov (United States)

    Souza, Kenneth A.

    1993-01-01

    correlation between the SEP and the dorsal lip of the blastopore will be determined. Under normal terrestrial conditions it was shown that the SEP typically is located on the side of the egg opposite the future dorsal side of the embryo. The neurulae will be examined for the normality and completeness of the neural plate and archenteron expansion. The tadpole stages will be used to study the allometry and morphology of the various organ systems.

  2. GENETIC MODIFICATION OF GIBBERELLIC ACID SIGNALING TO PROMOTE CARBON SEQUESTRATION IN TREE ROOTS AND STEMS

    Energy Technology Data Exchange (ETDEWEB)

    Busov, Victor

    2013-03-05

    poplar GA 2-oxidases predominantly expressed in roots also decreased lateral root formation. GAs negatively affected lateral root formation by inhibiting lateral root primordium initiation. A whole-genome microarray analysis of root development in GA-modified transgenic plants revealed 2069 genes with significantly altered expression. The expression of 1178 genes, including genes that promote cell proliferation, growth, and cell wall loosening, corresponded to the phenotypic severity of the root traits when transgenic events with differential phenotypic expression were compared. The array data and direct hormone measurements suggested crosstalk of GA signaling with other hormone pathways, including auxin and abscisic acid. Transgenic modification of a differentially expressed gene encoding an auxin efflux carrier suggests that GA modulation of lateral root development is at least partly imparted by polar auxin transport modification. These results suggest a mechanism for GA-regulated modulation of lateral root proliferation associated with regulation of plant allometry during the stress response. Here we summarize progress in identification of three classes of genes useful for control of plant architecture: those affecting hormone metabolism and signaling; transcription and other regulatory factors; and the cell cycle. We focus on strong modifiers of stature and form that may be useful for directed modification of plant architecture, rather than the detailed mechanisms of gene action. Gibberellin (GA) metabolic and response genes are particularly attractive targets for manipulation because many act in a dose-dependent manner; similar phenotypic effects can be readily achieved in heterologous species; and induced pleiotropic effects--such as on nitrogen assimilation, photosynthesis, and lateral root production--are usually positive with respect to crop performance. Genes encoding transcription factors represent strong candidates for manipulation of plant architecture. For