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Sample records for bahrelghazali mio-pliocene hominids

  1. MIO-PLIOCENE CRUSTACEANS FROM THE CANARY ISLANDS, SPAIN

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    JUAN FRANCISCO BETANCORT

    2014-11-01

    Full Text Available There are few previous references to fossil crustaceans for the Neogene marine layers of the Canary Islands (Spain. The Mio-Pliocene marine sedimentary layers in the eastern islands (Gran Canaria, Fuerteventura and Lanzarote were previously characterised by the presence of numerous fossil fauna, mainly anthozoans and molluscs, which correspond to an equatorial-typepalaeoclimate, warmer than the present climate. This Mio-Pliocene transition dated between 9.3 and 4.1 Ma. In this paper, 12 fossil crustacean taxa are identified and classified, including decapods and barnacles: Balanus concavus Bronn, 1831, Balanus spongicola Brown, 1827, Balanus perforatus Bruguière, 1789, Chenolobia testudinaria Linnè, 1767, Tetraclita cf. rubescens Darwin, 1854, Callianassa matsoni Rathbun, 1935, Callianassa sp., Upogebia sp, Eriphia aff. verrucosa (Forskal, 1775 , Maja sp., Scylla michelini Milne-Edwards, 1861 and Ocypode sp. Some of these taxa mean new references for the Atlantic islands and the North African Atlantic and definitely enlarge the palaeographic distribution of Neogene crustaceans beyond the Mediterranean region, extending it to the North Atlantic. Particularly significant are the presence of Tetraclita cf. rubescens ,this being the first reported fossil occurrence of this barnacle outside the North America Pacific coasts, and Chenolobia testudinaria , indicating for the first time the existence of marine turtles in these islands during the Neogene. These results are coherent with previous research hypothesising the existence of a flow of surface water between the Pacific and Atlantic in the Mio-Pliocene transition (Central American Seaway, CAS which explains the arrival of organisms, in larval stage, from Central America to the Canary Islands.

  2. Evidence for long-term uplift on the Canary Islands from emergent Mio Pliocene littoral deposits

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    Meco, Joaquín; Scaillet, Stéphane; Guillou, Hervé; Lomoschitz, Alejandro; Carlos Carracedo, Juan; Ballester, Javier; Betancort, Juan-Francisco; Cilleros, Antonio

    2007-06-01

    Several islands in the Canarian archipelago show marine deposits with identical fossil faunas, which are generally assigned to different glacioeustatic marine episodes: mainly Pleistocene episodes in Lanzarote and Fuerteventura, and Mio-Pliocene ones in Gran Canaria. Three fossil species ( Saccostrea chili, Nerita emiliana and Strombus coronatus) characterize all the marine deposits from southern Lanzarote, to the west and south of Fuerteventura and northeast of Gran Canaria. Three other species ( Ancilla glandiformis, Rothpletzia rudista and Siderastraea miocenica) confirm the chronostratigraphic attribution of these deposits. Other more occasional fossils (as Chlamys latissima, Isognomon soldanii and Clypeaster aegyptiacus) fit an upper Miocene and lower Pliocene age. This agrees with new K/Ar ages obtained from pillow lavas emplaced into the marine deposits (ca. 4.1 Ma in Gran Canaria, ca. 4.8 Ma in Fuerteventura) and from underlying (ca. 9.3 Ma in Gran Canaria) or overlying (ca. 9.8 Ma in Lanzarote) lava flows. The marine deposits are eroded but large continuous segments are preserved sloping gently towards the coast. Variations in the highest and the lowest elevations of the deposits apsl (above present sea level) indicate post-depositional uplift movements. Glacioeustatic causes are unlikely to be responsible for these variations on the basis of the coastal location of the deposits and their equatorial fauna characteristic of Mio-Pliocene corals. Differential uplift of the deposits across the archipelago is argued to result from the progressive seaward tilting of the islands along the insular volcanic trail marking the westward migration of hot spot head since 20 Ma. Successive westward accretion of younger volcanic edifices resulted in increasing lithostatic load of the crust with progressive (diachronous) tilting of the older edifices and their palaeo-shorelines marked by past coastal deposits.

  3. Revised Chronology for the Mio-Pliocene Successions of the Eastern Paratethys: Towards a Better Understanding of Paleoenvironmental Change

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    Krijgsman, W.; Chang, L.; Baak, C. V.; Palcu, D.; Vasiliev, I.

    2014-12-01

    Paratethys is a large epicontinental sea, stretching from Germany to China at the beginning of the Oligocene (~34 Myr ago), that progressively retreated by a complex combination of basin infill, glacio-eustatic sea-level lowering and tectonic uplift to its present-day remnants: Black Sea, Caspian Sea and Aral Lake. Paratethys experienced major paleoenvironmental changes towards anoxic, hypersaline, and fresh water conditions. An accurate geological time scale (GTS) is crucial to understand the timing and rates of these change and to determine the underlying mechanisms. Geological time scales for the Paratethys region are notoriously controversial and encompass mainly regional stages, which are all defined on the basis of characteristic faunal assemblages (mainly mollusks and ostracods) endemic to the Paratethys Sea. During the last decade, we have performed numerous integrated magneto-biostratigraphic studies on the Mio-Pliocene sedimentary successions of the Eastern Paratethys, which resulted in revised chronological frameworks for the Dacian, Black Sea and Caspian Sea basins. This allows high-resolution stratigraphic correlations between the individual Paratethys subbasins and with the Mediterranean successions and help to better understand the dramatic paleoenvironmental changes in the region, such as the Messinian Salinity Crisis. Rock magnetic analyses of the sedimentary sequences of the Paratethys indicate that greigite is the main magnetic carrier and that a range of magnetic properties cannot be explained by the presence of diagenetic greigite, but are instead consistent with those expected for a biogenetic (bacterial) origin.

  4. Depositional Environment of Mio-Pliocene Siwalik Sedimentary Strata from the Darjeeling Himalayan Foothills, India: A Palynological Approach.

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    More, Sandip; Paruya, Dipak Kumar; Taral, Suchana; Chakraborty, Tapan; Bera, Subir

    2016-01-01

    A rich and diverse palynoassemblage recovered from the Churanthi River section (26°53' 59.3" N, 88°34' 17.2" E), Darjeeling foothills Eastern Himalaya, has yielded 87 species assigned to 69 genera. The palynoassemblage is rich in angiosperm taxa (45.63%) followed by gymnosperms (0.45%), pteridophytes (18.49%) and fungal remains (23.88%). Based on their nearest living relatives, a wet evergreen to semi-evergreen forest under a humid tropical to sub-tropical environment during the Mio-Pliocene age has been suggested. A lot of angiosperms such as Palaeosantalaceaepites, Araliaceoipollenites, Malvacearampollis, Zonocostites, Neocouperipollis, Dicolpopollis, Palmidites, Palmaepollenites, isolated salt glands of mangrove plant leaves (Heliospermopsis) and Mediaverrunites type of fungal spores, along with ichnofossils like Planolites, Palaeophycus, Skolithos, Rosselia, Ophiomorpha and Teichichnus associated with rippled mudstone-siltstone suggest an environment strongly influenced by brackish water. Primary sedimentary structures in the associated strata indicate strong wave agitation common in shallow marine setting. Some high elevation components (5.14%) such as Alnipollenites, cf. Corylus (Betulaceae), Juglanspollenites, Engelhardtioipollenites (Juglandaceae), Quercoides, Cupuliferoidaepollenites, Lithocarpus, Castanopsis (Fagaceae), Abietineaepollenites (Pinaceae) represent hinterland vegetation possibly transported to the prograding deltaic coastline by the rivers. Reworked palynotaxa (Striatopodocarpites sp., Striatites sp., Faunipollenites sp., Circumstriatites sp., Crescentipollenites sp., Cuneatisporites sp., Parasaccites sp., Scheuringipollenites sp., Rhizomaspora sp., Marsupipollenites sp., Lophotriletes sp.) of Permian age have also been recorded in the palynoassemblage (11.55%) indicating the abundance of Permian Gondwana strata in the source area. PMID:26930664

  5. Les bois fossiles mio-pliocènes de Nkondo (lac Albert, Ouganda), composition minéralogique et mode de formationThe Mio-Pliocene fossil woods from Nkondo (Lake Albert, Uganda), mineralogical composition and formation.

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    Pailler, Delphine; Flicoteaux, René; Ambrosi, Jean-Paul; Médus, Jacques

    2000-08-01

    The fossil wood samples found in the Mio-Pliocene lacustrine sediments of the Nkondo Formation, on the eastern shore of Lake Albert (Uganda), have undergone different mineralisations. The first epigenetic replacement by hematite, goethite and apatite preserved the plant structures, whereas subsequent replacement by goethite erased it. Some precipitations likely to be of microbial origin are associated with the epigenesis in apatite. The characteristics of the different mineralisations reveal that the fossilisation of the wood samples started with their transportation into the lake and continued after their deposition into the ironstone levels that have yielded the fossil woods.

  6. Rodent faunas of the Mio-Pliocene continental sediments of the Teruel-Alfambra region, Spain

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    Weerd, A. van de

    1976-01-01

    In the large inland basin of Teruel-Calatayud the area around the town of Teruel is well known for its numerous remains of fossil mammals. They are found in Upper Miocene and Pliocene deposits, and some groups have already been studied in detail. Simultaneous with the collecting of fossil smaller ma

  7. Revision of the Mio-Pliocene bunodont otter-like mammals of the Indian Subcontinent

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    Pickford, M.

    2007-06-01

    Full Text Available A revision of the Enhydriodontini of the Indian Subcontinent is undertaken on the basis of previously described and recently collected bunodont otter-like fossils from the sub-Himalayan Siwalik Group. It is confirmed that, with the passage of geological time spanning the period 13 – 3 Ma, there occurred a progressive increase in body size, a reduction of the anterior part of the premolar row and an increase in degree of cheek tooth bunodonty and cusp mastoidization. Functional analysis of a snout with a partly preserved incisor battery of Enhydriodon sivalensis, reveals that it was probably a molluscivore, preying principally on bivalves, while other species of enhydriodonts were more likely to have been piscivores and cancrivores. One new species of Sivaonyx is described from the base of the Late Miocene of Pakistan. Bunodont otter-like mammals from Eurasia, Africa and North America are briefly discussed in light of the revision of the Indo-Pakistan ones. The origins and phylogenetic relationships of these mammals remains obscure. The major differences in dental anatomy indicate that these Old World otter-like mammals should not be classified in Enhydrini, but in a tribe of their own Enhydriodontini new tribe.La revisión de los Enhydriontinos del subcontinente Indio se aborda, tanto en base a los fósiles de nutrias bunodontas previamente descritos, como a los hallazgos recientemente realizados en el Grupo de los Siwaliks en el sub-Himalaya. Se confirma que durante el período de tiempo comprendido entre los 13 a 3 Ma hubo un progresivo incremento en la talla corporal, una reducción de la parte anterior de la serie premolar y un incremento en el grado de bunodoncia y mastoidización de las cúspides de los dientes. El análisis funcional de un hocico de Enhydriodon sivalensis con la batería de incisivos parcialmente conservados revela que esta especie fue parcialmente malacófaga, alimentándose principalmente de bivalvos, mientras que otras especies de enhydriontinos fueron más piscívoras y cancrívoras. En el trabajo también se describe una nueva especie de Sivaonyx procedente de la base del Mioceno Terminal de Paquistán. Los mamíferos bunodontos de tipo nutria de Eurasia, África y América del Norte son brevemente discutidos a la luz de la revisión realizada para las formas paquistaníes. El origen y relaciones filogenéticas de estos mamíferos permanecen oscuros. Las importantes diferencias en anatomía dental indican que estos mamíferos de tipo nutria del Viejo Mundo no deberían ser clasificados como Enhydrini, sino en una tribu propia, Enhydriodontini nueva tribu.

  8. Hominid evolution: genetics versus memetics

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    Carter, Brandon

    2012-01-01

    The last few million years on planet Earth have witnessed two remarkable phases of hominid development, starting with a phase of biological evolution characterized by rather rapid increase of the size of the brain. This has been followed by a phase of even more rapid technological evolution and concomitant expansion of the size of the population that began when our own particular ‘sapiens’ species emerged, just a few hundred thousand years ago. The present investigation exploits the analogy between the neo-Darwinian genetic evolution mechanism governing the first phase, and the memetic evolution mechanism governing the second phase. From the outset of the latter until very recently - about the year 2000 - the growth of the global population N was roughly governed by an equation of the form dN/Ndt=N/T*, in which T* is a coefficient introduced (in 1960) by von Foerster, who evaluated it empirically as about 200 000 million years. It is shown here how the value of this hitherto mysterious timescale governing the memetic phase is explicable in terms of what happened in the preceding genetic phase. The outcome is that the order of magnitude of the Foerster timescale can be accounted for as the product of the relevant (human) generation timescale, about 20 years, with the number of bits of information in the genome, of the order of 10 000 million. Whereas the origin of our ‘homo’ genus may well have involved an evolutionary hard step, it transpires that the emergence of our particular ‘sapiens’ species was rather an automatic process.

  9. Cranial morphometry of early hominids: facial region.

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    Bilsborough, A; Wood, B A

    1988-05-01

    We report here on early hominid facial diversity, as part of a more extensive morphometric survey of cranial variability in Pliocene and early Pleistocene Hominidae. Univariate and multivariate techniques are used to summarise variation in facial proportions in South and East African hominids, and later Quaternary groups are included as comparators in order to scale the variation displayed. The results indicate that "robust" australopithecines have longer, broader faces than the "gracile" form, but that all australopithecine species show comparable degrees of facial projection. "Robust" crania are characterised by anteriorly situated, deep malar processes that slope forwards and downwards. Smaller hominid specimens, formally or informally assigned to Homo (H. habilis, KNM-ER 1813, etc.), have individual facial dimensions that usually fall within the range of Australopithecus africanus, but which in combination reveal a significantly different morphological pattern; SK 847 shows similarly hominine facial proportions, which differ significantly from those of A. robustus specimens from Swartkrans. KNM-ER 1470 possesses a facial pattern that is basically hominine, but which in some respects mimics that of "robust" australopithecines. Early specimens referred to H. erectus possess facial proportions that contrast markedly with those of other Villafranchian hominids and which suggest differing masticatory forces, possibly reflecting a shift in dietary niche. Overall the results indicate two broad patterns of facial proportions in Hominidae: one is characteristic of Pliocene/basal Pleistocene forms with opposite polarities represented by A. boisei and H. habilis; the other pattern, which typifies hominids from the later Lower Pleistocene onwards, is first found in specimens widely regarded as early representatives of H. erectus, but which differ in which certain respects from the face of later members of that species. PMID:3136656

  10. Modelling the locomotor energetics of extinct hominids.

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    Kramer, P A

    1999-10-01

    Bipedality is the defining characteristic of Hominidae and, as such, an understanding of the adaptive significance and functional implications of bipedality is imperative to any study of human evolution. Hominid bipedality is, presumably, a solution to some problem for the early hominids, one that has much to do with energy expenditure. Until recently, however, little attention could be focused on the quantifiable energetic aspects of bipedality as a unique locomotor form within Primates because of the inability to measure empirically the energy expenditure of non-modern hominids. A recently published method provides a way of circumventing the empirical measurement dilemma by calculating energy expenditure directly from anatomical variables and movement profiles. Although the origins of bipedality remain clouded, two discernible forms of locomotor anatomy are present in the hominid fossil record: the australopithecine and modern configurations. The australopithecine form is best represented by AL 288-1, a partial skeleton of Australopithecus afarensis, and is characterized as having short legs and a wide pelvis. The modern form is represented by modern humans and has long legs and a narrow pelvis. Human walking is optimized to take advantage of the changing levels of potential and kinetic energy that occur as the body and limbs move through the stride cycle. Although this optimization minimizes energy expenditure, some energy is required to maintain motion. I quantify this energy by developing a dynamic model that uses kinematic equations to determine energy expenditure. By representing both configurations with such a model, I can compare their rates of energy expenditure. I find that the australopithecine configuration uses less energy than that of a modern human. Despite arguments presented in the anthropological literature, the shortness of the legs of AL 288-1 provides no evidence that she was burdened with a compromised or transitional locomotor anatomy

  11. Aquatic ape theory and fossil hominids.

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    Verhaegen, M J

    1991-06-01

    While most older palaeo-anthropological studies emphasise the similarities of the fossil hominids with modern man, recent studies often stress the unique and the apelike features of the australopithecine dentitions, skulls and postcranial bones. It is worth reconsidering the features of Australopithecus, Homo erectus and Homo neanderthalensis in the light of the so-called Aquatic Ape Theory (AAT) of Hardy and Morgan, and to compare the skeletal parts of our fossil relatives with those of (semi)aquatic animals. Possible convergences are observed with proboscis monkeys, beavers, sea-otters, hippopotamuses, seals, sea-lions, walruses, sea-cows, whales, dolphins, porpoises, penguins and crocodiles. PMID:1909768

  12. Sawfishes and Other Elasmobranch Assemblages from the Mio-Pliocene of the South Caribbean (Urumaco Sequence, Northwestern Venezuela)

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    2015-01-01

    The Urumaco stratigraphic sequence, western Venezuela, preserves a variety of paleoenvironments that include terrestrial, riverine, lacustrine and marine facies. A wide range of fossil vertebrates associated with these facies supports the hypothesis of an estuary in that geographic area connected with a hydrographic system that flowed from western Amazonia up to the Proto-Caribbean Sea during the Miocene. Here the elasmobranch assemblages of the middle Miocene to middle Pliocene section of the Urumaco sequence (Socorro, Urumaco and Codore formations) are described. Based on new findings, we document at least 21 taxa of the Lamniformes, Carcharhiniformes, Myliobatiformes and Rajiformes, and describe a new carcharhiniform species (†Carcharhinus caquetius sp. nov.). Moreover, the Urumaco Formation has a high number of well-preserved fossil Pristis rostra, for which we provide a detailed taxonomic revision, and referral in the context of the global Miocene record of Pristis as well as extant species. Using the habitat preference of the living representatives, we hypothesize that the fossil chondrichthyan assemblages from the Urumaco sequence are evidence for marine shallow waters and estuarine habitats. PMID:26488163

  13. Sawfishes and Other Elasmobranch Assemblages from the Mio-Pliocene of the South Caribbean (Urumaco Sequence, Northwestern Venezuela.

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    Jorge D Carrillo-Briceño

    Full Text Available The Urumaco stratigraphic sequence, western Venezuela, preserves a variety of paleoenvironments that include terrestrial, riverine, lacustrine and marine facies. A wide range of fossil vertebrates associated with these facies supports the hypothesis of an estuary in that geographic area connected with a hydrographic system that flowed from western Amazonia up to the Proto-Caribbean Sea during the Miocene. Here the elasmobranch assemblages of the middle Miocene to middle Pliocene section of the Urumaco sequence (Socorro, Urumaco and Codore formations are described. Based on new findings, we document at least 21 taxa of the Lamniformes, Carcharhiniformes, Myliobatiformes and Rajiformes, and describe a new carcharhiniform species (†Carcharhinus caquetius sp. nov.. Moreover, the Urumaco Formation has a high number of well-preserved fossil Pristis rostra, for which we provide a detailed taxonomic revision, and referral in the context of the global Miocene record of Pristis as well as extant species. Using the habitat preference of the living representatives, we hypothesize that the fossil chondrichthyan assemblages from the Urumaco sequence are evidence for marine shallow waters and estuarine habitats.

  14. Hydrogen isotopes on organic compounds express large hydrological changes in the Mio-Pliocene of the Dacian Basin (Romania)

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    Vasiliev, Iuliana; Reichart, Gert-Jan; Krijgsman, Wout

    2016-04-01

    During the late Miocene to Pliocene (˜11 to 3 Ma) large part of the southern Eurasian interior was covered by the Eastern Paratethys epicontinental sea. The western most part of the Eastern Paratethys was occupied by the Dacian Basin, in the foredeep of the Carpathians. The active subsidence in the front of the Carpathians led to the fast accumulation of up to 10 km think sedimentary load in the Dacian Basin, all during the latest Miocene and Pliocene. These deposits are now tilted and well exposed along river section in the Carpathian Foredeep. Here we are reconstructing the large-scale changes of hydrologic budget in the Dacian Basin area over a long time interval (8 to 2.5 Ma). The sampled Rîmnicu S\\varat Valley section covers the Messinian salinity crisis interval, times when the adjacent Mediterranean basin suffered severe restrictions of its connections to the Ocean and, subsequently was flooded by the Atlantic at the beginning of Pliocene. We are using compound-specific hydrogen isotopic composition (δD) measured on n-alkanes produced by plant waxes. We focus our analysis on long-chained δDn‑alkanes (n-C27 to n-C33) derived from the vascular plant waxes. The saturated hydrocarbon fraction of the extractable organic matter identified in the a-polar fraction of Rîmnicu S\\varat Valley is dominated by a homologous series of n-alkanes ranging from n-C16 to n-C35. The long-chain (>C25), predominantly odd-carbon number homologues are prevailing which is typical for terrestrial higher plant derived n-alkanes, indicating an important terrestrial organic matter input. The ˜ 60 ‰ amplitude of changes for seven consecutive sampled levels measured from both δDn-C17‑21 and δDn-C27‑31 can be majorly explained by significant changes in the stable hydrogen isotope ratios characterizing the Dacian basin waters and the meteoric waters reaching the Dacian Basin. This indicates that the hydrological regime in Dacian paleo-basin has significantly varied, with heaviest δD values being recorded from a time-interval corresponding to the exceptionally dry Messinian salinity crisis of the Mediterranean.

  15. New fission-track ages of mio-pliocene tuffs in the Sierras Pampeanas and Precordillera of Argentina

    International Nuclear Information System (INIS)

    Fission-track dates were determined for 18 volcanic tuff horizons located in nine Neogene foreland basin sequences distributed throughout the Precordillera and Sierras Pampeanas of Northwestern Argentina, an area of nearly horizontal subduction. These and other data indicate that a lower age limit for the sedimentary sequences studied is approximately 17 Ma. Therefore these fission-track dates constrain both the history of volcanic activity and the time of deposition in several foreland basins from the middle Miocene to Recent. Although the dates range from 3.6±0.8 Ma to 17.0±1.9 Ma, there is a marked increase in the number of ashes younger than 9 Ma. This implies that two distinct episodes of volcanic activity affected the region. The source of some of these tuffs is unknown but they are probably limited to the 'flat-slab' region between 27 deg and 32 deg S. Tuffs at Rio Blanco and Santa Florentina that are spatially associated with the Mogotes dacite domes of the Famatina Range represented magmatism bracketed from about 7 to 4 Ma in the region underlain by the flat-subducted plate. The stratigraphic relations in the basins show that the faulting that uplifted Sierra de Famatina was contemporaneous with the volcanism which reached the surface along the bounding faults. (Author)

  16. [The endocranial parietal vascular traces in the hominid line].

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    Saban, R

    1977-03-01

    The study of the grooves traced by the middle meningeal veins on the parietal bone or the endocast of Hominid fossils shows different patterns which correspond to each evolutive stage. Height types are characterised among the Hominids (Australopithecines, Archanthropines, Paleanthropines and Neanthropines): I, robust Australopithecine type; II, gracile Australopithecine type; III, earliest Pithecanthropine type; IV, evolved Pithecanthropine type; V, Preneandertal type; VI, neandertal type; VII, Neanthropine type; VIII, modern type. PMID:405108

  17. A reappraisal of early hominid phylogeny.

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    Strait, D S; Grine, F E; Moniz, M A

    1997-01-01

    We report here on the results of a new cladistic analysis of early hominid relationships. Ingroup taxa included Australopithecus afarensis, Australopithecus africanus, Australopithecus aethiopicus, Australopithecus robustus, Australopithecus boisei, Homo habilis, Homo rudolfensis, Homo ergaster and Homo sapiens. Outgroup taxa included Pan troglodytes and Gorilla gorilla. Sixty craniodental characters were selected for analysis. These were drawn from the trait lists of other studies and our own observations. Eight parsimony analyses were performed that differed with respect to the number of characters examined and the manner in which the characters were treated. Seven employed ordered characters, and included analyses in which (1) taxa that were variable with respect to a character were coded as having an intermediate state, (2) characters with variable states in any taxon were excluded; (3) a variable taxon was coded as having the state exhibited by the majority of its hypodigm, (4) variable taxa were coded as missing data for that character, (5) some characters were considered irreversible, (6) masticatory characters were excluded, and (7) characters whose states were unknown in some taxa were excluded. In the final analysis, (8) all characters were unordered. All analyses were performed using PAUP 3.0s. Despite the fact that the eight analyses differed with respect to methodology, they produced several consistent results. All agreed that the "robust" australopithecines form a clade, A. afarensis is the sister taxon of all other hominids, and the genus Australopithecus, as conventionally defined, is paraphyletic. All eight also supported trees in which A. africanus is the sister taxon of a joint Homo+ "robust" clade, although in one analysis an equally parsimonious topology found A. africanus to be the sister of the "robust" species. In most analyses, the relationships of A. africanus and H. habilis were unstable, in the sense that their positions vary in trees

  18. Hand function and tool behavior in early hominids.

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    Susman, R L

    1998-07-01

    Prompted by the discovery of the Olduvai Hominid 7 hand (Homo habilis) in 1960, studies of primate hands were conducted in order to understand better the functional morphology of the earliest hominids and the evolution of tool behavior. Since Napier's work in the early 1960's, the hand bones of a number of other species have been recovered in East and South Africa. New hominid finds and a prolific archaeological record have broadened our perspective on the evolution of tool behavior in Australopithecus, Paranthropus, and early Homo. A debate is underway at this time on the questions of what exactly we can glean from the fossil record regarding the evolution of tool behavior and what are the best approaches to interpreting the evidence. I support the model of Napier that identified morphological correlates of precision and power grasping in the hands of extant primates and in early hominid hand bones. At the same time, I question both the underlying rationale and attempts to identify more subtle aspects of precision grasping, based on present evidence. PMID:9680465

  19. Stepping out: a computer simulation of hominid dispersal from Africa.

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    Mithen, Steven; Reed, Melissa

    2002-10-01

    A succession of new discoveries and the recent application of new dating methods provide strong evidence that Eurasia was colonized soon after 2.0m.y.a. In light of this new evidence many scenarios have been proposed regarding the influence of glacial/interglacial cycles on hominid dispersal, the role of mountain chains and deserts as barriers, the significance of land bridges and the possibility of sea-crossings. Such factors have been proposed to explain the apparent early arrival of hominids in East Asia and relatively late arrival in Europe, although the evidence in both regions remains open to various interpretations. While it is relatively easy to propose environmental factors that may have influenced dispersal patterns, it is more difficult to evaluate such proposals and to establish what the combined impact of several factors might have been. Moreover, the role of historical contingency in creating the observed pattern of dispersal has yet to be considered. This paper describes a computer simulation model of hominid dispersal which seeks to provide a means to evaluate environmental and ecological factors in hominid dispersal. It creates probability distributions for arrival dates at six key localities and compares these with current estimates from the archaeological and fossil records. It uses these to support some of the current arguments about dispersal and to challenge others.

  20. Enamel hypoplasia in the middle pleistocene hominids from Atapuerca (Spain).

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    Bermúdez de Castro, J M; Pérez, P J

    1995-03-01

    The prevalence and chronology of enamel hypoplasias were studied in a hominid dental sample from the Sima de los Huesos (SH) Middle Pleistocene site at the Sierra de Atapuerca (Burgos, northern Spain). A total of 89 permanent maxillary teeth, 143 permanent mandibular teeth, and one deciduous lower canine, belonging to a minimum of 29 individuals, were examined. Excluding the antimeres (16 maxillary and 37 mandibular cases) from the sample, the prevalence of hypoplasias in the permanent dentition is 12.8% (23/179), whereas the deciduous tooth also showed an enamel defect. No statistically significant differences were found between both arcades and between the anterior and postcanine teeth for the prevalence of hypoplasias. In both the maxilla and the mandible the highest frequency of enamel hypoplasias was recorded in the canines. Only one tooth (a permanent upper canine) showed two different enamel defects, and most of the hypoplasias were expressed as faint linear horizontal defects. Taking into account the limitations that the incompleteness of virtually all permanent dentitions imposes, we have estimated that the frequency by individual in the SH hominid sample was not greater than 40%. Most of the hypoplasias occurred between birth and 7 years (N = 18, X = 3.5, SD = 1.3). Both the prevalence and severity of the hypoplasias of the SH hominid sample are significantly less than those of a large Neandertal sample. Furthermore, prehistoric hunter-gatherers and historic agricultural and industrial populations exhibit a prevalence of hypoplasias generally higher than that of the SH hominids. Implications for the survival strategies and life quality of the SH hominids are also discussed. PMID:7785727

  1. Palaeodemography of the Atapuerca-SH Middle Pleistocene hominid sample.

    Science.gov (United States)

    Bermúdez de Castro, J M; Nicolás, M E

    1997-01-01

    We report here on the palaeodemographic analysis of the hominid sample recovered to date from the Sima de los Huesos (SH) Middle Pleistocene cave site in the Sierra de Atapuerca (Burgos, Spain). The analysis of the mandibular, maxillary, and dental remains has made it possible to estimate that a minimum of 32 individuals, who probably belonged to the same biological population, are represented in the current SH human hypodigm. The remains of nine-individuals are assigned to males, and nine to females, suggesting that a 1:1 sex ratio characterizes this hominid sample. The survivorship curve shows a low representation of infants and children, a high mortality among the adolescents and prime-age adults, and a low older adult mortality. Longevity was probably no greater than 40 years. This mortality pattern (adolescents and adults); which in some aspects resembles that observed in Neandertals, is quite different from those reported for recent foraging human groups. The adult age-at-death distribution of the SH hominid sample appears to be neither the consequence of underaging the older adults, nor of differential preservation or of the recognition of skeletal remains. Thus if we accept that they had a life history pattern similar to that of modern humans there would appear to be a clear contradiction between the demographic distribution and the demographic viability of the population represented by the SH hominid fossils. The possible representational bias of the SH hominid sample, as well as some aspects of the reproductive biology of the Pleistocene populations are also discussed. PMID:9300346

  2. A hominid tibia from Middle Pleistocene sediments at Boxgrove, UK.

    Science.gov (United States)

    Roberts, M B; Stringer, C B; Parfitt, S A

    1994-05-26

    Fossil hominids from the earlier Middle Pleistocene of Europe are very rare and the Mauer mandible is generally accepted as the most ancient, with an estimated age of 500 kyr. We report here on the discovery of a human tibia, in association with stone tools, from calcareous silts at the Lower Palaeolithic site of Boxgrove, West Sussex, UK (Fig. 1). The silt units are correlated by mammalian biostratigraphy to an, as yet unnamed, major temperate stage or interglacial that immediately pre-dates the Anglian cold stage. Accordingly, the temperate sediments are equated with oxygen isotope stage 13 (ref. 6) and are therefore roughly coeval with the Mauer mandible. The massive tibia is the oldest hominid fragment from the British Isles and provides the first information about the manufacturers of the early Acheulian industries of Europe. It is assigned to Homo cf. heidelbergensis. PMID:8183368

  3. Encephalization in hominids: evidence for the model of punctuationalism.

    Science.gov (United States)

    Hofman, M A

    1983-01-01

    A progressive enlargement of the hominid brain started 3-2 million years ago, probably from a gracile australopithecine form. Since then, three major transitions in degree of encephalization have taken place, leading to modern Homo sapiens. In the present study it is shown that these transitions must have occurred in rapid bursts, interspersed with long periods of little or no evolutionary change (stasis). This stepwise mode of encephalization is in accordance with the model of punctuated evolutionary change. A further inquiry has been made into the size of the cerebral cortex of hominids and into the number of cortical neurons based on estimates which were derived from allometric equations in extant mammals. PMID:6405974

  4. Crown-formation time of a fossil hominid premolar tooth.

    Science.gov (United States)

    Beynon, A D; Dean, M C

    1987-01-01

    Studies using surface or internal enamel growth indicators in hominids have suggested that crown-formation times were shorter than those in modern man. The crown-formation time in a robust australopithecine premolar tooth was calculated by counting enamel cross-striations, which correspond to daily increments of formation, on a replica of the fractured internal enamel surface of cuspal enamel using scanning electron microscopy. Cervical enamel completion time was estimated using other growth indicators including striae, and using measured and calculated cross-striation repeat intervals, giving a completion time of approx. 2.4 yr. This is much shorter than reported premolar crown formation times in modern man. These findings support the concept of an abbreviated period of dental development, with implications on the duration of the growth period in early hominids. PMID:3130039

  5. Posterior dental size reduction in hominids: the Atapuerca evidence.

    Science.gov (United States)

    Bermúdez de Castro, J M; Nicolas, M E

    1995-04-01

    In order to reassess previous hypotheses concerning dental size reduction of the posterior teeth during Pleistocene human evolution, current fossil dental evidence is examined. This evidence includes the large sample of hominid teeth found in recent excavations (1984-1993) in the Sima de los Huesos Middle Pleistocene cave site of the Sierra de Atapuerca (Burgos, Spain). The lower fourth premolars and molars of the Atapuerca hominids, probably older than 300 Kyr, have dimensions similar to those of modern humans. Further, these hominids share the derived state of other features of the posterior teeth with modern humans, such as a similar relative molar size and frequent absence of the hypoconulid, thus suggesting a possible case of parallelism. We believe that dietary changes allowed size reduction of the posterior teeth during the Middle Pleistocene, and the present evidence suggests that the selective pressures that operated on the size variability of these teeth were less restrictive than what is assumed by previous models of dental reduction. Thus, the causal relationship between tooth size decrease and changes in food-preparation techniques during the Pleistocene should be reconsidered. Moreover, the present evidence indicates that the differential reduction of the molars cannot be explained in terms of restriction of available growth space. The molar crown area measurements of a modern human sample were also investigated. The results of this study, as well as previous similar analyses, suggest that a decrease of the rate of cell proliferation, which affected the later-forming crown regions to a greater extent, may be the biological process responsible for the general and differential dental size reduction that occurred during human evolution. PMID:7604890

  6. Age of the earliest known hominids in Java, Indonesia.

    Science.gov (United States)

    Swisher, C C; Curtis, G H; Jacob, T; Getty, A G; Suprijo, A; Widiasmoro

    1994-02-25

    40Ar/39Ar laser-incremental heating of hornblende separated from pumice recovered at two hominid sites in Java, Indonesia, has yielded well-defined plateaus with weighted mean ages of 1.81 +/- 0.04 and 1.66 +/- 0.04 million years ago (Ma). The hominid fossils, a juvenile calvaria of Pithecanthropus and a partial face and cranial fragments of Meganthropus, commonly considered part of the Asian Homo erectus hypodigm, are at least 0.6 million years older than fossils referred to as Homo erectus (OH-9) from Olduvai Gorge, Tanzania, and comparable in age with the oldest Koobi Fora Homo cf. erectus (Homo ergaster) in Kenya. These ages lend further credence to the view that Homo erectus may have evolved outside of Africa. If the ancestor of Homo erectus ventured out of Africa before 1.8 Ma, the dispersal would have predated the advent of the Acheulean culture at 1.4 Ma, possibly explaining the absence of these characteristic stone cleavers and hand axes in East Asia. PMID:8108729

  7. Brief communication: Gladysvale: first early hominid site discovered in South Africa since 1948.

    Science.gov (United States)

    Berger, L R; Keyser, A W; Tobias, P V

    1993-09-01

    We report here the discovery of fossil hominid teeth at Gladysvale, near Johannesburg in the southern Transvaal. This find makes the site the seventh in South Africa to yield australopithecine remains and the first new early hominid-bearing locality to be found in this region since 1948. Apart from the hominid specimens, our excavations at Gladysvale have added appreciably to the abundant Plio-Pleistocene fauna previously recorded from the cave deposit. The fauna indicates that savanna conditions prevailed during deposition of at least part of the fill. Preliminary faunal dating gives an age of deposition of between c1.7 and c2.5 mya. PMID:8238287

  8. Endocranial capacity in an early hominid cranium from Sterkfontein, South Africa.

    Science.gov (United States)

    Conroy, G C; Weber, G W; Seidler, H; Tobias, P V; Kane, A; Brunsden, B

    1998-06-12

    Two- and three-dimensional computer imaging shows that endocranial capacity in an approximately 2.8- to 2.6-million-year-old early hominid cranium (Stw 505) from Sterkfontein, South Africa, tentatively assigned to Australopithecus africanus, is approximately 515 cubic centimeters. Although this is the largest endocranial capacity recorded for this species, it is still markedly less than anecdotal reports of endocranial capacity exceeding 600 cubic centimeters. No australopithecine has an endocranial capacity approaching, let alone exceeding, 600 cubic centimeters. Some currently accepted estimates of early hominid endocranial capacity may be inflated, suggesting that the tempo and mode of early hominid brain evolution may need reevaluation. PMID:9624045

  9. Paleomagnetic dates of hominid remains from Yuanmou, China, and other Asian sites.

    Science.gov (United States)

    Hyodo, Masayuki; Nakaya, Hideo; Urabe, Atsushi; Saegusa, Haruo; Shunrong, Xue; Jiyun, Yin; Xuepin, Ji

    2002-07-01

    Two hominid upper central incisors found in the Yuanmou Basin in southwest China in 1965 have affinities with Homo erectus fossils from Zhoukoudian, but exhibit primitive features. The Yuanmou hominid remains are alleged to be coeval with or older than African specimens dated at about 1.8 m.y.a. Recent age refinements of geomagnetic short reversal events and excursions permit assigning the Yuanmou hominid-bearing bed to the early Brunhes chron (about 0.7 m.y.a.). Magnetochronological assessments confirm that the Lantian calotte which has been dated to about 1.2 m.y.a., is the oldest reliable evidence for the emergence of Homo in eastern Asia as well as China, and that hominid fossils from Sangiran and Mojokerto, Java, do not exceed 1.1 Ma in age. These results refute the view that the genus Homo migrated into eastern Asia in the late Pliocene or the earliest Pleistocene. PMID:12098208

  10. Studies in Neotropical Paleobotany. XV. A Mio-Pliocene palynoflora from the Eastern Cordillera, Bolivia: implications for the uplift history of the Central Andes.

    Science.gov (United States)

    Graham, A; Gregory-Wodzicki, K M; Wright, K L

    2001-09-01

    An assemblage of 33 fossil pollen and spores, recovered from the 3600-m high Pislepampa locality of E. W. Berry, Eastern Cordillera, Bolivia, adds considerably to our knowledge of three aspects of the region in late Neogene time: (1) the paleovegetation, (2) the paleoclimate, and (3) the paleoelevation of the Central Andes. The plant microfossils recognized are Isoetes, Lycopodium (three types), Cnemidaria, Cyathea (three types), Grammitis, Hymenophyllum, Pteris, trilete fern spores (two types), Danaea, monolete fern spores (four types), Podocarpus, Gramineae, Palmae, Ilex, cf. Oreopanax, Cavanillesia, cf. Pereskia, Compositae (three types), Ericaceae, Tetrorchidium, and unknowns (three types). The diversity of the Compositae suggest that this flora has a maximum age around the Miocene-Pliocene boundary, that is, 6-7 million years. All members of the paleocommunity presently grow in the bosque montano húmedo (cloud forest) along the eastern slope of the Central Andes of Bolivia, which occurs between MATs (mean annual temperatures) of ∼10° and 20°C. The Pislepampa flora probably represents the lower limits of this forest because the fossil leaves collected by Berry from the same locality all have entire margins, suggesting that the flora grew near the cloud forest-tropical forest transition. Presently, the lower limit of the cloud forest forest has MATs of ∼20°C, a mean annual precipitation between 1000 and 1500 mm, and that part containing most of the identified genera of fossil pollen is found at elevations ∼1200-1400 m. These conditions are thus inferred for the Pislepampa flora; however, because of the uncertainty of the magnitude of global climate change and of possible changes in the ecological range of plant genera, we estimate an error of at least ±1000 m for the paleoelevation estimate. When the total uplift is corrected for probable amounts of erosionally driven isostatic rebound, the paleoelevation estimate suggests that from one-third to one-half of the uplift of the Eastern Cordillera had occurred by the beginning of the Pliocene. This estimate is consistent with other paleoelevation estimates from the Central Andes. PMID:21669687

  11. Comparative taphonomy, taphofacies, and bonebeds of the Mio-Pliocene Purisima Formation, central California: strong physical control on marine vertebrate preservation in shallow marine settings.

    Directory of Open Access Journals (Sweden)

    Robert W Boessenecker

    Full Text Available Taphonomic study of marine vertebrate remains has traditionally focused on single skeletons, lagerstätten, or bonebed genesis with few attempts to document environmental gradients in preservation. As such, establishment of a concrete taphonomic model for shallow marine vertebrate assemblages is lacking. The Neogene Purisima Formation of Northern California, a richly fossiliferous unit recording nearshore to offshore depositional settings, offers a unique opportunity to examine preservational trends across these settings.Lithofacies analysis was conducted to place vertebrate fossils within a hydrodynamic and depositional environmental context. Taphonomic data including abrasion, fragmentation, phosphatization, articulation, polish, and biogenic bone modification were recorded for over 1000 vertebrate fossils of sharks, bony fish, birds, pinnipeds, odontocetes, mysticetes, sirenians, and land mammals. These data were used to compare both preservation of multiple taxa within a single lithofacies and preservation of individual taxa across lithofacies to document environmental gradients in preservation. Differential preservation between taxa indicates strong preservational bias within the Purisima Formation. Varying levels of abrasion, fragmentation, phosphatization, and articulation are strongly correlative with physical processes of sediment transport and sedimentation rate. Preservational characteristics were used to delineate four taphofacies corresponding to inner, middle, and outer shelf settings, and bonebeds. Application of sequence stratigraphic methods shows that bonebeds mark major stratigraphic discontinuities, while packages of rock between discontinuities consistently exhibit onshore-offshore changes in taphofacies.Changes in vertebrate preservation and bonebed character between lithofacies closely correspond to onshore-offshore changes in depositional setting, indicating that the dominant control of preservation is exerted by physical processes. The strong physical control on marine vertebrate preservation and preservational bias within the Purisima Formation has implications for paleoecologic and paleobiologic studies of marine vertebrates. Evidence of preservational bias among marine vertebrates suggests that careful consideration of taphonomic overprint must be undertaken before meaningful paleoecologic interpretations of shallow marine vertebrates is attempted.

  12. Stratigraphy, artefact industries and hominid associations for Sterkfontein, member 5.

    Science.gov (United States)

    Kuman, K; Clarke, R J

    2000-06-01

    A revised stratigraphy for the early hominid site of Sterkfontein (Gauteng Province, South Africa) reveals a complex distribution of infills in the main excavation area between 2.8 and 1.4 m.y.a, as well as deposits dating to the mid to late Pleistocene. New research now shows that the Member 4 australopithecine breccia (2.8-2.6 Ma) extends further west than was previously thought, while a late phase of Member 4 is recognized in a southern area. The artefact-bearing breccias were defined sedimentologically as Member 5, but one supposed part of these younger breccias, the StW 53 infill, lacks in situ stone tools, although it does appear to post-date 2.6 Ma when artefacts first appear in the archaeological record. The StW 53 hominid, previously referred to Homo habilis, is here argued to be Australopithecus. The first artefact-bearing breccia of Member 5 is the Oldowan Infill, estimated at 2-1.7 Ma. It occupies a restricted distribution in Member 5 east and contains an expedient, flake-based tool industry associated with a few fossils of Paranthropos robustus. An enlarged cave opening subsequently admitted one or more Early Acheulean infills associated in Member 5 west with Homo ergaster. The artefacts attest to a larger site accumulation between ca. 1.7 and 1.4 Ma, with more intensive use of quartzite over quartz and a subtle but important shift to large flakes and heavier-duty tools. The available information on palaeoenvironments is summarized, showing an overall change from tropical to sub-tropical gallery forest, forest fringe and woodland conditions in Member 4 to more open woodland and grassland habitats in the later units, but with suggestions of a wet localized topography in the Paranthropus -bearing Oldowan Infill. PMID:10835264

  13. Paleosol stable isotope evidence for early hominid occupation of East Asian temperate environments

    Science.gov (United States)

    Wang, Hongfang; Ambrose, S.H.; Liu, Chen; Follmer, L.R.

    1997-01-01

    Hominids left Africa and occupied mainland Asia by 1.8 myr ago. About 1.15 myr ago Homo erectus and an associated Stegodon-Ailuropoda fauna migrated from subtropical China across the Qinling Mountains into the temperate Loess Plateau. This migration may be an evolutionary milestone in human adaptability because it may represent the first occupation of a nontropical environment. Loess-paleosol stable isotope ratios from the last interglacial-glacial cycle provide comparative data for reconstructing the hominid paleoenvironments. The climate during Gongwangling hominid occupation about 1.15 myr ago was influenced by both Siberian-Mongolian winter and Indian summer monsoon systems characterized as a cold/cool, dry winter and warm/mild, semihumid summer and fall. The Gongwangling hominids preyed mainly on warm-climate-adapted animals such as Stegodon-Ailuropoda fauna, suggesting a warm season occupation. The stable isotope ratios also indicate that the Chenjiawo hominids occupied an environment similar to that of the Gongwangling about 650,000 yr ago. The associated fauna, with a mixture of forest and steppe, warm-and cold/cool-climate-adapted animal assemblage's, suggests a permanent occupation by this time. Thus, the reliable earliest and permanent occupation of temperate environments may have occurred 150,000 yr earlier in eastern Asia rather than in Europe. ?? 1997 University of Washington.

  14. Cenozoic vegetation, climate changes and hominid evolution in tropical Africa

    Science.gov (United States)

    Bonnefille, Raymonde

    2010-07-01

    This paper reviews information on past vegetation of tropical Africa during the Cenozoic, focused upon the last 10 Ma, a time spanning hominid record in Central and East Africa. Summary of palaeobotanical data collected at terrestrial sites are compared with new results on the long term evolution of the continental vegetation zones documented from marine pollen record of two deep sea cores recovered from the Atlantic and Indian Oceans. Section 2 includes a summary of modern distribution of vegetation belts in the African continent and a synthesis of the results of both macrobotanical (fossil wood, leaves and fruits) and microbotanical (mainly pollen) studies presented according to time scale and geographical location. The main features emphasized by the palaeobotanical results are 1) seasonal vegetation and climate documented as soon as the Eocene in Tanzania 2) well diversified forests existing in northern West Ethiopia during the Oligocene 3) high temporal and spatial variabilities of forests composition during the Miocene when deciduous Legume woodland was documented in Ethiopia whereas wetter evergreen forests existed in Western Kenya 4) lack of evidence for an evergreen forest belt, continuous from Western Congo to East Africa. Section 3 presents new original pollen data recovered from a long core in the Gulf of Aden documenting large scale past vegetation changes in East Africa during the last 11 Ma. These results are discussed in comparison with a summarized long pollen sequence previously published from a marine core offshore the Niger delta. This comparison illustrates variations in geographical distribution of large vegetation zone at the continental scale, through time. In Section 4, vegetation changes registered during the last 10 Ma are discussed in relation with the results of isotopic studies and an updated presentation of hominids evolution in Africa. Several changes are shown in the marine records. An expansion of savanna/grassland is shown at 10

  15. Interproximal grooving in the Atapuerca-SH hominid dentitions.

    Science.gov (United States)

    Bermúdez de Castro, J M; Arsuaga, J L; Pérez, P J

    1997-03-01

    The dental sample recovered from the Sima de los Huesos (SH) Middle Pleistocene cave site of the Sierra de Atapuerca (Spain) includes 296 specimens. Interproximal wear grooves have been observed in 20 maxillary and mandibular posterior teeth belonging to at least five of the 32 individuals identified so far in the SH hypodigm. Interproximal grooving affected only the adults, and at an age between 25 and 40 years. The appearance, morphology, and location pattern of the SH wear grooves are similar to those reported in other fossil hominids and in more recent human populations. Two alternative proposals, the toothpicking and the fiber or sinew processing hypotheses, compete for explaining the formation of this anomalous wear. The characteristics observed in the wear grooves of the SH teeth are compatible only with the habitual probing of interdental spaces by means of hard and inflexible objects. Dietary grit may also have contributed to the abrasion of the root walls during the motion of the dental probes. PMID:9098505

  16. Increased cranial capacity in hominid evolution and preeclampsia.

    Science.gov (United States)

    Chaline, Jean

    2003-08-01

    One of the major trends in primate evolution generally and hominid evolution in particular, is cranio-facial contraction accompanied by an increase in cranial capacity. Landmark-based morphometric methods are applied to adult skulls of great apes (Gorilla, Pan), australopithecines (Australopithecus and Paranthropus), and humans (Homo eragster, erectus, neanderthalensis, and sapiens). Morphological changes quantified by vector fields (Procrustes methods) indicate that these skull plans are characterized by distinctive degrees of cranio-facial contraction. These suggest the existence of three discrete skull organization plans: "great ape", "australopithecine" and "Homo". This paper focuses on the "Homo" skull bauplan and discusses the possible relationships between greatly increased cranial capacity and preeclampsia. The earliest species of the human lineage exhibit less cranio-facial contraction and smaller cranial capacity than Homo neanderthalensis and modern Homo sapiens. Neandertalization introduces a posterior elongation of the skull and leads to a large increase in cranial capacity in the last Neandertals, with values as large as in present-day H. sapiens. Consequently, a new biological hypothesis is proposed to account for the unexplained disappearance of H. neanderthalensis some 30000 years ago related to the possible appearance of preeclampsia as a factor affecting the survival of the species. PMID:12896818

  17. Gluteus maximus muscle function and the origin of hominid bipedality.

    Science.gov (United States)

    Marzke, M W; Longhill, J M; Rasmussen, S A

    1988-12-01

    Bipedality not only frees the hands for tool use but also enhances tool use by allowing use of the trunk for leverage in applying force and thus imparting greater final velocity to tools. Since the weight and acceleration of the trunk and forelimbs on the hindlimbs must be counteracted by muscles such as m. gluteus maximus that control pelvic and trunk movements, it is suggested that the large size of the cranial portion of the human gluteus maximus muscle and its unique attachment to the dorsal ilium (which is apparent in the Makapan australopithecine ilium) may have contributed to the effectiveness with which trunk movement was exploited in early hominid foraging activities. To test this hypothesis, the cranial portions of both right and left muscles were investigated in six human subjects with electromyography during throwing, clubbing, digging, and lifting. The muscles were found to be significantly recruited when the trunk is used in throwing and clubbing, initiating rotation of the pelvis and braking it as trunk rotation ceases and the forelimb accelerates. They stabilize the pelvis during digging and exhibit marked and prolonged activity when the trunk is maintained in partial flexion during lifting of heavy objects. PMID:3223519

  18. Comparative anatomy of the middle ear ossicles of extant hominids--Introducing a geometric morphometric protocol.

    Science.gov (United States)

    Stoessel, Alexander; Gunz, Philipp; David, Romain; Spoor, Fred

    2016-02-01

    The presence of three interconnected auditory ossicles in the middle ear is a defining characteristic of mammals, and aspects of ossicle morphology are related to hearing sensitivity. However, analysis and comparison of ossicles are complicated by their minute size and complex three-dimensional shapes. Here we introduce a geometric morphometric measurement protocol for 3D shape analysis based on landmarks and semilandmarks obtained from μCT images and apply it to ossicles of extant hominids (great apes and humans). We show that the protocol is reliable and reproducible over a range of voxel resolutions, and captures even subtle shape differences. Using this approach it is possible to distinguish the hominid taxa by mean shapes of their malleus and incus (p morphometric studies analyzing ossicles of extinct hominids, with a bearing on taxonomy, phylogeny and auditory function. PMID:26852810

  19. Early Pleistocene hominid teeth recovered in Mohui cave in Bubing Basin, Guangxi, South China

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; Richard Potts; HOU Yamei; CHEN Yunfa; WU Huaying; YUAN Baoyin; HUANG Weiwen

    2005-01-01

    Two hominid teeth recovered in Mohui cave are morphologically distinguished from Australopithecus in Africa, but close to Homo erectus in China. These teeth are therefore provisionally assigned to Homo erectus. The associated mammalian fauna include Gigantopithecus blacki, Nestoritherium sp., Sus xiaozhu, Sus peii and Ailuropoda microta, which are typical early Pleistocene taxa in South China. The general characteristics of the Mohui faunal assemblage are similar to the Longgupo site, which is dated to 2 Ma, implying a contemporaneity for the two sites. To date, compared with the discoveries in Africa, far fewer early Pleistocene hominid fossils have been recovered in Asia, and there are intensive controversies concerning their stratigraphic provenience and typological and temporal positions. The hominid fossils from Mohui cave, with their reliable biostratigraphic positions and distinct typological features, provide important evidence regarding the issue of early human origins and evolution.

  20. Earliest Pleistocene hominid cranial remains from Dmanisi, Republic of Georgia: taxonomy, geological setting, and age.

    Science.gov (United States)

    Gabunia, L; Vekua, A; Lordkipanidze, D; Swisher, C C; Ferring, R; Justus, A; Nioradze, M; Tvalchrelidze, M; Antón, S C; Bosinski, G; Jöris, O; Lumley, M A; Majsuradze, G; Mouskhelishvili, A

    2000-05-12

    Archaeological excavations at the site of Dmanisi in the Republic of Georgia have uncovered two partial early Pleistocene hominid crania. The new fossils consist of a relatively complete cranium and a second relatively complete calvaria from the same site and stratigraphic unit that yielded a hominid mandible in 1991. In contrast with the uncertain taxonomic affinity of the mandible, the new fossils are comparable in size and morphology with Homo ergaster from Koobi Fora, Kenya. Paleontological, archaeological, geochronological, and paleomagnetic data from Dmanisi all indicate an earliest Pleistocene age of about 1.7 million years ago, supporting correlation of the new specimens with the Koobi Fora fossils. The Dmanisi fossils, in contrast with Pleistocene hominids from Western Europe and Eastern Asia, show clear African affinity and may represent the species that first migrated out of Africa. PMID:10807567

  1. Locomotor energetics and leg length in hominid bipedality.

    Science.gov (United States)

    Kramer, P A; Eck, G G

    2000-05-01

    Because bipedality is the quintessential characteristic of Hominidae, researchers have compared ancient forms of bipedality with modern human gait since the first clear evidence of bipedal australopithecines was unearthed over 70 years ago. Several researchers have suggested that the australopithecine form of bipedality was transitional between the quadrupedality of the African apes and modern human bipedality and, consequently, inefficient. Other researchers have maintained that australopithecine bipedality was identical to that of Homo. But is it reasonable to require that all forms of hominid bipedality must be the same in order to be optimized? Most attempts to evaluate the locomotor effectiveness of the australopithecines have, unfortunately, assumed that the locomotor anatomy of modern humans is the exemplar of consummate bipedality. Modern human anatomy is, however, the product of selective pressures present in the particular milieu in which Homo arose and it is not necessarily the only, or even the most efficient, bipedal solution possible. In this report, we investigate the locomotion of Australopithecus afarensis, as represented by AL 288-1, using standard mechanical analyses. The osteological anatomy of AL 288-1 and movement profiles derived from modern humans are applied to a dynamic model of a biped, which predicts the mechanical power required by AL 288-1 to walk at various velocities. This same procedure is used with the anatomy of a composite modern woman and a comparison made. We find that AL 288-1 expends less energy than the composite woman when locomoting at walking speeds. This energetic advantage comes, however, at a price: the preferred transition speed (from a walk to a run) of AL 288-1 was lower than that of the composite woman. Consequently, the maximum daily range of AL 288-1 may well have been substantially smaller than that of modern people. The locomotor anatomy of A. afarensis may have been optimized for a particular ecological niche

  2. Evidence for widespread degradation of gene control regions in hominid genomes.

    Directory of Open Access Journals (Sweden)

    Peter D Keightley

    2005-02-01

    Full Text Available Although sequences containing regulatory elements located close to protein-coding genes are often only weakly conserved during evolution, comparisons of rodent genomes have implied that these sequences are subject to some selective constraints. Evolutionary conservation is particularly apparent upstream of coding sequences and in first introns, regions that are enriched for regulatory elements. By comparing the human and chimpanzee genomes, we show here that there is almost no evidence for conservation in these regions in hominids. Furthermore, we show that gene expression is diverging more rapidly in hominids than in murids per unit of neutral sequence divergence. By combining data on polymorphism levels in human noncoding DNA and the corresponding human-chimpanzee divergence, we show that the proportion of adaptive substitutions in these regions in hominids is very low. It therefore seems likely that the lack of conservation and increased rate of gene expression divergence are caused by a reduction in the effectiveness of natural selection against deleterious mutations because of the low effective population sizes of hominids. This has resulted in the accumulation of a large number of deleterious mutations in sequences containing gene control elements and hence a widespread degradation of the genome during the evolution of humans and chimpanzees.

  3. New evidence for hominid presence in the Lower Pleistocene of the Southern Levant.

    Science.gov (United States)

    Belmaker, Miriam; Tchernov, Eitan; Condemi, Silvana; Bar-Yosef, Ofer

    2002-07-01

    The site of 'Ubeidiya is located in the Jordan Valley, Israel and has been biochronologically dated to 1.5 m.y.a. It exhibits large lithic and faunal assemblages. Previous published hominid material includes a molar (UB 1701) and I(2) (UB 1700). A recent review of the faunal material from previous excavations has revealed a highly worn hominid right lateral lower incisor (UB 335). The tooth was found in situ in the Lower Pleistocene deposits of stratum I-26a, which is comprised of sand and conglomerates of flint, limestone and basalt indicative of a pebbled lakeshore environment. Taphonomic analysis of the macromammal assemblage indicates high-energy fluvial transport. Paleoecological reconstruction suggests a large woodland fauna with a small percent of open steppe species.UB 335 did not differ significantly from the Lower Pleistocene hominid and modern populations but did differ significantly from all other fossil populations. Two-tailed Student t -test and single classification Model II ANOVA of the buccolingual diameter did not distinguish between Lower Pleistocene species: Homo habilis, H. ergaster and H. cf. erectus. Thus, UB 335 can be identified as a Lower Pleistocene hominid although it cannot be securely assigned to any particular species within that time frame. The current date of the 'Ubeidiya deposits and the location of the site within the Levantine corridor suggests a tenative identification as H. ergaster. PMID:12098209

  4. Patterns and rates of enamel growth in the molar teeth of early hominids.

    Science.gov (United States)

    Beynon, A D; Wood, B A

    A recent study of the surface manifestation of incremental lines associated with enamel formation suggested that the crowns of early hominid incisor teeth were formed more rapidly than those of modern humans. In the absence of comparative data, the authors were forced to assume that enamel increments in fossil teeth were similar to those in modern humans. We have used evidence from the fractured surfaces of molar teeth to deduce estimates for both long- and short-period incremental growth markers within enamel in east African 'robust' australopithecine and early Homo teeth. We conclude that in these early hominids, crown formation times in posterior teeth, particularly in the large thick enamelled molar teeth of the east African 'robust' australopithecines, were shorter than those of modern humans. This evidence, considered together with data on crown and root formation times in modern apes, suggests that the posterior teeth in these hominids both formed and erupted more rapidly than those of modern man. These results have implications for attempts to assess dental and skeletal maturity in hominids. PMID:3104794

  5. Lapa vermelha IV Hominid 1: morphological affinities of the earliest known American

    Directory of Open Access Journals (Sweden)

    Neves Walter A.

    1999-01-01

    Full Text Available Several studies concerning the extra-continental morphological affinities of Paleo-Indian skeletons, carried out independently in South and North America, have indicated that the Americas were first occupied by non-Mongoloids that made their way to the New World through the Bering Strait in ancient times. The first South Americans show a clear resemblance to modern South Pacific and African populations, while the first North Americans seem to be at an unresolved morphological position between modern South Pacific and Europeans. In none of these analyses the first Americans show any resemblance to either northeast Asians or modern native Americans. So far, these studies have included affirmed and putative early skeletons thought to date between 8,000 and 10,000 years B.P. In this work the extra-continental morphological affinities of a Paleo-Indian skeleton well dated between 11,000 and 11,500 years B.P. (Lapa Vermelha IV Hominid 1, or "Luzia" is investigated, using as comparative samples Howells' (1989 world-wide modern series and Habgood's (1985 Old World Late Pleistocene fossil hominids. The comparison between Lapa Vermelha IV Hominid 1 and Howells' series was based on canonical variate analysis, including 45 size-corrected craniometric variables, while the comparison with fossil hominids was based on principal component analysis, including 16 size-corrected variables. In the first case, Lapa Vermelha IV Hominid 1 exhibited an undisputed morphological affinity firstly with Africans and secondly with South Pacific populations. In the second comparison, the earliest known American skeleton had its closest similarities with early Australians, Zhoukoudian Upper Cave 103, and Taforalt 18. The results obtained clearly confirm the idea that the Americas were first colonized by a generalized Homo sapiens population which inhabited East Asia in the Late Pleistocene, before the definition of the classic Mongoloid morphology.

  6. New Isotopic and Sedimentological Measurements of the Thabaseek Deposits (South Africa) and the Dating of the Taung Hominid

    Science.gov (United States)

    Tobias, Phillip V.; Vogel, John C.; Oschadleus, H. Dieter; Partridge, Timothy C.; McKee, Jeffrey K.

    1993-11-01

    Earlier attempts to date the Taung hominid type specimen of Australopithecus africanus Dart yielded conflicting results. Recent faunal studies pointed to an age of 2.3 myr. Radioisotopic results suggested 1.0 myr. New uranium studies reveal that the Thabaseek (the oldest Taung tufa) was not a closed system and that younger uranium entered the tufa after initial deposition, producing an apparent isotopic age younger than the age of deposition. The Thabaseek isotopic dates provide only a terminus ad quem and this technique is therefore not applicable to the older Taung tufas. Delson's dating (2.3 myr) of cercopithecoids from Hrdlicka's pinnacle ca. 50 m from the hominid site provides the best available approximation to the age of the hominid. In our new Taung excavation, stratigraphic analysis indicates that the hominid may somewhat predate most identified fauna. Sedimentologically the hominid matrix proves to be of fluvial deposition, and hence closely resembles one Hrdlicka deposit, both samples differing appreciably from all other Taung samples which bespeak eolian deposition. Thus, the conditions under which the hominid-bearing stratum was deposited were virtually identical to those pertaining to one of the Hrdlicka deposits. The newest results show that Taung was not the youngest South African australopithecine site and eliminate the discrepancy between the relative ages of the Taung A. africanus africanus and the Sterkfontein A. africanus transvaalensis.

  7. Direct dating of hominids using ESR and U-series dating

    Energy Technology Data Exchange (ETDEWEB)

    Gruen, R. [Australian National University, Canberra, ACT (Australia). Research School of Earth Science

    1999-11-01

    Full text: Dating studies on palaeoanthropological sites is usually carried out on material associated with the human remains, such as the sediment, charcoal or other fauna rather than the human specimen itself. The reason lies in the fact that most dating techniques are destructive and because the hominid remains are too rare to be sacrificed for dating. This indirect dating approach is in many cases not satisfactory, because:(i) the human remains are often buried into the sediments and the association with other materials is uncertain (e.g. Skhul, Qafzeh, etc.);(ii) faunal remains or minerals from the sediment are re-worked from older deposits (see e.g. present discussion of the age of the Homo erectus remains in Indonesia);(iii) the hominid specimen was discovered at a time when no careful excavations were carried out and it is impossible to correlate the specimen with other datable material (nearly 90% of all palaeoanthropological specimen). For example, the hominid burial site of Qafzeh in Israel has been dated by several independent dating laboratories with a multitude of methods. However, the data are still not accepted by some because the dating has not been carried out on the hominid specimen. Until recently, hominid fossils could only be dated by radiocarbon. This method reaches back to about 40,000 years. As a consequence, all the older fossils could not be analysed and many important questions in our understanding of human evolution could not be addressed. Human remains are scarce and extremely valuable, therefore any sort of destruction has to be kept to an absolute minimum. This is of particular importance in Australia where any human fossils are sacred. Thus, for the analysis of hominid material it was necessary to develop a more or less non-destructive techniques. This has been accomplished in recent years by the application of ESR dating of tooth enamel and a combination of gamma spectrometric and TIMS U-series dating of bones. The examples of

  8. Ecological Constraints on Hydrology in Early Hominid Environments

    Science.gov (United States)

    Magill, C.; Ashley, G. M.; Freeman, K. H.

    2010-12-01

    Paleoclimate studies increasingly apply the hydrogen isotopic composition of individual biomarkers as a proxy for the composition of environmental waters. However, the environmental, physical and ecologic influences on hydrologic signatures are complex. Here, we separate the influences of climate and physiology on the hydrogen isotopic compositions of plant and algae lipids in order to reconstruct ancient precipitation and lake waters in semi-arid East Africa using Plio-Pleistocene lake sediments from Olduvai Gorge (2°48'S, 35°06'E). We measured bulk organic δ13C and molecular δ13C and δD from perennial lacustrine sediments dated between ~1.79 and 1.95 million years ago, a time slice with recognized hominid diversification events. During this interval, bulk organic δ13C varies ~10‰ and correlates strongly with molecular δ13C signatures of alkane biomarkers derived from terrestrial plants (n-C31), which range between -20‰ and -36‰ (PDB). Molecular δD signatures of n-C31 range between ~-125‰ and -165‰ (SMOW). The δD of algal biomarkers (n-C17) range between ~-85‰ and -135‰ (SMOW). To account for physiological effects, we used the δ13C of n-C31 to estimate relative C4 monocot versus C3 dicot abundance in the Olduvai watershed, establishing a mixing line for deuterium fractionation between rainwater and plant lipids. This approach is based on models of modern ecologic succession in East Africa, where C4 monocots and C3 dicots dominate landscape biomass. In the present day, the isotopic composition of mean annual precipitation in East Africa is controlled by the ‘amount effect.’ Olduvai currently receives ~550 mm yr-1 of precipitation and δD = -10‰, with an average ‘amount effect’ of 32 mm per 7‰ change in δD, albeit based on sparse sampling. Using these constraints and assuming negligible evapotranspiration, we conservatively calculate that Olduvai experienced ~440 mm of precipitation during arid times and nearly 800 mm during

  9. Preliminary study on the living environment of hominids at the Donggutuo site,Nihewan Basin

    Institute of Scientific and Technical Information of China (English)

    PEI ShuWen; LI XiaoLi; LIU DeCheng; MA Ning; PENG Fei

    2009-01-01

    The Donggutuo site,situated in the east margin of Nihewan basin,is one of the most important Paleolithic sites in China,characterized by the longest excavation seasons and the most abundant cultural remains recovered in the region.Based on well-constructed sporopollen,sediment grain size analysis,magnetic susceptibility,and iron oxide analysis of the 2000-2001 excavated section,four stages of environmental change in the Nihewan Beds are identified by the authors.The results indicate four major stages of environment and climate change from 1) warm and humid forest grass to 2) temperate and humid forest grass to 3) temperate and dry forest grass to 4) warm and humid forest,which is suitable for hominid occupation.The changes correspond to the stages of lake transgression and regression.The environment after the lake died out away has been cold and dry boschveld.The hominid activities at the site took place in the Early Pleistocene (1.10 Ma),which corresponds to the early three environmental stages.Therefore,it can be inferred that the early hominids adapted to the relatively low lake level episodes through activities involving sporadic stone tool making,procuring of raw materials for tools,concentrating stone artifacts,and hunting and butchering.In conclusion,the results will be of great significance to research regarding the relationship between hominid occupation and environmental changes as well as the adaptive behaviors of early humans at the Donggutuo site.

  10. Uranium-series disequilibrium data for tooth fragments from the fossil hominid site at Ternifine, Algeria.

    Science.gov (United States)

    Szabo, B. J.

    1982-01-01

    I report here analyses of elephant molar-tooth fragments that were submitted by the late K.P.Oakley for uranium-series dating. The tooth fragments were collected by the late C. Arambourg from Pleistocene sand in association with the hominid fossils of Ternifine Man, Algeria. Of the results reported the minimum age of over 360 000 yr BP for the enamel appears to be the most reliable. -Authors

  11. Africa's wild C4 plant foods and possible early hominid diets.

    Science.gov (United States)

    Peters, Charles R; Vogel, John C

    2005-03-01

    A small minority of Africa's wild plant foods are C4. These are primarily the seeds of some of the C4 grasses, the rootstocks and stem/leaf bases of some of the C4 sedges (especially papyrus), and the leaves of some of the C4 herbaceous dicots (forbs). These wild food plants are commonly found in disturbed ground and wetlands (particularly the grasses and sedges). Multiple lines of evidence indicate that C4 grasses were present in Africa by at least the late Miocene. It is a reasonable hypothesis that the prehistory of the C4 sedges parallels that of the C4 grasses, but the C4 forbs may not have become common until the late Pleistocene. CAM plants may have a more ancient history, but offer few opportunities for an additional C4-like dietary signal. The environmental reconstructions available for the early South African hominid sites do not indicate the presence of large wetlands, and therefore probably the absence of a strong potential for a C4 plant food diet. However, carbon isotope analyses of tooth enamel from three species of early South African hominids have shown that there was a significant but not dominant contribution of C4 biomass in their diets. Since it appears unlikely that this C4 component could have come predominantly from C4 plant foods, a broad range of potential animal contributors is briefly considered, namely invertebrates, reptiles, birds, and small mammals. It is concluded that the similar average C4 dietary intake seen in the three South African hominid species could have been acquired by differing contributions from the various sources, without the need to assume scavenging or hunting of medium to large grazing ungulates. Effectively similar dominantly dryland paleo-environments may also be part of the explanation. Theoretically, elsewhere in southern and eastern Africa, large wetlands would have offered early hominids greater opportunities for a C4 plant diet. PMID:15737391

  12. Revisions of K/Ar ages for the Hadar hominid site, Ethiopia

    International Nuclear Information System (INIS)

    Conventional K/Ar age measurements are reported for two volcanic units from the hominid-bearing Hadar Formation. These ages represent revision of previously published ages for the BKT-2 tephra and the Kadada Moumou basalt. BKT-2 is revised from 2.65 to 2.9 Myr BP and the Kadada Moumou basalt is revised from 3.0 to 3.6 Myr BP. (author)

  13. Africa's wild C4 plant foods and possible early hominid diets.

    Science.gov (United States)

    Peters, Charles R; Vogel, John C

    2005-03-01

    A small minority of Africa's wild plant foods are C4. These are primarily the seeds of some of the C4 grasses, the rootstocks and stem/leaf bases of some of the C4 sedges (especially papyrus), and the leaves of some of the C4 herbaceous dicots (forbs). These wild food plants are commonly found in disturbed ground and wetlands (particularly the grasses and sedges). Multiple lines of evidence indicate that C4 grasses were present in Africa by at least the late Miocene. It is a reasonable hypothesis that the prehistory of the C4 sedges parallels that of the C4 grasses, but the C4 forbs may not have become common until the late Pleistocene. CAM plants may have a more ancient history, but offer few opportunities for an additional C4-like dietary signal. The environmental reconstructions available for the early South African hominid sites do not indicate the presence of large wetlands, and therefore probably the absence of a strong potential for a C4 plant food diet. However, carbon isotope analyses of tooth enamel from three species of early South African hominids have shown that there was a significant but not dominant contribution of C4 biomass in their diets. Since it appears unlikely that this C4 component could have come predominantly from C4 plant foods, a broad range of potential animal contributors is briefly considered, namely invertebrates, reptiles, birds, and small mammals. It is concluded that the similar average C4 dietary intake seen in the three South African hominid species could have been acquired by differing contributions from the various sources, without the need to assume scavenging or hunting of medium to large grazing ungulates. Effectively similar dominantly dryland paleo-environments may also be part of the explanation. Theoretically, elsewhere in southern and eastern Africa, large wetlands would have offered early hominids greater opportunities for a C4 plant diet.

  14. Dental size variation in the Atapuerca-SH Middle Pleistocene hominids.

    Science.gov (United States)

    Bermúdez de Castro, J M; Sarmiento, S; Cunha, E; Rosas, A; Bastir, M

    2001-09-01

    The Middle Pleistocene Atapuerca-Sima de los Huesos (SH) site in Spain has yielded the largest sample of fossil hominids so far found from a single site and belonging to the same biological population. The SH dental sample includes a total of 452 permanent and deciduous teeth, representing a minimum of 27 individuals. We present a study of the dental size variation in these hominids, based on the analysis of the mandibular permanent dentition: lateral incisors, n=29; canines, n=27; third premolars, n=30; fourth premolars, n=34; first molars, n=38; second molars, n=38. We have obtained the buccolingual diameter and the crown area (measured on occlusal photographs) of these teeth, and used the bootstrap method to assess the amount of variation in the SH sample compared with the variation of a modern human sample from the Museu Antropologico of the Universidade of Coimbra (Portugal). The SH hominids have, in general terms, a dental size variation higher than that of the modern human sample. The analysis is especially conclusive for the canines. Furthermore, we have estimated the degree of sexual dimorphism of the SH sample by obtaining male and female dental subsamples by means of sexing the large sample of SH mandibular specimens. We obtained the index of sexual dimorphism (ISD=male mean/female mean) and the values were compared with those obtained from the sexed modern human sample from Coimbra, and with data found in the literature concerning several recent human populations. In all tooth classes the ISD of the SH hominids was higher than that of modern humans, but the differences were generally modest, except for the canines, thus suggesting that canine size sexual dimorphism in Homo heidelbergensis was probably greater than that of modern humans. Since the approach of sexing fossil specimens has some obvious limitations, these results should be assessed with caution. Additional data from SH and other European Middle Pleistocene sites would be necessary to test

  15. A cranium for the earliest Europeans: Phylogenetic position of the hominid from Ceprano, Italy

    OpenAIRE

    Manzi, G; F. Mallegni; Ascenzi, A.

    2001-01-01

    The human fossil evidence unequivocally pertaining to the first inhabitants of Europe at present includes the sample from Atapuerca-TD6 (Spain) and the incomplete adult calvaria discovered near Ceprano, in Southern Latium (Italy). On the basis of regional correlations and a series of absolute dates, the age of the Ceprano hominid is estimated to range between 800 and 900 kilo-annum (ka). In addition, the association with archaic (Mode 1) Paleolithic findings from the s...

  16. Pattern of dental development in Hominid XVIII from the Middle Pleistocene Atapuerca-Sima de los Huesos site (Spain).

    Science.gov (United States)

    Bermudez De Castro, J M; Rosas, A

    2001-04-01

    . We describe the pattern of dental development of Hominid XVIII from the Middle Pleistocene Sima de los Huesos (SH) site of the Sierra de Atapuerca (Burgos, Spain). As expected, this pattern is similar to that of modern humans. A delay of development of the lower and upper canines was observed. In contrast, the relative advanced development of the lower second molars and, especially, the upper and lower third molars is noteworthy. This latter feature seems to be common in Pleistocene hominids, and suggests that the pattern of dental development evolved in the genus Homo during the Pleistocene. In European Middle Pleistocene hominids, this pattern probably was facilitated by the extra space available in the mandible and maxilla for developing teeth. PMID:11275961

  17. Human taxonomic diversity in the pleistocene: does Homo erectus represent multiple hominid species?

    Science.gov (United States)

    Kramer, A

    1993-06-01

    Recently, nomina such as "Homo heidelbergensis" and "H. ergaster" have been resurrected to refer to fossil hominids that are perceived to be specifically distinct from Homo sapiens and Homo erectus. This results in a later human fossil record that is nearly as speciose as that documenting the earlier history of the family Hominidae. However, it is agreed that there remains only one extant hominid species: H. sapiens. Has human taxonomic diversity been significantly pruned over the last few hundred millennia, or have the number of taxa been seriously overestimated? To answer this question, the following null hypothesis is tested: polytypism was established relatively early and the species H. erectus can accommodate all spatio-temporal variation from ca. 1.7 to 0.5 Ma. A disproof of this hypothesis would suggest that modern human polytypism is a very recent phenomenon and that speciation throughout the course of human evolution was the norm and not the exception. Cranial variation in a taxonomically mixed sample of fossil hominids, and in a modern human sample, is analyzed with regard to the variation present in the fossils attributed to H. erectus. The data are examined using both univariate (coefficient of variation) and multivariate (determinant) analyses. Employing randomization methodology to offset the small size and non-normal distribution of the fossil samples, the CV and determinant results reveal a pattern and degree of variation in H. erectus that most closely approximates that of the single species H. sapiens. It is therefore concluded that the null hypothesis cannot be rejected. PMID:8317558

  18. Huanglong Cave, a new late Pleistocene hominid site in Hubei Province, China

    Institute of Scientific and Technical Information of China (English)

    WU Xianzhu; LIU Wu; GAO Xing; YIN Gongming

    2006-01-01

    For the past 20 years the modern human origins debate has received a significant amount of attention in paleoanthropological research. Primarily supported by the evidence of earlier dates of anatomically modern human fossils and genetic studies, the "Out of Africa" hypothesis is based on the belief that the ancestor of all modern humans, including modern Chinese, came from Africa. The opposite hypothesis "Mutiregional evolution" proposes that continuous evolution occurred on a regional scale, for which human paleontology offers strong support. However, due to the paucity of hominid fossils in China between 100 and 50 ka, support to the latter hypothesis is currently weak. This is a report here of five human fossil teeth, and associated stone tools and mammal fossils from a newly discovered cave site, Huanglong Cave, located in Yunxi County,Hubei Province, China. Preliminary studies indicate:(1) the morphological features of the human fossils resemble those of late Pleistocene human fossils from China; (2) the stone tools display patterns of both the southern and northern Paleolithic cultures of China; (3) the mammal fossils represent the "Ailuropoda-Stegodon" faunal unit which lived in southern China throughout the Pleistocene. ESR and U-series dating on animal teeth and a stalagmite derived from the same layer as the human teeth indicate two possible ages: 103±1.6 ka and 44±12.5 ka. In addition to other evidence presented here, it is believed that hominid occupation of the cave was likely around 100 ka. If this age is further substantiated, Huanglong Cave will be the first late Pleistocene hominid fossil site in China where anatomically modern humans lived about 100 ka. The human fossils and other related materials from Huanglong Cave will provide important information for research on the origin of modern Chinese.

  19. Hominid mandibular corpus shape variation and its utility for recognizing species diversity within fossil Homo.

    Science.gov (United States)

    Lague, Michael R; Collard, Nicole J; Richmond, Brian G; Wood, Bernard A

    2008-12-01

    Mandibular corpora are well represented in the hominin fossil record, yet few studies have rigorously assessed the utility of mandibular corpus morphology for species recognition, particularly with respect to the linear dimensions that are most commonly available. In this study, we explored the extent to which commonly preserved mandibular corpus morphology can be used to: (i) discriminate among extant hominid taxa and (ii) support species designations among fossil specimens assigned to the genus Homo. In the first part of the study, discriminant analysis was used to test for significant differences in mandibular corpus shape at different taxonomic levels (genus, species and subspecies) among extant hominid taxa (i.e. Homo, Pan, Gorilla, Pongo). In the second part of the study, we examined shape variation among fossil mandibles assigned to Homo (including H. habilis sensu stricto, H. rudolfensis, early African H. erectus/H. ergaster, late African H. erectus, Asian H. erectus, H. heidelbergensis, H. neanderthalensis and H. sapiens). A novel randomization procedure designed for small samples (and using group 'distinctness values') was used to determine whether shape variation among the fossils is consistent with conventional taxonomy (or alternatively, whether a priori taxonomic groupings are completely random with respect to mandibular morphology). The randomization of 'distinctness values' was also used on the extant samples to assess the ability of the test to recognize known taxa. The discriminant analysis results demonstrated that, even for a relatively modest set of traditional mandibular corpus measurements, we can detect significant differences among extant hominids at the genus and species levels, and, in some cases, also at the subspecies level. Although the randomization of 'distinctness values' test is more conservative than discriminant analysis (based on comparisons with extant specimens), we were able to detect at least four distinct groups among the

  20. A new horned crocodile from the Plio-Pleistocene hominid sites at Olduvai Gorge, Tanzania.

    Directory of Open Access Journals (Sweden)

    Christopher A Brochu

    Full Text Available BACKGROUND: The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian diversity in Africa persisted after the Miocene. It had prominent triangular "horns" over the ears and a relatively deep snout, these resemble those of the recently extinct Malagasy crocodile Voay robustus, but the new species lacks features found among osteolaemines and shares derived similarities with living species of Crocodylus. METHODOLOGY/PRINCIPAL FINDINGS: The holotype consists of a partial skull and skeleton and was collected on the surface between two tuffs dated to approximately 1.84 million years (Ma, in the same interval near the type localities for the hominids Homo habilis and Australopithecus boisei. It was compared with previously-collected material from Olduvai Gorge referable to the same species. Phylogenetic analysis places the new form within or adjacent to crown Crocodylus. CONCLUSIONS/SIGNIFICANCE: The new crocodile species was the largest predator encountered by our ancestors at Olduvai Gorge, as indicated by hominid specimens preserving crocodile bite marks from these sites. The new species also reinforces the emerging view of high crocodylian diversity throughout the Neogene, and it represents one of the few extinct species referable to crown genus Crocodylus.

  1. Subnasal morphological variation in fossil hominids: a reassessment based on new observations and recent developmental findings.

    Science.gov (United States)

    McCollum, M A

    2000-06-01

    Quantitative and qualitative assessments of subnasal morphology in fossil hominids yield distinct patterns which have been used both to sort robust from nonrobust australopithecine taxa and to distinguish individual species. Recently, new developmental models have been applied to hominoid subnasal morphological variation. These studies require that certain features of the fossil hominid subnasal region, in particular the topography of the nasal cavity entrance and details of vomeral morphology, be reevaluated. This study does so for the robust and nonrobust australopithecines, early Homo (H. habilis/H. rudolfensis), and African H. erectus. Results reaffirm an overall similarity of the nonrobust Australopithecus subnasal morphological pattern with that of the chimpanzee. They further indicate that a vomeral insertion above the nasal surface of the premaxilla should be added to the list of traits characteristic of the robust australopithecine subnasal morphological pattern. Finally, reassessment of subnasal morphology in the early Homo and H. erectus samples from Africa suggest that these two taxa share a similar subnasal morphological pattern. This pattern consists of a smooth nasal cavity entrance, a horizontal nasal sill whose anterior edge is demarcated by a strong nasal crest, and a well-developed horizontal spine at the posterior edge of the nasal sill. Although none of the African fossil Homo specimens preserve a vomer, indirect evidence suggests that it would have inserted above the nasal sill. PMID:10813707

  2. Variation in hominid brain size: how much is due to method?

    Science.gov (United States)

    De Miguel, C; Henneberg, M

    2001-01-01

    Brain size represented by cranial capacity (CC) is one of the most frequently analysed characters of hominids. Accuracy of individual CC estimates depends on completeness of specimens and methods used for reconstruction and measurement. A file of published estimates of CC of hominids dated from 3.2 Ma (million years) to 10 Ka (thousand years) including 606 estimates for 243 specimens was compiled. In the file, 75 specimens are available with multiple values (3 to 15) obtained by various methods and/or by various authors. Using individuals as classes in ANOVA, intraclass variation, which represents "error" of estimates, was calculated. For the total sample of multiple estimates (N = 382) the error variance is 5315 ml2. The error standard deviation is 73 ml (coefficient of variation (CV = 7.3%), quite large in comparison to the actual variation in CC in modern humans, SD = 157 ml (CV = 11.6%). This large error makes us wonder whether any fossil can be reliably placed with respect to a particular "cerebral Rubicon" between palaeospecies. Recent discussions concerning cranial capacity of Stw505 are a case in point regarding errors in CC estimation. In actual repeated 30 time measurements on a research quality cast we obtained with various methods (water, seeds, plasticine) CC estimates ranging from 484 to 586 ml. The range of estimates in the literature is from 515 to 625 ml. When hominid CC by taxon with date as a covariate is subjected to ANOVA, taxon is responsible for 5% of the variance while date is responsible for the main portion, (89%). The relationship between CC and date is best characterised as a gradual time trend. It is proven by the ANOVA test for linearity, by gamma test for trend and by ASReml fitting of a linear function. The line of best fit to this time trend is a double exponential curve which explains 90% of the total variance in CC: CC = 306.63 (4.83(0.9995)DATE) Essentially the same curve fits subsamples of CC dated at less than 1 Ma and at 3

  3. Pedo-sedimentary dynamics of the Sangiran dome hominid bearing layers (Early to Middle Pleistocene, central Java, Indonesia) : a palaeopedological approach for reconstructing 'Pithecanthropus' (Javanese Homo erectus) palaeoenvironment

    OpenAIRE

    Brasseur, B.; Sémah, F.; Sémah, Anne-Marie; Djubiantono, T.

    2015-01-01

    Fossil soils and pedosediments displayed in Quaternary fossil-bearing formations are an important proxy to describe the evolution of climates and environments. Through a study of the palaeosols in the Sangiran dome, a rich hominid-bearing site of central Java (Indonesia), we characterized their record of terrestrialization through regional volcano-tectonic activity and describe palaeoenvironments colonized by hominids. The thick sedimentary formations of the Sangiran dome are known to reflect...

  4. Radiometric dating of quaternary deposits and the hominid mandible of lake banyolas, Spain

    Science.gov (United States)

    Julia, R.; Bischoff, J.L.

    1991-01-01

    We report results of U-series analyses of the travertine matrix surrounding the Banyolas mandible that indicate an age of 45??4 ka bp. The mandible, an archaic hominid fossil generally deemed of mid-Pleistocene age, was recovered from a travertine matrix in 1887. Similar analyses on 21 travertine samples from quarries near the discovery site yield coherent U-series dates in correct stratigraphic order, ranging from 44 ka bp to 117 ka bp. Isotopic composition of these samples and the mandible matrix show no evidence of open system behaviour. Coherent isotopic results from adjacent quarries support the validity of the date on the mandible travertine, and we conclude the mandible is much younger than previously believed. ?? 1991.

  5. Hominid cranium from Omo: Description and taxonomy of Omo-323-1976-896.

    Science.gov (United States)

    Alemseged, Zeresenay; Coppens, Yves; Geraads, Denis

    2002-02-01

    Omo-323-1976-896, a partial hominid cranium dated to ca. 2.1 from the Member G, Unit G-8 of the Shungura Formation, lower Omo Basin of Ethiopia, is described. It is suggested that the specimen is an adult male based on the well-developed and completely fused sagittal crest; heavily worn teeth; relatively large canine; and size of the articular eminence. Omo-323 consists of fragments of the frontal, both temporals, occipital, parietals, and the right maxilla, and is attributed to Australopithecus boisei, making it the oldest known cranium of this species. The specimen shares features with Australopithecus aethiopicus (KNM-WT 17000), thus supporting the existence of an evolving East African robust lineage between ca. 2.6-1.2 Ma. The morphology of Omo-323 increases our knowledge of the intraspecific variability of A.boisei. PMID:11815945

  6. On the age of the hominid fossils at the Sima de los Huesos, Sierra de Atapuerca, Spain: paleomagnetic evidence.

    Science.gov (United States)

    Parés, J M; Pérez-González, A; Weil, A B; Arsuaga, J L

    2000-04-01

    We report new paleomagnetic data for the Middle Pleistocene hominid-bearing strata in the Sima de los Huesos, North Spain. Sediments (brown muds with human and bear fossils and the underlying sterile clayey and sandy unit) preserve both normal and reversed magnetic components. The sterile unit has exclusively reversed magnetization, dating back to the Matuyama Chron, and thus is Lower Pleistocene in age. The overlying fossiliferous muds have a dominant normal magnetization that overprints a partially resolved reversed magnetization. These data are compatible with one of the reversal events that occurred during the Brunhes Chron. Combined with the existing U-series dates and evidence from the macro- and microfauna, these paleomagnetic results suggest an age of the hominid fossils between 325 to 205 ka, whereas the underlying sand and silts are older than 780 ka. PMID:10727965

  7. Hominid dispersal into Europe around the Matuyama/Brunhes boundary: origin and significance in human evolution

    Directory of Open Access Journals (Sweden)

    García Sánchez, Eduardo

    2006-06-01

    Full Text Available A review of the European Lower Palaeolithic record shows three human dispersal episodes. The second one is dated between OIS25/OIS24-OIS19/OIS18. It is recorded by lithic assemblages and human remains that point to an eastern Asian origin. This paper reviews this hominid dispersal, related to the Galerian faunal event. Also we analyse the most feasible migratory routes, and the reasons of its abrupt ending. The phylogenetic relationships of these populations are also proposed, putting their context into the human evolutionary sequences of the Lower and Middle Pleistocene.

    La revisión del registro inferopaleolítico europeo permite identificar tres episodios de poblamiento. El segundo de los mismos, datado entre OIS25/OIS24-OIS19/OIS18, ofrece industrias líticas y fósiles humanos que indican un posible origen esteasiático. Se ofrece una síntesis sobre este episodio de dispersión, relacionado con el reemplazo de faunas galerienses. Se analizan las posibles vías migratorias que siguió y los motivos que pudieron ocasionar su interrupción. También se plantean las relaciones filogenéticas de estas poblaciones, insertándolas en el marco evolutivo del Pleistoceno inferior y medio.

  8. A cranium for the earliest Europeans: phylogenetic position of the hominid from Ceprano, Italy.

    Science.gov (United States)

    Manzi, G; Mallegni, F; Ascenzi, A

    2001-08-14

    The human fossil evidence unequivocally pertaining to the first inhabitants of Europe at present includes the sample from Atapuerca-TD6 (Spain) and the incomplete adult calvaria discovered near Ceprano, in Southern Latium (Italy). On the basis of regional correlations and a series of absolute dates, the age of the Ceprano hominid is estimated to range between 800 and 900 kilo-annum (ka). In addition, the association with archaic (Mode 1) Paleolithic findings from the same area is suggested. After the completed reconstruction of the calvaria, we present here a new study dealing with the general and more detailed aspects of the morphology displayed by Ceprano, in comparison to fossil samples ranging between Early and Middle Pleistocene. According to our results, cranial features indicate that Ceprano represents a unique morphological bridge between the clade Homo ergaster/erectus and later Middle Pleistocene specimens commonly referred to Homo heidelbergensis (and/or to Homo rhodesiensis), particularly those belonging to the African fossil record that ultimately relates to the origin of modern humans. In conclusion, given its geographical, chronological, and phylogenetic position, an attribution to the species Homo antecessor is considered, although the sample from Atapuerca-TD6 is not directly comparable to Ceprano. Alternatively, a new species-ancestral to later European and African hominines-should be named to accommodate such a unique fossil specimen. PMID:11504953

  9. Elucidating the evolution of hominid dentition in the age of phenomics, modularity, and quantitative genetics.

    Science.gov (United States)

    Hlusko, Leslea J

    2016-01-01

    An organism's anatomy is the result of millions of years of interplay between DNA sequence, developmental processes, the environment, and evolutionary forces. The anatomical sciences are consequently highly integrative and interdisciplinary. That said, reaching across all of the relevant disciplines can be a daunting task because scientific publications are produced today at an astounding rate. This manuscript brings together insights from the quantitative genetic analysis of dental variation into the study of human evolutionary odontology within the context of genomics, genetic modularity, and phenomics. It primarily advocates the use of quantitative genetics to not only identify QTLs, but also to assess the patterns of genetic covariance that underlie phenotypic covariance, thereby enabling us to conceptualize phenotypic variation as a reflection of the underlying genetic mechanisms. By highlighting three phenotypes of importance within the study of human evolution (patterning of the dental arcade, enamel thickness, and taurodontism), it is demonstrated how an integrated consideration of quantitative genetics, genomic analyses, and paleontology can bring us to more detailed hypotheses about the evolution of the hominid clade.

  10. Analysis of the dental morphology of Plio-Pleistocene hominids. V. Maxillary postcanine tooth morphology.

    Science.gov (United States)

    Wood, B A; Engleman, C A

    1988-12-01

    A total of 139 maxillary molar crowns and 79 maxillary premolar crowns, from at least 98 individual East and Southern African Plio-Pleistocene hominids, has been subjected to detailed morphometric analysis. All but 16 of the 98 specimens were assigned to taxonomic categories identified as EAFROB, EAFHOM, SAFGRA, SAFROB and EAFHER. The analysis was based on whole crowns and the component cusps. While there was variable overlap between the ranges of measured crown base area of the two Southern African taxa, there was little, or no, overlap between the two major East African taxonomic categories. Crown shape distinguished EAFHOM from the three other australopithecine taxa, especially for P3, P4 and M1. Of the non-metrical traits, the expression of Carabelli's complex and the incidence of a distal cuspule discriminate best between the categories. Analysis of the absolute and relative cusp area data shows that the major taxonomic distinction in relative cusp area is in the premolars, in which it is apparent that EAFROB are distinguished by their larger buccal cusps. The principal conclusions of the assessment of the specimens in the 'unknown' category is that the postcanine dentitions of a skull, KNM-ER 1805, and a cranium, KNM-ER 1813, are closest in size and shape to EAFHOM. There is no dental evidence to suggest that these specimens should be assigned to A. africanus, the formal taxon making up the SAFGRA category. PMID:3254883

  11. Fifth metatarsal morphology does not predict presence or absence of fibularis tertius muscle in hominids.

    Science.gov (United States)

    Eliot, D J; Jungers, W L

    2000-02-01

    The leg muscle fibularis tertius (formerly peroneus tertius) is occasionally absent in humans, but it is rarely found in other primates. Phylogenetically and functionally it appears to be linked to efficient terrestrial bipedalism. An osseous indicator of the muscle would therefore be useful for interpreting the locomotor behavior of fossil hominids. To determine whether the presence of fibularis tertius can be detected osteologically, we isolated 58 human fifth metatarsals, noting which came from cadavers lacking the muscle. The bones were then ranked according to two characters that have been said to suggest presence of fibularis tertius in australopithecines: (1) sharpness of the dorsal shaft edge and (2) size and prominence of the dorsal tubercle. Presence of the muscle showed little association with the ranked characters, and the two criteria were uncorrelated. For example, one individual lacking a fibularis tertius exhibited nearly maximal expression of both features, whereas another possessing the muscle showed the weakest development of both. Only one of the 58 bones had a line comparable to that seen on SK 33380, a robust australopithecine fifth metatarsal from Member 3 of Swartkrans, South Africa. We conclude that fifth metatarsal morphology offers little reliable information about the presence of fibularis tertius or the timing of its appearance in the human career. PMID:10656782

  12. Pliocene and pleistocene hominid-bearing sites from west of lake turkana, kenya.

    Science.gov (United States)

    Harris, J M; Brown, F H; Leakey, M G; Walker, A C; Leakey, R E

    1988-01-01

    Pliocene and Pleistocene fossil localities near the western shoreline of Lake Turkana, ranging in age between 1 million and 3.5 million years in age, have produced important new hominid specimens including most of a Homo erectus skeleton and a relatively complete early robust australopithecine cranium. The lacustrine, fluviatile, and terrestrial strata are designated the Nachukui Formation, which is subdivided into eight members. The distribution of sedimentary facies within the Nachukui Formation suggests that, as today, the Labur and Murua Rith ranges formed the western margin of the basin and were drained by eastward-flowing rivers that fed into the forerunner of the present lake or a major river system. There is also stratigraphic evidence for tectonic movement during the deposition of these sediments. Twenty-three of the tuffs observed in the succession occur also in the Koobi Fora Formation east of the lake and in the Shungura Formation of the lower Omo Valley and permit precise correlation among these three localities. Fortyseven fossiliferous sites from West Turkana have yielded more than 1000 specimens of 93 mammalian species. The mammalian fossils represent nine sequential assemblages that augment information about faunal and environmental change from elsewhere in the basin. PMID:17820626

  13. Basicranial anatomy of Plio-Pleistocene hominids from East and South Africa.

    Science.gov (United States)

    Dean, M C; Wood, B A

    1982-10-01

    The results of a metrical analysis of the basicranium of 19 Plio-Pleistocene fossil hominid crania are presented. The sample includes crania attributed to Australopithecus africanus, Australopithecus boisei, and robustus, and Homo erectus as well as crania whose attribution is still under discussion. These results confirm significant differences between the cranial base patterns of the "gracile" and "robust" australopithecines and the three crania attributed to Homo erectus have a pattern which resembles that of modern humans. None of the crania examined from East Africa sites have base patterns which resemble that of the "gracile" australopithecines. The crania KNM-ER 407 and 732 have patterns which are compatible with them being smaller-bodied females of Australopithecus boisei; KNM-ER 1470 and 1813 have base patterns which most closely resemble that of Homo erectus. The cranial base pattern of KNM-ER 1805 is compatible with its inclusion in either Australopithecus boisei or Homo. When account is taken of the immaturity of Taung, the evidence of its cranial base pattern suggests that if it had reached adulthood it would have resembled the "gracile" australopithecine crania from Sterkfontein and Makapansgat. PMID:6816071

  14. 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. PMID:15164343

  15. Geometric pattern of the hominoid hallucal tarsometatarsal complex. Quantifying the degree of hallux abduction in early hominids

    Science.gov (United States)

    Berillon, Gilles

    1999-05-01

    The degree of hallux abduction in extant and fossil hominoids is analysed in terms of geometric relationships between the first metatarsal and the medial cuneiform and quantified by angular data, in relation to grasping ability and locomotor pattern. The 'australopithecine' pattern corresponds to an abducted first podal ray with some grasping abilities and seems to be derived from a ' Proconsul-like' pattern rather than a 'living African great ape-like' pattern. The Olduvai Hominid 8 condition closely resembles that of the modern human which corresponds to a full bipedalism.

  16. Mandibular postcanine dentition from the Shungura Formation, Ethiopia: crown morphology, taxonomic allocations, and Plio-Pleistocene hominid evolution.

    Science.gov (United States)

    Suwa, G; White, T D; Howell, F C

    1996-10-01

    Over 200 hominid specimens were recovered by the International Omo Expedition of 1967-1976. Despite the fragmentary nature of this primarily dental collection, these hominid remains represent a major body of evidence about hominid evolution in eastern Africa during the 2-3 myr time period. Our analysis of the Omo dental collection is based on a large comparative sample of 375 quantifiable mandibular postcanine teeth of A. afarensis, A. africanus, A. aethiopicus, A. boisei, A. robustus, and early Homo. A total of 48 isolated mandibular premolars and molars of the Omo collection spanning the 2-3 myr time period is sufficiently preserved to allow reliable serial allocations and intertaxon comparisons and is the object of study in this paper. We present taxonomic identifications of these teeth and seven other mandibular specimens preserving tooth crowns. Metric analyses of this study include cusp area and crown shape variables taken on occlusal view diagrams. Nonmetric analyses were based on simultaneous observations of all relevant material to ensure accuracy of categorical evaluations. First, a combined metric and morphological evaluation was conducted to allocate each Omo tooth to either robust or nonrobust categories. Further taxonomic affinities were then examined. Our results indicate that nonrobust and robust lineages cooccur by circa 2.7 myr. We consider the Shungura robust specimens from Members C through F to represent A. aethiopicus. A significant phenetic transformation occurs at circa 2.3 myr, with the mosaic emergence of the derived A. boisei morphology across Member G times. Characterization of the East African nonrobust lineage is more difficult because of the comparatively subtle morphological differences seen among the dentitions of A. afarensis, A. africanus, and early Homo. The earlier Members B and C nonrobust specimens are difficult to evaluate and are considered indeterminate to genus or species. Both molars and premolars from Members E through G

  17. The Great Ape Project: legislating for the control of the use of non-human hominids in research, testing and teaching--Animal Welfare Act 1999 (New Zealand).

    Science.gov (United States)

    Wells, Neil

    2004-06-01

    The Animal Welfare Act 1999 (New Zealand), which commenced on January 1 2000, provides that the use of non-human hominids in research, testing or teaching is not permitted unless the Director-General of Agriculture approves the use, and then, only if the use is in the interests of the non-human hominid itself or its species. The Animal Welfare Act 1999 originated with two parliamentary bills. The first, a private member's bill in the name of Pete Hodgson MP, was tabled in 1997, and the second, a Government measure, was tabled a year later. Neither bill made any reference to non-human hominids. The Great Ape Project made submissions that non-human hominids be afforded similar rights to humans, i.e. not to be deprived of life, not to be subjected to torture or cruel treatment and not to be subjected to medical or scientific experimentation. Proponents and opponents of the measure argued for and against the tenet of introducing "rights" issues into what was essentially "welfare" legislation. These arguments are analysed, and the legislative process that enabled this modification is examined.

  18. Analysis of the dental morphology of Plio-Pleistocene hominids. III. Mandibular premolar crowns.

    Science.gov (United States)

    Wood, B A; Uytterschaut, H

    1987-10-01

    Accurate measurements were made of the overall size of both the crown and its components of 91 mandibular premolar teeth of early hominids. The shape of the crown outline and the fissure pattern, and the expression of four morphological traits, were also recorded. Non-dental criteria were used to allocate the specimens into four major taxonomic categories (EAFROB, EAFHOM, SAFROB and SAFGRA), approximating to the hypodigms of, respectively, A. boisei, H. habilis and Homo sp., A. robustus and A. africanus. Those specimens that could not be so allocated were regarded as 'unknown'. Intertaxonomic overall size differences were established for both the P3 and P4, with the latter showing little overlap in crown size between the three taxonomic categories usually associated with East African sites (i.e. EAFROB, EAFHOM and SAFGRA). Crown shape is a better discriminator between taxonomic groups for P3 than for P4, with the P3s of EAFHOM showing less buccolingual expansion than the other taxonomic categories. Cusp number, the location of the lingual cusp and the expression of the median longitudinal fissure, show systematic variation between the main taxonomic categories, with the 'robust' taxa being distinguished by additional distal cusps, and a more deeply incised median longitudinal fissure, and EAFHOM being peculiar in having a distally situated lingual cusp. Marginal grooves show more overlap in their incidence and expression between taxonomic categories. Both the 'robust' australopithecine taxonomic categories have relatively large talonids, apparently at the expense of the size of the buccal cusp. The relative talonid enlargement was greater for P3 than for P4, a conclusion which is at variance with previous published assessments. Investigation of the allometric relationships between relative talonid size and overall crown size in the pooled 'non-robust' taxonomic categories did not suggest that talonid enlargement was a simple consequence of a larger-size crown. The

  19. Effects of size and locomotor adaptations on the hominid pelvis: evaluation of australopithecine bipedality with a new multivariate method.

    Science.gov (United States)

    Berge, C; Kazmierczak, J B

    1986-01-01

    Three pelves and eight innominate bones belonging to the fossil species, Australopithecus africanus, Australopithecus robustus, Homo erectus, and Homo sapiens, have been studied biometrically and compared with those of recent humans and apes. A new method of logarithmic factorial analysis suppresses both the size effects and the size reference on pelvic proportions. In combination with principal component analysis it allows specializations to be dissociated from allometrical variations. Some morphological differences on the hominid pelvis prove to be mainly allometric. However, the pelvic morphology of australopithecines is clearly differentiated from that of the genus Homo (including H. erectus, OH 28, KNMER 3227). A. africanus (Sts 14, MLD 7, AL 288) is nearer the humans than is A. robustus (SK 50, SK 3155), which appears to be more specialized in the australopithecine lineage. The pelvic morphology of A. africanus, as integrated with the articular pelvic-femoral link, appears to be biometrically equivalent to that of humans. PMID:3104176

  20. Cut marks and terminal Pleistocene hominids in the Ma'anshan site:Evidence for meat-eating

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yue; WANG ChunXue; ZHANG ShuangQuan; GAO Xing

    2009-01-01

    In this paper,cut marks on the long bones of class Ⅱ sized animals in the Ma'anshann site are studied.Based on the location and frequencies of the long bone cut marks,the distribution characteristics are analyzed as follows:(1) cut mark frequencies in the lower layer (LL) are much higher than those of the upper;(2) in the LL cut mark frequency of the upper limbs is the highest,and that of the middle and lower limbs is lower and the lowest;(3) In the upper layer (UL) the cut mark frequency,does not spread as orderly as in the LL.The data are compared to those of the experiment and it is demonstrated that values of the LL all fall into the experimental 95% confidence intervals,and the cut mark frequencies of the upper,middle and lower limbs coincide with those of the experiment;while the values of the UL are much lower,of which,those of the humerus,femur and radius are out of the intervals,and the frequencies of the upper,middle and lower limbs are far more different from those of the experiment.It implies that the earlier hominids (of the LL) defleshed the limbs of the class Ⅱ sized animals with stone tools more completely than the later hominids.With the evidence of burning marks,it is suggested that the difference on the roasting behaviors derived the cut mark difference of the Ma'anshan UL and LL.

  1. The Sima de los Huesos hominids date to beyond U/Th equilibrium (>350 kyr) and perhaps to 400-500 kyr: New radiometric dates

    Science.gov (United States)

    Bischoff, J.L.; Shamp, D.D.; Aramburu, Arantza; Arsuaga, J.L.; Carbonell, E.; Bermudez de Castro, Jose Maria

    2003-01-01

    The Sima de los Huesos site of the Atapuerca complex near Burgos, Spain contains the skeletal remains of at least 28 individuals in a mud breccia underlying an accumulation of the Middle Pleistocene cave bear (U. deningeri). Earlier dating estimates of 200 to 320 kyr were based on U-series and ESR methods applied to bones, made inaccurate by unquantifiable uranium cycling. We report here on a new discovery within the Sima de los Huesos of human bones stratigraphically underlying an in situ speleothem. U-series analyses of the speleothem shows the lower part to be at isotopic U/Th equilibrium, translating to a firm lower limit of 350 kyr for the SH hominids. Finite dates on the upper part suggest a speleothem growth rate of c. 1 cm/32 kyr. This rate, along with paleontological constraints, place the likely age of the hominids in the interval of 400 to 600 kyr. ?? 2002 Elsevier Science Ltd. All rights reserved.

  2. Longitudinal study of dental development in chimpanzees of known chronological age: implications for understanding the age at death of Plio-Pleistocene hominids.

    Science.gov (United States)

    Anemone, R L; Mooney, M P; Siegel, M I

    1996-01-01

    Reconstruction of life history variables of fossil hominids on the basis of dental development requires understanding of and comparison with the pattern and timing of dental development among both living humans and pongids. Whether dental development among living apes or humans provides a better model for comparison with that of Plio-Pleistocene hominids of the genus Australopithecus remains a contentious point. This paper presents new data on chimpanzees documenting developmental differences in the dentitions of modern humans and apes and discusses their significance in light of recent controversies over the human or pongid nature of australopithecine dental development. Longitudinal analysis of 299 lateral head radiographs from 33 lab-reared chimpanzees (Pan troglodytes) of known chronological age allows estimation of means and standard deviations for the age at first appearance of 8 developmental stages in the mandibular molar dentition. Results are compared with published studies of dental development among apes and with published standards for humans. Chimpanzees are distinctly different from humans in two important aspects of dental development. Relative to humans, chimpanzees show advanced molar development vis a vis anterior tooth development, and chimpanzees are characterized by temporal overlap in the calcification of adjacent molar crowns, while humans show moderate to long temporal gaps between the calcification of adjacent molar crowns. In combination with recent work on enamel incremental markers and CAT scans of developing dentitions of Plio-Pleistocene hominids, this evidence supports an interpretation of a rapid, essentially "apelike" ontogeny among australopithecines. PMID:8928715

  3. Stable isotope-based Plio-Pleistocene ecosystem reconstruction of some of the earliest hominid fossil sites in the East African Rift System (Chiwondo Beds, N Malawi)

    Science.gov (United States)

    Lüdecke, Tina; Thiemeyer, Heinrich; Schrenk, Friedemann; Mulch, Andreas

    2014-05-01

    The isotope geochemistry of pedogenic carbonate and fossil herbivore enamel is a powerful tool to reconstruct paleoenvironmental conditions in particular when climate change plays a key role in the evolution of ecosystems. Here, we present the first Plio-Pleistocene long-term carbon (δ13C), oxygen (δ18O) and clumped isotope (Δ47) records from pedogenic carbonate and herbivore teeth in the Malawi Rift. These data represent an important southern hemisphere record in the East African Rift System (EARS), a key region for reconstructing vegetation patterns in today's Zambezian Savanna and correlation with data on the evolution and migration of early hominids across the Inter-Tropical Convergence Zone. As our study site is situated between the well-known hominid-bearing sites of eastern and southern Africa in the Somali-Masai Endemic Zone and Highveld Grassland it fills an important geographical gap for early hominid research. 5.0 to 0.6 Ma fluviatile and lacustrine deposits of the Chiwondo Beds (NE shore of Lake Malawi) comprise abundant pedogenic carbonate and remains of a diverse fauna dominated by large terrestrial mammals. These sediments are also home to two hominid fossil remains, a mandible of Homo rudolfensis and a maxillary fragment of Paranthropus boisei, both dated around 2.4 Ma. The Chiwondo Beds therefore document early co-existence of these two species. We evaluate δ13C data from fossil enamel of different suid, bovid, and equid species and contrast these with δ13C and δ18O values of pedogenic carbonate. We complement the latter with clumped isotope soil temperature data. Results of almost 800 pedogenic carbonate samples from over 20 sections consistently average δ13C = -8.5 ‰ over the past 5 Ma with no significant short-term δ13C excursions or long-term trends. The data from molar tooth enamel of nine individual suids of the genera Metridiochoerus, Notochoerus and Nyanzachoerus support these findings with average δ13C = -10.0 ‰. The absence

  4. The view from the Lincoln Cave: mid- to late Pleistocene fossil deposits from Sterkfontein hominid site, South Africa.

    Science.gov (United States)

    Reynolds, S C; Clarke, R J; Kuman, K A

    2007-09-01

    The Lincoln-Fault cave system lies adjacent to the Sterkfontein Cave system in the Cradle of Humankind World Heritage Site, Gauteng Province, South Africa. Lincoln Cave contains a mid- to late Pleistocene fossiliferous deposit which has been dated using uranium series methods to between 252,600+/-35,600 and 115,300+/-7,700 years old. Although speleologists presumed that there was no connection between the Lincoln Cave and Sterkfontein Cave systems, results of excavations conducted in 1997 suggest a link between the deposits. Detailed comparisons of artifacts, fauna, hominid material, and a statistical correspondence analysis (CA) of the macromammalian fauna in the deposits strongly support this hypothesis. The recovery of Early Acheulean-type artifacts from the Lincoln Cave suggests that older artifacts eroded out of Sterkfontein Member 5 West and were redeposited into the younger Lincoln Cave deposits. The close physical proximity of these deposits, and the nature of the material recovered from them, indicates that the material was probably redeposited via a link between the two cave systems. Although faunal mixing is present, it is possible to say that large carnivorans become more scarce at Sterkfontein during the mid- to late Pleistocene, while small canids and felids appear to become more abundant, indicating that large and small carnivorans probably varied their use of the site through time. This may also reflect an increasing presence of humans in the Sterkfontein area during the mid- to late Pleistocene. PMID:17624409

  5. The diets of ungulates from the hominid fossil-bearing site of Elandsfontein, Western Cape, South Africa

    Science.gov (United States)

    Stynder, Deano D.

    2009-01-01

    The dietary regimes of 15 ungulate species from the middle Pleistocene levels of the hominid-bearing locality of Elandsfontein, South Africa, are investigated using the mesowear technique. Previous studies, using taxonomic analogy, classified twelve of the studied species as grazers ( Redunca arundinum, Hippotragus gigas, Hippotragus leucophaeus, Antidorcas recki, Homoiceras antiquus, Damaliscus aff. lunatus, Connochaetes gnou laticornutus, Rabaticerus arambourgi, Damaliscus niro, Damaliscus sp. nov., an unnamed "spiral horn" antelope and Equus capensis), one as a mixed feeder ( Taurotragus oryx) and two as browsers ( Tragelaphus strepsiceros and Raphicerus melanotis). Although results from mesowear analysis sustain previous dietary classifications in the majority of cases, five species were reclassified. Three species previously classified as grazers, were reclassified as mixed feeders ( H. gigas, D. aff. lunatus and R. arambourgi), one previously classified as a grazer, was reclassified as a browser (the "spiral horn" antelope), and one previously classified as a mixed feeder, was reclassified as a browser ( T. oryx). While current results broadly support previous reconstructions of the Elandsfontein middle Pleistocene environment as one which included a substantial C 3 grassy component, the reclassifications suggest that trees, broad-leaved bush and fynbos were probably more prominent than what was previously thought.

  6. Shadows on a changing landscape: comparing nesting patterns of hominids and chimpanzees since their last common ancestor.

    Science.gov (United States)

    Sept, J

    1998-01-01

    Studying the evolution of nesting behavior within the human-chimpanzee clade is problematic because evidence is sparse and difficult to interpret. Lacking a fossil or archaeological record for proto-chimpanzees, reconstructions of the antecedents of modern chimp nesting patterns can be reconstructed only from careful studies of variation in current chimpanzee and bonobo nesting patterns within the context of spatial and temporal landscape parameters. The ethology of nesting also provides an important frame of reference for reconstructions of early hominid nesting behavior. If the contemporary contrast between human and chimpanzee nesting patterns is seen as an evolutionary dichotomy, then African prehistoric landmarks that mark the origin of this split might include bipedalism and the origins of the hominidae, the first stone tools and the origins of Homo, the developmental and behavioral adaptations of Homo ergaster, shifts in Late Acheulian settlement patterns, and the origins of anatomically modern humans and the Middle Stone Age. The issue of whether Early Stone Age archaeological sites were used for nesting is unresolved because potential markers of such behavior, such as hearths, structures, or bedding, are not unambiguously recognizable in the archaeological record until the Middle Stone Age. PMID:9730215

  7. Multivariate analysis of the sexual dimorphism of the hip bone in a modern human population and in early hominids.

    Science.gov (United States)

    Arsuaga, J L; Carretero, J M

    1994-02-01

    A large sample of hip bones of known sex coming from one modern population is studied morphologically and by multivariate analysis to investigate sexual dimorphism patterns. A principal component analysis of raw data shows that a large amount of the hip bone sexual dimorphism is accounted for by size differences, but that sex-linked shape variation is also very conspicuous and cannot be considered an allometric consequence of differences in body size between the sexes. The PCA of transformed ("shape") variables indicates that the female hip bones are different in those traits associated with a relatively larger pelvic inlet (longer pubic bones, a greater degree of curvature of the iliopectineal line, and more posterior position of the auricular surface), as well as a broader sciatic notch. The analysis of nonmetric traits also shows marked sexual dimorphism in the position of the sacroiliac joint in the iliac bone, in the shape of the sciatic notch, in pubic morphology, and in the presence of the pre-auricular sulcus in females. When the australopithecine AL 288-1 and Sts 14 hip bones are included in the multivariate analysis, they appear as "ultra-females." In particular these early hominids exhibit extraordinarily long pubic bones and iliopectineal lines, which cannot be explained by allometry. PMID:8147439

  8. Early hominid dental pathology: interproximal caries in 1.5 million-year-old Paranthropus robustus from Swartkrans.

    Science.gov (United States)

    Grine, F E; Gwinnett, A J; Oaks, J H

    1990-01-01

    Carious lesions on the mesial and distal aspects of a RM1 of a young adult 'robust' australopithecine. Paranthropus robustus, are described. The specimen is from Member 1 sediments of the Swartkrans cave, which are dated to between about 1.8 and 1.5 million years before present. The mesial lesion, located cervically, had progressed further than the two distal lesions, which were situated along the cervix and in the enamel of the interproximal contact facet. This is the third specimen of P. robustus to be discovered with dental caries, but the other two cases were associated with occlusal and buccal enamel hypoplasia. Caries is present in less than about 3.0% of the approx. 116-128 P. robustus specimens at Swartkrans, and this incidence is noticeably lower than in the small Homo erectus sample from the same site. While this difference may simply be a sampling artefact, it may reflect dietary differences between these two synchronic and presumably sympatric early hominid species. PMID:2196866

  9. Alluvial systems as archives for environmental change at a Hominid site with Oldowan archaeological occurrences: the Homa Peninsula, southwestern Kenya

    Science.gov (United States)

    Vincent, Thomas; Whitfield, Elizabeth; Kirby, Jason; Hunt, Christopher; Bishop, Laura; Plummer, Thomas; Ditchfield, Peter

    2016-04-01

    The Homa Peninsula, southwestern Kenya, preserves fossiliferous sedimentary sequences dating to the Plio-Pleistocene. Evidence of hominids inhabiting an open grassland setting and utilising Oldowan tools has been reported here, as well as some of the oldest known traces of hominin activity. Reconstructions of the palaeoenvironment have suggested that alluvial and lake marginal environments on a grassy plain, between wooded slopes and a permanent water body might be plausible. However, these interpretations are based only on field sedimentological analyses and stable isotope analysis at a single site on the peninsula (Kanjera South). It is the aim of this study to utilise a multiproxy approach to develop our understanding of the palaeoenvironmental characteristics here. Sediments will also be characterized at a new site (Nyayanga) through field analyses, as well as through analyses of particle size, siliceous microfossils (diatoms, phytoliths and sponge spicules), pollen and stable isotopes. By utilizing this approach, new insights into the palaeoecology, palaeohydromorphology and palaeoclimate of the locale may be revealed, expanding the limited data available to palaeoanthropological studies of Oldowan occurrences in east Africa. Efforts to refine palaeoenvironmental reconstructions of Kanjera South through particle size analysis have shown that sediments in the lower beds of the sequence are characterised by poor sorting, a bimodal distribution and sand/silty-sand grade material. This suggests rapid deposition and/or a variable hydrological regime and may represent the role of relatively unconfined ephemeral channels in the transportation and deposition of sediments. Fluvial reworking of aeolian sediments, most likely during unconfined flood events may also have occurred.

  10. ESR analyses on tooth enamel from the Paleolithic layers at the Obi-Rakhmat hominid site, Uzbekistan: Tackling a dating controversy

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Anne R. [Department of Chemistry, Williams College, Williamstown, MA 01267 (United States); RFK Science Research Institute, Glenwood Landing, NY, 11547 (United States)], E-mail: anne.r.skinner@williams.edu; Blackwell, Bonnie A.B. [Department of Chemistry, Williams College, Williamstown, MA 01267 (United States); RFK Science Research Institute, Glenwood Landing, NY, 11547 (United States)], E-mail: bonnie.a.b.blackwell@williams.edu; Mian, Abubakar; Baboumian, Shaunte M. [RFK Science Research Institute, Glenwood Landing, NY, 11547 (United States); Blickstein, Joel I.B. [Department of Chemistry, Williams College, Williamstown, MA 01267 (United States); RFK Science Research Institute, Glenwood Landing, NY, 11547 (United States); Wrinn, Patrick J. [Department of Anthropology, University of Arizona, Tucson, AZ, 85721-0030 (United States)], E-mail: pwrinn@u.arizona.edu; Krivoshapkin, A.I.; Derevianko, A.P. [Institute of Archaeology and Ethnography, Russian Academy of Sciences, 630090 Novosibirsk (Russian Federation); Lundburg, Joyce A. [Department of Geography, Carleton University, Ottawa, ON, K1S 5B6 (Canada)], E-mail: joyce_lundberg@carleton.ca

    2007-07-15

    In the Tien Shan Mt., northeastern Uzbekistan, the Obi-Rakhmat rockshelter has yielded newly discovered hominid remains associated with an abundant Paleolithic industry and a rich faunal assemblage in typical cave fill sediment. Eight bovid teeth were dated by standard and isochron ESR to resolve the 50 ky discrepancy between the {sup 14}C and {sup 234}Th/{sup 234}U ages for Obi-Rakhmat. All the dentine contained high U concentrations, up to 150 ppm. External dose rates of 470-820{mu}Gy/y were calculated from volumetrically averaged sediment geochemistry for all layers and mineralogies within 30 cm of the teeth. One tooth from Layer 12.3 averaged 57{+-}2ka assuming linear U uptake, while three from Layer 13 averaged 66{+-}2ka, that from Layer 14.3,73{+-}4ka, and three from Layer 21.2,87{+-}4ka. Isochron and {sup 230}Th/{sup 234}U analyses suggest that the teeth did experience linear uptake with {approx}5% recent secondary U remobilization. These dates indicate that the site was inhabitted during Oxygen Isotope Stages (OIS) 5a-4, as climates were generally cooling, but beginning to fluctuate more widely. Assuming a constant sedimentation rate of 22 cm/ky, the hominid remains date to {approx}74ka.

  11. Estimate of the lower-limb-specific muscle parameters during bipedal walking for humans, apes and early hominids with the implications for the evolution of body proportion

    Institute of Scientific and Technical Information of China (English)

    Wang Weijie

    2007-01-01

    Modern human has different body proportion from early hominids and great apes. Comparing with others, in general, modern human adults have relatively long lower limb and heavier body weight. Since the lower limbs provide support to the whole body and play an important role in walking, it is proposed that the ratio of the lower limb to the whole body for modern human could be beneficial to bipedal walking. This study tried to estimate the muscle parameters of the lower limb in walking for the subjects with various body proportions. Using a simplified musculoskeletal model, some muscle parameters of the lower limb, e.g. muscle force, stress, work and power, were estimated for modern human adult, child, AL 288-1 (the fossil specimens of Australopithecus afarensis, 3.18 million years old) and apes. The results show that with the body proportion modern human adult spends less muscle work and power in walking than other subjects. The results imply that using the cost of transport (i.e. the muscle work of the lower limb per unit of displacement) as the criteria, the early hominids, if their body proportions were structurally similar to AL 288-1, could evolve towards what modern human adult looks like, in order to save energy during bipedal walking.

  12. An integrated approach to taphonomy and faunal change in the Shungura formation (Ethiopia) and its implication for hominid evolution.

    Science.gov (United States)

    Alemseged, Zeresenay

    2003-04-01

    Environmental and faunal changes through time have been recorded for many African Plio-Pleistocene sites. Fossil evidence suggests that there is a continuous, if not uniform, transformation of the fauna and flora from the Pliocene through the end of Pleistocene. However, discerning major biotic turnovers and linking them to global and regional climatic changes have been complicated by many factors, notably taphonomy and discontinuity of the fossil evidence, notwithstanding the considerable work of some researchers (e.g., Vrba, E.S., 1988. Late Pliocene climatic events and hominid evolution, in: Grine, F. (Ed.), Evolutionary History of the "Robust" Australopithecines. De Gruyter, New York, pp. 405-426, Vrba, E.S., 1995. The fossil record of African (Mammalia, Bovidae) in relation to human evolution and paleoclimate, in: Vrba, E.S., Denton, G.H., Partridge, T.C., Burkle, L.H. (Eds.), Paleoclimate and Evolution, with Emphasis on Human Origins. Yale University Press, New Haven, pp. 385-424). A sample of over 22,000 fossils collected by the French Omo Expedition, from the Shungura Formation of Ethiopia, was analyzed using an integrated approach to investigate taphonomic and faunal change patterns. The following results are obtained: (1) Univariate and multivariate studies support continuous faunal change from Member A through Member G of the Shungura sequence; (2) Correspondence analysis (CA) on extant bovids in African game parks shows that bovid tribes and genera are generally characterized by habitat specificity; (3) Taphonomic studies demonstrate that the relative abundance of different skeletal elements varies according to depositional environment; (4) CA on 73 localities of the Shungura Formation and 19 mammalian taxa points to a major faunal change around the base of Member G dated to ca. 2.3 Ma. This transformation is characterized by a change to open and edaphic grassland as a dominant type of environment; (5) This major faunal change correlates in time with

  13. A theory of marks and mind: the effect of notational systems on hominid brain evolution and child development with an emphasis on exchanges between mothers and children.

    Science.gov (United States)

    Sheridan, Susan Rich

    2005-01-01

    A model of human language requires a theory of meaningful marks. Humans are the only species who use marks to think. A theory of marks identifies children's scribbles as significant behavior, while hypothesizing the importance of rotational systems to hominid brain evolution. By recognizing the importance of children's scribbles and drawings in developmental terms as well as in evolutionary terms, a marks-based rather than a predominantly speech-based theory of the human brain, language, and consciousness emerges. Combined research in anthropology, primatology, art history, neurology, child development (including research with deaf and blind children), gender studies and literacy suggests the importance of notational systems to human language, revealing the importance of mother/child interactions around marks and sounds to the development of an expressive, communicative, symbolic human brain. An understanding of human language is enriched by identifying marks carved on bone 1.9 million years ago as observational lunar calendar-keeping, pushing proto-literacy back dramatically. Neurologically, children recapitulate the meaningful marks of early hominins when they scribble and draw, reminding us that literacy belongs to humankind's earliest history. Even more than speech, such meaningful marks played - and continue to play - decisive roles in human brain evolution. The hominid brain required a model for integrative, transformative neural transfer. The research strongly suggests that humankind's multiple literacies (art, literature, scientific writing, mathematics and music) depended upon dyadic exchanges between hominid mothers and children, and that this exchange and sharing of visuo-spatial information drove the elaboration of human speech in terms of syntax, grammar and vocabulary. The human brain was spatial before it was linguistic. The child scribbles and draws before it speaks or writes. Children babble and scribble within the first two years of life. Hands

  14. Hétérochronies dans l'évolution des hominidés. Le développement dentaire des australopithécines «robustes»Heterochronic process in hominid evolution. The dental development in 'robust' australopithecines.

    Science.gov (United States)

    Ramirez Rozzi, Fernando V.

    2000-10-01

    Heterochrony is defined as an evolutionary modification in time and in the relative rate of development [6]. Growth (size), development (shape), and age (adult) are the three fundamental factors of ontogeny and have to be known to carry out a study on heterochronies. These three factors have been analysed in 24 Plio-Pleistocene hominid molars from Omo, Ethiopia, attributed to A. afarensis and robust australopithecines ( A. aethiopicus and A. aff. aethiopicus) . Molars were grouped into three chronological periods. The analysis suggests that morphological modifications through time are due to heterochronic process, a neoteny ( A. afarensis - robust australopithecine clade) and a time hypermorphosis ( A. aethiopicus - A. aff. aethiopicus).

  15. Quantification de révolution morphologique du crâne des Hominidés et hétérochronies

    Science.gov (United States)

    Chaline, Jean; David, Bruno; Magniez-Jannin, Françoise; Malassé, Anne Dambricourt; Marchand, Didier; Courant, Frédéric; Millet, Jean-Jacques

    1998-02-01

    Comparisons of adult skulls of various species of great apes, fossil hominids and modern humans in the sagittal, Francfort and ortho-sagittal planes reveal a series of three separate organisation plans: 'Great Ape', 'Australopithecine' and 'Homo', the latter including primitive men ( Homo ergaster-erectus-neandertalensis) and modern humans ( Homo sapiens). Morphological changes between these plans are quantified for the first time here by vector fields. This study confirms the existence of cranio-facial contraction, which occurs as a series of leaps. The juvenile morphology of the great ape skull is broadly preserved in adult Homo sapiens, suggesting that numerous heterochronies have occurred in mosaic during ontogeny (hypermorphosis, hypomorphosis, post-displacements).

  16. Réflexion sur le processus coracoïde des hominoïdes et des atèles ; application à quelques hominidés fossiles

    OpenAIRE

    Voisin, Jean-Luc

    2001-01-01

    Remark on the coracoid process of hominoids and spider monkeys, application to some hominid fossils. The orientation of the coracoid process, in relation to the scapula, is different in man on one hand and other hominoids (Pan, Gorilla, Pongo, Hylobates), spider and colobus monkeys on the other hand. On the contrary, the orientation of the coracoid process is similar in all hominoids and spider monkeys when it is taken in relation to the axial skeleton. Morphology of the coracoid process reve...

  17. Freshwater on the route of hominids "out of Africa" during the last interglacial revealed by U-Th in northern Red Sea fossil reefs

    Science.gov (United States)

    Lazar, B.; Stein, M.; Agnon, A.; Shaked, Y.

    2012-04-01

    The migration of Anatomically Modern Hominids (AMH) "out of Africa" is a fundamental problem in the study of human culture concerning that the route passed through the presently hyperarid deserts surrounding the Red Sea. Here, we outline the evidence for significant presence of freshwater in a well developed phreatic coastal aquifer along the Red Sea shores during the last interglacial period. The fringing coral reefs were tectonically uplifted through the freshwater lens resulting in extensive recrystallization of reef framework from the primary aragonite into calcite. We developed a novel open-system U-Th dating methodology that enabled us estimating two ages for the calcitic reef terrace: 1. The original age of the reef terrace, deposited at ~190 ka BP; and 2. the time of freshwater recrystallization (from the primary aragonite into calcite) at ~140 ka BP. The age of freshwater recrystallization is consistent with other geological lines of evidence placing the time of AMH migration "out of Africa" at the onset of the last interglacial. It is likely therefore that during that time the hyperarid Red Sea area was wetter than today facilitating the migration of AMH to Europe and Asia.

  18. A reassessment of the study of cut mark patterns to infer hominid manipulation of fleshed carcasses at the Flk Zinj 22 site, Olduvai Gorge, Tanzania

    Directory of Open Access Journals (Sweden)

    Domínguez-Rodrigo, Manuel

    1997-12-01

    Full Text Available Previous experimental studies on cut marks have suggested that cut mark percentages and their anatomical distribution (based on element type and bone section type could be used to differentiate primary access to fleshed carcasses from secondary access to defleshed carcasses. In this study, the experimental sample of this type of studies is increased and further data are included to infer a primary access by hominids to carcasses at the FLK Zinj site of Olduvai.

    Estudios experimentales anteriores sobre marcas de corte han sugerido que los porcentajes de marcas de corte y su distribución (basada en tipo de hueso y tipo de sección ósea podrían usarse para diferenciar un acceso primario a carcasas con carne de un acceso secundario a carcasas descarnadas. En este estudio semejante muestra experimental se ve ampliada y se muestran más datos que sirven para inferir que los homínidos tuvieron un acceso primario a las carcasas representadas en el yacimiento FLK Zinj de Olduvai.

  19. High-resolution U-series dates from the Sima de los Huesos hominids yields 600 +∞-66: implications for the evolution of the early Neanderthal lineage

    Science.gov (United States)

    Bischoff, James L.; Williams, Ross W.; Rosenbauer, Robert J.; Aramburu, Arantza; Arsuaga, Juan Luis; Garcia, Nuria; Cuenca-Bescos, Gloria

    2007-01-01

    The Sima de los Huesos site of the Atapuerca complex near Burgos, Spain contains the skeletal remains of at least 28 individuals in a mud-breccia underlying an accumulation of the Middle Pleistocene cave bear (Ursus deningeri). We report here on new high-precision dates on the recently discovered speleothem SRA-3 overlaying human bones within the Sima de los Huesos. Earlier analyses of this speleothem by TIMS (thermal-ionization mass-spectrometry) showed the lower part to be indistinguishable from internal isotopic equilibrium at the precision of the TIMS instrumentation used, yielding minimum age of 350 kyr (kyr = 103 yr before present). Reanalysis of six samples of SRA-3 by inductively-coupled plasma-multicollector mass-spectrometry (ICP-MS) produced high-precision analytical results allowing calculation of finite dates. The new dates cluster around 600 kyr. A conservative conclusion takes the lower error limit ages as the minimum age of the speleothem, or 530 kyr. This places the SH hominids at the very beginnings of the Neandertal evolutionary lineage.

  20. Combined ESR/U-series chronology of Acheulian hominid-bearing layers at Trinchera Galería site, Atapuerca, Spain.

    Science.gov (United States)

    Falguères, Christophe; Bahain, Jean-Jacques; Bischoff, James L; Pérez-González, Alfredo; Ortega, Ana Isabel; Ollé, Andreu; Quiles, Anita; Ghaleb, Bassam; Moreno, Davinia; Dolo, Jean-Michel; Shao, Qingfeng; Vallverdú, Josep; Carbonell, Eudald; Bermúdez de Castro, Jose María; Arsuaga, Juan Luis

    2013-08-01

    The Sierra de Atapuerca, northern Spain, is known from many prehistoric and palaeontological sites documenting human prehistory in Europe. Three major sites, Gran Dolina, Galería and Sima del Elefante, range in age from the oldest hominin of Western Europe dated to 1.1 to 1.3 Ma (millions of years ago) at Sima del Elefante to c.a. 0.2 Ma on the top of the Galería archaeological sequence. Recently, a chronology based on luminescence methods (Thermoluminescence [TL] and Infrared Stimulated Luminescence [IRSL]) applied to cave sediments was published for the Gran Dolina and Galería sites. The authors proposed for Galería an age of 450 ka (thousands of years ago) for the units lower GIII and GII, suggesting that the human occupation there is younger than the hominid remains of Sima de los Huesos (>530 ka) around 1 km away. In this paper, we present new results obtained by combined Electron Spin Resonance/Uranium-series (ESR/U-series) dating on 20 herbivorous teeth from different levels at the Galería site. They are in agreement with the TL results for the upper part of the stratigraphic sequence (GIV and GIIIb), in the range of between 200 and 250 ka. But for the GIIIa to GIIb levels, the TL ages become abruptly older by 200 ka while ESR ages remain relatively constant. Finally, the TL and ESR data agree in the lowest part of the section (GIIa); both fall in the range of around 350-450 ka. Our results suggest a different interpretation for the GII, GIII and GIV units of Galería and the upper part of Gran Dolina (TD10 and TD11) than obtained by TL. The ESR/U-series results are supported by a Bayesian analysis, which allows a better integration between stratigraphic information and radiometric data. PMID:23830175

  1. Megalake Chad impact on climate and vegetation during the late Pliocene and the mid-Holocene

    Directory of Open Access Journals (Sweden)

    C. Contoux

    2013-07-01

    Full Text Available Given the growing evidence for megalakes in the geological record, assessing their impact on climate and vegetation is important for the validation of palaeoclimate simulations and therefore the accuracy of model–data comparison in lacustrine environments. Megalake Chad (MLC occurrences are documented not only for the mid-Holocene but also for the Mio-Pliocene (Schuster et al., 2009. At this time, the surface covered by water would have reached up to ~350 000 km2 (Ghienne et al., 2002; Schuster et al., 2005; Leblanc et al., 2006, making it an important evaporation source, possibly modifying climate and vegetation in the Chad Basin. We investigated the impact of such a giant continental water area in two different climatic backgrounds within the Paleoclimate Model Intercomparison Project phase 3 (PMIP3: the late Pliocene (3.3 to 3 Ma, i.e. the mid-Piacenzian warm period and the mid-Holocene (6 kyr BP. In all simulations including MLC, precipitation is drastically reduced above the lake surface because deep convection is inhibited by overlying colder air. Meanwhile, convective activity is enhanced around MLC because of the wind increase generated by the flat surface of the megalake, transporting colder and moister air towards the eastern shore of the lake. The effect of MLC on precipitation and temperature is not sufficient to widely impact vegetation patterns. Nevertheless, tropical savanna is present in the Chad Basin in all climatic configurations, even without MLC presence, showing that the climate itself is the driver of favourable environments for sustainable hominid habitats.

  2. Paléocontraintes et déformations syn- et post-collision Afrique Europe identifiées dans la couverture mésozoïque et cénozoïque du Haut Atlas occidental (Maroc)Syn- and post-collision Africa Europe palaeostresses and deformations identified in the West High-Atlas Mesozoic and Cenozoic cover (Morocco)

    Science.gov (United States)

    Amrhar, Mostafa

    Palaeostresses and deformation axis reconstruction related to the intracontinental High-Atlas uplift evidences two shortening phases from Upper Cretaceous to Quaternary. The first compression is oriented N20-30°E and is Maastrichtian to Oligocene age; the second one, oriented N120-160°E, is syn-Mio-Pliocene. Tectonic inversion of the lateral to compressive Jurassic regime is contemporaneous with the beginning of Africa and Europe collision. Rotation of the Mio-Pliocene shortening orientation could be linked to the change of the convergence direction between the Africa and Europe plates. To cite this article: M. Amrhar, C. R. Geoscience 334 (2002) 279-285.

  3. Metabolic correlates of hominid brain evolution.

    Science.gov (United States)

    Leonard, William R; Robertson, Marcia L; Snodgrass, J Josh; Kuzawa, Christopher W

    2003-09-01

    Large brain sizes in humans have important metabolic consequences as humans expend a relatively larger proportion of their resting energy budget on brain metabolism than other primates or non-primate mammals. The high costs of large human brains are supported, in part, by diets that are relatively rich in energy and other nutrients. Among living primates, the relative proportion of metabolic energy allocated to the brain is positively correlated with dietary quality. Humans fall at the positive end of this relationship, having both a very high quality diet and a large brain size. Greater encephalization also appears to have consequences for aspects of body composition. Comparative primate data indicate that humans are 'under-muscled', having relatively lower levels of skeletal muscle than other primate species of similar size. Conversely, levels of body fatness are relatively high in humans, particularly in infancy. These greater levels of body fatness and reduced levels of muscle mass allow human infants to accommodate the growth of their large brains in two important ways: (1) by having a ready supply of stored energy to 'feed the brain', when intake is limited and (2) by reducing the total energy costs of the rest of the body. Paleontological evidence indicates that the rapid brain evolution observed with the emergence of Homo erectus at approximately 1.8 million years ago was likely associated with important changes in diet and body composition. PMID:14527625

  4. Relative femoral head size in early hominids.

    Science.gov (United States)

    Corruccini, R S; McHenry, H M

    1978-07-01

    Relative growth of the human femur head is studied by a logarithmic principal components method. Growth rates differ according to the population sampled and the other body dimensions being compared, and especially according to sex. The results do not support biomechanical assumptions of strongly positive allometry of the femur head, which have been used to argue that the australopithecine hip joint was not relatively small. PMID:98052

  5. Messinian events in the Black Sea

    NARCIS (Netherlands)

    van Baak, Christiaan G C; Radionova, Eleanora P.; Golovina, Larisa A.; Raffi, Isabella; Kuiper, Klaudia F.; Vasiliev, Iuliana; Krijgsman, Wout

    2015-01-01

    Past hydrological interactions between the Mediterranean Sea and Black Sea are poorly resolved due to complications in establishing a high-resolution time frame for the Black Sea. We present a new greigite-based magnetostratigraphic age model for the Mio-Pliocene deposits of DSDP Hole 380/380A, dril

  6. Explaining the imperfection of the molecular clock of hominid mitochondria.

    Directory of Open Access Journals (Sweden)

    Eva-Liis Loogväli

    Full Text Available The molecular clock of mitochondrial DNA has been extensively used to date various genetic events. However, its substitution rate among humans appears to be higher than rates inferred from human-chimpanzee comparisons, limiting the potential of interspecies clock calibrations for intraspecific dating. It is not well understood how and why the substitution rate accelerates. We have analyzed a phylogenetic tree of 3057 publicly available human mitochondrial DNA coding region sequences for changes in the ratios of mutations belonging to different functional classes. The proportion of non-synonymous and RNA genes substitutions has reduced over hundreds of thousands of years. The highest mutation ratios corresponding to fast acceleration in the apparent substitution rate of the coding sequence have occurred after the end of the Last Ice Age. We recalibrate the molecular clock of human mtDNA as 7990 years per synonymous mutation over the mitochondrial genome. However, the distribution of substitutions at synonymous sites in human data significantly departs from a model assuming a single rate parameter and implies at least 3 different subclasses of sites. Neutral model with 3 synonymous substitution rates can explain most, if not all, of the apparent molecular clock difference between the intra- and interspecies levels. Our findings imply the sluggishness of purifying selection in removing the slightly deleterious mutations from the human as well as the Neandertal and chimpanzee populations. However, for humans, the weakness of purifying selection has been further exacerbated by the population expansions associated with the out-of Africa migration and the end of the Last Ice Age.

  7. Evolutionary relationships of wild hominids recapitulated by gut microbial communities.

    Directory of Open Access Journals (Sweden)

    Howard Ochman

    Full Text Available Multiple factors over the lifetime of an individual, including diet, geography, and physiologic state, will influence the microbial communities within the primate gut. To determine the source of variation in the composition of the microbiota within and among species, we investigated the distal gut microbial communities harbored by great apes, as present in fecal samples recovered within their native ranges. We found that the branching order of host-species phylogenies based on the composition of these microbial communities is completely congruent with the known relationships of the hosts. Although the gut is initially and continuously seeded by bacteria that are acquired from external sources, we establish that over evolutionary timescales, the composition of the gut microbiota among great ape species is phylogenetically conserved and has diverged in a manner consistent with vertical inheritance.

  8. A comparative morphometric study of the hominid lumbar spine.

    OpenAIRE

    Martelli, S. A.

    2005-01-01

    This thesis investigates the size/shape variation in the lumbar spine of extant and fossil hominoids. As a novelty, 3D coordinate data sets were obtained from the last five consecutive presacral vertebrae for comparative analyses. Size/shape variation of single vertebrae and patterns of metameric size/shape variation along the lumbar spine are investigated. Large samples of populations of Homo sapiens, Gorilla gorilla, Pan troglodytes, and Pongo pygmaeus are investigated. The fossil sample in...

  9. Perikymata spacing and distribution on hominid anterior teeth.

    Science.gov (United States)

    Dean, M C; Reid, D J

    2001-11-01

    We documented the spacing and distribution of perikymata on the buccal enamel surface of fossil hominin anterior teeth with reference to a sample of modern human and modern great ape teeth. A sample of 27 anterior teeth attributed to Australopithecus (5 to A. afarensis, 22 to A. africanus) and of 33 attributed to Paranthropus (6 to P. boisei, and 27 to P. robustus) were replicated and sputter-coated with gold to enable reflected light microscopy of their surface topography. Anterior teeth were then divided into 10 equal divisions of buccal crown height. The total perikymata count in each division of crown height was recorded using a binocular microscope fitted with a vernier micrometer eyepiece. Then the mean number of perikymata per millimeter was calculated for each division. Similar comparative data for a modern sample of 115 unworn human anterior teeth and 30 African great ape anterior teeth were collected from ground sections. Perikymata counts in each taxon (together with either known or presumed periodicities of perikymata) were then used to estimate enamel formation times in each division of crown height, for all anterior tooth types combined. The distributions of these estimates of time taken to form each division of crown height follow the same trends as the actual perikymata counts and differ between taxa in the same basic way. The distinction between modern African great apes and fossil hominins is particularly clear. Finally, we calculated crown formation times for each anterior tooth type by summing cuspal and lateral enamel formation times. Estimates of average crown formation times in australopiths are shorter than those calculated for both modern human and African great ape anterior teeth. The data presented here provide a better basis for exploring differences in perikymata spacing and distribution among fossil hominins, and provide the first opportunity to describe four specimens attributed to Homo in this context. Preliminary data indicate that differences may exist among the species attributed to early Homo, especially between Homo ergaster and Homo rudolfensis on the one hand, and Homo habilis sensu strico on the other. PMID:11596000

  10. Evidence of termite foraging by Swartkrans early hominids

    OpenAIRE

    Backwell, Lucinda R.; d'Errico, Francesco

    2001-01-01

    Previous studies have suggested that modified bones from the Lower Paleolithic sites of Swartkrans and Sterkfontein in South Africa represent the oldest known bone tools and that they were used by Australopithecus robustus to dig up tubers. Macroscopic and microscopic analysis of the wear patterns on the purported bone tools, pseudo bone tools produced naturally by known taphonomic processes, and experimentally used bone tools confirm the anthropic origin of the mo...

  11. Origin of hominids: European or African origin, neither or both?

    Directory of Open Access Journals (Sweden)

    Senut, B.

    2011-12-01

    Full Text Available For the last twenty years, some scientists have suggested that the African ape and humans lineages emerged in Europe, a scenario known as the “Back to Africa Hypothesis”. Even though hominoids were widespread in Eurasia during the Middle and Upper Miocene due to the tropical conditions which prevailed in this region, we cannot dismiss the fact that they were present in Africa (contra some authors. Actually, they were highly diverse at that same time (at least 10 lineages represented even if the fossil record is less complete than in Eurasia. Postcranial elements from African species suggest that some features of modern hominoids were already present in the Lower and Middle Miocene of Africa and were not restricted to European ones. Considering the available evidence, it is not possible at this stage to favour a European origin over an African one. Hominoids were living in the tropical areas of Northern Africa and Southern Eurasia and faunal exchanges between the two continents occurred throughout the Middle and Upper Miocene, as the Tethys did not act as an effective barrier to interchanges between Europe and Asia.

    Durante los últimos veinte años, algunos científicos han sugerido que los grandes monos africanos y los linajes humanos surgieron en Europa, un escenario conocido como la “ Hipótesis de la vuelta a Africa”. A pesar de que los homínidos se extendieron en Eurasia durante el Mioceno Medio y Superior debido a las condiciones tropicales que prevalecian en esta region, no podemos descartar el hecho de que ellos estuvieron presentes en Africa (contra algunos autores. En realidad, ellos tuvieron una alta diversidad al mismo tiempo (al menos 10 líneas representadas, incluso si el registro fosil es menos completo que el de Eurasia. Elementos postcraneales de especies africanas sugieren que en algunos carácteres los homínidos modernos estaban ya presentes en el Mioceno Inferior y Medio de Africa, no sólo restringidos a las formas europeas. Teniendo en cuenta las evidencias disponibles, no es posible, en el estado actual de conocimiento, favorecer más un origen europeo que otro africano. Los homínidos vivieron en áreas tropicales del Norte de África y del Sur de Eurasia, cambios faunísticos se sucedieron entre los dos continents a lo largo del Mioceno Medio y Superior, sin que el Tetis actuase como una barrera efectiva a los intercambios entre Europa y Asia.

  12. Enamel hypoplasia in a pliocene hominid from Chad.

    Science.gov (United States)

    Brunet, Michel; Fronty, Pierre; Sapanet, Michel; de Bonis, Louis; Viriot, Laurent

    2002-01-01

    Abel is the first Australopithecine known west of the East African Rift Valley. The fossil finds include a perisymphyseal fragment of an adult mandible with well-preserved crowns of the right I2-P4 and the left C-P4. Abel's dentition displays many enamel defects, which are described in detail for each tooth. Pitting affected every tooth, while larger, shallow depressions were observed on the canines alone. From two to four pit bands occurred on the different teeth, each resulting from a separate hypoplastic episode. In modern humans, a large number of causes, both environmental and genetic, have been suggested for such enamel defects. It seems probable that Abel's pathology was systemic. However, the occurrence of a number of bands and the variable intensity of the attacks make it difficult to say whether there was a single, repetitive cause or different etiologies. Possible causes discussed here include recurrent fevers and seasonal nutritional deficiencies. PMID:12489142

  13. Explaining the imperfection of the molecular clock of hominid mitochondria.

    Science.gov (United States)

    Loogväli, Eva-Liis; Kivisild, Toomas; Margus, Tõnu; Villems, Richard

    2009-12-29

    The molecular clock of mitochondrial DNA has been extensively used to date various genetic events. However, its substitution rate among humans appears to be higher than rates inferred from human-chimpanzee comparisons, limiting the potential of interspecies clock calibrations for intraspecific dating. It is not well understood how and why the substitution rate accelerates. We have analyzed a phylogenetic tree of 3057 publicly available human mitochondrial DNA coding region sequences for changes in the ratios of mutations belonging to different functional classes. The proportion of non-synonymous and RNA genes substitutions has reduced over hundreds of thousands of years. The highest mutation ratios corresponding to fast acceleration in the apparent substitution rate of the coding sequence have occurred after the end of the Last Ice Age. We recalibrate the molecular clock of human mtDNA as 7990 years per synonymous mutation over the mitochondrial genome. However, the distribution of substitutions at synonymous sites in human data significantly departs from a model assuming a single rate parameter and implies at least 3 different subclasses of sites. Neutral model with 3 synonymous substitution rates can explain most, if not all, of the apparent molecular clock difference between the intra- and interspecies levels. Our findings imply the sluggishness of purifying selection in removing the slightly deleterious mutations from the human as well as the Neandertal and chimpanzee populations. However, for humans, the weakness of purifying selection has been further exacerbated by the population expansions associated with the out-of Africa migration and the end of the Last Ice Age.

  14. Evolution of Lake Chad Basin hydrology during the mid-Holocene: A preliminary approach from lake to climate modelling

    Science.gov (United States)

    Sepulchre, Pierre; Schuster, Mathieu; Ramstein, Gilles; Krinnezr, Gerhard; Girard, Jean-Francois; Vignaud, Patrick; Brunet, Michel

    2008-03-01

    During the mid-Holocene (6000 yr Before Present, hereafter yr BP) the Chad Basin was occupied by a large endoreic lake, called Lake Mega-Chad. The existence of this lake at that time seems linked to increased monsoonal moisture supply to the Sahel and the Sahara, which in turn was probably ultimately caused by variations in the orbital forcing and higher temperature gradients between ocean and continent. This study provides a synthesis of several works carried out on the Lake Chad Basin and analyses the results of a simulation of the mid-Holocene climate with an Atmosphere General Circulation Model (LMDZ for Laboratoire de Météorologie Dynamique, IPSL Paris), with emphasis on the possible conditions leading to the existence of Lake Mega-Chad. The aim is to define the best diagnostics to understand which mechanisms lead to the existence of the large lake. This paper is the first step of an ongoing work that intends to understand the environmental conditions that this part of Africa experienced during the Upper Miocene (ca. 7 Ma BP), an epoch that was contemporaneous with the first known hominids. Indeed, early hominids of Lake Chad Basin, Australopithecus bahrelghazali [ Brunet, M., et al., 1995. The first australopithecine 2500 kilometers west of the Rift-Valley (Chad). Nature, 378(6554): 273-275] and Sahelanthropus tchadensis [Brunet, M., et al., 2002. A new hominid from the Upper Miocene of Chad, central Africa. Nature, 418(6894): 145-151; Brunet, M., et al., 2005. New material of the earliest hominid from the Upper Miocene of Chad. Nature, 434(7034): 752-755] are systematically associated with wet episodes that are documented for 7 Ma BP [Vignaud, P., et al., 2002. Geology and palaeontology of the Upper Miocene Toros-Menalla hominid locality, Chad. Nature, 418(6894): 152-155] and testified by extended lacustrine deposits (diatomites, pelites, various aquatic fauna). Because the mid-Holocene was the last such mega-lake episode, our aim here is to assess the

  15. Rapid Post-Miocene tectonic rotation associated with the San Gregorio Fault Zone in central California

    Science.gov (United States)

    Holm, Eric J.; Horns, Daniel M.; Verosub, Kenneth L.

    1991-12-01

    Paleomagnetic measurements of samples from the Mio-Pliocene Purisima Formation demonstrate that the Pomponio tectonic block of central coastal California has rotated clockwise by approximately 35° to 55° within the last 2.5 million years. The most likely interpretation of this data is that the Pomponio block is broken into several small blocks which have rotated by various amounts. The data suggest that rotations contribute to vertical deformation and secondary faulting within the central San Andreas Fault System, and that they play an important role in the accommodation of shear along the fault system.

  16. Depósitos epitermales de baja sulfuración ricos en sulfuros de metales base, distrito aurífero La Carolina, San Luis, Argentina

    OpenAIRE

    Gallard-Esquivel María Cecilia; Urbina, Nilda Esther; Sruoga, Patricia; Japas, María Silvia

    2011-01-01

    Low-sulfidation epithermal base-metal sulfide-rich deposits, La Carolina gold-bearing district,San Luis, Argentina. La Carolina gold-bearing district is located at the western end of the Metallogenetic Belt of San Luis, which is spatially and genetically related to the mesosilicic volcanism of mio-pliocene age. The volcanic arc experienced an eastward migration, due to the flattening of the Nazca plate in the segment 27°-33°S, known as the Pampean flat-slab. At La Carolina, the volcanic activ...

  17. Early hominin speciation at the Plio/Pleistocene transition.

    Science.gov (United States)

    Cameron, D W

    2003-01-01

    Over the last half-decade or so, there has been an explosion in the recognition of hominin genera and species. We now have the late Miocene genera Orrorin and Sahelanthropus, the mid Pliocene genus Kenyanthropus, three new Pliocene species of Australopithecus (A. anamensis, A. garhi and A. bahrelghazali) and a sub species of Ardipithecus (Ar. r. kadabba) to contend with. Excepting also the more traditional species allocated to Paranthropus, Australopithecus and early Homo we are approaching around 15 species over 5 million years (excluding hominin evolution over the last one million years). Can such a large number of hominin species be justified? An examination of extant hominid (Gorilla gorilla, Pan troglodytes, and Pan paniscus) anatomical variability indicates that the range of fossil hominin variability supports the recognition of this large number of fossil species. It is also shown that not all hominins are directly related to the emergence of early Homo and as such have become extinct. Indeed the traditional australopithecine species 'A'. anamensis, 'A'. afarensis and 'A'. garhi are considered here to belong to a distinct genus Praeanthropus. They are also argued not be hominins, but rather an as yet undefined hominid group from which the more derived hominins evolved. The first hominin is represented by A. africanus or a hominin very much like it. The Paranthropus clade is defined by a derived heterochronic condition of peramorphosis, associated with sequential progenesis (contraction of successive growth stages) in brain and dental development, but a mixture of peramorphic and paedomorphic features in its craniofacial anatomy. Conversely, Kenyanthropus and Homo both share a pattern of peramorphosis, associated with sequential hypermorphosis (prolongation of successive growth stages) in brain development, and paedomorphosis processes in cranial, facial and dental development. This suggests, that these two clades share an important synapomorphy not

  18. Mode of débitage and technical cognition of hominids at the Guanyindong site

    Institute of Scientific and Technical Information of China (English)

    LI YingHua; HOU YaMei; BO(E)DA Eric

    2009-01-01

    Exploring and interpreting the mode of cognition and behavioral patterns of prehistoric hunter-gatherers is always one of the main goals of current Paleolithic research.In the 1940s,French prehistorians proposed the technological method for studying lithic assemblages which opened a brand-new perspective on the prehistoric domain.In the 1960s,French ethnographer and anthropolobut complementary concepts:techno-cognition and techno-economy,which contributed not only to revealing the technical knowledge and know-how applied during lithic production but also to interpreting the technical behavior of prehistoric hunter-gatherers from social and economic viewpoints.The lithic technological study of the Guanyindong site,presented in this paper,was carried out for the first time by applying lithic technological method developed by French prehistorians to the Chinese materials.Our analytical results demonstrated that the debitage system of Guanyindong is quite distinct from the concept Levallois largely used in Europe,Near-East and Africa.The differentiation bePaleolithic between China and Europe,Near-East and Africa.

  19. Hominid and carnivore activity at Middle and Upper Paleolithic cave sites in eastern Spain.

    Directory of Open Access Journals (Sweden)

    John Lindly

    1988-01-01

    Full Text Available Recientes investigaciones zooarqueológicas han desarrollado métodos para distinguir entre residuos óseos producidos por depredadores carnívoros y animales de carroña, y residuos semejantes producidos por homínidos. Estas metodologías han sido aplicadas a yacimientos Pleistocénicos en Africa, mientras que sólo se han comenzado a utilizar para yacimientos paleolíticos de Europa Occidental. Un análisis preliminar del papel jugado por los carnívoros en la deposición del material faunístico en el norte de España (Straus, 1982 sugiere un alta implicación de carnívoros en la formación de depósitos musterienses con una disminución de su papel en el Paleolítico Superior. En este estudio, las relaciones entre carnívoros y ungulados de los yacimientos del Paleolítico Medio (Los Casares, Cova Negra y tres del Superior (Parpalló, Les Mallaetes, Volcán del Faro de la España levantina confirman la validez de este modelo. Sin embargo, métodos más precisos como el análisis de frecuencias de las partes del cuerpo y medidas de la atrición de los conjuntos faunísticos sugieren una implicación constante o mayor de carnívoros en la formación de estos conjuntos a lo largo del   tiempo, indicando que anteriores interpretaciones sobre estrategias de subsistencias en estos yacimientos pueden ser sospechosas e incluso completamente equivocadas.

  20. Loss of N-glycolylneuraminic acid in humans: Mechanisms, consequences, and implications for hominid evolution.

    Science.gov (United States)

    Varki, A

    2001-01-01

    The surface of all mammalian cells is covered with a dense and complex array of sugar chains, which are frequently terminated by members of a family of molecules called sialic acids. One particular sialic acid called N-glycolylneuraminic acid (Neu5Gc) is widely expressed on most mammalian tissues, but is not easily detectable on human cells. In fact, it provokes an immune response in adult humans. The human deficiency of Neu5Gc is explained by an inactivating mutation in the gene encoding CMP-N-acetylneuraminic acid hydroxylase, the rate-limiting enzyme in generating Neu5Gc in cells of other mammals. This deficiency also results in an excess of the precursor sialic acid N-acetylneuraminic acid (Neu5Ac) in humans. This mutation appears universal to modern humans, occurred sometime after our last common ancestor with the great apes, and happens to be one of the first known human-great ape genetic differences with an obvious biochemical readout. While the original selection mechanisms and major biological consequences of this human-specific mutation remain uncertain, several interesting clues are currently being pursued. First, there is evidence that the human condition can explain differences in susceptibility or resistance to certain microbial pathogens. Second, the functions of some endogenous receptors for sialic acids in the immune system may be altered by this difference. Third, despite the lack of any obvious alternate pathway for synthesis, Neu5Gc has been reported in human tumors and possibly in human fetal tissues, and traces have even been detected in normal human tissues. One possible explanation is that this represents accumulation of Neu5Gc from dietary sources of animal origin. Finally, a markedly reduced expression of hydroxylase in the brains of other mammals raises the possibility that the human-specific mutation of this enzyme could have played a role in human brain evolution.

  1. Y-Chromosome Variation in Hominids: Intraspecific Variation Is Limited to the Polygamous Chimpanzee

    OpenAIRE

    Gabriele Greve; Evguenia Alechine; Pasantes, Juan J.; Christine Hodler; Wolfram Rietschel; Robinson, Terence J.; Werner Schempp

    2011-01-01

    BACKGROUND: We have previously demonstrated that the Y-specific ampliconic fertility genes DAZ (deleted in azoospermia) and CDY (chromodomain protein Y) varied with respect to copy number and position among chimpanzees (Pan troglodytes). In comparison, seven Y-chromosomal lineages of the bonobo (Pan paniscus), the chimpanzee's closest living relative, showed no variation. We extend our earlier comparative investigation to include an analysis of the intraspecific variation of these genes in go...

  2. Y-Chromosome variation in hominids: intraspecific variation is limited to the polygamous chimpanzee.

    Directory of Open Access Journals (Sweden)

    Gabriele Greve

    Full Text Available BACKGROUND: We have previously demonstrated that the Y-specific ampliconic fertility genes DAZ (deleted in azoospermia and CDY (chromodomain protein Y varied with respect to copy number and position among chimpanzees (Pan troglodytes. In comparison, seven Y-chromosomal lineages of the bonobo (Pan paniscus, the chimpanzee's closest living relative, showed no variation. We extend our earlier comparative investigation to include an analysis of the intraspecific variation of these genes in gorillas (Gorilla gorilla and orangutans (Pongo pygmaeus, and examine the resulting patterns in the light of the species' markedly different social and mating behaviors. METHODOLOGY/PRINCIPAL FINDINGS: Fluorescence in situ hybridization analysis (FISH of DAZ and CDY in 12 Y-chromosomal lineages of western lowland gorilla (G. gorilla gorilla and a single lineage of the eastern lowland gorilla (G. beringei graueri showed no variation among lineages. Similar findings were noted for the 10 Y-chromosomal lineages examined in the Bornean orangutan (Pongo pygmaeus, and 11 Y-chromosomal lineages of the Sumatran orangutan (P. abelii. We validated the contrasting DAZ and CDY patterns using quantitative real-time polymerase chain reaction (qPCR in chimpanzee and bonobo. CONCLUSION/SIGNIFICANCE: High intraspecific variation in copy number and position of the DAZ and CDY genes is seen only in the chimpanzee. We hypothesize that this is best explained by sperm competition that results in the variant DAZ and CDY haplotypes detected in this species. In contrast, bonobos, gorillas and orangutans-species that are not subject to sperm competition-showed no intraspecific variation in DAZ and CDY suggesting that monoandry in gorillas, and preferential female mate choice in bonobos and orangutans, probably permitted the fixation of a single Y variant in each taxon. These data support the notion that the evolutionary history of a primate Y chromosome is not simply encrypted in its DNA sequences, but is also shaped by the social and behavioral circumstances under which the specific species has evolved.

  3. Bone strength and athletic ability in hominids: Ardipithecus ramidus to Homo sapiens

    Science.gov (United States)

    Lee, S. A.

    2013-03-01

    The ability of the femur to resist bending stresses is determined by its midlength cross-sectional geometry, its length and the elastic properties of the mineral part of the bone. The animal's athletic ability, determined by a ``bone strength index,'' is limited by this femoral bending strength in relation to the loads on the femur. This analysis is applied to the fossil record for Homo sapiens, Homo neanderthalensis, Homo erectus, Homo habilis, Australopithecus afarensis and Ardipithecus ramidus. Evidence that the femoral bone strength index of modern Homo sapiens has weakened over the last 50,000 years is found.

  4. A hominid from the lower Pleistocene of Atapuerca, Spain: possible ancestor to Neandertals and modern humans.

    Science.gov (United States)

    Bermúdez de Castro, J M; Arsuaga, J L; Carbonell, E; Rosas, A; Martínez, I; Mosquera, M

    1997-05-30

    Human fossil remains recovered from the TD6 level (Aurora stratum) of the lower Pleistocene cave site of Gran Dolina, Sierra de Atapuerca, Spain, exhibit a unique combination of cranial, mandibular, and dental traits and are suggested as a new species of Homo-H. antecessor sp. nov. The fully modern midfacial morphology of the fossils antedates other evidence of this feature by about 650, 000 years. The midfacial and subnasal morphology of modern humans may be a retention of a juvenile pattern that was not yet present in H. ergaster. Homo antecessor may represent the last common ancestor for Neandertals and modern humans. PMID:9162001

  5. : Quantification of the morphological evolution of the Hominid skull and heterochronies

    OpenAIRE

    Chaline, Jean; DAVID, Bruno; Magniez-Jannin, Françoise; Dambricourt Malassé, Anne; Marchand, Didier; Courant, Frédéric; Millet, Jean-Jacques

    1998-01-01

    Les comparaisons réalisées entre des crânes d'individus adultes de diverses espèces de singes supérieurs, d'hommes fossiles et modernes dans les plans sagittal, Francfort et orthosagittal, révèlent la succession de trois plans d'organisation distincts ; - Singe supérieur », « Australopithèque », et « Homo ». renfermant les hommes archaïques {Homo ergaster - erectus - neandertalensis) et les hommes modernes (Homo sapiens). Les changements morphologiques entre ces plans sont quantifiés pour la ...

  6. A New Horned Crocodile from the Plio-Pleistocene Hominid Sites at Olduvai Gorge, Tanzania

    OpenAIRE

    Brochu, Christopher A.; Jackson Njau; Robert J Blumenschine; Densmore, Llewellyn D

    2010-01-01

    BACKGROUND: The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian diversity in Africa persisted after the Miocene. It had prominent triangular "horns" over the ears and a relatively deep snout, these resem...

  7. Development of the palatal size in Pan troglodytes, Hominids and Homo sapiens.

    Science.gov (United States)

    Arnold, W H; Zoellner, A; Sebastian, T

    2004-12-01

    As the hard palate plays an important role in speech production it was the aim of this study whether similarities or dissimilarities in palatal size may allow conclusions about the ability to produce speech in the extant investigated species. The palatal size of Pan troglodytes, Homo sapiens, Australopithecus afarensis, Australopithecus africanus, Australopithecus robustus, Australopithecus boisei, Homo erectus, Homo neanderthalensis and Cro-Magnon has been investigated using euclidian distance matrix analysis (EDMA) and thin-plate-spline analysis. The results show that the palatal size of all australopithecine specimens and H. erectus is very similar to that of P toglodytes, whereas the palatal size of H. neanderthalensis more closely resembles that of H. sapiens. Postnatal development of palatal size in P troglodytes is different from that of H. sapiens. In P troglodytes not only the size of the palate changes but also the form. In H. sapiens there is little change in form, but a continuos uniform growth from infantile to adult specimens. From the results we conclude that in all australopithecine samples which have been investigated, the palatal size is similar to that of P troglodytes. Therefore, it is unlikely that austraopithecine individuals were capable of producing vowels and consonants. The palatal size of H. neandethalensis and Cro-Magnon is similar to that of H. sapiens which may indicate the possibility that they were capable of speech production. PMID:15646285

  8. Analysis of sedimentary-geomorphologic variation and the living environment of hominids at the Shuidonggou Paleolithic site

    Institute of Scientific and Technical Information of China (English)

    GAO Xing; YUAN BaoYin; PEI ShuWen; WANG HuiMin; CHEN FuYou; FENG XingWu

    2008-01-01

    Shuidonggou is one of the most important Upper Paleolithic sites in North China. Due to the presence of rich human remains, animal fossils, abundant sporopolien and unique geological sequence, it is the type site for Late Pleistocene to Holocene human occupation and environmental change in the Ningxia-lnner Mongolia region. Many scholars suggest that the site should be named the "Shuidong- gou Formation" of Late Pleistocene in North China. Dating results indicate that ancient human activities at the site took place 30-24 ka (Marine Isotope Stage [MIS] 3). The climate at that time was warmer and moister than present day, and adequate precipitation led to the formation of water pack depressions where broad-leaf trees and sparse forest vegetations, as well as herbivorous animals flourished, mak-ing the area suitable for early human hunting, gathering and survival. The Neolithic human occupation happened 9-5 ka at the site, while similar environmental conditions with MIS3 occurred. The absence of human activity record in the region during the Last Glacial Maximum (MIS2) suggests that the envi-ronment was too harsh for humans to live there.

  9. Genomic differentiation of Neanderthals and anatomically modern man allows a fossil-DNA-based classification of morphologically indistinguishable hominid bones.

    OpenAIRE

    Scholz, M.; Bachmann, L; Nicholson, G J; Bachmann, J.; Giddings, I; Rüschoff-Thale, B; Czarnetzki, A; Pusch, C. M.

    2000-01-01

    Southern blot hybridizations of genomic DNA were introduced as a relatively simple fossil-DNA-based approach to classify remains of Neanderthals. When hybridized with genomic DNA of either human or Neanderthal origin, DNA extracted from two Neanderthal finds-the Os parietale, from Warendorf-Neuwarendorf, Germany, and a clavicula, from Krapina, Croatia-was shown to yield hybridization signals that differ by at least a factor of two compared to the signals obtained with the use of fossil DNA of...

  10. Late Miocene/Pliocene Ostracod Biostratigraphy from South Carpathian Foredeep, Romania (Badislava-Topolog Area)

    Science.gov (United States)

    Floroiu, Alina; Stoica, Marius; Vasiliev, Iuliana; Krijgsman, Wout

    2016-04-01

    The Paratethys epicontinental sea has been an essential paleogeographic feature defining the Eurasian interior since Oligocene. By the end of the Miocene, ongoing tectonic activity in the region determined severe restrictions of the connection of the large former Paratethys sea resulting in the formation of several smaller subbasins: the Pannonian basin, the Dacian basin, the Black Sea and the Caspian Sea. In the western part of the Dacian Basin, the thick and continuous Mio-Pliocene sedimentary successions of the Getic Depression of Romania provide an exceptional opportunity to study the paleoecological changes in the Eastern Paratethys during the time when the Mediterranean and Black Sea experienced important sea level changes related to the Messinian Salinity Crisis. These sedimentary successions were the basis of high-resolution magnetobiostratigraphic studies that allow a detailed correlation to the Geological Time Scale. Here, we present the main characteristics of the ostracod assemblages of the Late Miocene/Pliocene sedimentary succession from Badislava-Topolog section covering the Eastern Paratethys regional Maeotian and Pontian, stages that are, at moment, under ongoing formal stratigraphic definition process. The Mio-Pliocene is exposed in the central part of the Getic Depression, especially Topolog-Arges area, where it riches up to 500 m in thickness being incorporated into a large monocline structure with 15o-20o plungeto the south. The Upper Maeotian deposits from the area have developed mainly in fluviatile-deltaic facies with frequent continental intercalations. The ostracod assemblage is represented by rare fresh water ostracods of Candona, Pseudocandona and Ilyocypris genera, capable to populate unstable environments like flood-plains, lakes and rivers with temporary existence. The scarce Maeotian ostracod fauna from this marginal section differs essentially from the more diversified one of the same age recorded in areas that evolved in basinal

  11. Divergence between Antarctic and South American marine invertebrates: What molecular biology tells us about Scotia Arc geodynamics and the intensification of the Antarctic Circumpolar Current

    Science.gov (United States)

    Poulin, Elie; González-Wevar, Claudio; Díaz, Angie; Gérard, Karin; Hüne, Mathias

    2014-12-01

    Continental drift processes such as major gateway openings have been historically advocated to explain the distribution of marine benthic taxa in the Southern Ocean (SO). The separation between Antarctic Peninsula and the southern tip of South America together with the onset of the Antarctic Circumpolar Current (ACC) represent the final step for the complete isolation of the Antarctic region. However, there is still controversy concerning the timing and mode of this process, and especially about the role of the Scotia Arc geodynamics in the development of a fully deep and intensified ACC circulation. Based on mitochondrial Cytochrome c Oxidase Subunit I (COI) sequences obtained from different taxa, we performed molecular comparisons between Antarctic and South American relatives to provide independent time estimations of Antarctica's isolation. We include in the analyses congeneric Antarctic and Patagonian near-shore marine benthic invertebrates including indirect developers (Nacella, Yoldia, Sterechinus, and Parbolasia) and brooders (Xymenopsis and Trophonella). Considering the levels of genetic differentiation between relatives from both regions and assuming the molecular clock hypothesis, we estimated the onset of their respective divergence. On one hand, similar levels of genetic distance in broadcast-spawners (7%-8.3%) support the hypothesis that the development of an effective barrier between Antarctica and South America occurred almost simultaneously for these groups. Divergence time estimations based on specific substitution rates indicate that the separation occurred near the Mio-Pliocene transition, long after the physical separation of both continents. Genetic distance and divergence time estimation in direct developers indicate an older separation time, close to the mid-Miocene. Even when the analyzed groups included both broadcast-spawners and brooder organisms, the divergence between Antarctic and South America lineages rather than being related to

  12. The role of docosahexaenoic and the marine food web as determinants of evolution and hominid brain development: the challenge for human sustainability.

    Science.gov (United States)

    Crawford, Michael A; Broadhurst, C Leigh

    2012-01-01

    Life originated on this planet about 3 billion years ago. For the first 2.5 billion years of life there was ample opportunity for DNA modification. Yet there is no evidence of significant change in life forms during that time. It was not until about 600 million years ago, when the oxygen tension rose to a point where air-breathing life forms became thermodynamically possible, that a major change can be abruptly seen in the fossil record. The sudden appearance of the 32 phyla in the Cambrian fossil record was also associated with the appearance of intracellular detail not seen in previous life forms. That detail was provided by cell membranes made with lipids (membrane fats) as structural essentials. Lipids thus played a major, as yet unrecognised, role as determinants in evolution. The compartmentalisation of intracellular, specialist functions as in the nucleus, mitochondria, reticulo-endothelial system and plasma membrane led to cellular specialisation and then speciation. Thus, not only oxygen but also the marine lipids were drivers in the Cambrian explosion. Docosahexaenoic acid (DHA) (all-cis-docosa-4,7,10,13,16,19-hexaenoic acid, C22:6ω3 or C22:6, n-3, DHA) is a major feature of marine lipids. It requires six oxygen atoms to insert its six double bonds, so it would not have been abundant before oxidative metabolism became plentiful. DHA provided the membrane backbone for the emergence of new photoreceptors that converted photons into electricity, laying the foundation for the evolution of other signalling systems, the nervous system and the brain. Hence, the ω3 DHA from the marine food web must have played a critical role in human evolution. There is also clear evidence from molecular biology that DHA is a determinant of neuronal migration, neurogenesis and the expression of several genes involved in brain growth and function. That same process was essential to the ultimate cerebral expansion in human evolution. There is now incontrovertible support of this hypothesis from fossil evidence of human evolution taking advantage of the marine food web. Lipids are still modifying the present evolutionary phase of our species; their signature is evident in the changing panorama of non-communicable diseases. The most worrying change in disease pattern is the sharp rise in brain disorders, which, in the European Union, has overtaken the cost of all other burdens of ill health at €386 billion for the 25 member states at 2004 prices. In 2007, the UK cost was estimated at £77 billion and confirmed in 2010 at £105 billion - greater than heart disease and cancer combined. The rise in mental ill health is now being globalised. The solution to the rising vascular disorders in the last century and now brain disorders in this century lies in a radical reappraisal of the food system, which last century was focussed on protein and calories, with little attention paid to the requirements of the brain - the very organ that was the determinant of human evolution. With the marine fish catch having plateaued 20 years ago and its sustainability now under threat, a critical aspect of this revision is the development of marine agriculture from estuarine, coastal and oceanic resources. Such action is likely to play a key role in future health and intelligence.

  13. Le comportement alimentaire des primates : de la socio-écologie régime éclectique des hominidés

    OpenAIRE

    Hladik, Claude Marcel

    2002-01-01

    Theories about hominization, taking into consideration dietary adaptations and brain size increase, are discussed after a review of major data on primate feeding behavior, including a summary of the author's papers. Field work on primate published since the seventies shows a persistence of ancient morphological, physiological and behavioral adaptations in the present food responses. For instance, distribution of insects determines the size of individual territories of prosimians; however the ...

  14. Geology and preliminary dating of the hominid-bearing sedimentary fill of the Sima de los Huesos Chamber, Cueva Mayor of the Sierra de Atapuerca, Burgos, Spain.

    Science.gov (United States)

    Bischoff, J L; Fitzpatrick, J A; León, L; Arsuagà, J L; Falgueres, C; Bahain, J J; Bullen, T

    1997-01-01

    Sediments of the Sima de los Huesos vary greatly over distances of a few meters. This is typical of interior cave facies, and caused by cycles of cut and fill. Mud breccias containing human bones, grading upwards to mud containing bear bones, fill an irregular surface cut into basal marks and sands. The lack of Bedding and the chaotic abundance of fragile speleothem clasts in the fossiliferous muds suggests that the deposit was originally a subterranean pond facies, and that after emplacement of the human remains, underwent vigorous post-depositional rotation and collapse and brecciation, caused by underlying bedrock dissolution and undermining. The fossiliferous deposits are capped by flowstone and guano-bearing muds which lack large-mammal fossils. U-series and radiocarbon dating indicates the capping flowstones formed from about 68 ka to about 25 ka. U-series analyses of speleothem clasts among the human fossils indicate that all are at, or close to, isotopic equilibrium (> 350 ka). The distribution of U-series dates for 25 bear bones (154 +/- 66 ka) and for 16 human bones (148 +/- 34 ka) is similar and rather broad. Because the human bones seem to be stratigraphically older than chose of the bears, the results would indicate that most of the bones have been accumulating uranium irregularly with time. Electron spin resonance (ESR) analyses of six selected bear bones indicates dates of 189 +/- 28 ka, for which each is cordant with their corresponding U-series date (181 +/- 41 ka). Combined ESR and U-series dates for these samples yielded 200 +/- 4 ka. Such agreement is highly suggestive that uranium uptake in these bones was close to the early-uptake (EU) model, and the dates are essentially correct. Another three selected samples yielded combined ESR U-series dates of 320 +/- 4 ka with a modeled intermediate-mode of uranium uptake. The dating results, therefore, seem to provide a firm minimum age of about 200 ka for the human entry: and suggestive evidence of entry before 320 ka. PMID:9300339

  15. The role of docosahexaenoic and the marine food web as determinants of evolution and hominid brain development: the challenge for human sustainability.

    Science.gov (United States)

    Crawford, Michael A; Broadhurst, C Leigh

    2012-01-01

    Life originated on this planet about 3 billion years ago. For the first 2.5 billion years of life there was ample opportunity for DNA modification. Yet there is no evidence of significant change in life forms during that time. It was not until about 600 million years ago, when the oxygen tension rose to a point where air-breathing life forms became thermodynamically possible, that a major change can be abruptly seen in the fossil record. The sudden appearance of the 32 phyla in the Cambrian fossil record was also associated with the appearance of intracellular detail not seen in previous life forms. That detail was provided by cell membranes made with lipids (membrane fats) as structural essentials. Lipids thus played a major, as yet unrecognised, role as determinants in evolution. The compartmentalisation of intracellular, specialist functions as in the nucleus, mitochondria, reticulo-endothelial system and plasma membrane led to cellular specialisation and then speciation. Thus, not only oxygen but also the marine lipids were drivers in the Cambrian explosion. Docosahexaenoic acid (DHA) (all-cis-docosa-4,7,10,13,16,19-hexaenoic acid, C22:6ω3 or C22:6, n-3, DHA) is a major feature of marine lipids. It requires six oxygen atoms to insert its six double bonds, so it would not have been abundant before oxidative metabolism became plentiful. DHA provided the membrane backbone for the emergence of new photoreceptors that converted photons into electricity, laying the foundation for the evolution of other signalling systems, the nervous system and the brain. Hence, the ω3 DHA from the marine food web must have played a critical role in human evolution. There is also clear evidence from molecular biology that DHA is a determinant of neuronal migration, neurogenesis and the expression of several genes involved in brain growth and function. That same process was essential to the ultimate cerebral expansion in human evolution. There is now incontrovertible support of this hypothesis from fossil evidence of human evolution taking advantage of the marine food web. Lipids are still modifying the present evolutionary phase of our species; their signature is evident in the changing panorama of non-communicable diseases. The most worrying change in disease pattern is the sharp rise in brain disorders, which, in the European Union, has overtaken the cost of all other burdens of ill health at €386 billion for the 25 member states at 2004 prices. In 2007, the UK cost was estimated at £77 billion and confirmed in 2010 at £105 billion - greater than heart disease and cancer combined. The rise in mental ill health is now being globalised. The solution to the rising vascular disorders in the last century and now brain disorders in this century lies in a radical reappraisal of the food system, which last century was focussed on protein and calories, with little attention paid to the requirements of the brain - the very organ that was the determinant of human evolution. With the marine fish catch having plateaued 20 years ago and its sustainability now under threat, a critical aspect of this revision is the development of marine agriculture from estuarine, coastal and oceanic resources. Such action is likely to play a key role in future health and intelligence. PMID:22544773

  16. The rise of ocean giants: maximum body size in Cenozoic marine mammals as an indicator for productivity in the Pacific and Atlantic Oceans

    Science.gov (United States)

    Vermeij, Geerat J.

    2016-01-01

    Large consumers have ecological influence disproportionate to their abundance, although this influence in food webs depends directly on productivity. Evolutionary patterns at geologic timescales inform expectations about the relationship between consumers and productivity, but it is very difficult to track productivity through time with direct, quantitative measures. Based on previous work that used the maximum body size of Cenozoic marine invertebrate assemblages as a proxy for benthic productivity, we investigated how the maximum body size of Cenozoic marine mammals, in two feeding guilds, evolved over comparable temporal and geographical scales. First, maximal size in marine herbivores remains mostly stable and occupied by two different groups (desmostylians and sirenians) over separate timeframes in the North Pacific Ocean, while sirenians exclusively dominated this ecological mode in the North Atlantic. Second, mysticete whales, which are the largest Cenozoic consumers in the filter-feeding guild, remained in the same size range until a Mio-Pliocene onset of cetacean gigantism. Both vertebrate guilds achieved very large size only recently, suggesting that different trophic mechanisms promoting gigantism in the oceans have operated in the Cenozoic than in previous eras. PMID:27381883

  17. Payenia volcanic province, southern Mendoza, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina; Holm, Paul Martin; Llambias, Eduardo Jorge

    2013-01-01

    to the low thickness of the lithospheric mantle and preheating of the lower crust by earlier Mio-Pliocene volcanism. Rare earth element modelling of mantle melting calls for enriched source compositions and a beginning of melting within the garnet stability field for all Payenia basalts. The Río Colorado......The Pleistocene to Holocene Payenia volcanic province is a backarc region of 60,000 km2 in Mendoza, Argentina, which is dominated by transitional to alkaline basalts and trachybasalts. We present major and trace element compositions of 139 rocks from this area of which the majority are basaltic...... rocks with 4 to 12 wt.% MgO and 44 to 50 wt.% SiO2. The southern Payenia province is dominated by intraplate basalts and the trace element patterns of the Río Colorado and Payún Matrú lavas suggest little or no influence from subducted slab components. The mantle source of these rocks is similar to some...

  18. Impact of climate changes during the last 5 million years on groundwater in basement aquifers

    Science.gov (United States)

    Aquilina, Luc; Vergnaud-Ayraud, Virginie; Les Landes, Antoine Armandine; Pauwels, Hélène; Davy, Philippe; Pételet-Giraud, Emmanuelle; Labasque, Thierry; Roques, Clément; Chatton, Eliot; Bour, Olivier; Ben Maamar, Sarah; Dufresne, Alexis; Khaska, Mahmoud; La Salle, Corinne Le Gal; Barbecot, Florent

    2015-01-01

    Climate change is thought to have major effects on groundwater resources. There is however a limited knowledge of the impacts of past climate changes such as warm or glacial periods on groundwater although marine or glacial fluids may have circulated in basements during these periods. Geochemical investigations of groundwater at shallow depth (80–400 m) in the Armorican basement (western France) revealed three major phases of evolution: (1) Mio-Pliocene transgressions led to marine water introduction in the whole rock porosity through density and then diffusion processes, (2) intensive and rapid recharge after the glacial maximum down to several hundred meters depths, (3) a present-day regime of groundwater circulation limited to shallow depth. This work identifies important constraints regarding the mechanisms responsible for both marine and glacial fluid migrations and their preservation within a basement. It defines the first clear time scales of these processes and thus provides a unique case for understanding the effects of climate changes on hydrogeology in basements. It reveals that glacial water is supplied in significant amounts to deep aquifers even in permafrosted zones. It also emphasizes the vulnerability of modern groundwater hydrosystems to climate change as groundwater active aquifers is restricted to shallow depths. PMID:26392383

  19. Time scales of regional circulation of saline fluids in continental aquifers (Armorican massif, Western France

    Directory of Open Access Journals (Sweden)

    A. Armandine Les Landes

    2014-06-01

    Full Text Available In recent decades, saline fluids have been sampled worldwide at great depths in continental basements. Although some of them have been attributed to marine transgressions the mechanisms allowing their circulation is not understood. In this paper, we describe the horizontal and vertical distribution of moderately saline fluids (60 to 1400 mg L−1 sampled at depths ranging from 41 to 200 m in aquifers at the regional scale of the Armorican Massif (northwestern France. The horizontal and vertical distributions of high chloride concentrations are in good agreement with both the altitudinal and vertical limits and succession of the three major transgressions between the Mio-Pliocene and Pleistocene ages. The mean chloride concentration for each transgression area is exponentially related to the time spanned until present. It defines the potential laws of leaching of marine waters by fresh meteoric waters. The results of the Armorican aquifers provide the first observed constraints for the time scales of seawater circulation in the continental basement and the subsequent leaching by fresh meteoric waters. The general trend of increasing chloride concentration with depth and the time frame for the flushing process provide useful information to develop conceptual models of the paleo-functionning of Armorican aquifers.

  20. Site characterization and site response in Port-au-Prince, Haiti

    Science.gov (United States)

    Hough, Susan E.; Yong, Alan K.; Altidor, Jean Robert; Anglade, Dieuseul; Given, Douglas D.; Mildor, Saint-Louis

    2011-01-01

    Waveform analysis of aftershocks of the Mw7.0 Haiti earthquake of 12 January 2010 reveals amplification of ground motions at sites within the Cul de Sac valley in which Port-au-Prince is situated. Relative to ground motions recorded at a hard-rock reference site, peak acceleration values are amplified by a factor of approximately 1.8 at sites on low-lying Mio-Pliocene deposits in central Port-au-Prince and by a factor of approximately 2.5–3 on a steep foothill ridge in the southern Port-au-Prince metropolitan region. The observed amplitude, predominant periods, variability, and polarization of amplification are consistent with predicted topographic amplification by a steep, narrow ridge. A swath of unusually high damage in this region corresponds with the extent of the ridge where high weak-motion amplifications are observed. We use ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) imagery to map local geomorphology, including characterization of both near-surface and of small-scale topographic structures that correspond to zones of inferred amplification.

  1. The rise of ocean giants: maximum body size in Cenozoic marine mammals as an indicator for productivity in the Pacific and Atlantic Oceans.

    Science.gov (United States)

    Pyenson, Nicholas D; Vermeij, Geerat J

    2016-07-01

    Large consumers have ecological influence disproportionate to their abundance, although this influence in food webs depends directly on productivity. Evolutionary patterns at geologic timescales inform expectations about the relationship between consumers and productivity, but it is very difficult to track productivity through time with direct, quantitative measures. Based on previous work that used the maximum body size of Cenozoic marine invertebrate assemblages as a proxy for benthic productivity, we investigated how the maximum body size of Cenozoic marine mammals, in two feeding guilds, evolved over comparable temporal and geographical scales. First, maximal size in marine herbivores remains mostly stable and occupied by two different groups (desmostylians and sirenians) over separate timeframes in the North Pacific Ocean, while sirenians exclusively dominated this ecological mode in the North Atlantic. Second, mysticete whales, which are the largest Cenozoic consumers in the filter-feeding guild, remained in the same size range until a Mio-Pliocene onset of cetacean gigantism. Both vertebrate guilds achieved very large size only recently, suggesting that different trophic mechanisms promoting gigantism in the oceans have operated in the Cenozoic than in previous eras. PMID:27381883

  2. The Cape element in the Afrotemperate flora: from Cape to Cairo?

    Science.gov (United States)

    Galley, Chloe; Bytebier, Benny; Bellstedt, Dirk U; Linder, H Peter

    2007-02-22

    The build-up of biodiversity is the result of immigration and in situ speciation. We investigate these two processes for four lineages (Disa, Irideae p.p., the Pentaschistis clade and Restionaceae) that are widespread in the Afrotemperate flora. These four lineages may be representative of the numerous clades which are species rich in the Cape and also occur in the highlands of tropical Africa. It is as yet unclear in which direction the lineages spread. Three hypotheses have been proposed: (i) a tropical origin with a southward migration towards the Cape, (ii) a Cape origin with a northward migration into tropical Africa, and (iii) vicariance. None of these hypotheses has been thoroughly tested. We reconstruct the historical biogeography of the four lineages using likelihood optimization onto molecular phylogenies. We find that tropical taxa are nested within a predominantly Cape clade. There is unidirectional migration from the Cape into the Drakensberg and from there northwards into tropical Africa. The amount of in situ diversification differs between areas and clades. Dating estimates show that the migration into tropical East Africa has occurred in the last 17 Myr, consistent with the Mio-Pliocene formation of the mountains in this area.

  3. The Transylvanian Basin (Romania) and its relation to the Carpathian fold and thrust belt: Insights in gravitational salt tectonics

    Energy Technology Data Exchange (ETDEWEB)

    Krezsek, Csaba [SNGN ROMGAZ, 4 Unirii 551025 Medias (Romania); Bally, Albert W. [Department of Geology and Geophysics, University of Rice, 6100 South Main Street, Houston, TX 77005-1892 (United States)

    2006-05-15

    Interpretation of regional seismic profiles, stratigraphic and sedimentologic data improved insights in the evolution of the Transylvanian Basin. The basin evolution was coeval with the post-Mid-Cretaceous to recent deformation of the Carpathian Mts. Four tectonostratigraphic megasequences are differentiated: Upper Cretaceous (rift), Paleogene (sag), Lower Miocene (flexural basin) and Middle to Upper Miocene (backarc sequence dominated by gravitational tectonics). The Mid-Miocene continental collision in the Eastern Carpathians is associated with the rising Carpathians. This uplift enhanced the differential load, which, together with the high heat flow induced by Late Miocene to Pliocene arc volcanism, triggered large-scale Mio-Pliocene gravity spreading of the salt overburden. This 'mega-slide' comprises three structural domains, as follows: extensional weld (upslope), contractional folds (central) and contractional toe thrust (downslope). The diapirs in the east indicate a pre-shortening reactive/passive growth stage. The central folds are mostly the result of late shortening. Basement involved thrusting uplifted the toe thrust domain by the Late Pliocene. The Late Neogene to recent Carpathians uplift, backarc volcanism and gravity spreading are largely coeval. (author)

  4. Late cenozoic magmatism in the South Patagonian batholith: SHRIMP U-Pb zircon age evidence

    International Nuclear Information System (INIS)

    The North Patagonian Batholith (NPB) has a zonal age pattern which includes a well defined belt of Miocene and Mio-Pliocene plutons in its central portion (Pankhurst et al., 1999) which are spatially, and probably genetically related to the Liquine-Ofqui Fault Zone. Previous geochronological studies in the Southern Patagonian Batholith (SPB), as summarized by Bruce et al. (1991), have yielded 9 late Cenozoic K-Ar or Ar-Ar ages out of a total of 116 age determinations. None of these young ages correspond to U-Pb determinations on zircons, and some of the young ages correspond to satellite plutons east of the SPB proper, such as the Torres del Paine intrusion. In this paper we present the first late Cenozoic SHRIMP U-Pb zircon ages in the area of the SPB. The morphology of the analysed zircon crystals is described and leads to some inferences on the methodology and on the geological interpretation of the obtained ages (au)

  5. Identification and environmental interpretation of diagenetic and biogenic greigite in sediments: A lesson from the Messinian Black Sea

    Science.gov (United States)

    Chang, Liao; Vasiliev, Iuliana; van Baak, Christiaan; Krijgsman, Wout; Dekkers, Mark J.; Roberts, Andrew P.; Gerald, John D. Fitz; van Hoesel, Annelies; Winklhofer, Michael

    2014-09-01

    (Fe3S4) is a widespread authigenic magnetic mineral in anoxic sediments and is also commonly biosynthesized by magnetotactic bacteria in aqueous environments. While the presence of fossilized bacterial magnetite (Fe3O4) has now been widely demonstrated, the preservation of greigite magnetofossils in the geological record is only poorly constrained. Here we investigate Mio-Pliocene sediments of the former Black Sea to test whether we can detect greigite magnetofossils and to unravel potential environmental controls on greigite formation. Our magnetic analyses and transmission electron microscope (TEM) observations indicate the presence of both diagenetic and bacterial greigite, and suggest a potentially widespread preservation of greigite magnetofossils in ancient sediments, which has important implications for assessing the reliability of paleomagnetic records carried by greigite. TEM-based chemical and structural analyses also indicate the common presence of nickel-substituted diagenetic iron sulfide crystals with a ferrimagnetic greigite structure. In addition, our cyclostratigraphic framework allows correlation of magnetic properties of Messinian Black Sea sediments (Taman Peninsula, Russia) to global climate records. Diagenetic greigite enhancements appear to be climatically controlled, with greigite mainly occurring in warm/wet periods. Diagenetic greigite formation can be explained by variations in terrigenous inputs and dissolved pore water sulfate concentrations in different sedimentary environments. Our analysis demonstrates the usefulness of greigite for studying long-term climate variability in anoxic environments.

  6. Brittle tectonics and state of stress in the basin of Tizi n'Test (High Atlas, Morocco during the Tertiary inversion

    Directory of Open Access Journals (Sweden)

    Qarbous, A.

    2008-06-01

    Full Text Available During the Atlasic compressional phase, the Tizi n’Test Triassic basin underwent a tectonic inversion responsible for the reactivation of the extensional Triassic structures. Contrary to former concepts suggesting a transpressional regime, the NE-SW to WNW-ESE trending faults had a reverse displacement, while the NW-SE to NNW-SSE ones were reactivated as strike-slip faults. The reverse motion of the initially normal faults led to the uplift of the basin and its basement in a pop-up style. This inversion is also responsible for a set of footwall synclines and hanging wall anticlines with variable half-wavelength, and related to basement reverse faulting. Striation analysis with the help of software R4DT was carried out at 45 sites in order to determine the state of stress. The 25 most reliable tensors show that the main compressive stress £m1 trends NW-SE to NNE. Analysis of the spatial distribution of the £m1 axis shows a main maximum at N012 and two secondary axes at N123 and N147. In absence of an absolute or relative chronology of the events, we interpret these directions as related to two distinct events, the age of which should be, by comparison with other studies, pre-Mio-Pliocene for the N012 phase and Mio-Pliocene for the NW-SE phase.Durante la fase de compresión Atlásica, la cuenca Triásica de Tizi n’Test ha sufrido un proceso de inversión tectónica responsable de la reactivación de las estructuras extensionales Triásicas. A diferencia de las teorías anteriores que hablaban de un régimen transpresivo, las fallas NE-SO a ONO-ESE han sido inversas, mientras que las de direcciones NO-SE a NNO-SSE han sido reactivadas en su mayoría como fallas de desgarre. El juego inverso de las fallas inicialmente normales provocó el levantamiento de la cuenca y su zócalo paleozoico mediante un estilo de “pop-upâ€�. Esta inversión también generó un conjunto de sinclinales en los compartimientos inferiores y

  7. Kinematics of a sigmoidal fold and vertical axis rotation in the east of the Zagros Makran syntaxis (southern Iran): Paleomagnetic, magnetic fabric and microtectonic approaches

    Science.gov (United States)

    Smith, B.; Aubourg, C.; Guézou, J. C.; Nazari, H.; Molinaro, M.; Braud, X.; Guya, N.

    2005-12-01

    The Zagros Simple Fold Belt is characterized by elongated, curved, or sigmoidal folds. The trend of these structures together with the structural style, change suddenly across the Zagros-Makran syntaxis which separates the continental collision domain of Zagros from the oceanic subduction one in Makran. This work focuses on the Minab anticline, outcropping in the easternmost part of Zagros. In order to understand the kinematics of a sigmoidal fold and underscore possible vertical axis rotations in the eastern side of the syntaxis, we performed a joint study of magnetic fabric, microtectonics and paleomagnetism of the northern termination of this fold. The two limbs have been sampled (7 sites, 134 samples) along three cross-sections corresponding to three different orientations of the fold axis. The rocks are weakly deformed fine-grained Mio-Pliocene reddish siltstones. The shortening directions deduced from both magnetic fabric analysis and microtectonic observations are consistent with each other, they are horizontal and roughly perpendicular to the local fold axis, following the torsion of the fold hinge line, and indicating a tectonic origin of the magnetic fabric. Rockmagnetic analyses (thermomagnetic curves, hysteresis loops) point to the presence of magnetite in the PSD and MD ranges as the main magnetic carriers, together with a minor contribution from hematite. Apart from a post-tilting sub-actual VRM and/or CRM (component A), paleomagnetic analyses yield mainly two pre-tilting magnetization components: Component B is carried by magnetite, spanning the intermediate to high unblocking temperature range (300 °C ≤ Tubs ≤ 580 °C). Component C has unblocking temperatures characteristic of hematite (580 °C ≤ Tubs ≤ 680 °C). Both are ante-folding, based on positive reversal and fold tests, inside each of the cross-section but also for the three sections together. However, because component C is biased by some inclination flattening, only component B is

  8. A partial distal humerus from the Middle Pleistocene deposits at Bodo, Middle Awash, Ethiopia

    OpenAIRE

    Carretero, José Miguel; Haile Selassie, Yohannes; Rodríguez García, Laura; Arsuaga, Juan Luis

    2009-01-01

    The Bodo partial distal humerus with an approximate age of 0.6 million years is one of the very few postcranial remains from the African Middle Pleistocene. Despite its fragmentary status, comparisons of the Bodo humerus with other fossil hominid and modern human samples reveal some insights into African hominids of this time period. The Bodo partial humerus displays distal humeral features very common in the European Middle and Late Pleistocene hominids, such as a relatively w...

  9. Refining upon the climatic background of the Early Pleistocene hominid settlement in western Europe: Barranco León and Fuente Nueva-3 (Guadix-Baza Basin, SE Spain)

    Science.gov (United States)

    Blain, Hugues-Alexandre; Lozano-Fernández, Iván; Agustí, Jordi; Bailon, Salvador; Menéndez Granda, Leticia; Espígares Ortiz, Maria Patrocinio; Ros-Montoya, Sergios; Jiménez Arenas, Juan Manuel; Toro-Moyano, Isidro; Martínez-Navarro, Bienvenido; Sala, Robert

    2016-07-01

    The Early Pleistocene sites of Barranco León and Fuente Nueva-3 (Guadix-Baza Basin, SE Spain) have yielded thousands of Mode 1 or Oldowan lithic artifacts (both sites) and one tooth (in layer D, formerly 5 of Barranco León), today considered to be some of the earliest evidence of humans in western Europe at ca. 1.2-1.5 Ma. Previous quantitative paleoclimatic reconstructions based on herpetile assemblages indicated that, during the formation of these two sites, the mean annual temperature and mean annual precipitation were higher than they are now in the southeastern Iberian Peninsula, with lower continentality. Here, we propose new climatic reconstructions where the mean monthly temperature and precipitation and the difference between the four driest months and the four rainiest months are estimated. Climatograms are built in order to specify the distribution and variation of temperature and precipitation during the year, and the Aridity Indices of Gaussen, Lautensach-Mayer, Dantin-Revenga and De Martonne are used to characterize ombroclimatic differences. According to these new climatic parameters, rainfall distribution through the year shows considerably higher precipitation in every season except summer and early autumn, which remain drier and thus consistent with a Mediterranean climate pattern. No change is observed in the duration of the aridity period, which remains four months long. However, the value of the Aridity Index of De Martonne is higher than 20 (subhumid climate) in Barranco León and Fuente Nueva-3, whereas today it is lower than 20 (semi-arid climate), suggesting major changes in the ombroclimatic type. These results yield a more precise scenario for the paleoclimatic conditions that prevailed during the late Early Pleistocene in the Guadix-Baza Basin and permit us to contrast the ages obtained from numerical dating and biochronology. The very warm and humid climate reconstructed for both Barranco León and Fuente Nueva-3 suggests that, in accordance with the numerical dating, these two sites are contemporaneous with the particularly warm interglacial peaks of Marine Isotope Stages 43-49 (i.e. between 1.35 and 1.47 Ma). The similarity between reconstructed climates, the high overlap between their estimated precipitation and between the difference of the driest from the rainiest season suggest that these sites may correspond to the same part of a climatic glacial/interglacial cycle, but because the evolutionary degree of the rodent Mimomys savini shows a slightly more derived state for Fuente Nueva-3 than for Barranco León (i.e a short chronological difference between the two sites), they may correspond to two consecutive warm interglacial peaks.

  10. Restoration of the Nanjing 2 Fossil Hominid Calvarium: Morphology and Taxonomic Implications%南京2号人类头骨化石的复位和形态

    Institute of Scientific and Technical Information of China (English)

    张银运; 刘武

    2006-01-01

    南京2号人类头骨化石仅保留部分的额骨、顶骨、枕骨和颞骨,为一不完整的颅盖骨.其顶骨和枕骨有数条断裂缝,各断块之间有程度不一的错动,致使该颅盖骨显得外形异常.本项研究是对该颅盖骨的错动部分进行复位,结果表明,南京2号头骨有较大的顶骨、较小的上枕鳞相对宽度、可能较大的颅容量.这些形态提示该头骨与直立人有所不同而与早期智人相近.该头骨所具有的角圆枕、颞鳞顶缘形状、枕骨圆枕发育程度、枕骨的枕平面与项平面过渡情况、枕内隆突点与枕外隆突点的距离、头骨骨壁厚度、脑膜中动脉分支情况、头骨枕面观之轮廓线样式等形态细节,还很难作为可靠的依据把南京2号头骨鉴定为直立人.南京2号头骨很大可能是属于智人亚种(Homo sapiens sapiens)中的一员.

  11. High-resolution U-series dates from the Sima de los Huesos hominids yields 600þN-66 kyrs: implications for the evolution of the early Neanderthal lineage

    OpenAIRE

    Bischoff, James L.; Williams, Ross W.; Rosenbauer, Robert J.; Aramburu Artano, Arantza; Arsuaga, Juan Luis; García García, Nuria; Cuenca Bescós, Gloria

    2007-01-01

    The Sima de los Huesos site of the Atapuerca complex near Burgos, Spain contains the skeletal remains of at least 28 individuals in a mudbreccia underlying an accumulation of the Middle Pleistocene cave bear (Ursus deningeri). We report here on new high-precision dates on the recently discovered speleothem SRA-3 overlaying human bones within the Sima de los Huesos. Earlier analyses of this speleothem by TIMS (thermal-ionization mass-spectrometry) showed the lower part to be indisting...

  12. Paratethys forcing of the Messinian Salinity Crisis

    Science.gov (United States)

    Krijgsman, Wout; Van Baak, Christiaan; Flecker, Rachel; Grothe, Arjen; Marzocchi, Alice; Stoica, Marius; Vasiliev, Iuliana

    2016-04-01

    During the Messinian Salinity Crisis (5.97-5.33 Ma), there is increasing evidence for the presence of fresh water input, not only during the final Lago-mare stage but even during times of evaporite formation. Here we present new strontium isotopic data from two well-dated Messinian sections in the Black and Caspian seas, which show remarkably similar Sr-values as the ones recorded in the Mediterranean during the final phase of the salinity crisis. This strongly suggests that a major fresh water pulse in the Mediterranean originated from the Paratethys. It highlights the importance of a Mediterranean-Black Sea connection during the entire MSC, adding an enormous drainage basin to the Mediterranean water balance. The presence of Paratethyan fauna in the Mediterranean Lago-Mare deposits has fuelled long-lasting controversies over the connectivity between the Mediterranean and Paratethys and contemporary sea level drops in both basins. We furthermore use results of sub-precessional climate simulations to calculate the freshwater budget of the Mediterranean and Paratethys in the Messinian. Using these numerical constraints, we propose a Mediterranean outflow pump as an alternative scenario for the most dramatic hydrological changes in the MSC. This "pump" mechanism significantly enhanced Paratethyan inflow to the Mediterranean, creating 1) suitable conditions for gypsum to form and 2) Lago-mare fauna to migrate and thrive. When the Mediterranean sea level finally reached the height of the Gibraltar sill, Mediterranean outflow restarted there and enhanced exchange with the Atlantic. During this reorganisation of the circulation, brackish and hypersaline waters were pumped out of the Mediterranean, and open marine conditions were re-established without major flooding at the Mio-Pliocene boundary.

  13. Gravimetry contributions to the study of the complex western Haouz aquifer (Morocco): Structural and hydrogeological implications

    Science.gov (United States)

    Chouikri, Ibtissam; el Mandour, Abdennabi; Jaffal, Mohammed; Baudron, Paul; García-Aróstegui, José-Luis; Manar, Ahmed; Casas, Albert

    2016-03-01

    This study provides new elements that illustrate the benefits of combining gravity, structural, stratigraphic and piezometric data for hydrogeological purposes. A combined methodology was applied to the western Haouz aquifer (Morocco), one of the main sources of water for irrigation and human consumption in the Marrakech region. First, a residual anomaly map was calculated from the Bouguer anomaly data. The computed map provided information on the ground density variation, revealing a strong control by a regional gradient. We then used various filtering techniques to delineate the major geological structures such as faults and basins: vertical and horizontal derivatives and upward continuation. This technique highlighted news structures and provided information on their dip. The gravity anomalies perfectly delineated the basement uplifts and the sedimentary thickening in depressions and grabens. The interpretation of gravimetric filtering, geological and hydrogeological data then highlighted two types of groundwater reservoirs, an unconfined aquifer hosted in conglomeratic mio-pliocene and quaternary rocks, covering the entire western Haouz and a deep confined aquifer contained in cenomanian-turonian limestone and eocene dolomitic formations in the south. Combining piezometric and residual anomaly maps revealed that groundwater flow and storage was in perfect agreement with the structures showing a negative anomaly, while structures with positive anomalies corresponded to groundwater divides. The study of gravity gradient zones by contact analysis enhanced the existing structural pattern of the study area and highlighted new structures, mainly oriented N70 and N130. The results of this study present a common framework and provide a notable step forward in the knowledge of the geometry and the groundwater flow pattern of the western Haouz aquifer, and will serve as a solid basis for a better water resource management.

  14. Probing atomic scale transformation of fossil dental enamel using Fourier transform infrared and nuclear magnetic resonance spectroscopy: a case study from the Tugen Hills (Rift Gregory, Kenya).

    Science.gov (United States)

    Yi, Haohao; Balan, Etienne; Gervais, Christel; Ségalen, Loïc; Roche, Damien; Person, Alain; Fayon, Franck; Morin, Guillaume; Babonneau, Florence

    2014-09-01

    A series of fossil tooth enamel samples was investigated by Fourier transform infrared (FTIR) spectroscopy, (13)C and (19)F magic-angle spinning nuclear magnetic resonance (MAS NMR) and scanning electron microscopy (SEM). Tooth remains were collected in Mio-Pliocene deposits of the Tugen Hills in Kenya. Significant transformations were observed in fossil enamel as a function of increasing fluorine content (up to 2.8wt.%). FTIR spectroscopy revealed a shift of the ν1 PO4 stretching band to higher frequency. The ν2 CO3 vibrational band showed a decrease in the intensity of the primary B-type carbonate signal, which was replaced by a specific band at 864cm(-1). This last band was ascribed to a specific carbonate environment in which the carbonate group is closely associated to a fluoride ion. The occurrence of this carbonate defect was consistently attested by the observation of two different fluoride signals in the (19)F NMR spectra. One main signal, at ∼-100ppm, is related to structural F ions in the apatite channel and the other, at -88ppm, corresponds to the composite defect. These spectroscopic observations can be understood as resulting from the mixture of two phases: biogenic hydroxylapatite (bioapatite) and secondary fluorapatite. SEM observations of the most altered sample confirmed the extensive replacement of the bioapatite by fluorapatite, resulting from the dissolution of the primary bioapatite followed by the precipitation of carbonate-fluorapatite. The ν2 CO3 IR bands can be efficiently used to monitor the extent of this type of bioapatite transformation during fossilization.

  15. Post Tyrrhénian deformation analysis in the Sahel coast (Eastern Tunisia): seismotectonic events implication

    Science.gov (United States)

    Mejrei, H.; Ghribi, R.; Bouaziz, S.; Balescu, S.

    2012-04-01

    The eastern coast of Tunisia is characterized by Pleistocene coastal deposits considered as a reference of interglacial high sea levels. In this region, the stratigraphy of Tunisian Pleistocene deposits was first established on the basis of geomorphological, lithostratigraphic, biostratigraphic criteria and U/Th data. They have been subdivided into three superimposed formations, from the oldest to the recent "Douira, Rejiche and Chebba" including coastal marine (Strombus bubonius), lagoonal and eolian sediments. These marine formations are organized into parallel bars to the actual shoreline overlaying unconformably the Mio-Pliocene and "Villafranchian" deposits. A luminescence dating method IRSL applied to alkali feldspar grains from the two sandy marines units of the Douira formation demonstrate for the first time the presence of two successive interglacial high sea level events correlative of MIS 7 and MIS 9. These sandy marine units are separated by a major erosional surface and by a continental pedogenised loamy deposit related to a low sea level event which might be assigned to MIS 8. Variations in the height of these marine unit (+13 to +32m) in the Sahel coast reflect a significant tectonic deformations and show precious geomorphological and tectonic markers. An extensive brittle deformations analysis has been carried out in several sites. A detailed analysis of fracturing is based on studies of fault-slip data population and of joint sets. It allows reconstructions of post Tyrrhenian stress regimes which are characterized by N170-016 compression and N095-100 extension. In this paper we present, the combination of IRSL data applied to these raised marine deposits and a reconstruction of tectonic evolution in term of stress pattern evolution since the Tyrrhenian allowed us to assign an accurate the recent tectonic calendar. These reconstituted events will be replaced and will be discussed in the regional setting of sismotectonic activities of the north

  16. Modes of rifting in magma-rich settings: Tectono-magmatic evolution of Central Afar

    Science.gov (United States)

    Stab, Martin; Bellahsen, Nicolas; Pik, Raphaël.; Quidelleur, Xavier; Ayalew, Dereje; Leroy, Sylvie

    2016-01-01

    Recent research in Afar (northern Ethiopia) has largely focused on the formation of the present-day ocean-continent transition at active segments (e.g., Manda Hararo). However, the Oligo-Miocene history of extension, from the onset of rifting at ~25 Ma to the eruption of the massive Stratoïd flood basalts at ~4 Ma, remains poorly constrained. Here we present new structural data and radiometric dating from Central Afar, obtained along a zone stretching from the undeformed Oligocene Ethiopian plateau to the Manda Hararo and Tat'Ale active volcanic segments. Basaltic and rhyolitic formations were mapped in two key areas corresponding to the proximal and distal parts of a half-rift. We present a balanced composite cross section of Central Afar, reconstructed using our new data and previously published geophysical data on the crustal structure. Our main findings are as follows: (1) Extension during the Mio-Pliocene corresponds to a "wide rift" style of rifting. (2) The lower crust has been underplated/intruded and rethickened during rifting by magmatic injection. (3) Our restoration points to the existence of midcrustal shear zones that have helped to distribute extension in the upper crust and to localize extension at depth in a necking zone. Moreover, we suggest that there is a close relationship between the location of a shear zone and the underplated/intruded material. In magma-rich environments such as Central Afar, breakup should be achieved once the initial continental crust has been completely replaced by the newly, magmatically accreted crust. Consequently, and particularly in Afar, crustal thickness is not necessarily indicative of breakup but instead reflects differences in tectono-magmatic regimes.

  17. Vicariance and Its Impact on the Molecular Ecology of a Chinese Ranid Frog Species-Complex (Odorrana schmackeri, Ranidae.

    Directory of Open Access Journals (Sweden)

    Yongmin Li

    Full Text Available Paleogeological events and Pleistocene climatic fluctuations have had profound influences on the genetic patterns and phylogeographic structure of species in southern China. In this study, we investigated the population genetic structure and Phylogeography of the Odorrana schmackeri species complex, mountain stream-dwelling odorous frogs, endemic to southern China. We obtained mitochondrial sequences (1,151bp of the complete ND2 gene and two flanking tRNAs of 511 individuals from 25 sites for phylogeographic analyses. Phylogenetic reconstruction revealed seven divergent evolutionary lineages, with mean pairwise (K2P sequence distances from 7.8% to 21.1%, except for a closer ND2 distance (3.4%. The complex geological history of southern China drove matrilineal divergence in the O. schmackeri species complex into highly structured geographical units. The first divergence between lineage A+B and other lineages (C-G had likely been influenced by the uplift of coastal mountains of Southeast China during the Mio-Pliocene period. The subsequent divergences between the lineages C-G may have followed the formation of the Three Gorges and the intensification of the East Asian summer monsoon during the late Pliocene and early Pleistocene. Demographic analyses indicated that major lineages A and C have been experienced recent population expansion (c. 0.045-0.245 Ma from multiple refugia prior to the Last Glacial Maximum (LGM. Molecular analysis suggest that these seven lineages may represent seven different species, three described species and four cryptic species and should at least be separated into seven management units corresponding to these seven geographic lineages for conservation.

  18. Depósitos epitermales de baja sulfuración ricos en sulfuros de metales base, distrito aurífero La Carolina, San Luis, Argentina

    Directory of Open Access Journals (Sweden)

    Gallard-Esquivel María Cecilia

    2011-12-01

    Full Text Available Low-sulfidation epithermal base-metal sulfide-rich deposits, La Carolina gold-bearing district,San Luis, Argentina. La Carolina gold-bearing district is located at the western end of the Metallogenetic Belt of San Luis, which is spatially and genetically related to the mesosilicic volcanism of mio-pliocene age. The volcanic arc experienced an eastward migration, due to the flattening of the Nazca plate in the segment 27°-33°S, known as the Pampean flat-slab. At La Carolina, the volcanic activity occurred between 8.2 and 6.3 Ma. It encompasses lavas and pyroclastics of andesitic, dacitic, latitic and trachytic composition. The mesosilicic magmas belong to normal to high-k calc-alkaline and shoshonitic suites. Structural analysis shows that previous structures have strongly controlled the emplacement of volcanic rocks and related mineral deposits at La Carolina allowing to define a pullapart.In this gold-bearing district there are eigth small mineralized prospects. The mineralogy consists of pyrite, arsenic rich pyrite, galena, sphalerite, marcasite, melnikovite, chalcopyrite, pyrrhotite, arsenopyrite, tennantitetetrahedrite, digenite, covellite, bornite, pyrargiryte, hessite, silvanite, pearceite, argirodite, gold, silver, greigite, boulangerite, jamesonite and electrum. The gangue consists of quartz, calcite, chalcedony and minor adularia.The hydrothermal alteration is widespread and comprise phyllic and argillic mineral assemblages characterized by sericite, illite, interstratified I/S, and silicic; propylitic alteration is also present as an outer halo. Fluid inclusions studies show that the formation temperatures range between 230º to 330º C. Boiling and mixing with meteoric water led to mineral precipitation. Based on the mineralogy, textures, hydrothermal alteration, formation temperatures,fluid chemistry and prospective geochemistry the mineralizations have been classified as low-sulfidation epithermal base-metal sulfide-rich deposits.

  19. Dental remains from Atapuerca-TD6 (Gran Dolina site, Burgos, Spain).

    Science.gov (United States)

    Bermúdez de Castro, J M; Rosas, A; Nicolás, M E

    1999-01-01

    A descriptive and comparative study of the human dental remains recovered from level six (Aurora stratum) of the Gran Dolina (TD) site, Sierra de Atapuerca, northern Spain, is presented. The TD6 dental sample consists of two deciduous and 28 permanent teeth, belonging to a minimum of six individuals. Paleomagnetic analyses of the TD sequence suggest an age for the Aurora stratum of greater than 780 ka. The associated fossil macro- and micrommals are consistent with a date for the Atapuerca-TD6 hominids at the end of the Early Pleistocene. As a whole, the size of the TD6 teeth is large and comparable to that of the African Lower Pleistocene hominids. Most morphological dental traits are plesiomorphic for the genus Homo, whereas the shape analysis has revealed some size-related trends that differ from those seen in early Homo. Thus, the relative size increase of the maxillary and mandibular anterior teeth and buccolingual diameter of the first molars, the reduction of the third molars and lower canines, and the P(3)>P(4)size sequence are all characteristic of the population represented by the TD6 hominids. The morphological evidence suggests that the TD6 hominids are closer to African Lower and early Middle Pleistocene hominids than they are to European Middle Pleistocene hominids. However, some dental traits of the TD6 hominids, such as the expansion of the anterior teeth, the P(3)>P(4)size sequence, and the morphology of the lower canine also suggest an evolutionary continuity between the population represented by these hominids and the European Middle Pleistocene population. Furthermore, dental evidence indicates that the TD6 hominids are clearly distinct from Asian H. erectus. Dental evidence also suggests that the TD6 hominids could represent an evolutionary connection between H. ergaster and H. heidelbergensis. PMID:10496999

  20. The ischium and hip extensor mechanism in human evolution.

    Science.gov (United States)

    McHenry, H M

    1975-07-01

    Although it is commonly stated that the ischia of the late Pliocence-early Pleistocene hominid fossils are long and ape-like, new interpretations show this view to be falacious. An important new theory proposed by Robinson concludes that the gracile form of early hominid was an efficient biped, but the robust form was a less efficient biped and was adapted for tree climbing. Interpretation of the ischium is crucial to this idea. The present study shows that (1) the gracile and robust australopithecine ischia had similar relative lenths and (2) that the hamstring mechanism was probably very similar in the two forms of South African early hominid. PMID:808140

  1. Extreme Erosion of the Eastern Himalayan Syntaxis Traced by Isotopic Compositions of River and Bengal Fan Sediments

    Science.gov (United States)

    France-Lanord, C.; Galy, V.; Pik, R.; Singh, S. K.

    2006-12-01

    Sediments of the Brahmaputra basin were collected in Assam and Bangladesh including the Siang-Tsangpo that drains the Namche Barwa syntaxis. Chemistry, and Sr and Nd isotopic compositions trace sediment provenance and erosion distribution in eastern Himalaya. Overall sediments display a large range of 87Sr/86Sr (0.705 to 0.825) and ɛNd (-20.5 to -6.9) (Singh et al. 2001). Nevertheless, sediments of the Siang and along course of the Brahmaputra show almost constant isotopic signatures. Mass balance calculations based on these data along with data available for the Tsangpo in Tibet and in Namche Barwa region show that the basin is marked with differential erosion. About half of the sediments is derived from the syntaxis, which is only 20% of the mountainous area. Zircon-He ages from the Brahmaputra in Bangladesh range from 0.4 to 77 Ma. 40% of the zircon have ages between 0.4 and 1 Ma defining a distribution peak centred at 0.5 Ma. These young ages correspond to extreme denudation rates of 5 to 7 mm/yr. Dispersed ages from 12 to 77 Ma do not define any disctinct group and the remaining 40% of the zircons have ages between 2.5 and 7 Ma, which correspond to the pool of ages recorded by on other Himalayan rivers. The Namche Barwa syntaxis shows the same type of very young zircon ages as observed in the Siang (Stewart et al., 2004). The intense erosion of the eastern syntaxis is likely sustained by the high incision potential of the Tsangpo river due to its very high water discharge prior to the Syntaxis. Sr-Nd isotopic compositions of the Brahmaputra are different from those of the Himalayan tributaries and of the Ganga due to the contribution of the Calc-alkaline formations of the Transhimalaya. This contribution is also traced on modern sediments of the delta as well as in upper Bengal fan aged between 30 and 20 000 years and suggest a rather steady erosion regime since the LGM. On a longer time scale, Mio-Pliocene sediments from the middle Bengal Fan (DSDP Site 218

  2. Neogene Palynology of the Snake River Plain: Climate Change and Volcanic Effects.

    Science.gov (United States)

    Davis, O. K.; Ellis, B.; Link, P.; Wood, S.; Shervais, J. W.

    2006-12-01

    Preliminary palynological analyses of lake sediment and inter-flow samples reveal environmental and vegetation changes in response to climatic and volcanic events over the late Neogene. On the evolutionary timescale, sagebrush steppe has expanded and coniferous and deciduous forests have declined. In part this trend has followed the cooling and drying of the late Neogene, but volcanic impact may also be recorded in the effects of long-term subsidence and in periodic deposition of volcanic tephra. The most detailed palynological record yet published for the region (Thompson, 1992) records increasing pine and juniper percentages and decreasing sagebrush and Sarcobatus percentages spanning the Pliocene Glenns Ferry Formation and Pleistocene Bruneau Formation. Palynology of a well in Lake Idaho sediments (Canyon County, Davis, this abstract) shows the same decline of sagebrush and Sarcobatus, but records decreasing juniper percentages during the Pliocene. These Lake Idaho records are spanned by the palynology of the Great Salt Lake (Davis, 2002), which records a modern pollen flora from the late Miocene onward. Salt sage and sagebrush steppe developed progressively from the late Miocene through the Holocene, with peaks in sagebrush pollen percentages during the Mio- Pliocene transition and the late Pleistocene. The Great Salt Lake and Glenns Ferry records both include low percentages of the pollen of deciduous forest taxa such as oak and elm throughout the Pliocene and sporadically into the Pleistocene. Recent studies of soils associated with volcanic tephra reveal a Pliocene upland with abundant grass and high percentages of the pollen and spores of aquatic vegetation: a landscape with drainages choked by ash falls. Palynology above the Fossil Gulch Ash (Hagerman Valley) contains abundant charcoal and high percentages of the pollen of mountain conifers, suggesting devastation of the local vegetation and erosion into Lake Idaho from the surrounding mountains

  3. Eroding and Inflating the Atacama Desert, Chile: Insights Through Cosmogenic 10-Be, 26-Al and 21-Ne

    Science.gov (United States)

    Heimsath, A. M.; Jungers, M. C.; Amundson, R.; Balco, G.; Shuster, D. L.

    2010-12-01

    quantify surface chronologies as well as the processes shaping these unusual landscapes. To do so we have combined standard surface exposure dating with an application of the burial and profile-dating methodology to surfaces that are expanding by salt inflation. Profiles of these nuclides are used to test simple end-member models for the timescale of surface inflation and initial results support Mio-Pliocene ages for landscapes previously dated by other methods. We also use profiles and burial-age methods to date and better estimate potential inheritance in the nuclide signals for extensive cobble deposits thought to originate from the Andes prior to the onset of hyperaridity. Preliminary results support Miocene deposition, which may suggest a significantly more recent onset time for hyperaridity than others have estimated.

  4. Are There High Meteorite Concentrations in the Atacama Desert/Chile?

    Science.gov (United States)

    Scherer, P.; Delisle, G.

    1992-07-01

    We have visited numerous regions of the Atacama desert between Copiapo (27 degrees, 15'S) and Calama (22 degrees, 25'S) to assess their potential as a high-yield meteorite concentration surface, easily exploitable by search efforts within a reasonable time frame. According to our observations, this desert is characterized by the following features: a) A high percentage of the desert consists of sloping surfaces on which soil movement occurs, presumably by very infrequent, though heavy rain. b) Vast areas of the desert are covered by a dm-thick sand layer of dark colour. Since the sand is too coarse-grained to be transported by wind it presumably resulted from in-situ weathering of rock debris derived from nearby mountains. We suspect that impacting smaller objects can easily penetrate the sand layer. c) The sand layer is typically dotted by rocks, fist-size or smaller, that are covered by a thick layer of desert paint (reddish-brown to black colour). Most country rocks are of volcanic origin (rhyolite, andesite, basalt) and are typically of grey to black colour. A noticeable colour contrast in particular to potential stony meteorites is almost nonexistent. d) Soil salts with a potential to speed up weathering processes are ubiquitous near the surface. e) The Pampa de Mejillones, 45 km north of Antofagasta, is one of the few light-coloured areas in the Atacama desert. The surface, being of Mio-Pliocene age, consists of an almost continuous layer of light-brown fossil shells (bivalves and gastropodes). Fluvially transported dark rocks from adjacent outcrops rest on top. The latter material is covered again by desert paint. Few meteorite discoveries have been reported from this area (Pampa (a),(b),(c)). f) Numerous old tire tracks, in particular around mines in operation, crisscross most areas of the Atacama. Undetected objects such as large masses of iron bodies are not likely to have remained undiscovered in great numbers any more. We conclude that the potential of

  5. Tectonic evolution of the El Salvador Fault Zone. Insights from analogue experiments.

    Science.gov (United States)

    Alonso-Henar, Jorge; Schreurs, Guido; Jesús Martínez-Díaz, José; Álvarez-Gómez, José Antonio

    2014-05-01

    The El Salvador Fault Zone (ESFZ) is an active, c. 150 km long and 20 km wide segmented, dextral strike-slip fault zone within the El Salvador Volcanic Arc striking N90°-100°E. Although several studies have investigated the surface expression of the ESFZ, little is known about its structure at depth and its kinematic evolution. Our analysis of structural field data, remote sensing images and morphometric indices reveals a trenchward migration of the volcanic arc and furthermore suggests that not all structures within the ESFZ can be explained within the current tectonic context, but require a phase of extension or an extensional component of deformation at some stage in the evolution of the ESFZ. Such an extension and trenchward migration of the volcanic arc could be related to subduction roll-back of the Cocos Plate beneath the Chortis Block in Mio-Pliocene times. Such a possible evolution leads to open questions that we address in our research: Is the ESFZ a neo-formed fault zone, i.e. did it form during one phase of strike-slip or transtensional deformation, or do the structures in the ESFZ reflect a two-phase evolution, i.e. an early phase of extension overprinted by a later phase of strike-slip or transtension? Did subduction roll-back occur beneath El Salvador? We carried out analogue model experiments to test whether or not an early phase of extension is required to form the present-day fault pattern in the ESFZ. Analogue modeling is an effective tool in testing various hypotheses, as it allows the experimenter to control specific parameters and to test their influence on the resulting structures. Our experiments suggest that a two-phase tectonic evolution best explains the ESFZ: an early pure extensional phase linked to a segmented volcanic arc is necessary to form the main structures of the ESFZ and can explain the shallow geometry of the fault zone. This extensional phase is followed by a strike-slip dominated regime, which results in inter

  6. Extreme extension across Seram and Ambon, eastern Indonesia: evidence for Banda slab rollback

    Science.gov (United States)

    Pownall, J. M.; Hall, R.; Watkinson, I. M.

    2013-09-01

    The island of Seram, which lies in the northern part of the 180°-curved Banda Arc, has previously been interpreted as a fold-and-thrust belt formed during arc-continent collision, which incorporates ophiolites intruded by granites thought to have been produced by anatexis within a metamorphic sole. However, new geological mapping and a re-examination of the field relations cause us to question this model. We instead propose that there is evidence for recent and rapid N-S extension that has caused the high-temperature exhumation of lherzolites beneath low-angle lithospheric detachment faults that induced high-temperature metamorphism and melting in overlying crustal rocks. These "Kobipoto Complex" migmatites include highly residual Al-Mg-rich garnet + cordierite + sillimanite + spinel + corundum granulites (exposed in the Kobipoto Mountains) which contain coexisting spinel + quartz, indicating that peak metamorphic temperatures likely approached 900 °C. Associated with these residual granulites are voluminous Mio-Pliocene granitic diatexites, or "cordierite granites", which crop out on Ambon, western Seram, and in the Kobipoto Mountains and incorporate abundant schlieren of spinel- and sillimanite-bearing residuum. Quaternary "ambonites" (cordierite + garnet dacites) emplaced on Ambon were also evidently sourced from the Kobipoto Complex migmatites as demonstrated by granulite-inherited xenoliths. Exhumation of the hot peridotites and granulite-facies Kobipoto Complex migmatites to shallower structural levels caused greenschist- to lower-amphibolite facies metapelites and amphibolites of the Tehoru Formation to be overprinted by sillimanite-grade metamorphism, migmatisation, and limited localised anatexis to form the Taunusa Complex. The extreme extension required to have driven Kobipoto Complex exhumation evidently occurred throughout Seram and along much of the northern Banda Arc. The lherzolites must have been juxtaposed against the crust at typical

  7. Mn oxides as efficient traps for metal pollutants in a polyphase low-temperature Pliocene environment: A case study in the Tamra iron mine, Nefza mining district, Tunisia

    Science.gov (United States)

    Decrée, Sophie; Ruffet, Gilles; De Putter, Thierry; Baele, Jean-Marc; Recourt, Philippe; Jamoussi, Fakher; Yans, Johan

    2010-05-01

    The Tamra mine, located in the Nefza mining district (NW Tunisia), exploits a 50 m-thick layer of Mio-Pliocene sediments that are heavily mineralized with Fe and other metals (Mn, Pb, Zn), especially in its eastern part, which is highly mineralized in Mn and known as the "manganiferous zone". The textural and geochemical studies of manganiferous minerals in the Tamra mine have allowed the determination of four main paragenetic stages. Stages 1 and 2 relate to the main pedogenetic event that gave rise to the currently exploited Fe ore deposit. The last two stages relate to mineralizing events closely connected with hydrothermal circulation and leaching of underlying mineralization of the Sidi Driss Pb-Zn sedex deposit, with subsequent crystallisation in the supergene environment. Stage 3 is characterized by the formation of massive romanechite, hollandite and Sr-cryptomelane, while stage 4 results in the formation of coronadite and chalcophanite. 39Ar- 40Ar analyses performed on hollandite (stage 3) and coronadite (stage 4) samples yielded ages of 4.7 ± 0.1 Ma and 3.35 ± 0.07 Ma, respectively. Tentative 39Ar- 40Ar analyses on chalcophanite provided aberrant results, due to the poor argon retention in this layer-structure mineral. The youngest age corresponds to the late phase of the late Alpine extension event in northern Tunisia, evidenced through an increased regional thermal gradient as well as by a N-S set of normal faults and fractures. The Tamra mine is obviously a polyphase mineral deposit, recording several distinct metal inputs, part of them originating from the underlying Sidi Driss Pb-Zn deposit, while another part is provided by hydrothermal circulations forced by the high thermal gradient. Three springs flowing from the Tamra ore series are regular sources for drinking water used by the local population. Although the Alpine thermal gradient could have facilitated extensive mixing between subsurface oxidizing meteoric fluids and deep reducing

  8. Past changes of the North African monsoon intensity between 5 and 6.2 My, impact of the Messinian Salinity Crisis (MSC)

    Science.gov (United States)

    Ségueni, F.; Colin, C.; Siani, G.; Frank, N.; Blamart, D.; Kissel, C.; Liu, Z.; Richter, T.; Suc, J.

    2006-12-01

    A high resolution multiproxy study by oxygen isotope record (δ18O) on benthic foraminifera (Cibicides wuellerstorfii), magnetic susceptibility, clay mineralogy (DRX), major - trace elements (XRF core scanner and ICPMS) and Rb/Sr - Nd isotopes was carried out from site ODP 659 along the Cape Verde off Africa. The aim was to reconstruct variations of African Monsoon during the Mio-Pliocene in the time interval from 5 My to 6,2 My. Chronology was established by linear interpolation between 3 bio-events based on calcareous nannoplancton zones, 2 glacial stages TG12 and TG22 identified on δ18O records and by tuning the δ18O and magnetic susceptibility records to the orbital parameter of obliquity and precession. Results indicate that between 5 to 6.2 My variability in the eolian input from Sahara and the coastal upwelling intensity are anti-correlated and make it possible to retrace the evolution of northern African Monsoon. The latter co- varies mainly with the insolation received by the earth at low latitude during the summer. Maximal insolation enhance summer monsoonal effects by increasing wetter conditions on Sahel and NE dominance wind system cause a reduced eolian input and an increased biogenic sea surface productivity by coastal upwelling. On the other hand, minimal insolation reinforce winter monsoon that create a more arid climate on Sahel and stronger westward winds that increase eolian flux on Cap Verde with a reduced upwelling effect on sea surface productivity. At a longer time scale, the end of the MSC is correlated with a major change of the African Monsoon intensity. Finally, the δ18O record on C.wuellerstorfii suggests that global eustatic processes didn't play a key role in the MSC history. Nevertheless, transition between glacial stage TG12 and the interglacial TG11 seems to correspond to a major event within the MSC, and associated to the beginning of the upper evaporite deposits. Thus, the facies of the Lago Mare of the upper evaporites would

  9. The Landslides Hazard Assessment Using Gis Techniques In The Province of Macerata (marches Region, Italy)

    Science.gov (United States)

    Farabollini, P.; Pambianchi, G.

    The present work illustrates the results of research aimed at identifying and assessing geological and geomorphological characteristics at preventing and/or mitigating hydrogeological hazard in an area subject to high anthropic impact. The study area is the Province of Macerata (ca 2700km2), which from the standpoint of geological, geomorphologic, hydrogeologic, and anthropic characteristics can be considered representative of the Adriatic side of central Italy. Particular attention was addressed to the surveying of active morphogenetic processes due to the gravity, above all those affecting structures and infrastructures; for each of the latter technical worksheets were prepared. The field surveys and monitoring carried out over several years allowed it to be shown how deep-seated processes, are in continuous evolution, which prompted the use of GIS-type information science instruments for setting up a databank that could be updated and easy to use in the various stages of planning the works. The analysis carried out showed that ca 10% of the study territory, and particularly the high hilly areas characterized by Mio-Pliocene terrigenous deposits, is subject to processes linked to the action of gravity. In particular ca 1700 landslides have been recognized (for each 870 landslides affected various structures or infrastructures) of which 1100 are active and 600 quiescent. If the really accident-prone areas are added to those potentially at risk, determined by means of semi-quantitative evaluation, the hydrogeological accident can be said to affect more than 35% of the study area. Moreover if the area subject to surface erosion processes (solifluction, soil creep), mostly connected with the high level of anthropic impact not supported by an adequate safeguarding of the environment, is added to that percentage, a value of ca 50% is reached for the whole study territory. The study, based on statistically significant data, confirm the scientific literature regarding

  10. Beginsels en metodes vir die bepaling van die ouderdom van hominied fossiele en hulle vindplekke

    Directory of Open Access Journals (Sweden)

    W.J. van Aardt

    2006-07-01

    Full Text Available Principles and methods used for the determination of the age of hominid fossils and their discovery sites Paleoanthropologists have an array of physical dating methods developed by researchers in the physical sciences. These techniques permit students of hominid evolution and associated culture to have increasing confidence that the evidence of past hominid morphology as expressed by the fossil finds is being placed in the correct chronological order. This article explains in a simple and straightforward way the evidence and logic that have led scientists to conclude that hominid fossils are not a few thousand years but at least several million years old. The main focus is on the 40Ar/ 39Ar technique, but other absolute dating techniques such as carbon-14, uranium-thorium-lead and radiocalcium are also reviewed. Relative dating methods are briefly discussed together with paleomagnetism (geomagnetism, optic stimulated luminescence and amino acids.

  11. A new skull of early Homo from Dmanisi, Georgia.

    Science.gov (United States)

    Vekua, Abesalom; Lordkipanidze, David; Rightmire, G Philip; Agusti, Jordi; Ferring, Reid; Maisuradze, Givi; Mouskhelishvili, Alexander; Nioradze, Medea; De Leon, Marcia Ponce; Tappen, Martha; Tvalchrelidze, Merab; Zollikofer, Christoph

    2002-07-01

    Another hominid skull has been recovered at Dmanisi (Republic of Georgia) from the same strata in which hominid remains have been reported previously. The Dmanisi site dated to approximately 1.75 million years ago has now produced craniofacial portions of several hominid individuals, along with many well-preserved animal fossils and quantities of stone artifacts. Although there are certain anatomical differences among the Dmanisi specimens, the hominids do not clearly represent more than one taxon. We assign the new skull provisionally to Homo erectus (=ergaster). The Dmanisi specimens are the most primitive and small-brained fossils to be grouped with this species or any taxon linked unequivocally with genus Homo and also the ones most similar to the presumed habilis-like stem. We suggest that the ancestors of the Dmanisi population dispersed from Africa before the emergence of humans identified broadly with the H. erectus grade. PMID:12098694

  12. Facial Orientation and Facial Shape in Extant Great Apes: A Geometric Morphometric Analysis of Covariation

    OpenAIRE

    Dimitri Neaux; Franck Guy; Emmanuel Gilissen; Walter Coudyzer; Patrick Vignaud; Stéphane Ducrocq

    2013-01-01

    The organization of the bony face is complex, its morphology being influenced in part by the rest of the cranium. Characterizing the facial morphological variation and craniofacial covariation patterns in extant hominids is fundamental to the understanding of their evolutionary history. Numerous studies on hominid facial shape have proposed hypotheses concerning the relationship between the anterior facial shape, facial block orientation and basicranial flexion. In this study we test these hy...

  13. Significance of some previously unrecognized apomorphies in the nasal region of Homo neanderthalensis.

    OpenAIRE

    Schwartz, J. H.; Tattersall, I.

    1996-01-01

    For many years, the Neanderthals have been recognized as a distinctive extinct hominid group that occupied Europe and western Asia between about 200,000 and 30,000 years ago. It is still debated, however, whether these hominids belong in their own species, Homo neanderthalensis, or represent an extinct variant of Homo sapiens. Our ongoing studies indicate that the Neanderthals differ from modern humans in their skeletal anatomy in more ways than have been recognized up to now. The purpose of ...

  14. Clavicles, scapulae and humeri from the Sima de los Huesos site (Sierra de Atapuerca, Spain).

    Science.gov (United States)

    Carretero, J M; Arsuaga, J L; Lorenzo, C

    1997-01-01

    The scapulae, clavicles and humeri recovered from the Sima de los Huesos (SH) site between 1976 and 1994 are studied. All elements are briefly described anatomically with metrics and compared with other fossil hominids in order to establish the morphological pattern of the SH hominids. A minimum of 13 individuals are represented by the humeri in the SH sample. Almost all of them can be classified as adolescents and young adults. The morphology of the SH hominid shoulder girdle and humeri indicates that much of the shoulder morphology recognized in the later true Neandertal was present in Europe long before they appeared. Thus, this morphological pattern is not exclusive to Neandertals alone. The SH clavicles, scapulae and humeri share with the Neandertals many traits usually considered to be Neandertal specializations. The comparative analysis of the SH evidence suggests that most of the SH and Neandertal shared traits are either primitive features within the genus Homo or even for all hominids, or display high variability within different hominid samples. These traits must be used with caution, or not used at all, in phylogenetic analysis. There are, however, traits that to date have only been detected in the SH hominids and the Neanderials, which could be exclusive to the European phyletic lineage (clade) of Homo. PMID:9300347

  15. 南京直立人的鼻骨形态及其与欧洲化石人类基因交流的可能性%THE MORPHOLOGY OF NASAL BONES OF HOMO ERECTUS FROM NANJING AND THE POSSIBILITY OF GENE FLOW FROM EUROPEAN FOSSIL HOMINIDS

    Institute of Scientific and Technical Information of China (English)

    张银运; 刘武; 张罗

    2004-01-01

    根据南京直立人1号头骨有高耸的鼻梁,有人认为南京直立人有西方血统.但学术界对欧洲人类的基因流进入中国境内的时间似有不同的理解.本文对非洲、欧洲和亚洲的远古人类的鼻骨作了观察.结果表明,在距今约20万年至180万年前期间,非洲尚未有高耸鼻梁的远古人类的化石证据;距今20万年前的欧洲也无高耸鼻梁的远古人类的化石证据.南京直立人生存的年代无论是距今58-62万年或是距今33-50万年,当时的欧洲、非洲和西亚都未出现高耸鼻梁的远古人类;南京直立人的高耸鼻梁未必意味着"西方血统".高耸的鼻梁,从其形成历史来看,有可能类似于同功特征.具有这一形态特征的东方人群与西方人群可以是血缘上并不一定相近但在各自谱系上都有过对某种气候的适应历史.

  16. Paleoanthropology and evolutionary theory.

    Science.gov (United States)

    Tattersall, Ian

    2012-01-01

    Paleoanthropologists of the first half of the twentieth century were little concerned either with evolutionary theory or with the technicalities and broader implications of zoological nomenclature. In consequence, the paleoanthropological literature of the period consisted largely of a series of descriptions accompanied by authoritative pronouncements, together with a huge excess of hominid genera and species. Given the intellectual flimsiness of the resulting paleoanthropological framework, it is hardly surprising that in 1950 the ornithologist Ernst Mayr met little resistance when he urged the new postwar generation of paleoanthropologists to accept not only the elegant reductionism of the Evolutionary Synthesis but a vast oversimplification of hominid phylogenetic history and nomenclature. Indeed, the impact of Mayr's onslaught was so great that even when developments in evolutionary biology during the last quarter of the century brought other paleontologists to the realization that much more has been involved in evolutionary histories than the simple action of natural selection within gradually transforming lineages, paleoanthropologists proved highly reluctant to follow. Even today, paleoanthropologists are struggling to reconcile an intuitive realization that the burgeoning hominid fossil record harbors a substantial diversity of species (bringing hominid evolutionary patterns into line with that of other successful mammalian families), with the desire to cram a huge variety of morphologies into an unrealistically minimalist systematic framework. As long as this theoretical ambivalence persists, our perception of events in hominid phylogeny will continue to be distorted.

  17. From apes to humans: locomotion as a key feature for phylogeny.

    Science.gov (United States)

    Senut, Brigitte

    2002-03-01

    If bipedalism has often been considered to be of a crucial interest for understanding hominid evolution, the acceptance of locomotor features to build phylogenies is still far from being a reality in the field. Especially for hominid evolution, it still seems to be difficult to accept that traits, other than craniodental ones, can be useful for defining the major dichotomies. The recent discovery of Australopithecus anamensis suggests a challenging view of the major dichotomy between apes and humans. Whilst it is widely accepted that Ardipithecus ramidus is ancestral to Australopithecus anamensis, which in its turn is ancestral to Australopithecus afarensis and then to later hominids, the postcranial adaptations, which should be taken into account, suggest another branching pattern. Based on the fact that by 4.0 million years two different locomotor patterns can be identified in hominids, two lineages would appear to be present: the "Australopithecine" lineage (with Australopithecus afarensis or Ardipithecus ramidus if the latter is really a hominid sensu stricto) and the "Hominine" lineage (with Australopithecus anamensis = Praeanthropus africanus). PMID:12050904

  18. Age of an Indonesian Fossil Tooth Determined by Electron Paramagnetic Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Bogard, JS

    2004-04-07

    The first fossil hominid tooth recovered during 1999 excavations from the Cisanca River region in West Java, Indonesia, was associated with a series of bovid teeth from a single individual that was recovered 190 cm beneath the hominid tooth. The age of the fossil bovid teeth was determined using electron paramagnetic resonance (EPR) analysis as part of an effort to bracket the age of the hominid tooth. The EPR-derived age of the bovid teeth is (5.16 {+-} 2.01) x 10{sup 5} years. However, the age estimate reported here is likely an underestimate of the actual age of deposition since evidence of heating was detected in the EPR spectra of the bovid teeth, and the heating may have caused a decrease in the intensity of EPR components on which the age calculation is based.

  19. Histoire tertiaire de l'Arche de Brahmaputra ; son rôle dans la prospection des hydrocarbures du Haut Assam (Inde (résumé Tertiary History of Brahmaputra Arch. Its Role in Hydrocarbon Prospects of Upper Assam, India (Abstract

    Directory of Open Access Journals (Sweden)

    Murty K. N.

    2006-10-01

    sub-surface regional structure of the present Upper Assam Valley is a broad arch - Brahmaputra arch - parallel to and just a little south of Brahmaputra river, formed by two opposite tiltings: an initial palaeoslope towards south-east during Palaeocene-Oligocene and the other towards north-west during Mio-Pliocene. Two phases of migration of hydrocarbons con be recognised. The study enables assessment of future hydrocarbon prospects in Upper Assam. This arch has similar geological history as that of Bend-arch of north-central Texas and Huffon-Seminole-Ozark Arch of Oklahoma where rich pools have been found in nearby oil the rocks involved in the arching.

  20. New Constraints on the Timing and Magnitude of Deformation and Basin Exhumation in the Eastern Cordillera of NW Argentina.

    Science.gov (United States)

    Trimble, J. D.; Carrapa, B.; Stockli, D. F.; Stutz, J.

    2008-12-01

    could be potentially related to the reactivation of Cretaceous relay-zone structures. Flexural-slip folding is the dominant mechanism of folding within the basin, with centimeter to meter scale fracture-rich and slickenside-rich beds of fine silts acting as primary slip-surfaces between thicker, more competent beds of coarse sand and conglomerate. A newly discovered intra-formational angular unconformity near the base of the Angastaco Fm. documents growth during the early stages of deposition. However, there is no clear evidence of continuous growth up section, implying at least two pulses of significant deformation during syn- and post- Miocene time. New apatite (U-Th)/He thermochronology (AHe) from six samples from the Eocene-Oligocene(?) Quebrada de los Colorados Fm and the Miocene Angastaco Fm (~18 Ma) in the Angastaco and surrounding Pucara and Tin Tin basins yields youngest ages between ca. 13.2 Ma (to the west) and ca. 10.3 Ma (to the east), and correlate with low Uranium content. We interpret these ages as representative of cooling following basin exhumation in the Miocene. The younging of those ages towards the east, together with structural data indicating young Mio-Pliocene deformation, suggests that those ages may be the result of eastward propagation of deformation into the foreland driving basin exhumation.

  1. Effects of Caribbean oceanic plateau shallow subduction on topographic uplift and exhumation of the northwestern Maracaibo block, Colombia

    Science.gov (United States)

    Sanchez, J.; Mann, P.

    2013-12-01

    central SP show several slope-break knickpoints and changes in steepness indices by factor of ~1.9, all indicative of fault control in this area; 3) perturbations in stream profiles with change in steepness indices by a factor of ~1.6 occur in the southern SP are interpreted as the expression of the active Santa-Marta Bucaramanga fault system, 4) although most of the knickpoints in SSM profiles seem to be associated with changes in bedrock lithology, the alignments, slope-breaking character, and change in steepness indices by factor of ~1.8-2.2 indicate active ENE-WSW fault control along the south-southeastern edge of the SSM, 5) generally undisturbed profiles at northern SSM suggest current quiescence in rock uplift in this area; and 6) basin modeling of the CRB constrain the most recent uplift event as Mio-Pliocene at rates of 0.15-0.18 mm/yr. We propose that the most likely tectonic mechanism to explain widespread active fault activity and uplift within the SSM and SP is oblique, low-angle (20 degrees), southeastward subduction of the Caribbean plate beneath the area. The present rate of subduction and length of slab would have initiated uplift and fault activity at Early Miocene.

  2. Mineralized and Barren Tourmaline Breccia at Río Blanco-Los Bronces Copper Deposit, Central Chile

    Science.gov (United States)

    Hohf, Michael; Seifert, Thomas; Ratschbacher, Lothar; Rabbia, Osvaldo; Krause, Joachim; Haser, Sabine; Cuadra, Patricio

    2014-05-01

    The Río Blanco-Los Bronces porphyry copper-molybdenum cluster (14.8-4.3 Ma) in central Chile is one of the largest mining districts of the world with more than 200 Mt of contained Cu; almost 30% of these resources are hosted by hydrothermal breccias. These breccia complexes are tourmaline-, biotite-, chlorite-, or iron oxide-cemented and are widespread in the Paleo-Eocene and Mio-Pliocene porphyry Cu-Mo belt of the central Andes. The ongoing research project aims to understand the time-space relationships between the different breccia bodies and the multiple porphyry intrusions. For this, two cross sections in the southern part of the deposit (Sur-Sur and La Americana areas) are studied. Most interesting from the economic/genetic point of view is the intermineral breccia (tourmaline- and biotite-cemented), which have high copper grades. It is under debate whether there is a vertical mineralogical zonation of the cement of the breccia body from tourmaline-rich at the top to biotite-dominated at the bottom, or there are two superimposed breccia formation events. Textural and mineralogical observations of benches- and tunnels-outcrops, drill cores, and polished-thin sections support the first hypothesis. Our work has been focused on tourmaline chemistry due to its high resistance to alteration and weathering, which allows this mineral to retain its original isotopic signature. Preliminary results of 127 microprobe measurements of tourmaline chemistry from the early mineralized breccia (BXT) and the late barren one (BXTTO) show that all the tourmalines belong to the alkali group and the composition ranges between the dravite-schorl end members. There is a pronounced negative correlation between Fe (ferric?) and Al, probably due to exchange at the Z octahedral position. The backscatter images of tourmaline show oscillatory and sector zonings, i.e., alternating light bands/zones (high CaO, FeO, Na2O) and darker ones (enriched in Al2O3 and MgO). There is no significant

  3. Geomorpho-pédogenèse dans des accumulations alluviales d'un piémont andin: Étude du contact Andes-Llanos Occidentaux au Venezuela (Région de Guanare-Barinas

    Directory of Open Access Journals (Sweden)

    Pouyllau, Daniel

    1990-06-01

    Full Text Available The piémont in the South-East region of the Andes In Venezuela we study, lying between the towns of Guanare and Barinas, spreads over 150.000 ha of a zone where a dry tropical forest constitutes the climatic vegetation. During the erogenic period of the Andes -i.e. mio-pliocene and quaternary-, a strong erosion produced at the same time a removal of material belonging to the high basins, its transportation towards the depressed areas of the Llanos, and the breaking up of the widespread sheet structures thus constituted, and finally created the present topography with terraces. The study of this piémont thus allows the formulation of a series of hypotheses concerning the géomorphologic evolution of this region.

    [fr] Le piémont sud-oriental des Andes vénézuéliennes étudié et située entre les villes de Guanare et de Barinas, s'étend sur 150.000 ha dans une zone où la forêt sèche tropicale est la végétation climacique. Durant l'orogenèse andine mio-pliocène et quaternaire, une intense érosion a entraîné, en même temps, le déblaiement des matériaux des hauts-bassins, leur transport vers la dépression des Llanos et le dépôt en nappes généralisées; le démantèlement de celles-ci a conduit à la topographie actuelle des terrasses. L'étude de ce piémont permet d'émettre une série d'hypothèses sur l'évolution géomorphologique régionale.
    [es] El piedemonte suroriental de los Andes venezolanos, ubicado entre las ciudades de Guanare y de Barinas, cubre 150.000 has. y su vegetación climácica es el bosque seco tropical. Durante la orogénesis andina, mio-pliocena y cuaternaria, una intensa erosión originó al mismo tiempo el arrastre de los materiales de las cuencas altas, su transporte hacia la depresión de loa Llanos, su deposición en mantos generalizados y el desmantelamiento de los mismos, formando la topografía actual de las terrazas. El estudio de este piedemonte permite emitir una serle de hip

  4. The promotion of geomorphosites on salt from Sovata - Praid and Turda using cultural and scientific tourism

    Science.gov (United States)

    Toma, B.; Irimus, I.; Petrea, D.

    2012-04-01

    The paper highlights the role of geomorphosites on salt, in experts and specialists training, in geography of tourism and planning, namely, the involvement of educational factor in defining managerial and marketing skills of future specialists in training. Geographical area of investigation belongs to the Transylvanian tectonic basin, overlapped to saliferous tectonic area from eastern Transylvania, represented by Praid - Sovata - Corund anticline and Sic -Cojocna - Turda anticline, analysis is focused on the Praid - Sovata and Turda diapirs. Saliferous area Praid - Sovata - Corund is situated on the contact area of the Transylvanian Basin with neo-eruptiv mountain chain of Eastern Carpathians, Calimani - Gurghiu - Harghita, and at the contact of Târnavelor Plateau with the orogen alignment of Gurghiu - Harghita Mountains. The salt body, in the horizontal plane, has a quasi-circular shape, slightly ellipsoidal, with diameters of 1.2 and 1.4 km, and is estimated to have a burial depth of 2.6 to 2.8 km. The salt massif from Praid, pierce the Mio-Pliocene blanket around and appears at the surface as diapir, flanked by sedimentary rocks that are partially covered by extrusive post-Pliocene volcanic formations and Quaternary deposits. Evaporitic deposits presents a varied lithology represented by gypsum, anhydrite, salt rock, potassium salt and celestine. The salt massif from Turda develops on the anticline Sic -Cojocna - Turda, oriented NE - SW, 2 km NE of Turda's downtown. It has an elongated shape, about 4 km, with widths ranging from 700 m to 200 m and also with a thickness ranging from 750 m to over 1000 m. In terms of stratigraphy, the salt massif is surrounded by deposits belonging to Badenian, Sarmatian and Quaternary. Due to salt dissolution by meteoric waters, carsto-saline lakes were formed, and due to ceiling collapse, because of an intensive exploitation, and infiltrations of rainwater and rivers, antropo-salted lakes were formed. The water and mud of

  5. Extreme extension across Seram and Ambon, eastern Indonesia: Evidence for Banda slab rollback

    Directory of Open Access Journals (Sweden)

    J. M. Pownall

    2013-04-01

    Full Text Available The island of Seram, which lies in the northern part of the 180°-curved Banda Arc, has previously been interpreted as a fold-and-thrust belt formed during arc-continent collision, which incorporates ophiolites intruded by granites thought to have been produced by anatexis within a metamorphic "sole". However, new geological mapping and a re-examination of the field relations cause us to question this model. We instead propose that there is evidence for recent N–S extension that has caused the high-temperature exhumation of hot mantle peridotites, granites, and granulites (the "Kobipoto Complex" beneath low-angle lithospheric detachment faults. Greenschist- to lower-amphibolite facies metapelites and amphibolites of the Tehoru Formation, which comprise the hanging wall above the detachment faults, were overprinted by sillimanite-grade metamorphism, migmatisation and limited localised diatexis to form the Taunusa Complex. Highly aluminous metapelitic garnet + cordierite + sillimanite + spinel + corundum + quartz granulites exposed in the Kobipoto Mountains (central Seram are intimately associated with the peridotites. Spinel + quartz inclusions in garnet, which indicate that peak metamorphic temperatures for the granulites likely approached 900 °C, confirm that peridotite was juxtaposed against the crust at typical lithospheric mantle temperatures and could not have been part of a cooled ophiolite. Some granulites experienced slight metatexis, but the majority underwent more advanced in situ anatexis to produce widespread granitic diatexites characterised by abundant cordierite and garnet xenocrysts and numerous restitic sillimanite + spinel "clots". These Mio-Pliocene "cordierite granites", which are present throughout Ambon, western Seram, and the Kobipoto Mountains in direct association with peridotites, demonstrate that the extreme extension required to have driven Kobipoto Complex exhumation must have occurred along much of the northern

  6. Modeling along-axis variations in fault architecture in the Main Ethiopian Rift: implications for Nubia-Somalia kinematics

    Science.gov (United States)

    Erbello, Asfaw; Corti, Giacomo; Sani, Federico; Kidane, Tesfaye

    2016-04-01

    The Main Ethiopian Rift (MER), at the northern termination of the East African Rift, is an ideal locale where to get insights into the long-term motion between Nubia and Somalia. The rift is indeed one of the few places along the plate boundary where the deformation is narrow: its evolution is thus strictly related to the kinematics of the two major plates, whereas south of the Turkana depression a two-plate model for the EARS is too simplistic as extension occurs both along the Western and Eastern branches and different microplates are present between the two major plates. Despite its importance, the kinematics responsible for development and evolution of the MER is still a matter of debate: indeed, whereas the Quaternary-present kinematics of rifting is rather well constrained, the plate kinematics driving the initial, Mio-Pliocene stages of extension is still not clear, and different hypothesis have been put forward, including: polyphase rifting, with a change in direction of extension from NW-SE extension to E-W extension; constant Miocene-recent NW-SE extension; constant Miocene-recent NE-SW extension; constant, post-11 Ma extension consistent with the GPS-derived kinematics (i.e., roughly E-W to ESE-WNW). To shed additional light on this controversy and to test these different hypothesis, in this contribution we use new crustal-scale analogue models to analyze the along-strike variations in fault architecture in the MER and their relations with the rift trend, plate motion and the resulting Miocene-recent kinematics of rifting. The extension direction is indeed one of the most important parameters controlling the architecture of continental rifts and the relative abundance and orientation of different fault sets that develop during oblique rifting is typically a function of the angle between the extension direction and the orthogonal to the rift trend (i.e., the obliquity angle). Since the trend of the MER varies along strike, and consequently it is

  7. New insights into the evolution of central Tyrrhenian margin of Italy (northern Latium off-shore area): evidences and constraints from seismic data interpretation

    Science.gov (United States)

    Buttinelli, M.; Vico, G.; Scrocca, D.; Petracchini, L.; de Rita, D.

    2009-04-01

    the formation of several small and narrow graben and half-graben basins with NW-SE and NE-SW direction of elongation, filled with up to 600m of conglomeratic, sandy and clayish sediments and a regional unconformity surface on top of the deformed basement. The sedimentation continued with the trasgressive deposition of the Plio-Pleitocene clayish units, separated by a Middle Pliocene unconformity; iii) a final stage of deformation, strictly localized around the Late Pliocene volcanic intrusions of the Tolfa and Ceriti dome complexes. This is associated with local uplift (up to 200m), normal faulting, and radial tilting of the sedimentary units strata of the Mio-Pliocene sedimentary units in the on-shore graben and half-graben filled basins, analogous to the geological setting of the basins recognised in the off-shore part of this area. Gravimetric and Magnetic anomaly data also suggest the possible presence of an off-shore intrusion just in front of the coastline of Civitavecchia city. Seismic reflection data analysis show in the same place a local perturbation of the sedimentation regime of the Plio-Pleistocene units due to the local change of basin morphology.

  8. Integrative geomorphological mapping approach for reconstructing meso-scale alluvial fan palaeoenvironments at Alborz southern foothill, Damghan basin, Iran

    Science.gov (United States)

    Büdel, Christian; Majid Padashi, Seyed; Baumhauer, Roland

    2013-04-01

    Alluvial fans and aprons are common depositional features in general Iranian geomorphology. The countries major cities as well as settlements and surrounding area have often been developed and been built up on this Quaternary sediment covers. Hence they periodically face the effects of varying fluvial and slope-fluvial activity occurring as part of this geosystem. The Geological Survey of Iran therefore supports considerable efforts in Quaternary studies yielding to a selection of detailed mapped Quaternary landscapes. The studied geomorphologic structures which are settled up around an endorheic basin in Semnan Province represent a typical type of landform configuration in the area. A 12-km-transect was laid across this basin and range formation. It is oriented in north-south direction from the southern saltpan, called "Kavir-e-Haj Aligholi"/"Chah-e-Jam" ("Damghan Kavir"), across a vast sandy braided river plain, which is entering from the north east direction of the city of Shahroud. At its northern rim it covers alluvial sediment bodies, which are mainly constituted by broad alluvial aprons, fed by watersheds in Alborz Mountains and having their genetic origins in Mio-/Pliocene times. During this study a fully analytical mapping system was used for developing a geodatabase capable of integrating geomorphological analyses. Therefore the system must provide proper differentiation of form, material and process elements as well as geometric separation. Hence the German GMK25 system was set up and slightly modified to fit to the specific project demands. Due to its structure it offers most sophisticated standards and scale independent hierarchies, which fit very well to the software-determinated possibilities of advanced geodatabase applications. One of the main aspects of mapping Quaternary sediments and structures is to acquire a proper description and systematic correlation and categorization of the belonging mapping-objects. Therefore the team from GSI and

  9. Parametric study of the impact of waste pollutants on groundwater: the case of Abidjan District (Ivory Coast)

    Science.gov (United States)

    Agnès Kouamé, Amenan; Jaboyedoff, Michel; Tacher, Laurent; Derron, Marc-Henri; Franz, Martin

    2015-04-01

    Abidjan like numerous African cities is experiencing a significant and uncontrolled population growth. The annual growth rate is estimated at 3.99% by the National Institute of Statistics. This rapid population growth also generates growing needs in general and especially for drinking water and economic activities. In the District of Abidjan, groundwater comes from the Mio-Pliocene age aquifer called "Continental Terminal". This unconfined aquifer is the main source of water supply. Its lithology consists of four levels. Actually only the two upper levels outcrop and constitute the main part of the Continental Terminal aquifer. Some recent studies report a potential overexploitation and pollution of Abidjan groundwater (Jourda, 1986, Kouame 2007, Deh, 2013). This deterioration in water quality could be due to the release of domestic and industrial waste water, pesticide and fertilizer from crops and toxic waste sites containing high doses of organochlorines, of hydrogen sulfide and sulfides. This risk is also linked to the economic activities such as car workshops, gas stations and the sand exploitation in the lagoon. To observe the likely evolution of such contaminants in the subsurface and we developed hydrogeological models that couple groundwater flow and transport with FEFLOW software. The model is composed of a sandy layer where two constant hydraulic heads of 55 m and 0.2 m are imposed on the north and the south respectively. We carried out grain size analysis of some samples (E2, E3, E4, E5, and E6) which shows particle size ranging between 0.0001 mm and 8 mm. This grain size analysis performed by sieving underwater and laser indicates that these five soils are: loamy sand with traces of clay and gravel for E2 and E5; Sandy loam with traces of clay for E3; Sand with traces of clay and gravel for E4 and Sand with traces of silt and clay for E6. Their porosity and average values of permeability coefficient K measured in the laboratory range from 0.2 to 0

  10. Analyse quantitative du réseau hydrographique du bassin versant du Slănic (Roumanie

    Directory of Open Access Journals (Sweden)

    Florina Grecu

    2007-12-01

    Full Text Available L'étude porte sur le bassin versant du Slănic, un affluent du Buzău. Ce bassin de taille relativement réduite (433 km2 est situé dans la région des Carpates et des Subcarpates de la Courbure, région très active sur le plan sismique. Du point de vue lithologique, le bassin du Slănic correspond à des flyschs paléogènes et à des molasses mio-pliocènes. Ces roches peu résistantes ont facilité une forte érosion du relief. Actuellement, les précipitations présentent souvent une forte intensité, et elles se produisent fréquemment après des périodes de sécheresse. Elles sont ainsi très agressives et déclenchent une érosion intense. L'analyse de quelques paramètres morphométriques [grand nombre de segments de cours d'eau d'ordres 1 (5230 et 2 (944 ; densité élevée des segments par rapport à la superficie du bassin (environ 15 segments / km2 ; longueur moyenne réduite des segments d'ordre 1 (260 m par rapport à ceux d'ordre 2 (530 m] s'accorde avec des temps de concentration des eaux courts et une forte énergie des écoulements. La vitesse de réaction aux précipitations des segments d'ordres inférieurs est en outre favorisée par la répartition spatiale des pluies et par les conditions lithologiques.The study is focused on the Slănic basin which has a small size (433 km2. The hydrographical basin of Slănic, situated in the Carpathian and Subcarpathian Curvature, a very active from neotectonical viewpoint area, is a part of the Buzău basin. From a petrographic point of view, the Slănic hydrographic basin belongs to the paleogen flysch deposits (within the Carpathian sector and to the mio-pliocen molasse (within the Subcarpathian area latter formed by predominantely friable rocks which have encouraged deep fragmentation of the relief. Actual rainfalls are often very intensive, and they frequently occur after dry seasons. The analysis of morphometric parameters shows many elementary segments of first

  11. Break-up of the Greater Indo-Australian Continent and accretion of blocks framing South and East Asia

    Science.gov (United States)

    Acharyya, S. K.

    1998-09-01

    composite block. Dislocations of the 90 °E Ridge, indicate that the main compression occurred during early Eocene which was followed by movement since late Miocene. The ophiolite trail on IBA does not represent the eastern suture of the Indian continent. As a result of Late Oligocene oblique terminal collision between Sibumasu and 1BA, Mesozoic early Eocene ophiolites. their mid-Eocene cover and trench sediments occur as klippen on IBA. Oblique convergence between IBA and the Indian plate in turn produced an active subduction regime along the western margin of the Indo-Burma mobile belt and the Andaman-Java trench. The activity produced Neogcne-Quaternary volcanism. dextral strike-slip movement in Central Burma-Andaman-Sumatran region, and opened up the Andaman sea. Northward, the Shillong massif, representing NE prolongation of the Indian sub-continent, is technically juxtaposed against the northern end of IBA. The collision of these blocks might have uplifted the Shillong massif during Mio-Pliocene. Far eastward, the convergence was orthogonal between the Australian continent and the Indonesian Arc resulting emplacement of the Lolotoi continental rocks. Maubissi exotic blocks and ophiolitic rocks as nappe over the Timor shelf which possibly remained attached to the Australian continent.

  12. The Cenozoic volcanism in the Kivu rift: Assessment of the tectonic setting, geochemistry, and geochronology of the volcanic activity in the South-Kivu and Virunga regions

    Science.gov (United States)

    Pouclet, A.; Bellon, H.; Bram, K.

    2016-09-01

    The Kivu rift is part of the western branch of the East African Rift system. From Lake Tanganyika to Lake Albert, the Kivu rift is set in a succession of Precambrian zones of weakness trending NW-SE, NNE-SSW and NE-SW. At the NW to NNE turn of the rift direction in the Lake Kivu area, the inherited faults are crosscut by newly born N-S fractures which developed during the late Cenozoic rifting and controlled the volcanic activity. From Lake Kivu to Lake Edward, the N-S faults show a right-lateral en echelon pattern. Development of tension gashes in the Virunga area indicates a clockwise rotation of the constraint linked to dextral oblique motion of crustal blocks. The extensional direction was W-E in the Mio-Pliocene and ENE-WSW in the Pleistocene to present time. The volcanic rocks are assigned to three groups: (1) tholeiites and sodic alkali basalts in the South-Kivu, (2) sodic basalts and nephelinites in the northern Lake Kivu and western Virunga, and (3) potassic basanites and potassic nephelinites in the Virunga area. South-Kivu magmas were generated by melting of spinel + garnet lherzolite from two sources: an enriched lithospheric source and a less enriched mixed lithospheric and asthenospheric source. The latter source was implied in the genesis of the tholeiitic lavas at the beginning of the South-Kivu tectono-volcanic activity, in relationships with asthenosphere upwelling. The ensuing outpouring of alkaline basaltic lavas from the lithospheric source attests for the abortion of the asthenospheric contribution and a change of the rifting process. The sodic nephelinites of the northern Lake Kivu originated from low partial melting of garnet peridotite of the sub-continental mantle due to pressure release during swell initiation. The Virunga potassic magmas resulted from the melting of garnet peridotite with an increasing degree of melting from nephelinite to basanite. They originated from a lithospheric source enriched in both K and Rb, suggesting the

  13. Fish as a proxy for African paleogeography: results from both extant and fossil taxa and prospects to constrain faunal exchange pathway through time

    Science.gov (United States)

    Otero, Olga; Joordens, Josephine; Dettai, Agnès; Christ, Leemans; Pinton, Aurélie

    2016-04-01

    : relationships between Chad and neighbouring basins throughout the Mio-Pliocene. Pa

  14. Fish as a proxy for African paleogeography: results from both extant and fossil taxa and prospects to constrain faunal exchange pathway through time

    Science.gov (United States)

    Otero, Olga; Joordens, Josephine; Dettai, Agnès; Christ, Leemans; Pinton, Aurélie

    2016-04-01

    : relationships between Chad and neighbouring basins throughout the Mio-Pliocene. Palaeobiogeograp

  15. Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge.

    Science.gov (United States)

    Kimura, Yuki

    2002-09-01

    The lithic analysis of the Bed I and II assemblages from Olduvai Gorge reveals both static and dynamic time trends in early hominids' technology from 1.8 to 1.2 m.y.a. The Bed I Oldowan (1.87-1.75 m.y.a.) is characterized by the least effort strategy in terms of raw material exploitation and tool production. The inclusion of new raw material, chert, for toolmaking in the following Developed Oldowan A (DOA, 1.65-1.53 m.y.a.) facilitated more distinctive and variable flaking strategies depending on the kind of raw materials. The unique characters of DOA are explainable by this raw material factor, rather than technological development of hominids. The disappearance of chert in the subsequent Developed Oldowan B and Acheulian (1.53-1.2 m.y.a.) necessitated a shift in tool production strategy more similar to that of Bed I Oldowan than DOA. However, the evidence suggests that Bed II hominids might have been more skillful toolmakers, intensive tool-users, and engaged in more active transport of stone tools than the Bed I predecessors. Koobi Fora hominids maintained a more static tool-using behavior than their Olduvai counterparts due mainly to a stable supply of raw materials. They differed from Olduvai hominids in terms of less battering of cores, consistent transport behavior, and few productions of side-struck flakes, indicating a regional variation of toolmaking and using practice. However, they shared with Olduvai hominids a temporal trend toward the production of larger flakes from larger cores after 1.6 m.y.a. Increased intake of animal resources and the expansion of ranging area of Homo ergaster would have led to the development of technological organization. Technological changes in the Oldowan industry are attested at Olduvai Gorge, Koobi Fora, and Sterkfontein, suggesting that it was a pan-African synchronous phenomenon, beginning at 1.5 m.y.a. PMID:12234546

  16. Dental metric assessment of the omo fossils: implications for the phylogenetic position of Australopithecus africanus.

    Science.gov (United States)

    Hunt, K; Vitzthum, V J

    1986-10-01

    The discovery of Australopithecus afarensis has led to new interpretations of hominid phylogeny, some of which reject A. africanus as an ancestor of Homo. Analysis of buccolingual tooth crown dimensions in australopithecines and Homo species by Johanson and White (Science 202:321-330, 1979) revealed that the South African gracile australopithecines are intermediate in size between Laetoli/hadar hominids and South African robust hominids. Homo, on the other hand, displays dimensions similar to those of A. afarensis and smaller than those of other australopithecines. These authors conclude, therefore, that A. africanus is derived in the direction of A. robustus and is not an ancestor of the Homo clade. However, there is a considerable time gap (ca. 800,000 years) between the Laetoli/Hadar specimens and the earliest Homo specimens; "gracile" hominids from Omo fit into this chronological gap and are from the same geographic area. Because the early specimens at Omo have been designated A. afarensis and the later specimens classified as Homo habilis, Omo offers a unique opportunity to test hypotheses concerning hominid evolution, especially regarding the phylogenetic status of A. africanus. Comparisons of mean cheek teeth breadths disclosed the significant (P less than or equal to 0.05) differences between the Omo sample and the Laetoli/Hadar fossils (P4, M2, and M3), the Homo fossils (P3, P4, M1, M2, and M1), and A. africanus (M3). Of the several possible interpretations of these data, it appears that the high degree of similarity between the Omo sample and the South African gracile australopithecine material warrants considering the two as geographical variants of A. africanus. The geographic, chronologic, and metric attributes of the Omo sample argue for its lineal affinity with A. afarensis and Homo. In conclusion, a consideration of hominid postcanine dental metrics provides no basis for removing A. africanus from the ancestry of the Homo lineage. PMID:3099582

  17. Re-visiting the notion of Deep Incarnation in light of 1 Corinthians 15:28 and emergence theory

    Directory of Open Access Journals (Sweden)

    Wessel Bentley

    2016-05-01

    Full Text Available Niels Hendrik Gregersen’s ‘Deep Incarnation’ is opening up possibilities for engagementbetween science and theology. Recent discoveries, like that of Homo naledi, raise questions abouthow inclusive a Christian doctrine of Incarnation is. Is Jesus only God incarnate for Homo sapiensapiens, or is the incarnation inclusive of preceding hominid species as well? Does the incarnationstretch beyond the hominid line? This chapter engages Gregersen’s understanding of DeepIncarnation in light of 1 Corinthians 15:28 and emergence theory. It proposes that there is a directcorrelation between worldview and how we believe in the inclusive nature of divine incarnation.

  18. The geological, isotopic, botanical, invertebrate, and lower vertebrate contexts for aripithecus ramidus

    Energy Technology Data Exchange (ETDEWEB)

    Woldegabriel, Giday [Los Alamos National Laboratory; Ambrose, Stanley H [UNIV OF ILLINOIS; Barboni, Doris [CEREGE, FRANCE; Bonneffille, Raymond [CEREGE, FRANCE; Bremond, Laurent [MONTPELLIER, FRANCE; Currie, Brian [MIAMI UNIV, OXFORD, OHIO; Degusta, David [STANFORD UNIV.; Hart, William K [MIAMI UNIV, OXFORD, OHIO; Murray, Alison M [UNIV OF ALBERTA; Renne, Paul R [UC/BERKELEY; Jolly - Saad, M C [NANTERRE, FRANCE; Stewart, Kathlyn M [CANADA; White, Tim D [UC/BERKELEY

    2009-01-01

    Sediments containing Ardipithecus ramidus were deposited 4.4 million years ago on an alluvial floodplain in Ethiopia's western Afar rift. The Lower Aramis Member hominid-bearing unit, now exposed across a >9-kilometer structural arc, is sandwiched between two volcanic tuffs that have nearly identical {sup 40}Ar/{sup 39}Ar ages. Geological data presented here, along with floral, invertebrate, and vertebrate paleontological and taphonomic evidence associated with the hominids, suggest that they occupied a wooded biotope over the western three-fourths of the paleotransect. Phytoliths and oxygen and carbon stable isotopes of pedogenic carbonates provide evidence of humid cool woodlands with a grassy substrate.

  19. L'outillage lithique du site de dépeçage à Elephas recki ileretensis de Barogali (république de Djibouti)Stone tools from the butchery site with Elephas recki ileretensis of Barogali (Republic of Djibouti)

    Science.gov (United States)

    Berthelet, Arlette

    2001-03-01

    Three seasons of excavations (1985-1987) in the Gobaad region of the Republic of Djibouti have unearthed the fossilized skeletal remains of an Elephas recki (1.3-1.6 million years old). Numerous stone artefacts discovered among the bones indicates that the excavation is a butchery site where hominids cut up and perhaps consumed the elephant meat. The discovery of cores and small flakes near the elephant carcass indicates that the hominids knapped choppers and polyhedrons and retouched flakes during the scavenging operation.

  20. Editor's note

    Institute of Scientific and Technical Information of China (English)

    WU XinZhi

    2009-01-01

    @@ This year is the 80th anniversary of the discovery of the first skull-cap of Homo erectus from Zhoukoudian (Peking Man).The first fossil of Peking Man was found in 1921 or 1923.Among the specimens unearthed at Zhoukoudian and transported to Sweden a premolar of hominid was identified in 1926.The announcement of this finding made Zhoukoudian well known in the world.A well preserved hominid molar was found in 1927 in situ based on which the new genus and species,Sinanthropus pekinensis was proposed.

  1. Evolution de la morphologie claviculaire au sein du genre Homo. Conséquences architecturales et fonctionnelles
    sur la ceinture scapulaire

    OpenAIRE

    Voisin, Jean-Luc

    2001-01-01

    La clavicule est un os qui a été peu étudié en anthropologie et paléoanthropologie malgré son importance fonctionnelle. Le travail présenté ici est une étude des courbures claviculaires chez les hominidés actuels et chez quelques hominidés fossiles (Homo habilis, Homo ergaster, Homo antecessor et néandertaliens). La morphologie claviculaire en vue supérieure traduit essentiellement les capacités d'élévation du bras de l'individu, alors que la morphologie claviculaire en vue postérieure inform...

  2. First fossil insectivores from Flores

    NARCIS (Netherlands)

    Hoek Ostende, van den L.W.; Berch, van der G.; Awe Due, R.

    2006-01-01

    The hominid bearing strata from the Liang Bua cave on Flores have yielded a large amount of microvertebrate remains. Among these are three mandibles of shrews, the first record of fossil insectivores from the island. The fossils, representing two different species, are not referable to any of the kn

  3. Beyond the Pleistocene: Using Phylogeny and Constraint to Inform the Evolutionary Psychology of Human Mating

    Science.gov (United States)

    Eastwick, Paul W.

    2009-01-01

    Evolutionary psychologists explore the adaptive function of traits and behaviors that characterize modern Homo sapiens. However, evolutionary psychologists have yet to incorporate the phylogenetic relationship between modern Homo sapiens and humans' hominid and pongid relatives (both living and extinct) into their theorizing. By considering the…

  4. Evolution of Humans: Understanding the Nature and Methods of Science through Cooperative Learning

    Science.gov (United States)

    Lee, Yeung Chung

    2011-01-01

    This article describes the use of an enquiry-based approach to the study of human evolution in a practical context, integrating role-playing, jigsaw cooperative learning and scientific argumentation. The activity seeks to unravel the evolutionary relationships of five hominids and one ape from rather "messy" evidence. This approach enhanced the…

  5. Chromosome Connections: Compelling Clues to Common Ancestry

    Science.gov (United States)

    Flammer, Larry

    2013-01-01

    Students compare banding patterns on hominid chromosomes and see striking evidence of their common ancestry. To test this, human chromosome no. 2 is matched with two shorter chimpanzee chromosomes, leading to the hypothesis that human chromosome 2 resulted from the fusion of the two shorter chromosomes. Students test that hypothesis by looking for…

  6. The evolutionary significance of the Wajak skulls

    NARCIS (Netherlands)

    Storm, P.

    1995-01-01

    Ever since their description by Dubois (1920, 1922) the Wajak skulls Java) have played an important role in the discussions on the evolution of modern humans in Australasia. Because of the robust morphology of the skull, Wajak Man was seen as a link between Pleistocene hominids from Java (Solo) and

  7. Comment on "A complete skull from Dmanisi, Georgia, and the evolutionary biology of early Homo".

    Science.gov (United States)

    Schwartz, Jeffrey H; Tattersall, Ian; Chi, Zhang

    2014-04-25

    Lordkipanidze et al. (Research Article, 18 October 2013, p. 326) conclude, from gross morphological comparisons and geometric-morphometric analysis of general shape, that the five hominid crania from Dmanisi in Georgia represent a single regional variant of Homo erectus. However, dental, mandibular, and cranial morphologies all suggest taxic diversity and, in particular, validate the previously named H. georgicus. PMID:24763572

  8. Evolution & Phylogenetic Analysis: Classroom Activities for Investigating Molecular & Morphological Concepts

    Science.gov (United States)

    Franklin, Wilfred A.

    2010-01-01

    In a flexible multisession laboratory, students investigate concepts of phylogenetic analysis at both the molecular and the morphological level. Students finish by conducting their own analysis on a collection of skeletons representing the major phyla of vertebrates, a collection of primate skulls, or a collection of hominid skulls.

  9. The Power of Natural Selection: A Guided Investigation of Three Case Studies

    Science.gov (United States)

    Beachly, William

    2010-01-01

    I describe a quantitative approach to three case studies in evolution that can be used to challenge college freshmen to explore the power of natural selection and ask questions that foster a deeper understanding of its operation and relevance. Hemochromatosis, the peppered moth, and hominid cranial capacity are investigated with a common algebraic…

  10. Climate change and evolving human diversity in Europe during the last glacial.

    Science.gov (United States)

    Gamble, Clive; Davies, William; Pettitt, Paul; Richards, Martin

    2004-02-29

    A link between climate change and human evolution during the Pleistocene has often been assumed but rarely tested. At the macro-evolutionary level Foley showed for hominids that extinction, rather than speciation, correlates with environmental change as recorded in the deep sea record. Our aim is to examine this finding at a smaller scale and with high-resolution environmental and archaeological archives. Our interest is in changing patterns of human dispersal under shifting Pleistocene climates during the last glacial period in Europe. Selecting this time frame and region allows us to observe how two hominid taxa, Neanderthals and Crô-Magnons, adapted to climatic conditions during oxygen isotope stage 3. These taxa are representative of two hominid adaptive radiations, termed terrestrial and aquatic, which exhibited different habitat preferences but similar tolerances to climatic factors. Their response to changing ecological conditions was predicated upon their ability to extend their societies in space and time. We examine this difference further using a database of all available radiocarbon determinations from western Europe in the late glacial. These data act as proxies for population history, and in particular the expansion and contraction of regional populations as climate changed rapidly. Independent assessment of these processes is obtained from the genetic history of Europeans. The results indicate that climate affects population contraction rather than expansion. We discuss the consequences for genetic and cultural diversity which led to the legacy of the Ice Age: a single hominid species, globally distributed.

  11. Baboon feeding ecology informs the dietary niche of Paranthropus boisei.

    Directory of Open Access Journals (Sweden)

    Gabriele A Macho

    Full Text Available Hominins are generally considered eclectic omnivores like baboons, but recent isotope studies call into question the generalist status of some hominins. Paranthropus boisei and Australopithecus bahrelghazali derived 75%-80% of their tissues' δ(13C from C4 sources, i.e. mainly low-quality foods like grasses and sedges. Here I consider the energetics of P. boisei and the nutritional value of C4 foods, taking into account scaling issues between the volume of food consumed and body mass, and P. boisei's food preference as inferred from dento-cranial morphology. Underlying the models are empirical data for Papio cynocephalus dietary ecology. Paranthropus boisei only needed to spend some 37%-42% of its daily feeding time (conservative estimate on C4 sources to meet 80% of its daily requirements of calories, and all its requirements for protein. The energetic requirements of 2-4 times the basal metabolic rate (BMR common to mammals could therefore have been met within a 6-hour feeding/foraging day. The findings highlight the high nutritional yield of many C4 foods eaten by baboons (and presumably hominins, explain the evolutionary success of P. boisei, and indicate that P. boisei was probably a generalist like other hominins. The diet proposed is consistent with the species' derived morphology and unique microwear textures. Finally, the results highlight the importance of baboon/hominin hand in food acquisition and preparation.

  12. "Mitochondrial Eve", "Y Chromosome Adam", testosterone, and human evolution.

    Science.gov (United States)

    Howard, James Michael

    2002-01-01

    I suggest primate evolution began as a consequence of increased testosterone in males which increased aggression and sexuality, therefore, reproduction and success. With time, negative effects of excessive testosterone reduced spermatogenesis and started a decline of the group. Approximately 30-40 million years ago, the gene DAZ (Deleted in AZoospermia) appeared on the Y chromosome, increased spermatogenesis, and rescued the early primates from extinction. (Note: DAZ is considered by some to specifically, positively affect spermatogenesis; others suggest it has no effect on spermatogenesis.) Hominid evolution continued with increasing testosterone. The advent of increased testosterone in females of Homo erectus (or Homo ergaster) increased the female-to-male body size ratio, and eventually produced another era of excessive testosterone. Excessive testosterone caused a reduction in population size (bottleneck) that produced the "Mitochondrial Eve" (ME) mechanism. (Only certain females continued during the bottleneck to transmit their mitochondrial DNA.) That is, the ME mechanism culminated, again, in excessive testosterone and reduced spermatogenesis in the hominid line. Approximately 50,000 to 200,000 years ago, a "doubling" of the DAZ gene occurred on the Y chromosome in hominid males which rescued the hominid line with increased spermatogenesis in certain males. This produced the "Y Chromosome Adam" event. The doubling of DAZ allowed further increases in testosterone in hominids that resulted in the increased size and development of the brain. Modern humans periodically fluctuate between the positive and negative consequences of increased levels of testosterone, currently identifiable as the secular trend, increased infections, and reduced spermatogenesis. PMID:12449688

  13. A new interdisciplinary approach to the study of the origins of traditional polyphony

    Directory of Open Access Journals (Sweden)

    Jordania Joseph

    2015-01-01

    Full Text Available The article discusses a new model of the origins of choral singing in the context of human evolutionary history. Hominid interaction with predators is seen as a crucial force in the evolution of human morphology and behaviour. Group singing and dancing, with body painting and the use of masks, are perceived as critical elements of the strategy to deter predators and to put hominids into an altered state of consciousness. In this state, humans do not feel fear and pain and are ready to sacrifice their lives for the common goal. This psychological condition is still important to many human group activities, particularly in religion and the military. The mosaic distribution of polyphonic traditions is discussed in the context of the origins of language and articulated speech.

  14. Development and progress: advancing towards environmental crisis

    International Nuclear Information System (INIS)

    Physical, biological and social evolution is doubtless. One of its first manifestations is the arrival of technique when hominids emerge from pre-hominids. Those first technical developments implied a new relation man/environment that was expressed in three components that appeared successively and pushed each other in time and space like this: dominion over nature, population concentration (urbanism), and population growth. Techniques are to generate three notorious effects on the relation man/nature: 1. Deep intervention on the physical environment: mining and industrial transformation processes; 2. Deep intervention on the biological environment: development of agriculture with a decrease in biodiversity; and 3. Deep intervention on the social environment: going from a pre-modern communitarian world, to the individualism of modernity; and from the agrarian field to the big city. All these technical developments boosted dominion of the technosphere over the ecosphere, which led to the appearance of the Environmental Crisis, whose most notable manifestation is Climatic Change.

  15. Human remains and the environment of Early Pleistocene in the Nihewan Basin

    Institute of Scientific and Technical Information of China (English)

    CAI; Baoquan; LI; Qiang

    2004-01-01

    A new Early Pleistocene Paleolithic site was found in July 2001 in the Nihewan Basin, Hebei Province. Totally 500 mammal specimens assigned to 21 species and 5 lithic artifacts were collected. The coexistence of Allophaiomys deucalion, Borsodia chinensis and Yangia tingi provides important evidence of chronology. On the basis of the comparison of mammalian fauna, the date of Paleolithic artifacts is probably earlier than 1.8 MaBP, possibly 2.0 MaBP. This is the earliest evidence of hominid activity found so far in North China. The hominid at that time in the Nihewan Basin lived in an environment of arid grasslands with scattered trees of temperate zone. This discovery is significant to the study of human origin and cultural development.

  16. Dental development of the Taung skull from computerized tomography.

    Science.gov (United States)

    Conroy, G C; Vannier, M W

    Just over 60 years ago, Dart's description and analysis of the Taung child's skull triggered an intellectual revolution about human origins. Recently, several authors have suggested that one of the most significant hominid-like traits of australopithecines, delayed maturation, may not after all be valid. This is a radical departure from Mann's classic study of australopithecine maturation and palaeodemography based on dental eruption patterns. The resolution of this debate has important implications for the history of the biological and social evolution of the human species. In view of the controversies generated by recent studies, and particularly because the Taung skull is the type specimen of Australopithecus africanus, we have investigated the relevant anatomy of the Taung 'child' using computerized tomography. We conclude that the Taung 'child' shows some important dental maturational affinities with great apes, although as Dart noted, other hominid-like features are clearly present. PMID:3116435

  17. The relative cost of bent-hip bent-knee walking is reduced in water.

    Science.gov (United States)

    Kuliukas, Algis V; Milne, Nick; Fournier, Paul

    2009-01-01

    The debate about how early hominids walked may be characterised as two competing hypotheses: They moved with a fully upright (FU) gait, like modern humans, or with a bent-hip, bent-knee (BK) gait, like apes. Both have assumed that this bipedalism was almost exclusively on land, in trees or a combination of the two. Recent findings favoured the FU hypothesis by showing that the BK gait is 50-60% more energetically costly than a FU human gait on land. We confirm these findings but show that in water this cost differential is markedly reduced, especially in deeper water, at slower speeds and with greater knee flexion. These data suggest that the controversy about australopithecine locomotion may be eased if it is assumed that wading was a component of their locomotor repertoire and supports the idea that shallow water might have been an environment favourable to the evolution of early forms of "non-optimal" hominid bipedalism. PMID:19853850

  18. Estimation of australopithecine stature from long bones: A.L.288-1 as a test case.

    Science.gov (United States)

    Geissmann, T

    1986-01-01

    Regression equations for the estimation of stature from long bones, although derived from modern human populations, are frequently applied to early hominids. In fact, some of these equations have even been recommended or especially created to be applied to Australopithecus remains. In this study, 45 sets of regression and correlation formulae, recurrent in anthropological and medico-legal literature, are applied to long bones of the Pliocene hominid A.L.288-1 ('Lucy'), in order to assess which, if any, could be considered suitable for stature reconstruction in 'gracile' australopithecines. Virtually every method based on regression equations overestimates stature as compared with the estimate based on reconstruction of all the preserved skeletal parts. In addition, most methods failed to give consistent results with data from different limb segments. None of the sets of regression formulae tested here can be recommended as a reliable means of stature estimation in 'gracile' australopithecines. PMID:3108121

  19. A new pelvic fragment from Swartkrans and the relationship between the robust and gracile australopithecines.

    Science.gov (United States)

    McHenry, H M

    1975-09-01

    A recently discovered hominid pelvic fragment from Swartkrans (SK 3155) is described in detail with particular reference to the relationship of the two presently recognized forms of australopithecines in South Africa. Results of this examination and metrical analysis indicate that the acetabulum and iliac blade of the early hominids are similar to Homo sapiens except for a unique pattern of traits: a relatively small sacral articular surface, a relatively small acetabulum, a relatively large iliac fossa, and wide lateral splaying of the iliac blades. The new Swartkrans fossil expresses these traits more strongly than does the gracile australopithecine (Sts 14) and is therefore somewhat less similar to Homo sapiens but it is very unlike any pongid. PMID:810037

  20. Primate facial allometry and interpretations of australopithecine variation.

    Science.gov (United States)

    Corruccini, R S; Ciochon, R L

    1979-09-01

    Pilbeam and Gould have discussed African Plio-Pleistocene hominid evolution in the context of allometry (size-dependent morphological change). These authors demonstrate that some general aspects of australopithecine morphology (tooth, brain and body size) support the hypothesis that certain early African hominids were merely scaled variations of each other at different sizes. They also speculate that the methods applied to these very broad anatomical categories can be extended to more specific and detailed traits, especially in the face and cranium. Such traits underlie most taxonomic and phylogenetic discussions of the early African Hominidae, so it is useful to follow Pilbeam and Gould's lead, as we do here, and investigate the structural differences in the australopithecine face and cranimum in a quantificiable fashion. PMID:121762

  1. [Classification of a 300,000-year-old dental crown of the upper loamy deposit of the Bad Canstatter travertine zone].

    Science.gov (United States)

    Czarnetzki, A; Pusch, C M

    2001-01-01

    Hominid dental remains were recovered in association with fossil bones and artifacts during systematic excavations in a loamy deposit located between the two travertine zones T4 and T5 at Stuttgart-Bad Cannstatt, Southwest Germany. Direct dating of a hominid tooth crown with thermoluminescence resulted in a date of 300 kya, which is in agreement with the Holstein Interglacial floral and faunal composition of this layer. The specimen is a lower left canine with hypoplastic morphology. This interpretation is supported by thorough assessment of its overall morphology, comparative metric evaluation, and by scanning electron microscopy analyses of the enamel prisms. Additional microstructural comparison of these dental remains with a tooth from the same site, but derived from a Cervidae specimen supported the distinct differences between both teeth. Here we discuss both the classification and significance of the specimen's evolutionary position as well as compare this specimen with stomatologic results from previous palaeopathological research. PMID:11838044

  2. Evolutionary Psychology, Adaptation, and the Evoltion of Lanaguage: Is there a Need for Comparsion?

    OpenAIRE

    Krause, Mark A.

    1997-01-01

    A general assumption held by evolutionary psychologists is that a reference point for examining the origins and evolution of human psychological adaptations exists within a time range beginning roughly two million years ago. Scenarios for explaining the evolution of human psychological processes often allude to possible election pressures encountered by hominids during this time. unfortunately, comparative psychology and ethology are relatively absent from much current evolutionary psychologi...

  3. SP8 Sequencing Extinct Genomes

    OpenAIRE

    Poinar, H.

    2007-01-01

    Nucleic acids, which hold clues to the evolution of various animal and hominid taxa, are comparatively weak molecules from other cellular debris, and thus evolutionary biologists are in essence time trapped. Fortunately, DNA and protein fragments do exist in fossil remains beyond what theoretical experimentation would suggest. Sequestering of DNA molecules in humic or Maillard-like complexes likely represents a rich source of DNA molecules from the past, which have yet to be tapped. These mol...

  4. Chimpanzee hand preference for throwing and infant cradling:implications for the origin of human handedness

    OpenAIRE

    Hopkins, William D.; Bard, Kim A.; Jones, A.; Bales, S. L.

    1993-01-01

    Calvin (i983) has hypothesized that the neurophysiological, perceptual, and cognitive demands of throwing may have served as important evolutionary precursors to a variety of traits( e.g., handedness, tool use, and language processing) in early hominids. Eighty-eight percent of humans throw with their right hands (Healey, Liederman, and Geschwind I986), and Calvin has argued that this right-handed throwing evolved as a result of a left-hemisphere specialization for planned sequential movement...

  5. Culture, Urbanism and Changing Human Biology

    OpenAIRE

    Schell, L M

    2014-01-01

    Anthropologists have long known that human activity driven by culture changes the environment. This is apparent in the archaeological record and through the study of the modern environment. Perhaps the largest change since the paleolithic era is the organization of human populations in cities. New environments can reshape human biology through evolution as shown by the evolution of the hominid lineage. Evolution is not the only process capable of reshaping our biology. Some changes in our hum...

  6. The evolution of shelter: ecology and ethology of chimpanzee nest building

    OpenAIRE

    Stewart, Fiona Anne

    2011-01-01

    Human beings of all cultures build some form of shelter, and the global distribution of Homo sapiens depends on this basic trait. All great apes (chimpanzee, bonobo, gorilla, and orangutan) build analogous structures (called nests or beds) at least once a day throughout their adult lives, which suggests that this elementary technology was present before the hominid lines separated. This thesis investigates the variability and function of specifically wild chimpanzee shelters. I compared ch...

  7. Le rôle écologique des bonobos : service écologique de dispersion de graine en forêt du Congo

    OpenAIRE

    Beaune, David

    2012-01-01

    Bonobos (Pan paniscus) are threatened with extinction. They are the largest primates, and the only apes (except human), of the southern bank of the Congo Basin. Along with chimpanzees, they are our closest living relatives and are studied by anthropologists to include/understand our hominid origins; but what about their functional role in the forest? Would their disappearance have serious consequences for forest ecology? Answering this question is the aim of this new project, with several yea...

  8. Evolutionary History of a Brain Controlling Brain Size

    OpenAIRE

    Natalay Kouprina; Adam Pavlicek; Mochida, Ganeshwaran H.; Gregory Solomon; William Gersch; Young-Ho Yoon; Randall Collura; Maryellen Ruvolo; J Carl Barrett; C Geoffrey Woods; Walsh, Christopher A.; Jerzy Jurka; Vladimir Larionov

    2004-01-01

    Primary microcephaly (MCPH) is a neurodevelopmental disorder characterized by global reduction in cerebral cortical volume. The microcephalic brain has a volume comparable to that of early hominids, raising the possibility that some MCPH genes may have been evolutionary targets in the expansion of the cerebral cortex in mammals and especially primates. Mutations in ASPM, which encodes the human homologue of a fly protein essential for spindle function, are the most common known cause of MCPH....

  9. : New approach of Javanese Homo erectus cranial evolution

    OpenAIRE

    Dambricourt Malassé, Anne

    2001-01-01

    Colloque international de la Fondation Singer-Polignac, organisé à Paris, du 3 au 5 juin 1998 The fossil cranium represente a highly organized state of a dynamic System which achieved its structure beginning with the organization of the embryo. Angular values acquired during early embryogenie stages are still measurable on the adull skull. The cranio-facial architecture was studied on a population including Pan, modem humans and fossil hominids. The Sangiran 17 skull, as well as Hanoman 13...

  10. Brains, tools, innovation and biogeography in crows and ravens

    DEFF Research Database (Denmark)

    Jønsson, Knud Andreas; Fabre, Pierre-Henri Fréderic; Irestedt, Martin

    2012-01-01

    BACKGROUND:Crows and ravens (Passeriformes: Corvus) are large-brained birds with enhanced cognitive abilities relative to other birds. They are among the few non-hominid organisms on Earth to be considered intelligent and well-known examples exist of several crow species having evolved innovative....... Hence, we propose that all crows and ravens have relatively large brains compared to other birds and thus the potential to be innovative if conditions and circumstances are right....

  11. Climate change and evolving human diversity in Europe during the last glacial.

    OpenAIRE

    Gamble, Clive; Davies, William; Pettitt, Paul; Richards, Martin

    2004-01-01

    A link between climate change and human evolution during the Pleistocene has often been assumed but rarely tested. At the macro-evolutionary level Foley showed for hominids that extinction, rather than speciation, correlates with environmental change as recorded in the deep sea record. Our aim is to examine this finding at a smaller scale and with high-resolution environmental and archaeological archives. Our interest is in changing patterns of human dispersal under shifting Pleistocene clima...

  12. The robust australopithecine face: a morphogenetic perspective.

    Science.gov (United States)

    McCollum, M A

    1999-04-01

    The robust australopithecines were a side branch of human evolution. They share a number of unique craniodental features that suggest their monophyletic origin. However, virtually all of these traits appear to reflect a singular pattern of nasomaxillary modeling derived from their unusual dental proportions. Therefore, recent cladistic analyses have not resolved the phylogenetic history of these early hominids. Efforts to increase cladistic resolution by defining traits at greater levels of anatomical detail have instead introduced substantial phyletic error. PMID:10195892

  13. Australopithecine endocast (Taung specimen, 1924): a new volume determination.

    Science.gov (United States)

    Holloway, R L

    1970-05-22

    A redetermination of endocranial volume of the original 1924 Taung australopithecine described by Dart indicates a volume of 405 cubic centimeters, rather than the 525 cubic centimeters published earlier. The adult volume is estimated to have been 440 cubic centimeters. This value, plus other redeterminations of australopithecine endocasts, lowers the average to 442 cubic centimeters, and increase the likelihood of statistically significant differences from both robust australopithecines and the Olduvai Gorge hominid No. 7. PMID:5441027

  14. The expression of asymmetry in hand bones from the medieval cemetery at Écija, Spain

    OpenAIRE

    Cashmore, Lisa; Zakrzewski, Sonia R.

    2009-01-01

    The unique nature of ‘handedness’ in modern humans poses questions about the development of this trait in both extinct hominid species and archaeological populations. An examination of the expression of hand preference in skeletal material is required to answer such questions. The main focus of previous research on asymmetry and hand preference has been on the bones of the upper limb, rather than those of the hand. This study addresses this issue by exploring the expression of asymmetry in th...

  15. A zooarchaeological study of bone assemblages from the Ma’anshan Paleolithic site

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Ten thousands of bone fragments were recovered from the Ma’anshan Paleolithic site, of which 4358 pieces can be identified to skeletal elements or species. In this research, the bone assemblages are quantified based on elements of MNI, MNE, and MAU. Then bone surface modifications and skeletal element profiles of the bone assemblages are studied to understand shlepping behaviors and reveal the technique of disarticulating and defleshing the animals’ bodies, etc. Based on the analyses of bone assemblages and the comparative study with the ethnoarchaeological as well as experimental data, it is assumed that later hominids at the site made fuller use of the game animals than the earlier hominids. Incorporating the lines of evidence from chronological dating, paleoenvironment, and polished bone tools between the two cultural layers, here we propose three hypotheses suggesting that the changes of environment, the migrations of the hominids from the North, or the demographic pulses may cause such a behavioral difference. However, it is yet to be determined which hypothesis can better explain the changes.

  16. Brief communication: Reaction to fire by savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal: Conceptualization of "fire behavior" and the case for a chimpanzee model.

    Science.gov (United States)

    Pruetz, Jill D; LaDuke, Thomas C

    2010-04-01

    The use and control of fire are uniquely human traits thought to have come about fairly late in the evolution of our lineage, and they are hypothesized to correlate with an increase in intellectual complexity. Given the relatively sophisticated cognitive abilities yet small brain size of living apes compared to humans and even early hominins, observations of wild chimpanzees' reactions to naturally occurring fire can help inform hypotheses about the likely responses of early hominins to fire. We use data on the behavior of savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal during two encounters with wildfires to illuminate the similarities between great apes and humans regarding their reaction to fire. Chimpanzees' close relatedness to our lineage makes them phylogenetically relevant to the study of hominid evolution, and the open, hot and dry environment at Fongoli, similar to the savanna mosaic thought to characterize much of hominid evolution, makes these apes ecologically important as a living primate model as well. Chimpanzees at Fongoli calmly monitor wildfires and change their behavior in anticipation of the fire's movement. The ability to conceptualize the "behavior" of fire may be a synapomorphic trait characterizing the human-chimpanzee clade. If the cognitive underpinnings of fire conceptualization are a primitive hominid trait, hypotheses concerning the origins of the control and use of fire may need revision. We argue that our findings exemplify the importance of using living chimpanzees as models for better understanding human evolution despite recently published suggestions to the contrary. PMID:20027607

  17. The temporal bones from Sima de los Huesos Middle Pleistocene site (Sierra de Atapuerca, Spain). A phylogenetic approach.

    Science.gov (United States)

    Martínez, I; Arsuaga, J L

    1997-01-01

    Three well-preserved crania and 22 temporal bones were recovered from the Sima de los Huesos Middle Pleistocene site up to and including the 1994 field season. This is the largest sample of hominid temporal bones known from a single Middle Pleistocene site and it offers the chance to characterize the temporal bone morphology of an European Middle Pleistocene population and to study the phylogenetic relationships of the SH sample with other Upper and Middle Pleistocene hominids. We have carried out a cladistic analysis based on nine traits commonly used in phylogenetic analysis of Middle and Late Pleistocene hominids: shape of the temporal squama superior border, articular eminence morphology, contribution of the sphenoid bone to the median glenoid wall, postglenoid process projection, tympanic plate orientation, presence of the styloid process, mastoid process projection, digastric groove morphology and anterior mastoid tubercle. We have found two autapomorphies on the Home erectus temporal bone: strong reduction of the postglenoid process and absence of the styloid process. Modern humans, Neandertals and the Middle Pleistocene fossils from Europe and Africa constitute a clade characterized by a convex superior border of the temporal squama. The European Middle Pleistocene fossils from Sima de los Huesos, Petralona, Steinheim, Bilzingsleben and Castel di Guido share a Neandertal apomorphy: a relatively flat articular eminence. The fossils from Ehringsdorf, La Chaise Suardi and Biache-Saint-Vaast also display another Neandertal derived trait: an anteriorly obliterated digastric groove. Modern humans and the African Middle Pleistocene fossils share a synapomorphy: a sagittally orientated tympanic plate. PMID:9300344

  18. Neanderthal teeth from Moula-Guercy, Ardèche, France.

    Science.gov (United States)

    Hlusko, Leslea J; Carlson, Joshua P; Guatelli-Steinberg, Debbie; Krueger, Kristin L; Mersey, Ben; Ungar, Peter S; Defleur, Alban

    2013-07-01

    Here we describe dental remains from a Neanderthal fossil assemblage from Moula-Guercy, France. Our report demonstrates that the Moula-Guercy hominid remains contribute important morphological, developmental, and behavioral data to understanding Neanderthal evolutionary history. We include gross comparative morphological descriptions and enamel surface microstructure and microwear data. These teeth reveal numerous characteristics that are diagnostic of Neanderthals and provide no evidence for the presence of any other hominid taxa. Enamel growth increment data from the Moula-Guercy specimens yield evidence of a Neanderthal pattern of development, although at the lower end of the range of variation. The presence of a significant number of linear enamel hypoplasias indicates that these individuals were stressed during childhood. Molar microwear data suggest that these Neanderthals did not differ significantly from modern humans in terms of the fracture properties of the food they were consuming. The incisor microwear and macro striations provide evidence that these individuals may have been using their anterior teeth as tools, similar to the practices of several modern human populations such as the Inuit, Ipiutak, and Australian Aboriginals, and reminiscent of evidence from other Neanderthals from Krapina, Croatia, as well as the 600,000 year old hominids from Sima de los Huesos, Spain. Am J Phys Anthropol 151:477-491, 2013.© 2013 Wiley Periodicals, Inc. PMID:23737145

  19. The hunters and the hunted revisited.

    Science.gov (United States)

    Lee-Thorp, J; Thackeray, J F; van der Merwe, N

    2000-12-01

    The dietary niches of extinct animals, including hominids and predators, may be constrained using stable carbon isotope ratios in fossil tooth enamel.(13)C/(12)C ratios of many of the primates abundant in the faunal assemblages of Members 1 and 2 at Swartkrans, including cercopithecoids and Australopithecus (Paranthropus) robustus, and a range of other possible prey species, have been reported previously. Resulting suggestions of a mixed, or omnivorous, diet for A. robustus raise questions about niche overlap with coeval, larger brained Homo. Here we present(13)C/(12)C data from Homo and several large predators including Panthera pardus, Dinofelis sp., Megantereon cultridens and Chasmoporthetes nitidula in Member 1, and P. pardus and P. leo in Member 2, in order to compare the two hominid species and to determine likely predators of the various primates and other macrovertebrates. Results for three Homo cf. ergaster individuals are indistinguishable from those of A. robustus, showing that proportions of C(3)- and C(4)-based foods in their diets did not differ. P. pardus, Megantereon and Crocuta are shown to be likely predators of the hominids and Papio baboons in Member 1, while the Dinofelis individual concentrated on prey which consumed C(4)grasses. The hunting hyaenid C. nitidula preyed on either mixed feeders or on a range of animals across the spectrum of C(3)and C(4)variation. The data from Members 1 and 2 confirm a shift in leopard diets towards animals that consumed C(4)grasses. PMID:11102267

  20. Early Homo and associated artefacts from Asia.

    Science.gov (United States)

    Huang, W; Ciochon, R; Gu, Y; Larick, R; Qiren, F; Schwarcz, H; Yonge, C; de Vos, J; Rink, W

    1995-11-16

    The site of Longgupo Cave was discovered in 1984 and excavated in 1985-1988 by the Institute of Vertebrate Paleontology and Paleoanthropology (Beijing) and the Chongqing National Museum (Sichuan Province). Important finds include very archaic hominid dental fragments, Gigantopithecus teeth and primitive stone tools. Palaeomagnetic analysis and the presence of Ailuropoda microta (pygmy giant panda) suggested that the hominid-bearing levels dated to the earliest Pleistocene. In 1992, joint Chinese-American-Canadian geochronological research corroborated the age using electron spin resonance (ESR) analysis. We report here that the hominid dentition and stone tools from Longgupo Cave are comparable in age and morphology with early representives of the genus Homo (H. habilis and H. ergaster) and the Oldowan technology in East Africa. The Longgupo dentition is demonstrably more primitive than that seen in Asian Homo erectus. Longgupo's diverse and well preserved Plio-Pleistocene fauna of 116 species provide a sensitive contextual base for interpreting the early arrival of the genus Homo in Asia. PMID:7477345

  1. Human evolution.

    Science.gov (United States)

    Wood, B

    1996-12-01

    The common ancestor of modern humans and the great apes is estimated to have lived between 5 and 8 Myrs ago, but the earliest evidence in the human, or hominid, fossil record is Ardipithecus ramidus, from a 4.5 Myr Ethiopian site. This genus was succeeded by Australopithecus, within which four species are presently recognised. All combine a relatively primitive postcranial skeleton, a dentition with expanded chewing teeth and a small brain. The most primitive species in our own genus, Homo habilis and Homo rudolfensis, are little advanced over the australopithecines and with hindsight their inclusion in Homo may not be appropriate. The first species to share a substantial number of features with later Homo is Homo ergaster, or 'early African Homo erectus', which appears in the fossil record around 2.0 Myr. Outside Africa, fossil hominids appear as Homo erectus-like hominids, in mainland Asia and in Indonesia close to 2 Myr ago; the earliest good evidence of 'archaic Homo' in Europe is dated at between 600-700 Kyr before the present. Anatomically modern human, or Homo sapiens, fossils are seen first in the fossil record in Africa around 150 Kyr ago. Taken together with molecular evidence on the extent of DNA variation, this suggests that the transition from 'archaic' to 'modern' Homo may have taken place in Africa. PMID:8976151

  2. Geochronology and geochemistry of volcanic glasses associated with early Homo sapiens in Ethiopia.

    Science.gov (United States)

    Morgan, L. E.; Renne, P. R.; Woldegabriel, G.; White, T. D.

    2005-12-01

    In past work at hominid sites in Ethiopia, 40Ar/39Ar dating was used to constrain obsidian from the base of the Upper Herto Member of the Bouri Formation to 160 ± 2 ka. An overlying vitric tuff was then geochemically correlated to one from the Konso region of Ethiopia, which is constrained to be older than 154 ± 7 ka, thus leaving only 6 ± 7 ky between eruption and deposition of the fossils and artifacts at Herto. To continue these studies, we have collected and are currently analyzing obsidian and associated volcanic ashes from Middle Stone Age (MSA) archaeological and paleontological sites in the Middle Awash, Ethiopia. Distinctive geochemical signatures among most obsidian fragments collected (n=20 per site) suggest that obsidian was being derived from a variety of sources. By comparing our geochemical data with that from known obsidian deposits in Ethiopia and elsewhere in East Africa, we hope to determine the source localities for the obsidian and thus gauge the extent of trade networks during the MSA. Thus, by characterizing obsidian using both 40Ar/39Ar geochronology and trace element geochemistry, will make it possible to temporally refine the stratigraphy and prehistory at hominid sites, which in turn improves understanding of hominid behavior and evolution.

  3. Our Magnetic Planet (Arthur Holmes Medal Lecture)

    Science.gov (United States)

    Laj, Carlo

    2015-04-01

    and Turkey) allowed to show that the main post-cretaceous geodynamical evolution of the Aegean Realm is dominated since 30 My by two phases of rotational deformation in opposite sense around two poles: one just north of Albania for the western part, the second in the South Eastern Mediterranean for the eastern part. During the sampling of Mio-Pliocene marls in Crete, using a LETI portable magnetometer to the development of which I have participated, we sampled a geomagnetic reversal registered over about 50 cm of sediments. Interestingly, some intermediate directions were clearly apparent. This gave me the idea that the dynamical directional behaviour of the reversing field could be studied. At the time, only a very few and very incomplete similar records existed. For me, this has been the beginning of an extraordinary adventure still going on today. From the accumulation of data, first from Crete, then from other worldwide spread sites, it became apparent, as illustrated in a cover of Nature, that sedimentary reversal transition paths had a tendency to coincide with the seismically cold deep regions, suggesting that a lower mantle control existed over the reversing geodynamo. This idea, sometimes greeted with scepticism, has stimulated joint efforts to test it both from different disciplines and different experimental and theoretical approaches. It is fair to say that 25 years after it was proposed, our idea is still "on the table" and discussed. We then turned to the study of the changes of the geomagnetic field intensity, still inadequately described at the time. Because measurements of traditional small cubic samples was largely too time consuming to allow surveys of the amplitude we had in mind, I adapted the u-channel measurement techniques to small access pass-through cryogenic magnetometers, and suggested to W. Goree of 2G-Enterprises a modification of the standard pick-up coil geometry (called the Laj-system by the manufacturer) to allow high spatial

  4. Our Magnetic Planet (Arthur Holmes Medal Lecture)

    Science.gov (United States)

    Laj, Carlo

    2015-04-01

    and Turkey) allowed to show that the main post-cretaceous geodynamical evolution of the Aegean Realm is dominated since 30 My by two phases of rotational deformation in opposite sense around two poles: one just north of Albania for the western part, the second in the South Eastern Mediterranean for the eastern part. During the sampling of Mio-Pliocene marls in Crete, using a LETI portable magnetometer to the development of which I have participated, we sampled a geomagnetic reversal registered over about 50 cm of sediments. Interestingly, some intermediate directions were clearly apparent. This gave me the idea that the dynamical directional behaviour of the reversing field could be studied. At the time, only a very few and very incomplete similar records existed. For me, this has been the beginning of an extraordinary adventure still going on today. From the accumulation of data, first from Crete, then from other worldwide spread sites, it became apparent, as illustrated in a cover of Nature, that sedimentary reversal transition paths had a tendency to coincide with the seismically cold deep regions, suggesting that a lower mantle control existed over the reversing geodynamo. This idea, sometimes greeted with scepticism, has stimulated joint efforts to test it both from different disciplines and different experimental and theoretical approaches. It is fair to say that 25 years after it was proposed, our idea is still "on the table" and discussed. We then turned to the study of the changes of the geomagnetic field intensity, still inadequately described at the time. Because measurements of traditional small cubic samples was largely too time consuming to allow surveys of the amplitude we had in mind, I adapted the u-channel measurement techniques to small access pass-through cryogenic magnetometers, and suggested to W. Goree of 2G-Enterprises a modification of the standard pick-up coil geometry (called the Laj-system by the manufacturer) to allow high spatial

  5. Control estructural en el emplazamiento del volcanismo y mineralizaciones neógenas, distrito Cañada Honda, San Luis Structural control on Neogene volcanism and related ore deposits at Cañada Honda district, San Luis province

    Directory of Open Access Journals (Sweden)

    María Silvia Japas

    2010-12-01

    Tertiary volcanic belt records the eastward migration of the Andean volcanic arc due to the flattening of the Nazca Plate in Mio-Pliocene times. The tertiary volcanic belt encompasses several very important metallogenetic districts in the San Luis Pampean Ranges. Volcanic rocks and associated ore-deposits crop out following a NW-WNW trending belt at La Carolina, Cañada Honda - Cerros Largos, Cerros del Rosario and El Morro volcanic fields. The available geochronological data indicate that the volcanic activity began early at the western end of the belt and ended ~ 10 Ma later at its eastern border. Cañada Honda district represents the oldest and longest-lived volcanic field of the tertiary volcanic belt. It records eruptive events and related hydrothermal alteration from 12-13 Ma to 7.3 Ma, including lavas and volcaniclastic products. Preliminary structural analysis shows that previous structures have strongly controlled, either directly or indirectly, the emplacement of volcanic rocks and related mineral deposits. Kinematic and strain fabric analyses allow to recognize two volcano-tectonic associations. One of these associations would be related to dextral reactivations of structures parallel to basement foliation. On the other hand, the main one would be linked with the generation of two volcano-tectonic depressions which are aligned in a NW-WNW direction. Their dominant structures trend NW-WNW and reveal sinistral-normal motions, both at local and Tertiary volcanic belt scales.

  6. The antler finds at Bilzingsleben, excavations 1969-1993

    Directory of Open Access Journals (Sweden)

    Jürgen Vollbrecht

    2000-09-01

    Full Text Available 2820 antler remains from the Lower Palaeolithic site of Bilzingsleben, Thuringia, Germany (excavations 1969-1993 were the subject of detailed investigations. The two major goals were: 1.the consideration of taphonomic aspects 2.the critical evaluation of suggestions about artificial modifications to the antler material A detailed morphological description of the antler material provided the basis for the investigation. A prerequisite was the transfer of provenance data onto an x-y coordinate grid. Taphonomic aspects considered in this work include the relative frequencies of antler elements, estimates regarding the minimum number of individual deer, their age structure and seasonality, and, insofar as the condition of the antlers allowed, the classification of surface preservation, size classes and spatial distribution of the finds. The assemblage of antler finds, the majority of which seems to have come from red deer, is dominated by small fragments, mostly of tines. About one quarter of the finds are larger than 150 mm. Lower beams are more abundant than upper beams (e.g. crowns. Detailed counting, substantiated by systematic reconstruction, shows that in general the antlers are incomplete. After reconstruction of unshed antlers, it was possible to assess the minimum number of heads at 150 animals. Preliminary counting of postcranial and cranial (non antler cervid material points to about 70 cervids. Intentional accumulation of antlers by hominids can only be accepted as the reason for these disproportionate figures if other site formation processes can be ruled out. In fact, the correlation between sediment thickness and maximum antler densities, at least for finds smaller than 120mm, suggests that fluvial accumulation has to be taken into account as a probable element of the site formation history. Further, the mixture of unifacially abraded finds together with finds that exhibit bifacial abrasion points to a succession of changing fluvial

  7. The behavioral ecology of sympatric African apes: implications for understanding fossil hominoid ecology.

    Science.gov (United States)

    Stanford, Craig B

    2006-01-01

    The behavioral ecology of the great apes is key evidence used in the reconstruction of the behavior of extinct ape and hominid taxa. Chimpanzees and gorillas have been studied in detail in the wild, and some studies of their behavioral ecology in sympatry have also been been carried out. Although the two ape species have divergent behavior and ecology in important respects, recent studies have shown that the interspecific differences are not as stark as previously thought and subsequently urge new consideration of how they share forest resources when sympatric. These new data require re-examination of assumptions about key aspects of chimpanzee-gorilla ecological divergence, such as diet, ranging and nesting patterns, and the mating system. Diet is a key component of the species' adaptive complexes that facilitates avoidance of direct competition from the other. While the nutritional basis for chimpanzee food choice remains unclear and no doubt varies from site to site, this species is a ripe fruit specialist and ranges farther during periods of ripe fruit scarcity. Gorillas in the same habitat also feed on ripe fruit when widely available, but fall back onto fibrous plant foods during lean periods. The inclusion of animal protein in the diet of the chimpanzees and its absence in that of the gorillas also distinguish the species ecologically. It may also offer clues to aspects of ecological divergence among early members of the hominid phylogeny. The paper concludes by suggesting likely characteristics of sympatric associations of Pliocene hominids, based on field data from extant sympatric apes. PMID:16283423

  8. The Functional Anatomy of the Carpometacarpal Complex in Anthropoids and Its Implications for the Evolution of the Hominoid Hand.

    Science.gov (United States)

    Selby, Michael S; Simpson, Scott W; Lovejoy, C Owen

    2016-05-01

    Previously, we described several features of the carpometacarpal joints in extant large-bodied apes that are likely adaptations to the functional demands of vertical climbing and suspension. We observed that all hominids, including modern humans and the 4.4-million-year-old hominid Ardipithecus ramidus, lacked these features. Here, we assess the uniqueness of these features in a large sample of monkey, ape, and human hands. These new data provide additional insights into the functional adaptations and evolution of the anthropoid hand. Our survey highlights a series of anatomical adaptations that restrict motion between the second and third metacarpals (MC2 and MC3) and their associated carpals in extant apes, achieved via joint reorganization and novel energy dissipation mechanisms. Their hamate-MC4 and -MC5 joint surface morphologies suggest limited mobility, at least in Pan. Gibbons and spider monkeys have several characters (angled MC3, complex capitate-MC3 joint topography, variably present capitate-MC3 ligaments) that suggest functional convergence in response to suspensory locomotion. Baboons have carpometacarpal morphology suggesting flexion/extension at these joints beyond that observed in most other Old World monkeys, probably as an energy dissipating mechanism minimizing collision forces during terrestrial locomotion. All hominids lack these specializations of the extant great apes, suggesting that vertical climbing was never a central feature of our ancestral locomotor repertoire. Furthermore, the reinforced carpometacarpus of vertically climbing African apes was likely appropriated for knuckle-walking in concert with other novel potential energy dissipating mechanisms. The most parsimonious explanation of the structural similarity of these carpometacarpal specializations in great apes is that they evolved independently. PMID:26916787

  9. Dating the Homo erectus bearing travertine from Kocabaş (Denizli, Turkey) at at least 1.1 Ma

    Science.gov (United States)

    Lebatard, Anne-Elisabeth; Alçiçek, M. Cihat; Rochette, Pierre; Khatib, Samir; Vialet, Amélie; Boulbes, Nicolas; Bourlès, Didier L.; Demory, François; Guipert, Gaspard; Mayda, Serdar; Titov, Vadim V.; Vidal, Laurence; de Lumley, Henry

    2014-03-01

    Since its discovery within a travertine quarry, the fragmentary cranium of the only known Turkish Homo erectus, the Kocabaş hominid, has led to conflicting biochronological estimations. First estimated to be ˜500 ka old, the partial skull presents a combination of archaic and evolved features that puts it as an intermediate specimen between the Dmanisi fossils (Homo georgicus) and the Chinese Zhoukoudian skulls (Homo erectus) respectively dated to 1.8 to ˜0.8 Ma. Here we present a multidisciplinary study combining sedimentological, paleontological and paleoanthropological observations together with cosmogenic nuclide concentration and paleomagnetic measurements to provide an absolute chronological framework for the Upper fossiliferous Travertine unit where the Kocabaş hominid and fauna were discovered. The 26Al/10Be burial ages determined on pebbles from conglomeratic levels framing the Upper fossiliferous Travertine unit, which exhibits an inverse polarity, constrains its deposition to before the Cobb Mountain sub-chron, that is between 1.22 and ˜1.5 Ma. The alternative match of the normal polarity recorded above the travertine with the Jaramillo subchron (lower limit 1.07 Ma) may also be marginally compatible with cosmogenic nuclides interpretation, thus the proposed minimum age of 1.1 Ma for the end of massive travertine deposition. The actual age of the fossils is likely to be in the 1.1-1.3 Ma range. This absolute date is in close agreement with the paleoanthropological conclusions based on morphometric comparisons implying that Kocabaş hominid belongs to the Homo erectus s.l. group that includes Chinese and African fossils, and is different from Middle and Upper Pleistocene specimens. Furthermore, this date is confirmed by the large mammal assemblage, typical of the late Villafranchian. Because it attests to the antiquity of human occupation of the Anatolian Peninsula and one of the waves of settlements out of Africa, this work challenges the current

  10. Sédimentation et tectonique dans le bassin marin Eocène supérieur-Oligocène des Alpes du Sud Sedimentation and Tectonics in the Upper Eocene-Oligocene Marine Basin in the Southern Alps

    Directory of Open Access Journals (Sweden)

    Riche P.

    2006-11-01

    'exprime nettement moins que précédemment. Le toit des grès est marqué par une surface de discontinuité fortement érosive correspondant à des canyons sous-marins de direction NE-SO. Cette surface peut être mise en relation avec l'écoulement des olistostromes qui termine le remplissage du bassin. La mise en place de ces olistostromes et des olistolithes qui les accompagnent n'est pas paléontologiquement datée : elle débute avec la fin de la sédimentation gréseuse. L'ensemble est encore affecté par une distension E-O ce qui tend à montrer que cette mise en place est antérieure à la phase de serrage miocène. La confrontation entre les observations de terrain, les expériences de sédimentation en canal et l'interprétation sismique de bassins offshore argumente les interprétations proposées. This paper is based on local field surveys performed recently by Institut Français du Pétrole (IFP and Ecole Nationale Supérieure du Pétrole et des Moteurs (ENSPM in the western part of the southern Alps nummulitic basin, to help interpret seismic data. It underlines the role of extensional tectonics during sedimentation. It questions the geodynamic interpretation of the basin as a foredeep basin in the Alpine orogenic belt. On a Mesozoic basement folded by the Pyreneo-Provençale orogeny, as early as the Lutetian the nummulitic transgression flooded the eastern area, which was subsequently obscured by the Pennine main fault during Mio-Pliocene times. It spread westward during the Upper Eocene. In the meantime, an E-W extension, shown clearly along the Var River faults and along the edge of the Pelvoux range, fragmented the fringes of the basin with blocks tilted during sedimentation. The result is fast changes of facies within the basal carbonates, which pass from platform types to slope types and to thin gravitational sediments farther into the basin. The overlying marls correspond to slope facies wrapping the inherited topography. The Gres d'Annot s. l

  11. Brain Morphology of the Zhoukoudian H.erectus Half a Million Years Ago

    Institute of Scientific and Technical Information of China (English)

    WU Xiujie

    2010-01-01

    @@ In the process of human evolution,how has the brain changed? When did it happen? Why did it happen?These questions are some of the hottest topics in paleoanthropology today.The study of brain evolution falls into the sub-discipline of paleoneurology and is based on direct examination of the fossil record of humans and their closest hominid relatives.Unfortunately,brains are not preserved in the fossil record.The most direct evidence of ancestral brains is available,however,from endocasts.An endocast is the impression taken from the inside of a cranium retaining the surface features of the brain.

  12. Endocasts-the direct evidence and recent advances in the study of human brain evolution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Brain evolution is one of the most important aspects of human evolution, usually studied through endocasts. Analysis of fossil hominid endocasts allows inferences on functional anatomy, physiology, and phylogeny. In this paper, we describe the general features of endocast studies and review some of the major topics in paleoneurology. These are: absolute and relative brain size evolution; brain shape variation; brain asymmetry and lateralization; middle meningeal vessels and venous sinuses; application of computed tomography and virtual imaging; the history of Chinese brain endocast studies. In particular, this review emphasizes endocast studies on Chinese hominin fossils.

  13. Mind and Language Architecture

    OpenAIRE

    Robert K. Logan

    2010-01-01

    A distinction is made between the brain and the mind. The architecture of the mind and language is then described within a neo-dualistic framework. A model for the origin of language based on emergence theory is presented. The complexity of hominid existence due to tool making, the control of fire and the social cooperation that fire required gave rise to a new level of order in mental activity and triggered the simultaneous emergence of language and conceptual thought. The mind is shown to h...

  14. The Origin of Modern Humans and the Impact of Chronometric Dating, edited by M.J. Aitken, C.B. Stringer, and P.A. Mellars. Princeton University Press, Princeton, 1993

    Directory of Open Access Journals (Sweden)

    Marc Kodack

    1993-11-01

    Full Text Available The origin of humans, whether at the "point" of divergence from other primates, from other hominid species, or within the last several hundred thousand years, are very active and contested areas of paleoanthropological research. The Aitken et al. volume represents 14 papers and an overview of the evidence for and against the emergence of modern humans with a focus on the dating evidence. The papers were originally presented in a 1987 symposium in England and were previously published in two special journal issues.

  15. Injury, inflammation and the emergence of human-specific genes.

    Science.gov (United States)

    Baird, Andrew; Costantini, Todd; Coimbra, Raul; Eliceiri, Brian P

    2016-05-01

    In light of the central role of inflammation in normal wound repair and regeneration, we hypothesize that the preponderance of human-specific genes expressed in human inflammatory cells is commensurate with the genetic versatility of inflammatory response and the emergence of injuries associated with uniquely hominid behaviors, like a bipedal posture and the use of tools, weapons and fire. The hypothesis underscores the need to study human-specific signaling pathways in experimental models of injury and infers that a selection of human-specific genes, driven in part by the response to injury, may have facilitated the emergence of multifunctional genes expressed in other tissues. PMID:26874655

  16. Los fósiles humanos de Ibeas (Sierra de Atapuerca, Burgos). Inventario y determinación del número mínimo de individuos.

    OpenAIRE

    Aguirre, E.; Arsuaga, J.L.; Bermúdez de Castro, J. M.; Martínez, I; Rosas, A

    1986-01-01

    During 1983-1986 excavations carried out in some Middle Pleistocene sites of the Sierra de Atapuerca (Burgos), a total of 141 human remains were recovered in the Sima de los Huesos site, one of the cavities of the Cueva Mayor-Cueva del Silo karst system. These findings come to be added to the ones, occurred in 1976 in the same site, which were attributed to hominids of the so called «anteneandertalians- group. Aa. offer in this paper the inventory of all the human fossils recovered up to the ...

  17. Gamma-ray spectrometric dating of late Homo erectus skulls from Ngandong and Sambungmacan, Central Java, Indonesia.

    Science.gov (United States)

    Yokoyama, Yuji; Falguères, Christophe; Sémah, François; Jacob, Teuku; Grün, Rainer

    2008-08-01

    Hominid fossils from Ngandong and Sambungmacan, Central Java, Indonesia, are considered to be the most anatomically derived and youngest representatives of Homo erectus. Nondestructive gamma-ray spectrometric dating of three of these Homo erectus skulls showed that all samples underwent uranium leaching. Nevertheless, we could establish minimum age estimates of around 40ka, with an upper age limit of around 60 to 70ka. This means that the Homo erectus of Java very likely survived the Toba eruption and may have been contemporaneous with the earliest Homo sapiens in Southeast Asia and Australasia.

  18. The characteristics and chronology of the earliest Acheulean at Konso, Ethiopia.

    Science.gov (United States)

    Beyene, Yonas; Katoh, Shigehiro; Woldegabriel, Giday; Hart, William K; Uto, Kozo; Sudo, Masafumi; Kondo, Megumi; Hyodo, Masayuki; Renne, Paul R; Suwa, Gen; Asfaw, Berhane

    2013-01-29

    The Acheulean technological tradition, characterized by a large (>10 cm) flake-based component, represents a significant technological advance over the Oldowan. Although stone tool assemblages attributed to the Acheulean have been reported from as early as circa 1.6-1.75 Ma, the characteristics of these earliest occurrences and comparisons with later assemblages have not been reported in detail. Here, we provide a newly established chronometric calibration for the Acheulean assemblages of the Konso Formation, southern Ethiopia, which span the time period ∼1.75 to Homo erectus-like hominid morphology. PMID:23359714

  19. African Homo erectus: Old radiometric ages and young Oldowan assemblages in the middle Awash Valley, Ethiopia

    Energy Technology Data Exchange (ETDEWEB)

    Clark, J.D.; White, T.D.; Selassie, Y.H. (Univ. of California, Berkeley, CA (United States)); Heinzelin, J. de (Institut Royal des Sciences Naturelles de Belgique, Brussels (Belgium)); Schick, K.D. (Indiana Univ., Bloomington, IN (United States)); Hart, W.K. (Miami Univ., Oxford, OH (United States)); WoldeGabriel, G. (Los Alamos National Lab., NM (United States)); Walter, R.C. (Institute of Human Origins, Berkeley, CA (United States)); Suwa, G. (Univ. of Tokyo (Japan)); Asfaw, B. (Addis Ababa (Ethiopia)) (and others)

    1994-06-24

    Fossils and artifacts recovered from the middle Awash Valley of Ethiopia's Afar depression sample the Middle Pleistocene transition from Homo erectus to Homo sapiens. Ar/Ar ages, biostratigraphy, and tephrachronology from this area indicate that the Pleistocene Bodo hominid cranium and newer specimens are approximately 0.6 million years old. Only Oldowan chopper and flake assemblages are present in the lower stratigraphic units but Acheulean bifacial artifacts are consistently prevalent and widespread in directly overlying deposits. This technological transition is related to a shift in sedimentary regime, supporting the hypothesis that Middle Pleistocene Oldowan assemblages represent a behavioral facies of the Acheulean industrial complex.

  20. A Review of "Human Security in World Affairs: Problems and Opportunities"

    Directory of Open Access Journals (Sweden)

    Arthur L. Fredeen

    2013-01-01

    Full Text Available While security of our hominid encampments and settlements must have been at or near the top of our species priorities since our evolution some several hundred thousand years ago, awareness of the magnitude of our alterations, interactions and impacts on our world is a very recent event. Even more recent is our collective and growing angst over how are species is to secure some sort of permanence on a planet that is ultimately governed by natural forces and is forever changing.

  1. Mental Darwinism and the evolution of the emotion-processing mind.

    Science.gov (United States)

    Langs, R

    1996-01-01

    The cognitive mental module with which humans process and adapt to emotionally charged environmental or triggering events is identified as the emotion-processing mind. The current architecture of this mental module presents several anomalous features. In an effort to clarify their basis, the evolution of this module is traced for the 6,000,000-year history of hominid existence. In addition, the nature of its current adaptive resources are explored as a way of introducing mental Darwinism, the concept that the emotion-processing mind is an adaptive entity that operates according to the principles of universal Darwinism.

  2. Biometrical studies upon hominoid teeth: the coefficient of variation, sexual dimorphism and questions of phylogenetic relationship.

    Science.gov (United States)

    Blumenberg, B

    1985-01-01

    Sexual dimorphism as a function of variation in hominoid tooth metrics has been investigated for four groups of taxa: Recent great apes (two subfamilies), Dryopiths (one subfamily), Ramapiths (one subfamily) and hominids (one family). Gorilla, and to a lesser extent Pan, appear characterized by very high levels of sexual dimorphism and meet several criteria for statistical outliers. Recent great apes are the only group exhibiting consistently high levels of sexual dimorphism. Ramapiths are the only group characterized by low levels of sexual dimorphism and their relative canine length is most similar to Dryopiths. Both Dryopiths and hominids contain taxa with low and intermediate levels of sexual dimorphism. The Gingerich and Shoeninger hypothesis relating coefficients of variation to occlusal complexity is supported. Non-parametric statistics suggest that homogeneity of coefficient of variation profiles over most of the tooth row is characteristic of only the Dryopiths and a composite data set composed of the Dryopith plus Ramapith tooth measurements. Oxnard's model for the multifactorial basis of multiple sexual dimorphisms is also supported. The Dryopith and hominid patterns of sexual dimorphism are similar, an observation that suggests phylogenetic relationship. At the taxonomic level of subfamily or family, sexual dimorphism is a character of cladistic usefulness and possible phylogenetic valence. Assuming that breeding system and sexual dimorphism are functional correlates as many workers suggest, then Ramapithecus sp. China, Sivapithecus indicus and possibly Australopithecus boisei are good candidates for having possessed monogamous breeding/social structures. All Dryopith taxa, S. sivalensis, Sivapithecus sp. China, A. afarensis, Homo habilis and H. erectus emerge as the best candidates for having possessed a polygynous breeding/social structure. No biometrical affinities of Ramapiths with hominids can be demonstrated and some phylogenetic relationship with

  3. U-series dating of Zhangkou Cave in Yiliang, Yunnan Province: Evidence for human activities in China during 40-100 ka

    Institute of Scientific and Technical Information of China (English)

    SHEN Guanjun; LI Jiankun; JI Xueping

    2005-01-01

    The cultural deposits at pits T1 and T2 in Zhangkou Cave are intercalated with several flowstone layers. U-series dates show that the capping and 2nd flowstone layers are Holocene of age. The 4th and 5th flowstone layers are ca. 55 and 110 ka old respectively. The lithic artifacts bracketed by them provide unequivocal evidence for hominid presence during this time interval. The "temporal gap" of hominid fossil, widely quoted as in support of the out-of-Africa hypothesis, is most probably an artifact due to systematic errors of dating techniques. The infillings under 6th flowstone layer date to >300 ka, much older than the previous estimate at 15 ka based on classical 14C dating of fossil bones, providing one more example of the limited reliability of this chronometer. With rich relics and favorable conditions for precise dating, this site is promising for further multidisciplinary studies to address issues concerning recent human evolution in China.

  4. Human origins and evolution: Cold Spring Harbor, deja vu.

    Science.gov (United States)

    White, T D

    2009-01-01

    The Cold Spring Harbor Symposia of the 1950s were key to integrating human evolutionary studies into biology. That integration provided a solid foundation for systematic and functional interpretations of an expanding base of fossil and molecular evidence during the latter half of the 20th century. Today, the paleontological record of human evolution amassed during the last 150 years illuminates the human clade on life's tree. However, the rise of Hennegian parsimony cladistics and punctuationalism during the end of the last century witnessed the partial abandonment of classificatory conventions cemented by Mayr, Simpson, Dobzhansky, and others at Cold Spring Harbor. This has led to an artificial, postmillennial amplification of apparent species diversity in the hominid clade. Work on a stratigraphically thick and temporally deep sedimentary sequence in the Middle Awash study area of Ethiopia's Afar Depression reveals an assembly order of hominid anatomies and behaviors that was impossible for Darwin to discern. Large parts of that record appear to reflect phyletic evolution, consistent with the lessons and expectations of Cold Spring Harbor in 1950. Molecular biology cannot reveal the assembly sequences or contexts of human origins and evolution without reference to adequate geological, geochronological, paleobiological, and archaeological records. Today's consilience of these disparate data sets would have impressed Charles Darwin.

  5. Hunting behavior of wild chimpanzees in the Taï National Park.

    Science.gov (United States)

    Boesch, C; Boesch, H

    1989-04-01

    Hunting is often considered one of the major behaviors that shaped early hominids' evolution, along with the shift toward a drier and more open habitat. We suggest that a precise comparison of the hunting behavior of a species closely related to man might help us understand which aspects of hunting could be affected by environmental conditions. The hunting behavior of wild chimpanzees is discussed, and new observations on a population living in the tropical rain forest of the Taï National Park, Ivory Coast, are presented. Some of the forest chimpanzees' hunting performances are similar to those of savanna-woodlands populations; others are different. Forest chimpanzees have a more specialized prey image, intentionally search for more adult prey, and hunt in larger groups and with a more elaborate cooperative level than savanna-woodlands chimpanzees. In addition, forest chimpanzees tend to share meat more actively and more frequently. These findings are related to some theories on aspects of hunting behavior in early hominids and discussed in order to understand some factors influencing the hunting behavior of wild chimpanzees. Finally, the hunting behavior of primates is compared with that of social carnivores. PMID:2540662

  6. Accelerated evolution of the ASPM gene controlling brain size begins prior to human brain expansion.

    Directory of Open Access Journals (Sweden)

    Natalay Kouprina

    2004-05-01

    Full Text Available Primary microcephaly (MCPH is a neurodevelopmental disorder characterized by global reduction in cerebral cortical volume. The microcephalic brain has a volume comparable to that of early hominids, raising the possibility that some MCPH genes may have been evolutionary targets in the expansion of the cerebral cortex in mammals and especially primates. Mutations in ASPM, which encodes the human homologue of a fly protein essential for spindle function, are the most common known cause of MCPH. Here we have isolated large genomic clones containing the complete ASPM gene, including promoter regions and introns, from chimpanzee, gorilla, orangutan, and rhesus macaque by transformation-associated recombination cloning in yeast. We have sequenced these clones and show that whereas much of the sequence of ASPM is substantially conserved among primates, specific segments are subject to high Ka/Ks ratios (nonsynonymous/synonymous DNA changes consistent with strong positive selection for evolutionary change. The ASPM gene sequence shows accelerated evolution in the African hominoid clade, and this precedes hominid brain expansion by several million years. Gorilla and human lineages show particularly accelerated evolution in the IQ domain of ASPM. Moreover, ASPM regions under positive selection in primates are also the most highly diverged regions between primates and nonprimate mammals. We report the first direct application of TAR cloning technology to the study of human evolution. Our data suggest that evolutionary selection of specific segments of the ASPM sequence strongly relates to differences in cerebral cortical size.

  7. High-resolution record of the Matuyama-Brunhes transition constrains the age of Javanese Homo erectus in the Sangiran dome, Indonesia.

    Science.gov (United States)

    Hyodo, Masayuki; Matsu'ura, Shuji; Kamishima, Yuko; Kondo, Megumi; Takeshita, Yoshihiro; Kitaba, Ikuko; Danhara, Tohru; Aziz, Fachroel; Kurniawan, Iwan; Kumai, Hisao

    2011-12-01

    A detailed paleomagnetic study conducted in the Sangiran area, Java, has provided a reliable age constraint on hominid fossil-bearing formations. A reverse-to-normal polarity transition marks a 7-m thick section across the Upper Tuff in the Bapang Formation. The transition has three short reversal episodes and is overlain by a thick normal polarity magnetozone that was fission-track dated to the Brunhes chron. This pattern closely resembles another high-resolution Matuyama-Brunhes (MB) transition record in an Osaka Bay marine core. In the Sangiran sediments, four successive transitional polarity fields lie just below the presumed main MB boundary. Their virtual geomagnetic poles cluster in the western South Pacific, partly overlapping the transitional virtual geomagnetic poles from Hawaiian and Canary Islands' lavas, which have a mean (40)Ar/(39)Ar age of 776 ± 2 ka. Thus, the polarity transition is unambiguously the MB boundary. A revised correlation of tuff layers in the Bapang Formation reveals that the hominid last occurrence and the tektite level in the Sangiran area are nearly coincident, just below the Upper Middle Tuff, which underlies the MB transition. The stratigraphic relationship of the tektite level to the MB transition in the Sangiran area is consistent with deep-sea core data that show that the meteorite impact preceded the MB reversal by about 12 ka. The MB boundary currently defines the uppermost horizon yielding Homo erectus fossils in the Sangiran area. PMID:22106291

  8. Remains of Homo erectus from Bouri, Middle Awash, Ethiopia.

    Science.gov (United States)

    Asfaw, Berhane; Gilbert, W Henry; Beyene, Yonas; Hart, William K; Renne, Paul R; WoldeGabriel, Giday; Vrba, Elisabeth S; White, Tim D

    2002-03-21

    The genesis, evolution and fate of Homo erectus have been explored palaeontologically since the taxon's recognition in the late nineteenth century. Current debate is focused on whether early representatives from Kenya and Georgia should be classified as a separate ancestral species ('H. ergaster'), and whether H. erectus was an exclusively Asian species lineage that went extinct. Lack of resolution of these issues has obscured the place of H. erectus in human evolution. A hominid calvaria and postcranial remains recently recovered from the Dakanihylo Member of the Bouri Formation, Middle Awash, Ethiopia, bear directly on these issues. These approximately 1.0-million-year (Myr)-old Pleistocene sediments contain abundant early Acheulean stone tools and a diverse vertebrate fauna that indicates a predominantly savannah environment. Here we report that the 'Daka' calvaria's metric and morphological attributes centre it firmly within H. erectus. Daka's resemblance to Asian counterparts indicates that the early African and Eurasian fossil hominids represent demes of a widespread palaeospecies. Daka's anatomical intermediacy between earlier and later African fossils provides evidence of evolutionary change. Its temporal and geographic position indicates that African H. erectus was the ancestor of Homo sapiens. PMID:11907576

  9. On the taxonomic affinities of the Dmanisi mandible (Georgia).

    Science.gov (United States)

    Rosas, A; Bermúdez de Castro, J M

    1998-10-01

    The recent discovery of unexpectedly ancient human remains has fuelled interest about the first dispersion of Homo outside Africa. The Dmanisi mandible is perhaps one of the most interesting findings, as it supposedly represents one of the oldest hominids outside of Africa. Recently, different interpretations have been published about this specimen. Our comparison of the Dmanisi mandible with a large sample of mandibles and teeth has led us to a new interpretation. In our view, the Dmanisi mandible exhibits a unique combination of traits. Some of its features, taken in isolation, may be attributed to morphological extremes within the genus Homo. The architecture of the mandible as well as the morphology and dimensions of incisors, canines, and P3s are clearly primitive. However, dental traits such as the reduction of the talonid in the P4s and a distally decreasing molar series seems to be derived. Some combinations of these traits are found in specimens of Homo ergaster and differ from those generally present in later hominids. Thus, we propose that the Dmanisi mandible might be taxonomically classified as Homo sp. indet. (aff. ergaster). Furthermore, some aspects of the dentition in Dmanisi display close similarities to Asian Homo erectus. If the 1.8-1.6 Myr dating for the Dmanisi mandible is correct, the differentiation of the Asian branch of the genus Homo could be regarded as a very ancient event. PMID:9786330

  10. The ATD6-5 mandibular specimen from Gran Dolina (Atapuerca, Spain). Morphological study and phylogenetic implications.

    Science.gov (United States)

    Rosas, A; Bermúdez de Castro, J M

    1999-01-01

    Metric and shape features of the Lower Pleistocene mandibular specimen ATD605 from the level 6 of Gran Dolina site (Atapuerca, Spain) are compared with a large sample of fossil hominid mandibles. The analysis shows that ATD6-5 displays a generalized morphology largely shared with both African and European Lower and Middle Pleistocene samples. However, distinctive African traits, such as corpus robustness and strong alveolar prominence, are absent in the Gran Dolina specimen. At the same time, none of the apomorphic features that characterize Middle and early Upper Pleistocene European hominids can be recognized in ATD6-5. Finally, the Gran Dolina specimen displays a remarkable position of the mylohyoid groove, only comparable to that found in immature specimens of Homo ergaster, and very rarely in adult H. sapiens. The morphology of ATD6-5 supports the hypothesis of an African origin for the first Europeans with subsequent phylogenetic continuity with Middle Pleistocene populations in Europe. These findings are consistent with H. antecessor being the last common ancestor of Neandertals and H. sapiens. PMID:10497000

  11. Human evolution and cognition.

    Science.gov (United States)

    Tattersall, Ian

    2010-09-01

    Human beings are distinguished from all other organisms by their symbolic way of processing information about the world. This unique cognitive style is qualitatively different from all the earlier hominid cognitive styles, and is not simply an improved version of them. The hominid fossil and archaeological records show clearly that biological and technological innovations have typically been highly sporadic, and totally out of phase, since the invention of stone tools some 2.5 million years ago. They also confirm that this pattern applied in the arrival of modern cognition: the anatomically recognizable species Homo sapiens was well established long before any population of it began to show indications of behaving symbolically. This places the origin of symbolic thought in the realms of exaptation, whereby new structures come into existence before being recruited to new uses, and of emergence, whereby entire new levels of complexity are achieved through new combinations of attributes unremarkable in themselves. Both these phenomena involve entirely routine evolutionary processes; special as we human beings may consider ourselves, there was nothing special about the way we came into existence. Modern human cognition is a very recent acquisition; and its emergence ushered in an entirely new pattern of technological (and other behavioral) innovation, in which constant change results from the ceaseless exploration of the potential inherent in our new capacity.

  12. Y-chromosome evidence for no independent origin of mod-ern human in China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    East Asia is one of the few regions in the world where a large number of human fossils have been unearthed. The continuity of hominid fossils in East Asia, particularly in China has been presented as strong evidence supporting an independent origin of modern humans in this area. To search for such evidence of a possible independent origin of modern humans in China, a total of 9988 male individuals were sam-pled across China. Three Y-chromosome biallelic markers (M89, M130 and YAP), which were located at the non-re- combinant region of Y-chromosome, were typed among the samples. Our result showed that all the individuals carry a mutation at one of the three loci. The three mutations (M89T, M130T, YAP+) coalesce to another mutation (M168T), which was originally derived from Africa about 31000 to 79000 years ago. In other words, all Y-chromosome samples from China, with no exception, were originally derived from a lineage of African origin. Hence, we conclude that even a very minor contribution of in situ hominid origin in China cannot be supported by the Y-chromosome evidence.

  13. The evolution of culture: from primate social learning to human culture.

    Science.gov (United States)

    Castro, Laureano; Toro, Miguel A

    2004-07-01

    Cultural transmission in our species works most of the time as a cumulative inheritance system allowing members of a group to incorporate behavioral features not only with a positive biological value but sometimes also with a neutral, or even negative, biological value. Most of models of dual inheritance theory and gene-culture coevolution suggest that an increase, either qualitative or quantitative, in the efficiency of imitation is the key factor to explain the transformation of primate social learning in a cumulative cultural system of inheritance as it happens during hominization. We contend that more efficient imitation is necessary but not enough for this transformation to occur and that the key factor enabling such a transformation is that some hominids developed the capacity to approve or disapprove their offspring's learned behavior. This capacity to approve or disapprove offspring's behavior makes learning both less costly and more accurate, and it transformed the hominid culture into a system of cumulative cultural inheritance similar to that of humans, although the system was still prelinguistic in nature.

  14. Habiline variation: a new approach using STET.

    Science.gov (United States)

    Lee, Sang-Hee; Wolpoff, Milford H

    2005-08-01

    The problem of whether the hominid fossil sample of habiline specimens is comprised of more than one species has received much attention in paleoanthropology. The core of this debate has critical implications about when and how variation can be explained by taxonomy. In this paper, we examine the problem of whether the observed variation in habiline samples reflects species differences. We test the null hypothesis of no difference by examining the degree of variability in habiline sample in comparison with other single-species early hominid fossil samples from Sterkfontein and Swartkrans (Sterkfontein is earlier than the habiline sample, Swartkrans may be within the habiline time span). We developed a new method for this examination, which we call STandard Error Test of the null hypothesis of no difference (STET). Our sampling statistic is based on the standard error of the slope of regressions between pairs of specimens, relating all of the homologous measurements that each pair shares. We show that the null hypothesis for the habiline sample cannot be rejected. The similarities of specimen pairs within the habiline sample are not more than those observed between the specimens in the australopithecine samples we analyzed. PMID:17046346

  15. Modeling three-dimensional sculptures of australopithecines (Australopithecus afarensis) for the Museum of Natural History of Vienna (Austria): the post-cranial hypothesis.

    Science.gov (United States)

    Berge, C; Daynes, E

    2001-12-01

    In March 1999, E. Daynes, a sculptor specializing in fossil hominid reconstruction, asked C. Berge to take over the scientific supervision of the reconstruction of two australopithecine post-crania. The heads had been modeled from two skulls found in Hadar (AL 444-2, AL 417). The sculptures were to be represented in a walking stance. The female proportions (AL 417) are estimated from the skeleton of 'Lucy' (AL 288), and the male proportions (AL 444-2) extrapolated from the female ones. Biomechanical and anatomical data (comparison with great apes and humans) are used to reconstruct both dynamic equilibrium and muscular systems. The reconstruction suggests that the fossils moved the pelvis and shoulders extensively when they walked. The hindlimb muscles (such as adductors, gluteal muscles and calf) are fleshy and not or very little tendinous. As indicated by the Laetoli step prints (belonging to a close and contemporaneous species), the foot is adducted during the walk and the support is internal just before take off. In spite of inevitable approximations, such a reconstruction appears to be particularly helpful to bring out morphological and functional traits of the first hominids which are both close to and different from modern humans. PMID:11733173

  16. Quantum Field Theory in Curved Spacetime

    Science.gov (United States)

    Reynolds, Sally C.; Gallagher, Andrew

    2012-03-01

    List of contributors; Foreword J. T. Francis Thackeray; 1. African genesis: an evolving paradigm Sally C. Reynolds; 2. Academic genealogy Peter Ungar and Phillip V. Tobias; Part I. In Search of Origins: Evolutionary Theory, New Species, and Paths into the Past: 3. Speciation in hominin evolution Colin Groves; 4. Searching for a new paradigm for hominid origins in Chad (Central Africa) Michel Brunet; 5. From hominoid arboreality to hominid bipedalism Brigitte Senut; 6. Orrorin and the African ape/hominid dichotomy Martin Pickford; 7. A brief history and results of 40 years of Sterkfontein excavations Ronald J. Clarke; Part II. Hominin Morphology Through Time: Brains, Bodies and Teeth: 8. Hominin brain evolution, 1925-2011: an emerging overview Dean Falk; 9. The issue of brain reorganisation in Australopithecus and early hominids: Dart had it right Ralph L. Holloway; 10. The mass of the human brain: is it a spandrel? Paul R. Manger, Jason Hemingway, Muhammad Spocter and Andrew Gallagher; 11. Origin and diversity of early hominin bipedalism Henry M. McHenry; 12. Forelimb adaptations in Australopithecus afarensis Michelle S. M. Drapeau; 13. Hominin proximal femur morphology from the Tugen Hills to Flores Brian G. Richmond and William L. Jungers; 14. Daily rates of dentine formation and root extension rates in Paranthropus boisei, KNM-ER 1817, from Koobi Fora, Kenya M. Christopher Dean; 15. On the evolutionary development of early hominid molar teeth and the Gondolin Paranthropus molar Kevin L. Kuykendall; 16. Digital South African fossils: morphological studies using reference-based reconstruction and electronic preparation Gerhard W. Weber, Philipp Gunz, Simon Neubauer, Philipp Mitteroecker and Fred L. Bookstein; Part III. Modern Human Origins: Patterns, and Processes: 17. Body size in African Middle Pleistocene Homo Steven E. Churchill, Lee R. Berger, Adam Hartstone-Rose and Headman Zondo; 18. The African origin of recent humanity Milford H. Wolpoff and Sang-Hee Lee

  17. Environmental availability, behavioural diversity and diet: a zooarchaeological approach from the TD10-1 sublevel of Gran Dolina (Sierra de Atapuerca, Burgos, Spain) and Bolomor Cave (Valencia, Spain)

    Science.gov (United States)

    Blasco, Ruth; Rosell, Jordi; Fernández Peris, Josep; Arsuaga, Juan Luis; Bermúdez de Castro, José María; Carbonell, Eudald

    2013-06-01

    The suggestion that the Neanderthal linage hominids had predominantly rich diet in meat derived from large game is progressing towards views which propose a higher nutritional diversity, at least in some regions. These postulates situate hominids as the knower of their natural surroundings and make them capable of selecting within the range of resources available in their landscapes. Using a zooarchaeological approach, the taxonomical representation in an anthropogenic site could indicate both the environment diversity that human groups can exploit and the decisions that they make when selecting prey. The Optimal Foraging theory is a basic decision model that is ideally applied within a larger framework of constraining conditions such as differential prey distributions, food-consumer imbalances and/or competition, among others. Nevertheless, if this theory is applied to human behaviour, uncontrolled variables could exist and substantially alter some predictions. These variables may not always be related to the need to optimise the resources; additionally, they can respond to the questions related to nutritional ecology, cultural standards or social relationships conditioned by ecological or technological factors. Environmental and socio-cultural aspects invite us to reflect on the characteristics that delimit the pre-Upper Palaeolithic diet and its correct assessment in relation to the availability of prey in the environment and the human behavioural parameters. In this study, we present data from several levels of Bolomor Cave (Valencia, Spain, MIS 9-5e) and a sample from the TD10-1 sublevel of Gran Dolina (Sierra de Atapuerca, Burgos, Spain, MIS 9). Both sites have been interpreted as habitat places and allow us to infer the high plasticity of human groups with respect to methods and techniques of acquisition and use of a diverse spectrum of prey. Environmental availability, duration and type of settlement seem to significantly influence the taxonomical

  18. 桦甸仙人洞遗址出土的动物化石与孢粉%A Preliminary Report of Animal Fossils and Pollen from the Xianrendong Paleolithic Site in Huadian City, Jilin Province

    Institute of Scientific and Technical Information of China (English)

    陈全家; 赵海龙; 王法岗; 王春雪

    2013-01-01

    Exactly 1066 bone fragment pieces were recovered from the Xianrendong Paleolithic site, of which 384 were identified to skeletal element. In this paper, distribution of bone fragments, bone surface modifications and skeletal element profiles of the bone assemblage are studied in order to understand hunting behaviors of hominids in different phases. Clearly hunting was the main living strategy at this site, with later hominids making fuller use of the animals than earlier hominids. Based on the bone fragments and stone artifacts, it is assumed that this site was a temporary campsite or butchering site. Comparative analyses of bone assemblages, chronological data and palynology, over time the climate deteriorated and became colder and drier, with grassland vegetation and scattered clusters of trees or shrubs.%桦甸仙人洞旧石器遗址的上、下文化层出土了大量动物化石,本文通过动物化石的分布状况、出土状态分析,复原了上、下文化层沉积时期古人类的狩猎和处置猎物的行为,总体来看,远古人类生计方式以狩猎为主,晚期古人类比早期对猎物资源开发得更彻底.另外,从洞穴内大量碎骨片和石制品来看,该洞穴可能为临时的营地或者屠宰场.通过对动物群组成、年代和孢粉分析的综合研究,认为该遗址所处环境经历了剧烈的变化,总体处于寒冷干燥的气候环境中,植被以草原为主,伴有少量森林.这一研究为探讨中国东北地区晚更新世人类的生存行为和演化特征提供了重要的研究材料和数据.

  19. The role of tephra studies in African paleoanthropology as exemplified by the Sidi Hakoma Tuff

    Science.gov (United States)

    WoldeGabriel, Giday; Endale, Tamrat; White, Tim D.; Thouveny, Nicolas; Hart, William K.; Renne, Paul R.; Asfaw, Berhane

    2013-01-01

    Beginning in the 1960s, geological and paleoanthropological exploration of the Ethiopian rift system's basins have led to the discovery and assembly of the most comprehensive record of human biological and technological change during the last 6 million years. The hominid fossils, including partial skeletons, were primarily discovered in the Afar Rift, the Main Ethiopian Rift, and in the Omo Basin of the broadly rifted zone of SW Ethiopia. The paleoanthropological research areas within the SW Afar Rift that have yielded many diverse hominid species and the oldest stone tools are, from north to south, Woranso-Mille (aff. Ardipithecus and Au. afarensis), Hadar (Au. afarensis, Homo sp.), Dikika (Au. afarensis), Gona (Ar. kadabba, Ar. ramidus, H. erectus, and oldest stone tools), Middle Awash (Ar. kadabba, Ar. ramidus, Au. anamensis, Au. afarensis, Au. garhi, H. erectus, H. rhodesiensis, H. sapiens idaltu, and the oldest paleo-butchery locality), and Galili (Au. afarensis). Additional hominid remains were discovered at Melka Kunture on the banks of the Awash River near its source along the western margin of the central part of the Main Ethiopian Rift (H. erectus), at Konso (H. erectus and A. boisei), and at the southern end of the MER, and in the Omo Basin (Au. anamensis, Au. afarensis, Au. aethiopicus, Au. boisei, H. habilis, and H. erectus). Distal and sometimes proximal tephra units interbedded within fossilifeous sedimentary deposits have become key elements in this work by providing chronological and correlative control and depositional contexts. Several regional tephra markers have been identified within the northern half of the eastern African rift valley in Ethiopia and Kenya, and in marine sediments of the Gulf of Aden Rift and the NW Indian Ocean. Out of the many regional tephra stratigraphic markers that range in age from the early Pliocene (3.97 Ma) to the late Pleistocene (0.16 Ma), the Sidi Hakoma Tuff (SHT) has been more widely identified and thoroughly

  20. A new Euprox from the Late Miocene of Yuanmou, Yunnan Province, China, with interpretation of its paleoenvironment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The Yuanmou Basin of Yunnan Province is a hotspot for the research of early hominid evolution and its environmental background. During the implementation of the Program "Research of the Origin and Evolution of Early Man and Its Environmental Background" from 1998 to 2001, a huge quantity of hominoid and mammal fossils were collected. The present report systematically describes an Euprox robustus sp. nov. identified during the recent laboratory work on the collected material. Euprox is a group of earliest cervids with true antlers. The new species is the third one of the genus discovered in China. Judged by its morphologic characteristics, the new species feed on juicy and tender leaves of dicotyledon. It implies that the vegetation of its epoch in the Yuanmou Basin is a kind of southern subtropical evergreen forest and the climate is humid and temperate with evident seasonality. The latter is mostly influenced by the monsoon and secondly by the latitude.

  1. The Evolution of Suidae.

    Science.gov (United States)

    Frantz, Laurent; Meijaard, Erik; Gongora, Jaime; Haile, James; Groenen, Martien A M; Larson, Greger

    2016-01-01

    The Suidae are a family of Cetartiodactyla composed of 17 species classified in a minimum of five extant genera that originated at least 20 million years ago. Their success is evident in the multitude of habitats in which they are found as both natural and feral populations in tropical Island Southeast Asia, the high plateau of the Himalayas, Siberia, North Africa, the Pacific Islands, Australia, and the Americas. Morphological and molecular analyses of these species have revealed numerous aspects of their biology, including the ease with which many lineages have and continue to hybridize. This trait has made them an ideal model for evolutionary biologists. Suid species have also shared a deep history with humans, from their association with early hominids in Africa to their domestication. Here we review the current knowledge of this fascinating group and provide a comprehensive evolutionary history from the Oligocene to the present day. PMID:26526544

  2. Archaeogenetics in evolutionary medicine.

    Science.gov (United States)

    Bouwman, Abigail; Rühli, Frank

    2016-09-01

    Archaeogenetics is the study of exploration of ancient DNA (aDNA) of more than 70 years old. It is an important part of the wider studies of many different areas of our past, including animal, plant and pathogen evolution and domestication events. Hereby, we address specifically the impact of research in archaeogenetics in the broader field of evolutionary medicine. Studies on ancient hominid genomes help to understand even modern health patterns. Human genetic microevolution, e.g. related to abilities of post-weaning milk consumption, and specifically genetic adaptation in disease susceptibility, e.g. towards malaria and other infectious diseases, are of the upmost importance in contributions of archeogenetics on the evolutionary understanding of human health and disease. With the increase in both the understanding of modern medical genetics and the ability to deep sequence ancient genetic information, the field of archaeogenetic evolutionary medicine is blossoming. PMID:27289479

  3. Two possible driving forces supporting the evolution of animal communication. Comment on "Towards a Computational Comparative Neuroprimatology: Framing the language-ready brain" by Michael A. Arbib

    Science.gov (United States)

    Moulin-Frier, Clément; Verschure, Paul F. M. J.

    2016-03-01

    In the target paper [1], M.A. Arbib proposes a quite exhaustive review of the (often computational) models developed during the last decades that support his detailed scenario on language evolution (the Mirror System Hypothesis, MSH). The approach considers that language evolved from a mirror system for grasping already present in LCA-m (the last common ancestor of macaques and humans), to a simple imitation system for grasping present in LCA-c (the last common ancestor of chimpanzees and humans), to a complex imitation system for grasping that developed in the hominid line since that ancestor. MSH considers that this complex imitation system is a key evolutionary step for a language-ready brain, providing all the required elements for an open-ended gestural communication system. The transition from the gestural (bracchio-manual and visual) to the vocal (articulatory and auditory) domain is supposed to be a less important evolutionary step.

  4. Music as a technology for social bonding: Comment on "Music, empathy, and cultural understanding" by E. Clarke et al.

    Science.gov (United States)

    Launay, Jacques

    2015-12-01

    From the perspective of evolutionary psychology music can be seen as problematic. Despite its ubiquity there is still no clearly agreed function in terms of improving the fitness of the species. Is it therefore fairer to judge it as 'auditory cheesecake' (see [1]) rather than attributing it with any specific purpose? An alternative argument is that it plays a fundamental role in the formation of human social bonds, and the authors of "Music, empathy, and cultural understanding" concur with the view that music has a unique capacity to help people connect with others [2]. There is now evidence that even in the modern world there is a significant effect of our social bonds on health and longevity [3], suggesting that our hominid ancestors might have relied heavily on their social network for survival. If music has the capacity to encourage the formation of these social bonds it could form a powerful tool in the success of our species.

  5. The finished DNA sequence of human chromosome 12.

    Science.gov (United States)

    Scherer, Steven E; Muzny, Donna M; Buhay, Christian J; Chen, Rui; Cree, Andrew; Ding, Yan; Dugan-Rocha, Shannon; Gill, Rachel; Gunaratne, Preethi; Harris, R Alan; Hawes, Alicia C; Hernandez, Judith; Hodgson, Anne V; Hume, Jennifer; Jackson, Andrew; Khan, Ziad Mohid; Kovar-Smith, Christie; Lewis, Lora R; Lozado, Ryan J; Metzker, Michael L; Milosavljevic, Aleksandar; Miner, George R; Montgomery, Kate T; Morgan, Margaret B; Nazareth, Lynne V; Scott, Graham; Sodergren, Erica; Song, Xing-Zhi; Steffen, David; Lovering, Ruth C; Wheeler, David A; Worley, Kim C; Yuan, Yi; Zhang, Zhengdong; Adams, Charles Q; Ansari-Lari, M Ali; Ayele, Mulu; Brown, Mary J; Chen, Guan; Chen, Zhijian; Clerc-Blankenburg, Kerstin P; Davis, Clay; Delgado, Oliver; Dinh, Huyen H; Draper, Heather; Gonzalez-Garay, Manuel L; Havlak, Paul; Jackson, Laronda R; Jacob, Leni S; Kelly, Susan H; Li, Li; Li, Zhangwan; Liu, Jing; Liu, Wen; Lu, Jing; Maheshwari, Manjula; Nguyen, Bao-Viet; Okwuonu, Geoffrey O; Pasternak, Shiran; Perez, Lesette M; Plopper, Farah J H; Santibanez, Jireh; Shen, Hua; Tabor, Paul E; Verduzco, Daniel; Waldron, Lenee; Wang, Qiaoyan; Williams, Gabrielle A; Zhang, Jingkun; Zhou, Jianling; Allen, Carlana C; Amin, Anita G; Anyalebechi, Vivian; Bailey, Michael; Barbaria, Joseph A; Bimage, Kesha E; Bryant, Nathaniel P; Burch, Paula E; Burkett, Carrie E; Burrell, Kevin L; Calderon, Eliana; Cardenas, Veronica; Carter, Kelvin; Casias, Kristal; Cavazos, Iracema; Cavazos, Sandra R; Ceasar, Heather; Chacko, Joseph; Chan, Sheryl N; Chavez, Dean; Christopoulos, Constantine; Chu, Joseph; Cockrell, Raynard; Cox, Caroline D; Dang, Michelle; Dathorne, Stephanie R; David, Robert; Davis, Candi Mon'Et; Davy-Carroll, Latarsha; Deshazo, Denise R; Donlin, Jeremy E; D'Souza, Lisa; Eaves, Kristy A; Egan, Amy; Emery-Cohen, Alexandra J; Escotto, Michael; Flagg, Nicole; Forbes, Lisa D; Gabisi, Abdul M; Garza, Melissa; Hamilton, Cerissa; Henderson, Nicholas; Hernandez, Omar; Hines, Sandra; Hogues, Marilyn E; Huang, Mei; Idlebird, DeVincent G; Johnson, Rudy; Jolivet, Angela; Jones, Sally; Kagan, Ryan; King, Laquisha M; Leal, Belita; Lebow, Heather; Lee, Sandra; LeVan, Jaclyn M; Lewis, Lakeshia C; London, Pamela; Lorensuhewa, Lorna M; Loulseged, Hermela; Lovett, Demetria A; Lucier, Alice; Lucier, Raymond L; Ma, Jie; Madu, Renita C; Mapua, Patricia; Martindale, Ashley D; Martinez, Evangelina; Massey, Elizabeth; Mawhiney, Samantha; Meador, Michael G; Mendez, Sylvia; Mercado, Christian; Mercado, Iracema C; Merritt, Christina E; Miner, Zachary L; Minja, Emmanuel; Mitchell, Teresa; Mohabbat, Farida; Mohabbat, Khatera; Montgomery, Baize; Moore, Niki; Morris, Sidney; Munidasa, Mala; Ngo, Robin N; Nguyen, Ngoc B; Nickerson, Elizabeth; Nwaokelemeh, Ogechi O; Nwokenkwo, Stanley; Obregon, Melissa; Oguh, Maryann; Oragunye, Njideka; Oviedo, Rodolfo J; Parish, Bridgette J; Parker, David N; Parrish, Julia; Parks, Kenya L; Paul, Heidie A; Payton, Brett A; Perez, Agapito; Perrin, William; Pickens, Adam; Primus, Eltrick L; Pu, Ling-Ling; Puazo, Maria; Quiles, Miyo M; Quiroz, Juana B; Rabata, Dina; Reeves, Kacy; Ruiz, San Juana; Shao, Hongmei; Sisson, Ida; Sonaike, Titilola; Sorelle, Richard P; Sutton, Angelica E; Svatek, Amanda F; Svetz, Leah Anne; Tamerisa, Kavitha S; Taylor, Tineace R; Teague, Brian; Thomas, Nicole; Thorn, Rachel D; Trejos, Zulma Y; Trevino, Brenda K; Ukegbu, Ogechi N; Urban, Jeremy B; Vasquez, Lydia I; Vera, Virginia A; Villasana, Donna M; Wang, Ling; Ward-Moore, Stephanie; Warren, James T; Wei, Xuehong; White, Flower; Williamson, Angela L; Wleczyk, Regina; Wooden, Hailey S; Wooden, Steven H; Yen, Jennifer; Yoon, Lillienne; Yoon, Vivienne; Zorrilla, Sara E; Nelson, David; Kucherlapati, Raju; Weinstock, George; Gibbs, Richard A

    2006-03-16

    Human chromosome 12 contains more than 1,400 coding genes and 487 loci that have been directly implicated in human disease. The q arm of chromosome 12 contains one of the largest blocks of linkage disequilibrium found in the human genome. Here we present the finished sequence of human chromosome 12, which has been finished to high quality and spans approximately 132 megabases, representing approximately 4.5% of the human genome. Alignment of the human chromosome 12 sequence across vertebrates reveals the origin of individual segments in chicken, and a unique history of rearrangement through rodent and primate lineages. The rate of base substitutions in recent evolutionary history shows an overall slowing in hominids compared with primates and rodents.

  6. The Impact of Evolutionary Driving Forces on Human Complex Diseases: A Population Genetics Approach.

    Science.gov (United States)

    Saeb, Amr T M; Al-Naqeb, Dhekra

    2016-01-01

    Investigating the molecular evolution of human genome has paved the way to understand genetic adaptation of humans to the environmental changes and corresponding complex diseases. In this review, we discussed the historical origin of genetic diversity among human populations, the evolutionary driving forces that can affect genetic diversity among populations, and the effects of human movement into new environments and gene flow on population genetic diversity. Furthermore, we presented the role of natural selection on genetic diversity and complex diseases. Then we reviewed the disadvantageous consequences of historical selection events in modern time and their relation to the development of complex diseases. In addition, we discussed the effect of consanguinity on the incidence of complex diseases in human populations. Finally, we presented the latest information about the role of ancient genes acquired from interbreeding with ancient hominids in the development of complex diseases. PMID:27313952

  7. Damage and repair of ancient DNA

    DEFF Research Database (Denmark)

    Mitchell, David; Willerslev, Eske; Hansen, Anders

    2005-01-01

    , and extensive degradation. In the course of this review, we will discuss the current aDNA literature describing the importance of aDNA studies as they relate to important biological questions and the difficulties associated with extracting useful information from highly degraded and damaged substrates derived......Under certain conditions small amounts of DNA can survive for long periods of time and can be used as polymerase chain reaction (PCR) substrates for the study of phylogenetic relationships and population genetics of extinct plants and animals, including hominids. Because of extensive DNA...... degradation, these studies are limited to species that lived within the past 10(4)-10(5) years (Late Pleistocene), although DNA sequences from 10(6) years have been reported. Ancient DNA (aDNA) has been used to study phylogenetic relationships of protists, fungi, algae, plants, and higher eukaryotes...

  8. Archaeological study of ostrich eggshell beads collected from SDG site

    Institute of Scientific and Technical Information of China (English)

    WANG ChunXue; ZHANG Yue; GAO Xing; ZHANG XiaoLing; WANG HuiMin

    2009-01-01

    Ostrich eggshell beads and fragments collected from SDG site reflect primordial art and a kind of symbolic behavior of modern humans.Based on stratigraphic data and OSL dating,these ostrich eggshell beads are probably in Early Holocene (<10 ka BP).Two different prehistoric manufacturing pathways are usually used in the manufacture of ostrich eggshell beads in Upper Paleolithic.According to statistic analysis of the characteristics of ostrich eggshell beads,Pathway 1 is identified from these collections.In pathway 1,blanks are drilled prior to being trimmed to rough discs.They exhibit great potential for the study of the origin of primordial art and the development of ancient cultures and provide important data for studying behavioral options adopted by hominids in SDG area.In addition,they bear important implications for the origin of modern humans in East Asia.

  9. Paleo-oncology: the role of ancient remains in the study of cancer.

    Science.gov (United States)

    Halperin, Edward C

    2004-01-01

    Paleo-oncology is the study of carcinomas and sarcomas in ancient human populations and their hominid precursors. These populations are informative concerning the possible influences on cancer of morphologic and functional evolution, diet, lifestyle, and other environmental factors. The prevalence of cancer in ancient populations might have differed from that in modern humans, because of substantial differences in tobacco and alcohol use, diet, life expectancy, and the availability of treatment. The available physical data concerning cancer in antiquity includes evidence of its existence in animal fossils and ancient humans and their precursors. The difficulties of paleo-oncologic research include a limited soft tissue record. In evaluating cancer in ancient remains, one must also deal with the problem of pseudopathology: whether an observed tissue change is all antemortem pathologic lesion or a postmortem artifact. Future archeological discoveries and the application of improved diagnostic techniques may enable paleo-oncology to make further contributions to our understanding of cancer. PMID:15061165

  10. The Impact of Evolutionary Driving Forces on Human Complex Diseases: A Population Genetics Approach

    Directory of Open Access Journals (Sweden)

    Amr T. M. Saeb

    2016-01-01

    Full Text Available Investigating the molecular evolution of human genome has paved the way to understand genetic adaptation of humans to the environmental changes and corresponding complex diseases. In this review, we discussed the historical origin of genetic diversity among human populations, the evolutionary driving forces that can affect genetic diversity among populations, and the effects of human movement into new environments and gene flow on population genetic diversity. Furthermore, we presented the role of natural selection on genetic diversity and complex diseases. Then we reviewed the disadvantageous consequences of historical selection events in modern time and their relation to the development of complex diseases. In addition, we discussed the effect of consanguinity on the incidence of complex diseases in human populations. Finally, we presented the latest information about the role of ancient genes acquired from interbreeding with ancient hominids in the development of complex diseases.

  11. Possible ancestral structure in human populations.

    Directory of Open Access Journals (Sweden)

    Vincent Plagnol

    2006-07-01

    Full Text Available Determining the evolutionary relationships between fossil hominid groups such as Neanderthals and modern humans has been a question of enduring interest in human evolutionary genetics. Here we present a new method for addressing whether archaic human groups contributed to the modern gene pool (called ancient admixture, using the patterns of variation in contemporary human populations. Our method improves on previous work by explicitly accounting for recent population history before performing the analyses. Using sequence data from the Environmental Genome Project, we find strong evidence for ancient admixture in both a European and a West African population (p approximately 10(-7, with contributions to the modern gene pool of at least 5%. While Neanderthals form an obvious archaic source population candidate in Europe, there is not yet a clear source population candidate in West Africa.

  12. Central Africa: prospects for a cultural emergency

    Directory of Open Access Journals (Sweden)

    Jean-Arsène Yao

    2014-08-01

    Full Text Available In recent decades, biennials and festivals have multiplied across Africa, proof of the growing dynamism of the cultural sector, to which private actors and governments take a special interest, for several reasons. Cultural reasons related to the preservation of diversity with the threat of globalization seen as potential factor of standardization. But also economics reasons on having turned the African creators into conquerors of markets. Based on the case of the countries of Central Africa –considered to be the Cradle of Humankind, as the oldest hominid fossil was found in 2001 in Chad–, the aim of this article is to determine cultural policies in this region. Also it highlights the challenges and the opportunities to carry out development mechanisms of the cultural industry from policies that generate wealth, jobs and, above all, to return dignity to peoples.

  13. What Pinnipeds Have to Say about Human Speech, Music, and the Evolution of Rhythm.

    Science.gov (United States)

    Ravignani, Andrea; Fitch, W Tecumseh; Hanke, Frederike D; Heinrich, Tamara; Hurgitsch, Bettina; Kotz, Sonja A; Scharff, Constance; Stoeger, Angela S; de Boer, Bart

    2016-01-01

    Research on the evolution of human speech and music benefits from hypotheses and data generated in a number of disciplines. The purpose of this article is to illustrate the high relevance of pinniped research for the study of speech, musical rhythm, and their origins, bridging and complementing current research on primates and birds. We briefly discuss speech, vocal learning, and rhythm from an evolutionary and comparative perspective. We review the current state of the art on pinniped communication and behavior relevant to the evolution of human speech and music, showing interesting parallels to hypotheses on rhythmic behavior in early hominids. We suggest future research directions in terms of species to test and empirical data needed. PMID:27378843

  14. Contrast of hemispheric lateralization for oro-facial movements between learned attention-getting sounds and species-typical vocalizations in chimpanzees: extension in a second colony.

    Science.gov (United States)

    Wallez, Catherine; Schaeffer, Jennifer; Meguerditchian, Adrien; Vauclair, Jacques; Schapiro, Steven J; Hopkins, William D

    2012-10-01

    Studies involving oro-facial asymmetries in nonhuman primates have largely demonstrated a right hemispheric dominance for communicative signals and conveyance of emotional information. A recent study on chimpanzee reported the first evidence of significant left-hemispheric dominance when using attention-getting sounds and rightward bias for species-typical vocalizations (Losin, Russell, Freeman, Meguerditchian, Hopkins & Fitch, 2008). The current study sought to extend the findings from Losin et al. (2008) with additional oro-facial assessment in a new colony of chimpanzees. When combining the two populations, the results indicated a consistent leftward bias for attention-getting sounds and a right lateralization for species-typical vocalizations. Collectively, the results suggest that both voluntary-controlled oro-facial and gestural communication might share the same left-hemispheric specialization and might have coevolved into a single integrated system present in a common hominid ancestor. PMID:22867751

  15. Comment on "Environmental change and human occupation of southern Ethiopia and northern Kenya during the last 20,000 years. Quaternary Science Reviews 129: 333-340"

    Science.gov (United States)

    Wright, David K.; Forman, Steven L.

    2016-06-01

    In the past decade Late Quaternary research has accelerated in the Lake Turkana Basin and nearby catchments yielding new paleoclimatic records from sediment cores (e.g., Morrissey and Scholz, 2014), centennial-scale lake level records (e.g., Bloszies et al., 2015; Garcin et al., 2012), a better understanding of the archaeological record (e.g., Ashley et al., 2011; Hildebrand et al., 2014; Ndiema et al., 2011), and regional syntheses (Wright et al., 2015). From the perspective of new sediment cores from the Chew Bahir Basin, Foerster et al. (2015:339) recently concluded that climatic "deterioration" in northeastern Africa "seemed to have caused large-scale migration" of human populations into what they term the "refugia" of the southwestern Ethiopian Highlands. They present a 20 ka reconstruction of potassium content as a proxy for water level for paleo-Lake Chew Bahir as part of the Hominid Sites and Paleolakes Drilling Project (HSPDP, http://hspdp.asu.edu/)

  16. What Pinnipeds Have to Say about Human Speech, Music, and the Evolution of Rhythm

    Science.gov (United States)

    Ravignani, Andrea; Fitch, W. Tecumseh; Hanke, Frederike D.; Heinrich, Tamara; Hurgitsch, Bettina; Kotz, Sonja A.; Scharff, Constance; Stoeger, Angela S.; de Boer, Bart

    2016-01-01

    Research on the evolution of human speech and music benefits from hypotheses and data generated in a number of disciplines. The purpose of this article is to illustrate the high relevance of pinniped research for the study of speech, musical rhythm, and their origins, bridging and complementing current research on primates and birds. We briefly discuss speech, vocal learning, and rhythm from an evolutionary and comparative perspective. We review the current state of the art on pinniped communication and behavior relevant to the evolution of human speech and music, showing interesting parallels to hypotheses on rhythmic behavior in early hominids. We suggest future research directions in terms of species to test and empirical data needed. PMID:27378843

  17. Paleoparasitology: the origin of human parasites

    Directory of Open Access Journals (Sweden)

    Adauto Araujo

    2013-09-01

    Full Text Available Parasitism is composed by three subsystems: the parasite, the host, and the environment. There are no organisms that cannot be parasitized. The relationship between a parasite and its host species most of the time do not result in damage or disease to the host. However, in a parasitic disease the presence of a given parasite is always necessary, at least in a given moment of the infection. Some parasite species that infect humans were inherited from pre-hominids, and were shared with other phylogenetically close host species, but other parasite species were acquired from the environment as humans evolved. Human migration spread inherited parasites throughout the globe. To recover and trace the origin and evolution of infectious diseases, paleoparasitology was created. Paleoparasitology is the study of parasites in ancient material, which provided new information on the evolution, paleoepidemiology, ecology and phylogenetics of infectious diseases.

  18. Paleo-oncology: the role of ancient remains in the study of cancer.

    Science.gov (United States)

    Halperin, Edward C

    2004-01-01

    Paleo-oncology is the study of carcinomas and sarcomas in ancient human populations and their hominid precursors. These populations are informative concerning the possible influences on cancer of morphologic and functional evolution, diet, lifestyle, and other environmental factors. The prevalence of cancer in ancient populations might have differed from that in modern humans, because of substantial differences in tobacco and alcohol use, diet, life expectancy, and the availability of treatment. The available physical data concerning cancer in antiquity includes evidence of its existence in animal fossils and ancient humans and their precursors. The difficulties of paleo-oncologic research include a limited soft tissue record. In evaluating cancer in ancient remains, one must also deal with the problem of pseudopathology: whether an observed tissue change is all antemortem pathologic lesion or a postmortem artifact. Future archeological discoveries and the application of improved diagnostic techniques may enable paleo-oncology to make further contributions to our understanding of cancer.

  19. A complete human pelvis from the Middle Pleistocene of Spain.

    Science.gov (United States)

    Arsuaga, J L; Lorenzo, C; Carretero, J M; Gracia, A; Martínez, I; García, N; Bermúdez de Castro, J M; Carbonell, E

    1999-05-20

    The Middle Pleistocene site of Sima de los Huesos in Sierra de Atapuerca, Spain, has yielded around 2,500 fossils from at least 33 different hominid individuals. These have been dated at more than 200,000 years ago and have been classified as ancestors of Neanderthals. An almost complete human male pelvis (labelled Pelvis 1) has been found, which we associate with two fragmentary femora. Pelvis 1 is robust and very broad with a very long superior pubic ramus, marked iliac flare, and a long femoral neck. This pattern is probably the primitive condition from which modern humans departed. A modern human newborn would pass through the birth canal of Pelvis 1 and this would be even larger in a female individual. We estimate the body mass of this individual at 95 kg or more. Using the cranial capacities of three specimens from Sima de los Huesos, the encephalization quotients are substantially smaller than in Neanderthals and modern humans. PMID:10353247

  20. Three new human skulls from the Sima de los Huesos Middle Pleistocene site in Sierra de Atapuerca, Spain.

    Science.gov (United States)

    Arsuaga, J L; Martínez, I; Gracia, A; Carretero, J M; Carbonell, E

    1993-04-01

    Three important fossil hominids were found in July 1992 in the Middle Pleistocene cave site called Sima de los Huesos (Sierra de Atapuerca, Burgos, Northern Spain). One is a complete calvaria (cranium 4), the second a virtually complete cranium (cranium 5), the third represents a more fragmentary cranium of an immature individual (cranium 6). There is a large difference in size between the two adult specimens (for example endocranial volume 1,125 cm3 versus 1,390 cm3). The Atapuerca human remains are dated to > 300,000 years. The Atapuerca cranial sample fits within the 'archaic Homo sapiens' group, but is well differentiated from the Asian Homo erectus group. The extensive Atapuerca human collection is the most complete sample of Middle Pleistocene humans yet discovered from one site, and appears to document an early stage in Neanderthal evolution. PMID:8464493

  1. A tentative framework for the acquisition of language and modern human cognition.

    Science.gov (United States)

    Tattersall, Ian

    2016-06-20

    Modern human beings process information symbolically, rearranging mental symbols to envision multiple potential realities. They also express the ideas they form using structured articulate language. No other living creature does either of these things. Yet it is evident that we are descended from a non-symbolic and non-linguistic ancestor. How did this astonishing transformation occur? Scrutiny of the fossil and archaeological records reveals that the transition to symbolic reasoning happened very late in hominid history - indeed, within the tenure of anatomically recognizable Homo sapiens. It was evidently not simply a passive result of the increase in brain size that typified multiple lineages of the genus Homo over the Pleistocene. Instead, a brain exaptively capable of complex symbolic manipulation and language acquisition was acquired in the major developmental reorganization that gave rise to the anatomically distinctive species Homo sapiens. The new capacity it conferred was later recruited through the action of a cultural stimulus, most plausibly the spontaneous invention of language.

  2. A boom of bones and books: The "popularization industry" of Atapuerca and human-origins research in contemporary Spain.

    Science.gov (United States)

    Hochadel, Oliver

    2013-07-01

    Atapuerca is an important prehistoric site in northern Spain that yielded the oldest hominid fossils in Europe in 1994. Since 1998 the three co-directors of the research team have in sum (co-)authored more than twenty-five popular science books, a boom without precedent in human-origins research. This paper will put forward three hypotheses. First, that these books were instrumental in achieving public recognition and financial support for the research project. Second, popular books on human origins serve as "enlarged battlefields" and as a meta-forum to expose new ideas to the scientific community. Third, the public visibility of these publications enables their authors to assume new roles that go well beyond their part as paleoanthropologists.

  3. Culture - the hen and the egg of human cognition

    Directory of Open Access Journals (Sweden)

    Alenka Gril

    2000-12-01

    Full Text Available Culture refers to shared meanings, common knowledge and behavioral patterns of groups and societies. These knowledge structures or models of reality are conceptual tools for coordinating social interactions and communications and regulating adaptive behavioral strategies. Their construction and maintenance depend on groups' structure and cultural artifacts and also on the changing environmental demands. The article presents the Donald's model of cultural and cognitive evolution, according to which three major transitions in the representations of reality have taken place during the evolution of hominids along with the accompanying changes in the social structure, technology and cultural artifacts: from episodic to mimetic culture, then to mythic culture and finally to theoretic culture. The author examines ontogenetic correlates to the proposed evolutionary model of modern mind and tries to assess the role of social interaction in the development of capacity for symbolic representations.

  4. A nonadaptive scenario explaining the genetic predisposition to obesity: the "predation release" hypothesis.

    Science.gov (United States)

    Speakman, John R

    2007-07-01

    The "thrifty gene hypothesis" suggests we evolved genes for efficient food collection and fat deposition to survive periods of famine and that now that food is continuously available, these genes are disadvantageous because they make us obese in preparation for a famine that never comes. However, famines are relatively infrequent modern phenomena that involve insufficient mortality for thrifty genes to propagate. I suggest here that early hominids would have been subjected to stabilizing selection for body fatness, with obesity selected against by the risk of predation. Around two million years ago predation was removed as a significant factor by the development of social behavior, weapons, and fire. The absence of predation led to a change in the population distribution of body fatness due to random mutations and drift. Because this novel hypothesis involves random drift, rather than directed selection, it explains why, even in Western society, most people are not obese. PMID:17618852

  5. Tortoises as a dietary supplement: A view from the Middle Pleistocene site of Qesem Cave, Israel

    Science.gov (United States)

    Blasco, Ruth; Rosell, Jordi; Smith, Krister T.; Maul, Lutz Christian; Sañudo, Pablo; Barkai, Ran; Gopher, Avi

    2016-02-01

    Dietary reconstructions can offer an improved perspective on human capacities of adaptation to the environment. New methodological approaches and analytical techniques have led to a theoretical framework for understanding how human groups used and adapted to their local environment. Faunal remains provide an important potential source of dietary information and allow study of behavioural variation and its evolutionary significance. Interest in determining how hominids filled the gaps in large prey availability with small game or what role small game played in pre-Upper Palaeolithic societies is an area of active research. Some of this work has focused on tortoises because they represent an important combination of edible and non-edible resources that are easy to collect if available. The exploitation of these slow-moving animals features prominently in prey choice models because the low handling costs of these reptiles make up for their small body size. Here, we present new taphonomic data from two tortoise assemblages extracted from the lower sequence of the Middle Pleistocene site of Qesem Cave, Israel (420-300 ka), with the aim of assessing the socio-economic factors that may have led to the inclusion of this type of resource in the human diets. We show that hominid damage on large tortoise specimens from Qesem Cave is not unusual and that evidence such as cut marks, percussion marks and consistent patterns of burning suggests established sequences of processing, including cooking in the shell, defleshing, and direct percussion to access the visceral content. These matters make it possible not only to assess the potential role of tortoises as prey, but also to evaluate collecting behaviour in the resource acquisition systems and eco-social strategies at the Acheulo-Yabrudian Cultural Complex (AYCC) in the southern Levant.

  6. A cross-species study of gesture and its role in symbolic development: Implications for the gestural theory of language evolution

    Directory of Open Access Journals (Sweden)

    Kristen eGillespie-Lynch

    2013-06-01

    Full Text Available Using a naturalistic video database, we examined whether gestures scaffolded the symbolic development of a language-enculturated chimpanzee, a language-enculturated bonobo, and a human child during the second year of life. These three species constitute a complete clade: species possessing a common immediate ancestor. A basic finding was the functional and formal similarity of many gestures between chimpanzee, bonobo, and human child. The child’s symbols were spoken words; the apes’ symbols were lexigrams, noniconic visual signifiers. A developmental pattern in which gestural representation of a referent preceded symbolic representation of the same referent appeared in all three species (but was statistically significant only for the child. Nonetheless, across species, the ratio of symbol to gesture increased significantly with age. But even though their symbol production increased, the apes continued to communicate more frequently by gesture than by symbol. In contrast, by15-18 months of age, the child used symbols more frequently than gestures. This ontogenetic sequence from gesture to symbol, present across the clade but more pronounced in child than ape, provides support for the role of gesture in language evolution. In all three species, the overwhelming majority of gestures were communicative (paired with eye-contact, vocalization, and/or persistence. However, vocalization was rare for the apes, but accompanied the majority of the child’s communicative gestures. This finding suggests the co-evolution of speech and gesture after the evolutionary divergence of the hominid line. Multimodal expressions of communicative intent (e.g., vocalization plus persistence were normative for the child, but less common for the apes. This finding suggests that multimodal expression of communicative intent was also strengthened after hominids diverged from apes.

  7. A cross-species study of gesture and its role in symbolic development: implications for the gestural theory of language evolution.

    Science.gov (United States)

    Gillespie-Lynch, K; Greenfield, P M; Feng, Y; Savage-Rumbaugh, S; Lyn, H

    2013-01-01

    Using a naturalistic video database, we examined whether gestures scaffold the symbolic development of a language-enculturated chimpanzee, a language-enculturated bonobo, and a human child during the second year of life. These three species constitute a complete clade: species possessing a common immediate ancestor. A basic finding was the functional and formal similarity of many gestures between chimpanzee, bonobo, and human child. The child's symbols were spoken words; the apes' symbols were lexigrams - non-iconic visual signifiers. A developmental pattern in which gestural representation of a referent preceded symbolic representation of the same referent appeared in all three species (but was statistically significant only for the child). Nonetheless, across species, the ratio of symbol to gesture increased significantly with age. But even though their symbol production increased, the apes continued to communicate more frequently by gesture than by symbol. In contrast, by 15-18 months of age, the child used symbols more frequently than gestures. This ontogenetic sequence from gesture to symbol, present across the clade but more pronounced in child than ape, provides support for the role of gesture in language evolution. In all three species, the overwhelming majority of gestures were communicative (i.e., paired with eye contact, vocalization, and/or persistence). However, vocalization was rare for the apes, but accompanied the majority of the child's communicative gestures. This species difference suggests the co-evolution of speech and gesture after the evolutionary divergence of the hominid line. Multimodal expressions of communicative intent (e.g., vocalization plus persistence) were normative for the child, but less common for the apes. This species difference suggests that multimodal expression of communicative intent was also strengthened after hominids diverged from apes. PMID:23750140

  8. Allometric and metameric shape variation in Pan mandibular molars: a digital morphometric analysis.

    Science.gov (United States)

    Singleton, Michelle; Rosenberger, Alfred L; Robinson, Chris; O'neill, Rob

    2011-02-01

    The predominance of molar teeth in fossil hominin assemblages makes the patterning of molar shape variation a topic of bioanthropological interest. Extant models are the principal basis for understanding dental variation in the fossil record. As the sister taxon to the hominin clade, Pan is one such model and the only widely accepted extant hominid model for both interspecific and intraspecific variation. To explore the contributions of allometric scaling and meristic variation to molar variation in Pan, we applied geometric shape analysis to 3D landmarks collected from virtual replicas of chimpanzee and bonobo mandibular molars. Multivariate statistical analysis and 3D visualization of metameric and allometric shape vectors were used to characterize shape differences and test the hypothesis that species of Pan share patterns of metameric variation and molar shape allometry. Procrustes-based shape variables were found to effectively characterize crown shape, sorting molars into species and tooth-row positions with ≥ 95% accuracy. Chimpanzees and bonobos share a common pattern of M(1) -M(2) metameric variation, which is defined by differences in the relative position of the metaconid, size of the hypoconulid, curvature of the buccal wall, and proportions of the basins and foveae. Allometric scaling of molar shape is homogeneous for M(1) and M(2) within species, but bonobo and chimpanzee allometric vectors are significantly different. Nevertheless, the common allometric shape trend explains most molar-shape differences between P. paniscus and P. troglodytes. When allometric effects are factored out, chimpanzee and bonobo molars are not morphometrically distinguishable. Implications for hominid taxonomy and dietary reconstruction are discussed. PMID:21235007

  9. How is sagittal balance acquired during bipedal gait acquisition? Comparison of neonatal and adult pelves in three dimensions. Evolutionary implications.

    Science.gov (United States)

    Tardieu, Christine; Bonneau, Noémie; Hecquet, Jérôme; Boulay, Christophe; Marty, Catherine; Legaye, Jean; Duval-Beaupère, Geneviève

    2013-08-01

    We compare adult and intact neonatal pelves, using a pelvic sagittal variable, the angle of sacral incidence, which presents significant correlations with vertebral curvature in adults and plays an important role in sagittal balance of the trunk on the lower limbs. Since the lumbar curvature develops in the child in association with gait acquisition, we expect a change in this angle during growth which could contribute to the acquisition of sagittal balance. To understand the mechanisms underlying the sagittal balance in the evolution of human bipedalism, we also measure the angle of incidence of hominid fossils. Fourty-seven landmarks were digitized on 50 adult and 19 intact neonatal pelves. We used a three-dimensional model of the pelvis (DE-VISU program) which calculates the angle of sacral incidence and related functional variables. Cross-sectional data from newborns and adults show that the angle of sacral incidence increases and becomes negatively correlated with the sacro-acetabular distance. During ontogeny the sacrum becomes curved, tends to sink down between the iliac blades as a wedge and moves backward in the sagittal plane relative to the acetabula, thus contributing to the backwards displacement of the center of gravity of the trunk. A chain of correlations links the degree of the sacral slope and of the angle of incidence, which is tightly linked with the lumbar lordosis. We sketch a model showing the coordinated changes occurring in the pelvis and vertebral column during the acquisition of bipedalism in infancy. In the australopithecine pelves, Sts 14 and AL 288-1, and in the Homo erectus Gona pelvis the angle of sacral incidence reaches the mean values of humans. Discussing the incomplete pelves of Ardipithecus ramidus, Australopithecus sediba and the Nariokotome Boy, we suggest how the functional linkage between pelvis and spine, observed in humans, could have emerged during hominid evolution. PMID:23838060

  10. The Palaeolithic colonization of Europe: an archaeological and biogeographic perspective

    Directory of Open Access Journals (Sweden)

    Rolland, Nicolas

    1992-12-01

    Full Text Available Current knowledge on the Lower Palaeolithic peopling of Europe is synthesized, using toolmaking repertoires, geochronological. biogeographical and palaegeographic evidence. The oldest traces belong to a non-Acheulian horizon, dating between 0.90 to 0.55 my. Tracing hominid geographic origin and dispersal routes into Europe identifies three alternatives: through the Levant corridor, across Gibraltar strait or more remotely, from a Central Asia filter route. No conclusive proof exists for any of these but there is more coherent empirical support for Central Asia where a non-Acheulian industry is also present. In this alternative, ancient hominid colonization of Europe was synchronous with a major Pleistocene mamalian turnover, the end-Villafranchian/Galerian dispersal event, originating in Central Asia.

    Sintetizamos el conocimiento actual sobre el poblamiento de Europa durante el Paleolítico inferior, empleando datos de repertorios líticos, así como evidencia geocronológica, biogeográfica y paleogeográfica. Los vestigios humanos más antiguos pertenecen a un horizonte no-Achelense con una edad entre 0.90 y 0.55 ma. Buscando el origen geográfico y los caminos de dispersión hasta Europa, identificamos tres alternativas: a través del corredor del Levante, del estrecho de Gibraltar O, más improbablemente, por un camino de tipo filtro desde Asia Central. No existen pruebas definitivas para ninguna de esas alternativas pero hay un apoyo empírico más coherente para la hipótesis de Asia Central, donde existe también un repertorio no-Achelense. Según esta alternativa, la colonización de Europa coincide con un importante cambio en la fauna pleistocénica, la dispersión del final del Villafranquiense/Galeriense, la cual también se originó en Asia Central.

  11. Taxonomic identification of Lower Pleistocene fossil hominins based on distal humeral diaphyseal cross-sectional shape.

    Science.gov (United States)

    Lague, Michael R

    2015-01-01

    The coexistence of multiple hominin species during the Lower Pleistocene has long presented a challenge for taxonomic attribution of isolated postcrania. Although fossil humeri are well-suited for studies of hominin postcranial variation due to their relative abundance, humeral articular morphology has thus far been of limited value for differentiating Paranthropus from Homo. On the other hand, distal humeral diaphyseal shape has been used to justify such generic distinctions at Swartkrans. The potential utility of humeral diaphyseal shape merits larger-scale quantitative analysis, particularly as it permits the inclusion of fragmentary specimens lacking articular morphology. This study analyzes shape variation of the distal humeral diaphysis among fossil hominins (c. 2-1 Ma) to test the hypothesis that specimens can be divided into distinct morphotypes. Coordinate landmarks were placed on 3D laser scans to quantify cross-sectional shape at a standardized location of the humeral diaphysis (proximal to the olecranon fossa) for a variety of fossil hominins and extant hominids. The fossil sample includes specimens attributed to species based on associated craniodental remains. Mantel tests of matrix correlation were used to assess hypotheses about morphometric relationships among the fossils by comparing empirically-derived Procrustes distance matrices to hypothetical model matrices. Diaphyseal shape variation is consistent with the hypothesis of three distinct morphotypes (Paranthropus, Homo erectus, non-erectus early Homo) in both eastern and southern Africa during the observed time period. Specimens attributed to non-erectus early Homo are unique among hominids with respect to the degree of relative anteroposterior flattening, while H. erectus humeri exhibit morphology more similar to that of modern humans. In both geographic regions, Paranthropus is characterized by a morphology that is intermediate with respect to those morphological features that differentiate

  12. Thickened cranial vault and parasagittal keeling: correlated traits and autapomorphies of Homo erectus?

    Science.gov (United States)

    Balzeau, Antoine

    2013-06-01

    Homo erectus sensu lato (s.l.) is a key species in the hominin fossil record for the study of human evolution, being one of the first species discovered and perhaps the most documented, but also because of its long temporal range and having dispersed out of Africa earlier than any other human species. Here I test two proposed autapomorphic traits of H. erectus, namely the increased thickness of the upper cranial vault and parasagittal keeling. The definition of these two anatomical features and their expression and variation among hominids are discussed. The results of this study indicate that the upper vault in Asian H. erectus is not absolutely thicker compared with fossil anatomically modern Homo sapiens, whereas Broken Hill and Petralona have values above the range of variation of H. erectus. Moreover, this anatomical region in Asian H. erectus is not significantly thicker compared with Pan paniscus. In addition, these results demonstrate that cranial vault thickness should not be used to make hypotheses regarding sexual attribution of fossil hominin specimens. I also show that the relation between relief on the external surface of the upper vault, parasagittal keeling and bregmatic eminence, and bone thickness is complex. In this context, the autapomorphic status of the two analysed traits in H. erectus may be rejected. Nevertheless, different patterns in the distribution of bone thickness on the upper vault were identified. Some individual variations are visible, but specificities are observable in samples of different species. The pattern of bone thickness distribution observed in Asian H. erectus, P. paniscus, possibly australopiths, and early Homo or Homo ergaster/erectus appears to be shared by these different species and would be a plesiomorphic trait among hominids. In contrast, two apomorphic states for this feature were identified for Neandertals and H. sapiens. PMID:23541383

  13. Mysteries of Youth in the Period of Mankind Birth%人类诞生时期的青春奥秘

    Institute of Scientific and Technical Information of China (English)

    谢昌逵

    2011-01-01

    Ever since human history, there is youth, the study of anthropology, archeology and other disciplines shows that youth appearance and the birth of mankind completely synchronized. In Hominid evolution to Homo sapiens, the youthfulization of breed has become the key to Hominid evolution. In primitive society, young people grow in myth, magic and other original culture and become exalted hero. To the patriarchal society, there is more attention of young people, and with the Rite of passage, Patriarchy bring up youth as soldiers through training and control. Intergenerational relations had been formed in prehistoric times, young people is absolute obedient and at the same time dare to resist, the pursuit of free and the love of life show the youthful vitality of prehistoric humans.%自从有了人类历史就存在青年,人类学、考古学等多学科的研究说明,青春的出场与人类的诞生完全同步。在原人向智人的进化中,族类的青春化成为原人进化的关键。在原始社会,青年在神话、巫术等原创文化中成长,成为开天辟地的英雄。到了父系社会,青年的存在更加受到重视,有了成人仪式,成为父权为了培养战士对青年进行的训练与控制。代际关系在史前时期就已形成,青年在表示绝对服从的同时也敢于对抗,追求自由热爱生命,展示出史前人类中的青春活力。

  14. Genome Data Exploration Using Correspondence Analysis.

    Science.gov (United States)

    Tekaia, Fredj

    2016-01-01

    Recent developments of sequencing technologies that allow the production of massive amounts of genomic and genotyping data have highlighted the need for synthetic data representation and pattern recognition methods that can mine and help discovering biologically meaningful knowledge included in such large data sets. Correspondence analysis (CA) is an exploratory descriptive method designed to analyze two-way data tables, including some measure of association between rows and columns. It constructs linear combinations of variables, known as factors. CA has been used for decades to study high-dimensional data, and remarkable inferences from large data tables were obtained by reducing the dimensionality to a few orthogonal factors that correspond to the largest amount of variability in the data. Herein, I review CA and highlight its use by considering examples in handling high-dimensional data that can be constructed from genomic and genetic studies. Examples in amino acid compositions of large sets of species (viruses, phages, yeast, and fungi) as well as an example related to pairwise shared orthologs in a set of yeast and fungal species, as obtained from their proteome comparisons, are considered. For the first time, results show striking segregations between yeasts and fungi as well as between viruses and phages. Distributions obtained from shared orthologs show clusters of yeast and fungal species corresponding to their phylogenetic relationships. A direct comparison with the principal component analysis method is discussed using a recently published example of genotyping data related to newly discovered traces of an ancient hominid that was compared to modern human populations in the search for ancestral similarities. CA offers more detailed results highlighting links between modern humans and the ancient hominid and their characterizations. Compared to the popular principal component analysis method, CA allows easier and more effective interpretation of results

  15. The posterior border of the sphenoid greater wing and its phylogenetic usefulness in human evolution.

    Science.gov (United States)

    Braga, J; Crubézy, E; Elyaqtine, M

    1998-12-01

    The elucidation of patterns of cranial skeletal maturation and growth in fossil hominids is possible not only through dental studies but also by mapping different aspects of ossification in both extant African apes and humans. However, knowledge of normal skeletal development in large samples of extant great apes is flimsy. To remedy this situation, this paper offers an extensive survey and thorough discussion of the ossification of the posterior border of the sphenoid greater wing. Indeed, this area provides much information about basicranial skeletal maturation. We investigate three variants: the absence of the foramen spinosum and the position of both the foramen spinosum and the foramen ovale in relation to the sphenosquamosal suture. Providing original data about humans and 1,425 extant great ape skulls and using a sample of 64 fossil hominids, this study aimed to test whether different ossification patterns occurred during the course of human evolution. The incidence of three derived morphologies located on the posterior border of the sphenoid greater wing increases during human evolution at different geological periods. The evolutionary polarity of these three derived morphologies is assessed by outgroup comparison and ontogenetic methods. During human evolution, there is a clear trend for the foramen spinosum to be present and wholly located on the posterior area of the sphenoid greater wing. Moreover, in all the great ape species and in Australopithecus afarensis, the sphenosquamosal suture may split the foramen ovale. Inversely, the foramen ovale always lies wholly within the sphenoid greater wing in Australopithecus africanus, robust australopithecines, early Homo, H. erectus (and/or H. ergaster), and Homo sapiens. From ontogenetic studies in humans, we conclude that, during human evolution, the ossification of the posterior area of the sphenoid greater wing progressively surrounded the middle meningeal artery (passing through the foramen spinosum) and

  16. Comparing communicative competence in child and chimp: the pragmatics of repetition.

    Science.gov (United States)

    Greenfield, P M; Savage-Rumbaugh, E S

    1993-02-01

    Through an analysis of chimpanzee-human discourse, we show that two Pan troglodytes chimpanzees and two Pan paniscus chimpanzees (bonobos) exposed to a humanly devised symbol system use partial or complete repetition of others' symbols, as children do: they do not produce rote imitations, but instead use repetition to fulfil a variety of pragmatic functions in discourse. These functions include agreement, request, promise, excitement, and selection from alternatives. In so doing, the chimpanzees demonstrate contingent turn-taking and the use of simple devices for lexical cohesion. In short, they demonstrate conversational competence. Because of the presence of this conversational competence in three sibling species, chimpanzees, bonobos, and humans, it is concluded that the potential to express pragmatic functions through repetition was part of the evolutionary history of human language, present in our common ancestor before the phylogenetic divergence of hominids and chimpanzees. In the context of these similarities, two interesting differences appeared: (I) Human children sometimes used repetition to stimulate more talk in their conversational partner; the chimpanzees, in contrast, use repetition exclusively to forward the non-verbal action. This difference may illuminate a unique feature of human linguistic communication, or it may simply reflect a modality difference (visual symbols used by the chimpanzees, speech used by the children) in the symbol systems considered in this research. A second difference seems likely to reflect a true species difference: utterance length. The one- and two-symbol repetitions used by the chimpanzees to fulfil a variety of pragmatic functions were less than half the maximum length found in either the visual symbol combinations addressed to them by their adult human caregivers or the oral repetitions of two-year-old children. This species difference probably reflects the evolution of increased brain size and consequent increased

  17. Genome Data Exploration Using Correspondence Analysis.

    Science.gov (United States)

    Tekaia, Fredj

    2016-01-01

    Recent developments of sequencing technologies that allow the production of massive amounts of genomic and genotyping data have highlighted the need for synthetic data representation and pattern recognition methods that can mine and help discovering biologically meaningful knowledge included in such large data sets. Correspondence analysis (CA) is an exploratory descriptive method designed to analyze two-way data tables, including some measure of association between rows and columns. It constructs linear combinations of variables, known as factors. CA has been used for decades to study high-dimensional data, and remarkable inferences from large data tables were obtained by reducing the dimensionality to a few orthogonal factors that correspond to the largest amount of variability in the data. Herein, I review CA and highlight its use by considering examples in handling high-dimensional data that can be constructed from genomic and genetic studies. Examples in amino acid compositions of large sets of species (viruses, phages, yeast, and fungi) as well as an example related to pairwise shared orthologs in a set of yeast and fungal species, as obtained from their proteome comparisons, are considered. For the first time, results show striking segregations between yeasts and fungi as well as between viruses and phages. Distributions obtained from shared orthologs show clusters of yeast and fungal species corresponding to their phylogenetic relationships. A direct comparison with the principal component analysis method is discussed using a recently published example of genotyping data related to newly discovered traces of an ancient hominid that was compared to modern human populations in the search for ancestral similarities. CA offers more detailed results highlighting links between modern humans and the ancient hominid and their characterizations. Compared to the popular principal component analysis method, CA allows easier and more effective interpretation of results

  18. The natural history of the helicoidal occlusal plane and its evolution in early Homo.

    Science.gov (United States)

    Tobias, P V

    1980-08-01

    In modern man the pitch of the occlusal plane may vary along the tooth-row. When anterior cheek-teeth show a plane sloping upward palatally, whilst that on posterior cheek-teeth slopes upward buccally, there results a twisted or helicoidal occlusal plane (Ackermann). Several hypotheses have been proposed for the structural basis of the helicoidal occlusal plane. Campbell's proposal ('25) has gained widest acceptance, namely that the helicoid results from anteroposterior differences in upper and lower alveolar arch width. In the early 1960s, while studying the Olduvai hominids assigned to Homo habilis, the author noted changing occlusal slopes along the tooth-row and a slight helicoid, although these featues had not been noted in other early hominids. Subsequently, Wallace showed a total absence of the helicoid from South African australopithecines, and its presence in Swartkrans Homo, SK 45 and SK 80. Recent studies confirm the presence of the helicoid in all available specimens of H. habilis, including Stw 53 found at Sterkfontein in 1976. Hence, this trait may distinguish between Australopithecus and early Homo. Measurements of the maxillary arch widths have shown that, whereas in Australopithecus arch widths increase to a maximum at M3, in early Homo maxillary arch widths are greatest at M2. The decline in posterior maxillary arch width is part of a general reduction of that region. Thus despite striking elongation of premolars and M1 in early Homo, M2 and M3 are mesiodistally abbreviated. It is hypothesized that the onset of posterior arch reduction, with the appearance of a helicoid, was a structural and functional concomitant of the transition from the presumed australopithecine ancestor to H. habilis. PMID:6774617

  19. Evidence from facial morphology for similarity of Asian and African representatives of Homo erectus.

    Science.gov (United States)

    Rightmire, G P

    1998-05-01

    It has been argued that Homo erectus is a species confined to Asia. Specialized characters displayed by the Indonesian and Chinese skulls are said to be absent in material from eastern Africa, and individuals from Koobi Fora and Nariokotome are now referred by some workers to H. ergaster. This second species is held to be the ancestor from which later human populations are derived. The claim for two taxa is evaluated here with special reference to the facial skeleton. Asian fossils examined include Sangiran 4 and Sangiran 17, several of the Ngandong crania, Gongwangling, and of course the material from Zhoukoudian described by Weidenreich ([1943] Palaeontol. Sin. [New Ser. D] 10:1-484). African specimens compared are KNM-ER 3733 and KNM-ER 3883 from Koobi Fora and KNM-WT 15000 from Nariokotome. Hominid 9 from Olduvai is useful only insofar as the brows and interorbital pillar are preserved. Neither detailed anatomical comparisons nor measurements bring to light any consistent patterns in facial morphology which set the African hominids apart from Asian H. erectus. Faces of the African individuals do tend to be high and less broad across the orbits. Both of the Koobi Fora crania but not KNM-WT 15000 have nasal bones that are narrow superiorly, while the piriform aperture is relatively wide. In many other characters, including contour of the supraorbital torus, glabellar prominence, nasal bridge dimensions, internasal keeling, anatomy of the nasal sill and floor, development of the canine jugum, orientation of the zygomaticoalveolar pillar, rounding of the anterolateral surface of the cheek, formation of a malar tubercle, and palatal rugosity, there is variation among individuals from localities within the major geographic provinces. Here it is not possible to identify features that are unique to either the Asian or African assemblages. Additional traits such as a forward sloping "crista nasalis," presence of a "sulcus maxillaris," a high (and massive) cheek coupled

  20. Experimental observation, theoretical models, and biomechanical inference in the study of mandibular form.

    Science.gov (United States)

    Daegling, D J; Hylander, W L

    2000-08-01

    Experimental studies and mathematical models are disparate approaches for inferring the stress and strain environment in mammalian jaws. Experimental designs offer accurate, although limited, characterization of biomechanical behavior, while mathematical approaches (finite element modeling in particular) offer unparalleled precision in depiction of strain magnitudes, directions, and gradients throughout the mandible. Because the empirical (experimental) and theoretical (mathematical) perspectives differ in their initial assumptions and their proximate goals, the two methods can yield divergent conclusions about how masticatory stresses are distributed in the dentary. These different sources of inference may, therefore, tangibly influence subsequent biological interpretation. In vitro observation of bone strain in primate mandibles under controlled loading conditions offers a test of finite element model predictions. Two issues which have been addressed by both finite element models and experimental approaches are: (1) the distribution of torsional shear strains in anthropoid jaws and (2) the dissipation of bite forces in the human alveolar process. Not surprisingly, the experimental data and mathematical models agree on some issues, but on others exhibit discordance. Achieving congruence between these methods is critical if the nature of the relationship of masticatory stress to mandibular form is to be intelligently assessed. A case study of functional/mechanical significance of gnathic morphology in the hominid genus Paranthropus offers insight into the potential benefit of combining theoretical and experimental approaches. Certain finite element analyses claim to have identified a biomechanical problem unrecognized in previous comparative work, which, in essence, is that the enlarged transverse dimensions of the postcanine corpus may have a less important role in resisting torsional stresses than previously thought. Experimental data have identified

  1. Variation and diversity in Homo erectus: a 3D geometric morphometric analysis of the temporal bone.

    Science.gov (United States)

    Terhune, Claire E; Kimbel, William H; Lockwood, Charles A

    2007-07-01

    Although the level of taxonomic diversity within the fossil hominin species Homo erectus (sensu lato) is continually debated, there have been relatively few studies aiming to quantify the morphology of this species. Instead, most researchers have relied on qualitative descriptions or the evaluation of nonmetric characters, which in many cases display continuous variation. Also, only a few studies have used quantitative data to formally test hypotheses regarding the taxonomic composition of the "erectus" hypodigm. Despite these previous analyses, however, and perhaps in part due to these varied approaches for assessing variation within specimens typically referred to H. erectus (sensu lato) and the general lack of rigorous statistical testing of how variation within this taxon is partitioned, there is currently little consensus regarding whether this group is a single species, or whether it should instead be split into separate temporal or geographically delimited taxa. In order to evaluate possible explanations for variation within H. erectus, we tested the general hypothesis that variation within the temporal bone morphology of H. erectus is consistent with that of a single species, using great apes and humans as comparative taxa. Eighteen three-dimensional (3D) landmarks of the temporal bone were digitized on a total of 520 extant and fossil hominid crania. Landmarks were registered by Generalized Procrustes Analysis, and Procrustes distances were calculated for comparisons of individuals within and between the extant taxa. Distances between fossil specimens and between a priori groupings of fossils were then compared to the distances calculated within the extant taxa to assess the variation within the H. erectus sample relative to that of known species, subspecies, and populations. Results of these analyses indicate that shape variation within the entire H. erectus sample is generally higher than extant hominid intraspecific variation, and putative H. ergaster

  2. Can Cooler Heads Prevail?

    Science.gov (United States)

    Rice, A. R.

    2015-12-01

    The significant correlation between dropping temperatures throughout the Pliocene and the concomitant explosive expansion of the Hominid brain has led a number of workers to postulate climate change drove human evolution. Our brain (that of Homo sapiens), comprises 1-2 percent of our body weight but consumes 20 -25 percent of the body's caloric intake. We are "hotheads". Brains are extremely sensitive to overheating but we are endowed with unparalleled thermal regulation, much of it given over to protecting the Central Nervous System (CNS). Will there be reversed trends with global warming? The human brain has been shrinking since the end of the Ice Ages, losing about 150cc over the past 10,000 years. Polar bear skulls have been downsizing as well. Almost all mass extinctions or evolutionary upheavals are attributed to global warming: e.g. the Permian/Triassic (P/T) event, i.e., "The Great Dying", 250 million years ago (~90% of all life forms wiped out); the Paleocene/ Eocene Thermal Maximum (PETM) 55 million years ago. They may be analogs for what might await us. Large creatures, whose body size inhibits cooling, melted away during the PETM. Horses, initially the size of dogs then, reduced to the size of cats. An unanticipated hazard for humans that may attend extreme global warming is dumbing down or needing to retreat to the Poles as did those creatures that survived the P/T event (some references: http://johnhawks.net/research/hawks-2011-brain-size-selection-holocene; Kandel, E. et al Principles of Neural Science 4th ed. New York (US): McGraw-Hill, 2000; Selective Brain Cooling in Early Hominids:phylogenetic and evolutionary implications, Reeser, H., reeser@flmnh.ufl.edu; How the body controls brain temperature; the temperature shielding effect of cerebral blood flow, Mingming Z. et al. J Appl Physiol. 2006 November; 101(5): 1481-1488; news.nationalgeographic.com/ news/2014/03/140327-climate-change-shrinks-salamanders-global-warming-science/; Heat illness and

  3. India at the cross-roads of human evolution.

    Science.gov (United States)

    Patnaik, R; Chauhan, P

    2009-11-01

    The Indian palaeoanthropological record, although patchy at the moment, is improving rapidly with every new find. This broad review attempts to provide an account of (a) the Late Miocene fossil apes and their gradual disappearance due to ecological shift from forest dominated to grassland dominated ecosystem around 9-8 Ma ago, (b) the Pliocene immigration/evolution of possible hominids and associated fauna, (c) the Pleistocene record of fossil hominins, associated fauna and artifacts, and (d) the Holocene time of permanent settlements and the genetic data from various human cultural groups within India. Around 13 Ma ago (late Middle Miocene) Siwalik forests saw the emergence of an orangutan-like primate Sivapithecus. By 8 Ma, this genus disappeared from the Siwalik region as its habitat started shrinking due to increased aridity influenced by global cooling and monsoon intensification. A contemporary and a close relative of Sivapithecus, Gigantopithecus (Indopithecus), the largest ape that ever-lived, made its first appearance at around 9 Ma. Other smaller primates that were pene-contemporaneous with these apes were Pliopithecus (Dendropithecus), Indraloris, Sivaladapis and Palaeotupia. The Late Pliocene and Early Pleistocene witnessed northern hemisphere glaciations, followed by the spread of arid conditions on a global scale, setting the stage for hominids to explore "Savanahastan". With the prominent expansion of grassland environments from East Africa to China and Indonesia in the Pliocene, monkeys and baboons dispersed into the Indian subcontinent from Africa along with other mammals. Though debated, there are several claims of the presence of early hominins in this part of the world during the Late Pliocene, based primarily on the recovery of Palaeolithic tools. Fossils of our own ancestor and one of the first globe-trotters, early Homo erectus, has been documented from the Early Pleistocene of East Africa, Western Asia and Southeast Asia, thus indirectly

  4. Model-based analyses of whole-genome data reveal a complex evolutionary history involving archaic introgression in Central African Pygmies.

    Science.gov (United States)

    Hsieh, PingHsun; Woerner, August E; Wall, Jeffrey D; Lachance, Joseph; Tishkoff, Sarah A; Gutenkunst, Ryan N; Hammer, Michael F

    2016-03-01

    Comparisons of whole-genome sequences from ancient and contemporary samples have pointed to several instances of archaic admixture through interbreeding between the ancestors of modern non-Africans and now extinct hominids such as Neanderthals and Denisovans. One implication of these findings is that some adaptive features in contemporary humans may have entered the population via gene flow with archaic forms in Eurasia. Within Africa, fossil evidence suggests that anatomically modern humans (AMH) and various archaic forms coexisted for much of the last 200,000 yr; however, the absence of ancient DNA in Africa has limited our ability to make a direct comparison between archaic and modern human genomes. Here, we use statistical inference based on high coverage whole-genome data (greater than 60×) from contemporary African Pygmy hunter-gatherers as an alternative means to study the evolutionary history of the genus Homo. Using whole-genome simulations that consider demographic histories that include both isolation and gene flow with neighboring farming populations, our inference method rejects the hypothesis that the ancestors of AMH were genetically isolated in Africa, thus providing the first whole genome-level evidence of African archaic admixture. Our inferences also suggest a complex human evolutionary history in Africa, which involves at least a single admixture event from an unknown archaic population into the ancestors of AMH, likely within the last 30,000 yr.

  5. DNA sequence and analysis of human chromosome 8.

    Science.gov (United States)

    Nusbaum, Chad; Mikkelsen, Tarjei S; Zody, Michael C; Asakawa, Shuichi; Taudien, Stefan; Garber, Manuel; Kodira, Chinnappa D; Schueler, Mary G; Shimizu, Atsushi; Whittaker, Charles A; Chang, Jean L; Cuomo, Christina A; Dewar, Ken; FitzGerald, Michael G; Yang, Xiaoping; Allen, Nicole R; Anderson, Scott; Asakawa, Teruyo; Blechschmidt, Karin; Bloom, Toby; Borowsky, Mark L; Butler, Jonathan; Cook, April; Corum, Benjamin; DeArellano, Kurt; DeCaprio, David; Dooley, Kathleen T; Dorris, Lester; Engels, Reinhard; Glöckner, Gernot; Hafez, Nabil; Hagopian, Daniel S; Hall, Jennifer L; Ishikawa, Sabine K; Jaffe, David B; Kamat, Asha; Kudoh, Jun; Lehmann, Rüdiger; Lokitsang, Tashi; Macdonald, Pendexter; Major, John E; Matthews, Charles D; Mauceli, Evan; Menzel, Uwe; Mihalev, Atanas H; Minoshima, Shinsei; Murayama, Yuji; Naylor, Jerome W; Nicol, Robert; Nguyen, Cindy; O'Leary, Sinéad B; O'Neill, Keith; Parker, Stephen C J; Polley, Andreas; Raymond, Christina K; Reichwald, Kathrin; Rodriguez, Joseph; Sasaki, Takashi; Schilhabel, Markus; Siddiqui, Roman; Smith, Cherylyn L; Sneddon, Tam P; Talamas, Jessica A; Tenzin, Pema; Topham, Kerri; Venkataraman, Vijay; Wen, Gaiping; Yamazaki, Satoru; Young, Sarah K; Zeng, Qiandong; Zimmer, Andrew R; Rosenthal, Andre; Birren, Bruce W; Platzer, Matthias; Shimizu, Nobuyoshi; Lander, Eric S

    2006-01-19

    The International Human Genome Sequencing Consortium (IHGSC) recently completed a sequence of the human genome. As part of this project, we have focused on chromosome 8. Although some chromosomes exhibit extreme characteristics in terms of length, gene content, repeat content and fraction segmentally duplicated, chromosome 8 is distinctly typical in character, being very close to the genome median in each of these aspects. This work describes a finished sequence and gene catalogue for the chromosome, which represents just over 5% of the euchromatic human genome. A unique feature of the chromosome is a vast region of approximately 15 megabases on distal 8p that appears to have a strikingly high mutation rate, which has accelerated in the hominids relative to other sequenced mammals. This fast-evolving region contains a number of genes related to innate immunity and the nervous system, including loci that appear to be under positive selection--these include the major defensin (DEF) gene cluster and MCPH1, a gene that may have contributed to the evolution of expanded brain size in the great apes. The data from chromosome 8 should allow a better understanding of both normal and disease biology and genome evolution. PMID:16421571

  6. Facial expression of fear in the context of human ethology: Recognition advantage in the perception of male faces.

    Science.gov (United States)

    Trnka, Radek; Tavel, Peter; Tavel, Peter; Hasto, Jozef

    2015-01-01

    Facial expression is one of the core issues in the ethological approach to the study of human behaviour. This study discusses sex-specific aspects of the recognition of the facial expression of fear using results from our previously published experimental study. We conducted an experiment in which 201 participants judged seven different facial expressions: anger, contempt, disgust, fear, happiness, sadness and surprise (Trnka et al. 2007). Participants were able to recognize the facial expression of fear significantly better on a male face than on a female face. Females also recognized fear generally better than males. The present study provides a new interpretation of this sex difference in the recognition of fear. We interpret these results within the paradigm of human ethology, taking into account the adaptive function of the facial expression of fear. We argue that better detection of fear might be crucial for females under a situation of serious danger in groups of early hominids. The crucial role of females in nurturing and protecting offspring was fundamental for the reproductive potential of the group. A clear decoding of this alarm signal might thus have enabled the timely preparation of females for escape or defence to protect their health for successful reproduction. Further, it is likely that males played the role of guardians of social groups and that they were responsible for effective warnings of the group under situations of serious danger. This may explain why the facial expression of fear is better recognizable on the male face than on the female face. PMID:26071575

  7. Cladistic analysis of continuous modularized traits provides phylogenetic signals in Homo evolution.

    Science.gov (United States)

    González-José, Rolando; Escapa, Ignacio; Neves, Walter A; Cúneo, Rubén; Pucciarelli, Héctor M

    2008-06-01

    Evolutionary novelties in the skeleton are usually expressed as changes in the timing of growth of features intrinsically integrated at different hierarchical levels of development. As a consequence, most of the shape-traits observed across species do vary quantitatively rather than qualitatively, in a multivariate space and in a modularized way. Because most phylogenetic analyses normally use discrete, hypothetically independent characters, previous attempts have disregarded the phylogenetic signals potentially enclosed in the shape of morphological structures. When analysing low taxonomic levels, where most variation is quantitative in nature, solving basic requirements like the choice of characters and the capacity of using continuous, integrated traits is of crucial importance in recovering wider phylogenetic information. This is particularly relevant when analysing extinct lineages, where available data are limited to fossilized structures. Here we show that when continuous, multivariant and modularized characters are treated as such, cladistic analysis successfully solves relationships among main Homo taxa. Our attempt is based on a combination of cladistics, evolutionary-development-derived selection of characters, and geometric morphometrics methods. In contrast with previous cladistic analyses of hominid phylogeny, our method accounts for the quantitative nature of the traits, and respects their morphological integration patterns. Because complex phenotypes are observable across different taxonomic groups and are potentially informative about phylogenetic relationships, future analyses should point strongly to the incorporation of these types of trait.

  8. Quantifying lateral femoral condyle ellipticalness in chimpanzees, gorillas, and humans.

    Science.gov (United States)

    Sylvester, Adam D; Pfisterer, Theresa

    2012-11-01

    Articular surfaces of limb bones provide information for understanding animal locomotion because their size and shape are a reflection of habitual postures and movements. Here we present a novel method for quantifying the ellipticalness (i.e., departure from perfectly circular) of the lateral femoral condyle (LFC), applying this technique to hominid femora. Three-dimensional surface models were created for 49 Homo sapiens, 34 Pan troglodytes and 25 Gorilla gorilla femora. Software was developed that fit separate cylinders to each of the femoral condyles. These cylinders were constrained to have a single axis, but could have different radii. The cylinder fit to the LFC was allowed to assume an elliptical cross-section, while the cylinder fit to the medial condyle was constrained to remain circular. The shape of the elliptical cylinder (ratio of the major and minor axes of the ellipse) was recorded, and the orientation of the elliptical cylinder quantified as angles between the major axis of the ellipse and the anatomical and mechanical axes of the femur. Species were compared using analysis of variance and post hoc multiple comparisons tests. Confirming qualitative descriptions, human LFCs are more elliptical than those of chimpanzees and gorillas. Human femora exhibit a narrow range for the angle between the major axis of the elliptical cylinder and femoral axes. Conversely, the chimpanzee sample is bimodal for these angles, exhibiting two ellipse orientations, while Gorilla shows no preferred angle. Our results suggest that like modern human femora, chimpanzee femoral condyles have preferentially used regions. PMID:23042636

  9. Separation anxiety: at the neurobiological crossroads of adaptation and illness.

    Science.gov (United States)

    Battaglia, Marco

    2015-09-01

    Physiological and adaptive separation anxiety (SA) is intimately connected with the evolutionary emergence of new brain structures specific of paleomammalians, the growth of neomammalian--and later hominid--brain and skull size, and the appearance of bipedalism. All these evolutionary milestones have contributed to expanding the behavioral repertoire and plasticity of prehuman and human beings, at the cost of more prolonged dependency of the infant and of the child on parental care. Separation anxiety disorder (SAD) can be seen as an exaggerated/inappropriate manifestation of SA that constitutes a gateway to poorer mental and physical health. By blending epidemiological, genetic-epidemiological, endophenotypic, and animal laboratory approaches, it is possible to delineate some of the mechanisms that link childhood-adolescence SA and SAD to health problems later in life. Causal mechanisms include gene-environment interplays and likely differential regulation of genes and functional net-works that simultaneously affect multiple behavioral and physical phenotypes after exposure to early-life adversity, including parental separation/loss.

  10. THE SIGNIFICANCE OF THE SUBPLATE FOR EVOLUTION AND DEVELOPMENTAL PLASTICITY OF THE HUMAN BRAIN

    Directory of Open Access Journals (Sweden)

    MILOS eJUDAS

    2013-08-01

    Full Text Available The human life-history is characterized by long development and introduction of new developmental stages, such as childhood and adolescence. The developing brain had important role in these life-history changes because it is expensive tissue which uses up to 80% of resting metabolic rate in the newborn and continues to use almost 50% of it during the first 5 postnatal years. Our hominid ancestors managed to lift-up metabolic constraints to increase in brain size by several interrelated ecological, behavioral and social adaptations, such as dietary change, invention of cooking, creation of family-bonded reproductive units, and life-history changes. This opened new vistas for the developing brain, because it became possible to metabolically support transient patterns of brain organization as well as developmental brain plasticity for much longer period and with much greater number of neurons and connectivity combinations in comparison to apes. This included the shaping of cortical connections through the interaction with infant's social environment, which probably enhanced typically human evolution of language, cognition and self-awareness. In this review, we propose that the transient subplate zone and its postnatal remnant (interstitial neurons of the gyral white matter probably served as the main playground for evolution of these developmental shifts, and describe various features that makes human subplate uniquely positioned to have such a role in comparison with other primates.

  11. 2004年丹江口库区调查发现的石制品%A Study on the Stone Artifacts from 2004 Field Investigation in Danjiangkou Reservoir Area, Hubei and Henan, China

    Institute of Scientific and Technical Information of China (English)

    李浩; 李超荣; 冯兴无

    2012-01-01

    -to-middle Middle Pleistocene. The age of the secondterrace, based on geomorphological survey, likely belongs to the Late Pleistocene. Early hominids living at the Hanshui River and Danjiang tributary, near the Danjiangkou reservoir, selected cobbles as raw material from nearby gravel levels of a river bank for making stone artifacts. The artifacts include cores, flakes, chopper-chopping tools, scrapers, spheroids, picks and handaxes. The predominant raw materials are quartz and siliceous limestone, and secondarily, quartzite, sandstone and quartz sandstone. Generally speaking, quartz is the most common material amongst cores and flakes, while the heavy-duty tools, like picks and handaxes, were mostly composed of siliceous limestone. This shows distinct selection criteria for raw materials amongst these early hominids. At Danjiangkou reservoir area, flakes are the most abundant artifacts, accounting for 29.43% of the total assemblage, most of them ranging from medium to large size(>50mm). Within the tool category, 91 were made from cobble blanks, accounting for 71.09%; 31 were made from medium and large flake blanks, accounting for 24.22%; and 6 were made from blocks. Chopper-chopping tools were made mainly from cobbles, among them 56 were unifacial worked, accounting for 64.37%; while the remaining 31 were bifacial worked. Scrapers were mainly made from medium and large flake, meanwhile, there were some small size scrapers made from quartz flakes, which are similar to the light-duty tools in northern China. Picks were all unifacial working and had a relatively low intensity of reduction, furthermore, retouch was mainly focused on the distal end which preserved a high proportion of cortex. Handaxes have symmetrical features, with a cutting edge typically spanning more than half of the length of the body, while some specimens were fully worked. But considering that siliceous limestone is a poor-quality raw material with a very platy structure, it is difficult to control the

  12. 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

  13. 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

  14. Size and placement of developing anterior teeth in immature Neanderthal mandibles from Dederiyeh Cave, Syria: implications for emergence of the modern human chin.

    Science.gov (United States)

    Fukase, Hitoshi; Kondo, Osamu; Ishida, Hajime

    2015-03-01

    Evolutionary and functional significance of the human chin has long been explored from various perspectives including masticatory biomechanics, speech, and anterior tooth size. Recent ontogenetic studies have indicated that the spatial position of internally forming anterior teeth partially constrains adult mandibular symphyseal morphology. The present study therefore preliminarily examined the size and placement of developing anterior teeth in immature Neanderthal mandibles of Dederiyeh 1 and 2, compared with similarly-aged modern humans (N = 16) and chimpanzees (N = 7) whose incisors are comparatively small and large among extant hominids, respectively. The Dederiyeh 1 mandible is described as slightly presenting a mental trigone and attendant mental fossa, whereas Dederiyeh 2 completely lacks such chin-associated configurations. Results showed that, despite symphyseal size being within the modern human range, both Dederiyeh mandibles accommodated overall larger anterior dentition and displayed a remarkably wide bicanine space compared to those of modern humans. Dederiyeh 2 had comparatively thicker deciduous incisor roots and more enlarged permanent incisor crypts than Dederiyeh 1, but both Dederiyeh individuals exhibited a total dental size mostly intermediate between modern humans and chimpanzees. These findings potentially imply that the large deciduous/permanent incisors collectively distended the labial alveolar bone, obscuring an incipient mental trigone. It is therefore hypothesized that the appearance of chin-associated features, particularly of the mental trigone and fossa, can be accounted for partly by developmental relationships between the sizes of the available mandibular space and anterior teeth. This hypothesis must be, however, further addressed with more referential samples in future studies.

  15. Auditory capacities in Middle Pleistocene humans from the Sierra de Atapuerca in Spain

    Science.gov (United States)

    Martínez, I.; Rosa, M.; Arsuaga, J.-L.; Jarabo, P.; Quam, R.; Lorenzo, C.; Gracia, A.; Carretero, J.-M.; de Castro, J.-M. Bermúdez; Carbonell, E.

    2004-01-01

    Human hearing differs from that of chimpanzees and most other anthropoids in maintaining a relatively high sensitivity from 2 kHz up to 4 kHz, a region that contains relevant acoustic information in spoken language. Knowledge of the auditory capacities in human fossil ancestors could greatly enhance the understanding of when this human pattern emerged during the course of our evolutionary history. Here we use a comprehensive physical model to analyze the influence of skeletal structures on the acoustic filtering of the outer and middle ears in five fossil human specimens from the Middle Pleistocene site of the Sima de los Huesos in the Sierra de Atapuerca of Spain. Our results show that the skeletal anatomy in these hominids is compatible with a human-like pattern of sound power transmission through the outer and middle ear at frequencies up to 5 kHz, suggesting that they already had auditory capacities similar to those of living humans in this frequency range. PMID:15213327

  16. Pleistocene Hominins as a Resource for Carnivores: A c. 500,000-Year-Old Human Femur Bearing Tooth-Marks in North Africa (Thomas Quarry I, Morocco.

    Directory of Open Access Journals (Sweden)

    Camille Daujeard

    Full Text Available In many Middle Pleistocene sites, the co-occurrence of hominins with carnivores, who both contributed to faunal accumulations, suggests competition for resources as well as for living spaces. Despite this, there is very little evidence of direct interaction between them to-date. Recently, a human femoral diaphysis has been recognized in South-West of Casablanca (Morocco, in the locality called Thomas Quarry I. This site is famous for its Middle Pleistocene fossil hominins considered representatives of Homo rhodesiensis. The bone was discovered in Unit 4 of the Grotte à Hominidés (GH, dated to c. 500 ky and was associated with Acheulean artefacts and a rich mammalian fauna. Anatomically, it fits well within the group of known early Middle Pleistocene Homo, but its chief point of interest is that the diaphyseal ends display numerous tooth marks showing that it had been consumed shortly after death by a large carnivore, probably a hyena. This bone represents the first evidence of consumption of human remains by carnivores in the cave. Whether predated or scavenged, this chewed femur indicates that humans were a resource for carnivores, underlining their close relationships during the Middle Pleistocene in Atlantic Morocco.

  17. Pleistocene Hominins as a Resource for Carnivores: A c. 500,000-Year-Old Human Femur Bearing Tooth-Marks in North Africa (Thomas Quarry I, Morocco).

    Science.gov (United States)

    Daujeard, Camille; Geraads, Denis; Gallotti, Rosalia; Lefèvre, David; Mohib, Abderrahim; Raynal, Jean-Paul; Hublin, Jean-Jacques

    2016-01-01

    In many Middle Pleistocene sites, the co-occurrence of hominins with carnivores, who both contributed to faunal accumulations, suggests competition for resources as well as for living spaces. Despite this, there is very little evidence of direct interaction between them to-date. Recently, a human femoral diaphysis has been recognized in South-West of Casablanca (Morocco), in the locality called Thomas Quarry I. This site is famous for its Middle Pleistocene fossil hominins considered representatives of Homo rhodesiensis. The bone was discovered in Unit 4 of the Grotte à Hominidés (GH), dated to c. 500 ky and was associated with Acheulean artefacts and a rich mammalian fauna. Anatomically, it fits well within the group of known early Middle Pleistocene Homo, but its chief point of interest is that the diaphyseal ends display numerous tooth marks showing that it had been consumed shortly after death by a large carnivore, probably a hyena. This bone represents the first evidence of consumption of human remains by carnivores in the cave. Whether predated or scavenged, this chewed femur indicates that humans were a resource for carnivores, underlining their close relationships during the Middle Pleistocene in Atlantic Morocco.

  18. Stamping, Clapping and Chanting: An Ancient Learning Pathway?

    Directory of Open Access Journals (Sweden)

    Marion M. Long

    2006-04-01

    Full Text Available In this review I explore the effect of temporal integration as a means of improving learning in schoolchildren. I focus first on theorists that have linked physical activity with a positive effect on children’s learning and second to psychological studies that have established the existence of innate temporal patterns. These findings are related to a model of temporal integration that I have developed from Croce’s writings on aesthetics (1900. From philosophy to neurology, I discuss recent neurological findings relating to timing and conclude that an organ of temporal integration, regulation and coordination operates in the brain with respect to physical, intuitive and higher cognitive function. I link recent findings in neurophysiology to notably similar findings in recent biomusicological studies. The finding that humans have an involuntary physical response to loud, low-frequency sounds are attributed to an innate legacy of proto-music and proto-dance behaviour among hominids. I develop the model of temporal integration further by examining the literature on stamping and clapping patterns of ancient traditional dances in relation to Husserl’s writings on theoretical succession. From philosophy to pedagogy, I summarise the review by proposing stamping, clapping and chanting as a means of achieving improved temporal integration.

  19. Brain disorders and the biological role of music.

    Science.gov (United States)

    Clark, Camilla N; Downey, Laura E; Warren, Jason D

    2015-03-01

    Despite its evident universality and high social value, the ultimate biological role of music and its connection to brain disorders remain poorly understood. Recent findings from basic neuroscience have shed fresh light on these old problems. New insights provided by clinical neuroscience concerning the effects of brain disorders promise to be particularly valuable in uncovering the underlying cognitive and neural architecture of music and for assessing candidate accounts of the biological role of music. Here we advance a new model of the biological role of music in human evolution and the link to brain disorders, drawing on diverse lines of evidence derived from comparative ethology, cognitive neuropsychology and neuroimaging studies in the normal and the disordered brain. We propose that music evolved from the call signals of our hominid ancestors as a means mentally to rehearse and predict potentially costly, affectively laden social routines in surrogate, coded, low-cost form: essentially, a mechanism for transforming emotional mental states efficiently and adaptively into social signals. This biological role of music has its legacy today in the disordered processing of music and mental states that characterizes certain developmental and acquired clinical syndromes of brain network disintegration.

  20. The role of climate in the spread of modern humans into Europe

    Science.gov (United States)

    Müller, Ulrich C.; Pross, Jörg; Tzedakis, Polychronis C.; Gamble, Clive; Kotthoff, Ulrich; Schmiedl, Gerhard; Wulf, Sabine; Christanis, Kimon

    2011-02-01

    The spread of anatomically modern humans (AMH) into Europe occurred when shifts in the North Atlantic meridional overturning circulation triggered a series of large and abrupt climate changes during the last glacial. However, the role of climate forcing in this process has remained unclear. Here we present a last glacial record that provides insight into climate-related environmental shifts in the eastern Mediterranean region, i.e. the gateway for the colonisation of Europe by AMH. We show that the environmental impact of the Heinrich Event H5 climatic deterioration c. 48 kyr ago was as extreme as that of the glacial maximum of Marine Isotope Stage (MIS) 4 when most of Europe was deserted by Neanderthals. We argue that Heinrich H5 resulted in a similar demographic vacuum so that invasive AMH populations had the opportunity to spread into Europe and occupy large parts before the Neanderthals were able to reoccupy this territory. This spread followed the resumption of the Atlantic meridional overturning circulation at the beginning of Greenland Interstadial (GIS) 12 c. 47 kyr ago that triggered an extreme and rapid shift from desert-steppe to open woodland biomes in the gateway to Europe. We conclude that the extreme environmental impact of Heinrich H5 within a situation of competitive exclusion between two closely related hominids species shifted the balance in favour of modern humans.

  1. Closing of the Indonesian seaway as a precursor to east African aridification around 3-4 million years ago.

    Science.gov (United States)

    Cane, M A; Molnar, P

    2001-05-10

    Global climate change around 3-4 Myr ago is thought to have influenced the evolution of hominids, via the aridification of Africa, and may have been the precursor to Pleistocene glaciation about 2.75 Myr ago. Most explanations of these climatic events involve changes in circulation of the North Atlantic Ocean due to the closing of the Isthmus of Panama. Here we suggest, instead, that closure of the Indonesian seaway 3-4 Myr ago could be responsible for these climate changes, in particular the aridification of Africa. We use simple theory and results from an ocean circulation model to show that the northward displacement of New Guinea, about 5 Myr ago, may have switched the source of flow through Indonesia-from warm South Pacific to relatively cold North Pacific waters. This would have decreased sea surface temperatures in the Indian Ocean, leading to reduced rainfall over eastern Africa. We further suggest that the changes in the equatorial Pacific may have reduced atmospheric heat transport from the tropics to higher latitudes, stimulating global cooling and the eventual growth of ice sheets. PMID:11346785

  2. Permanent tooth calcification in chimpanzees (Pan troglodytes): patterns and polymorphisms.

    Science.gov (United States)

    Kuykendall, K L; Conroy, G C

    1996-01-01

    Tooth calcification is an important developmental marker for use in constructing models for early hominid life history, particularly for its application to the fossil record. As chimpanzees are commonly utilized in interspecific comparisons in such research, this study aims to improve available baseline data for tooth calcification patterns in chimpanzees (Pan troglodytes), and to quantify basic patterns and polymorphisms. We present an analysis of developmental patterns for the left mandibular dentition (I1-M3) based on intraoral radiographs obtained from a cross-sectional sample of chimpanzees (58 males, 60 females) housed at LEMSIP (NYU Medical Center) and Yerkes (Emory University). No significant differences with previous descriptions of the basic sequences of tooth calcification in chimpanzees were found, but variation in such patterns was documented for the first time. In the overall sequence, polymorphisms between the canine and the group (M2 P4 P3) reached significant levels. This is due to the relative delay in canine crown formation compared to other teeth. Differences in the basic sequence between males and females were recorded, but are due to minor shifts in the percentages of occurrence for polymorphic sequences which are common to both genders. Perhaps our most important findings are that a) different polymorphic sequences occur in tooth calcification and tooth emergence in chimpanzees, and b) developmental relationships among teeth fluctuate throughout tooth calcification. Thus, characterizations of dental developmental patterns based on particular stages of development cannot necessarily be extrapolated to other stages without supporting data. PMID:8928717

  3. Regional DNA methylation differences between humans and chimpanzees are associated with genetic changes, transcriptional divergence and disease genes.

    Science.gov (United States)

    Fukuda, Kei; Ichiyanagi, Kenji; Yamada, Yoichi; Go, Yasuhiro; Udono, Toshifumi; Wada, Seitaro; Maeda, Toshiyuki; Soejima, Hidenobu; Saitou, Naruya; Ito, Takashi; Sasaki, Hiroyuki

    2013-07-01

    Changes in gene expression have been proposed to have an important role in the evolutionary changes in phenotypes. Interspecific changes in gene expression can result not only from genetic changes in regulatory regions but also from epigenetic changes in such regions. Here we report the identification of genomic regions showing differences in DNA methylation between humans and chimpanzees (termed S-DMRs for species-specific differentially methylated regions) on chromosomes 21 and 22. These regional methylation differences are frequently associated with genes, including those relevant to a disease, such as Alzheimer's disease, diabetes mellitus or cancer. Methylation differences are often correlated with changes in promoter activity or alternative splicing. Comparative studies including other great ape species provide evidence for the contribution of genetic changes to some of these S-DMRs. Genetic changes responsible for the S-DMRs include gain or loss of CTCF-binding site and changes in CpG density in microsatellite repeats. Our results suggest that DNA methylation changes, often caused by small sequence changes, contribute to transcriptional and phenotypic diversification in hominid evolution. PMID:23739127

  4. Savanna chimpanzees, Pan troglodytes verus, hunt with tools.

    Science.gov (United States)

    Pruetz, Jill D; Bertolani, Paco

    2007-03-01

    Although tool use is known to occur in species ranging from naked mole rats [1] to owls [2], chimpanzees are the most accomplished tool users [3-5]. The modification and use of tools during hunting, however, is still considered to be a uniquely human trait among primates. Here, we report the first account of habitual tool use during vertebrate hunting by nonhumans. At the Fongoli site in Senegal, we observed ten different chimpanzees use tools to hunt prosimian prey in 22 bouts. This includes immature chimpanzees and females, members of age-sex classes not normally characterized by extensive hunting behavior. Chimpanzees made 26 different tools, and we were able to recover and analyze 12 of these. Tool construction entailed up to five steps, including trimming the tool tip to a point. Tools were used in the manner of a spear, rather than a probe or rousing tool. This new information on chimpanzee tool use has important implications for the evolution of tool use and construction for hunting in the earliest hominids, especially given our observations that females and immature chimpanzees exhibited this behavior more frequently than adult males. PMID:17320393

  5. Performance of human groups in social foraging: the role of communication in consensus decision making.

    Science.gov (United States)

    King, Andrew J; Narraway, Claire; Hodgson, Lindsay; Weatherill, Aidan; Sommer, Volker; Sumner, Seirian

    2011-04-23

    Early hominids searched for dispersed food sources in a patchy, uncertain environment, and modern humans encounter equivalent spatial-temporal coordination problems on a daily basis. A fundamental, but untested assumption is that our evolved capacity for communication is integral to our success in such tasks, allowing information exchange and consensus decisions based on mutual consideration of pooled information. Here we examine whether communication enhances group performance in humans, and test the prediction that consensus decision-making underlies group success. We used bespoke radio-tagging methodology to monitor the incremental performance of communicating and non-communicating human groups (small group sizes of two to seven individuals), during a social foraging experiment. We found that communicating groups (n = 22) foraged more effectively than non-communicating groups (n = 21) and were able to reach consensus decisions (an 'agreement' on the most profitable foraging resource) significantly more often than non-communicating groups. Our data additionally suggest that gesticulations among group members played a vital role in the achievement of consensus decisions, and therefore highlight the importance of non-verbal signalling of intentions and desires for successful human cooperative behaviour.

  6. A tentative framework for the acquisition of language and modern human cognition.

    Science.gov (United States)

    Tattersall, Ian

    2016-06-20

    Modern human beings process information symbolically, rearranging mental symbols to envision multiple potential realities. They also express the ideas they form using structured articulate language. No other living creature does either of these things. Yet it is evident that we are descended from a non-symbolic and non-linguistic ancestor. How did this astonishing transformation occur? Scrutiny of the fossil and archaeological records reveals that the transition to symbolic reasoning happened very late in hominid history - indeed, within the tenure of anatomically recognizable Homo sapiens. It was evidently not simply a passive result of the increase in brain size that typified multiple lineages of the genus Homo over the Pleistocene. Instead, a brain exaptively capable of complex symbolic manipulation and language acquisition was acquired in the major developmental reorganization that gave rise to the anatomically distinctive species Homo sapiens. The new capacity it conferred was later recruited through the action of a cultural stimulus, most plausibly the spontaneous invention of language. PMID:27014833

  7. 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.

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

    Directory of Open Access Journals (Sweden)

    J Braga

    Full Text Available 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.

  9. Evolution of the brain: from behavior to consciousness in 3.4 billion years.

    Science.gov (United States)

    Oró, John J

    2004-06-01

    Once life began as single-cell organisms, evolution favored those able to seek nutrients and avoid risks. Receptors sensed the environment, memory traces were laid, and adaptive responses were made. Environmental stress, at times as dramatic as the collision of an asteroid, resulted in extinctions that favored small predators with dorsal nerve cords and cranially positioned brains. Myelination, and later thermoregulation, led to increasingly efficient neural processing. As somatosensory, visual, and auditory input increased, a neocortex developed containing both sensory and motor neural maps. Hominids, with their free hands, pushed cortical development further and began to make simple stone tools. Tools and increasing cognition allowed procurement of a richer diet that led to a smaller gut, thus freeing more energy for brain expansion. Multimodal association areas, initially developed for processing incoming sensory information, blossomed and began to provide the organism with an awareness of self and environment. Advancements in memory storage and retrieval gave the organism a sense of continuity through time. This developing consciousness eventually left visible traces, which today are dramatically evident on cave walls in France and Spain. We will take this journey from the single cell to human consciousness.

  10. Exploring the Potential of Laser Ablation Carbon Isotope Analysis for Examining Ecology during the Ontogeny of Middle Pleistocene Hominins from Sima de los Huesos (Northern Spain.

    Directory of Open Access Journals (Sweden)

    Nuria Garcia

    Full Text Available Laser ablation of tooth enamel was used to analyze stable carbon isotope compositions of teeth of hominins, red deer, and bears from middle Pleistocene sites in the Sierra de Atapuerca in northern Spain, to investigate the possibility that this technique could be used as an additional tool to identify periods of physiological change that are not detectable as changes in tooth morphology. Most of the specimens were found to have minimal intra-tooth variation in carbon isotopes (< 2.3‰, suggesting isotopically uniform diets through time and revealing no obvious periods of physiological change. However, one of the two sampled hominin teeth displayed a temporal carbon isotope shift (3.2‰ that was significantly greater than observed for co-occurring specimens. The δ13C value of this individual averaged about -16‰ early in life, and -13‰ later in life. This isotopic change occurred on the canine crown about 4.2 mm from the root, which corresponds to an approximate age of two to four years old in modern humans. Our dataset is perforce small owing to the precious nature of hominid teeth, but it demonstrates the potential utility of the intra-tooth isotope profile method for extracting ontogenetic histories of human ancestors.

  11. A probabilistic approach to the assessment of some life history pattern parameters in a Middle Pleistocene human population.

    Science.gov (United States)

    Durand, A I; Ipina, S L; Bermúdez de Castro, J M

    2000-06-01

    Parameters of a Middle Pleistocene human population such as the expected length of the female reproductive period (E(Y)), the expected interbirth interval (E(X)), the survival rate (tau) for females after the expected reproductive period, the rate (phi(2)) of women who, given that they reach first birth, do not survive to the end of the expected reproductive period, and the female infant plus juvenile mortality rate (phi(1)) have been assessed from a probabilistic standpoint provided that such a population were stationary. The hominid sample studied, the Sima de los Huesos (SH) cave site, Sierra de Atapuerca (Spain), is the most exhaustive human fossil sample currently available. Results suggest that the Atapuerca (SH) sample can derive from a stationary population. Further, in the case that the expected reproductive period ends between 37 and 40 yr of age, then 24 less, similarE(Y) less, similar27 yr, E(X)=3 yr, 0.224

  12. Auditory capacities in Middle Pleistocene humans from the Sierra de Atapuerca in Spain.

    Science.gov (United States)

    Martínez, I; Rosa, M; Arsuaga, J-L; Jarabo, P; Quam, R; Lorenzo, C; Gracia, A; Carretero, J-M; Bermúdez de Castro, J-M; Carbonell, E

    2004-07-01

    Human hearing differs from that of chimpanzees and most other anthropoids in maintaining a relatively high sensitivity from 2 kHz up to 4 kHz, a region that contains relevant acoustic information in spoken language. Knowledge of the auditory capacities in human fossil ancestors could greatly enhance the understanding of when this human pattern emerged during the course of our evolutionary history. Here we use a comprehensive physical model to analyze the influence of skeletal structures on the acoustic filtering of the outer and middle ears in five fossil human specimens from the Middle Pleistocene site of the Sima de los Huesos in the Sierra de Atapuerca of Spain. Our results show that the skeletal anatomy in these hominids is compatible with a human-like pattern of sound power transmission through the outer and middle ear at frequencies up to 5 kHz, suggesting that they already had auditory capacities similar to those of living humans in this frequency range. PMID:15213327

  13. Exploring the Potential of Laser Ablation Carbon Isotope Analysis for Examining Ecology during the Ontogeny of Middle Pleistocene Hominins from Sima de los Huesos (Northern Spain).

    Science.gov (United States)

    Garcia, Nuria; Feranec, Robert S; Passey, Benjamin H; Cerling, Thure E; Arsuaga, Juan Luis

    2015-01-01

    Laser ablation of tooth enamel was used to analyze stable carbon isotope compositions of teeth of hominins, red deer, and bears from middle Pleistocene sites in the Sierra de Atapuerca in northern Spain, to investigate the possibility that this technique could be used as an additional tool to identify periods of physiological change that are not detectable as changes in tooth morphology. Most of the specimens were found to have minimal intra-tooth variation in carbon isotopes (< 2.3‰), suggesting isotopically uniform diets through time and revealing no obvious periods of physiological change. However, one of the two sampled hominin teeth displayed a temporal carbon isotope shift (3.2‰) that was significantly greater than observed for co-occurring specimens. The δ13C value of this individual averaged about -16‰ early in life, and -13‰ later in life. This isotopic change occurred on the canine crown about 4.2 mm from the root, which corresponds to an approximate age of two to four years old in modern humans. Our dataset is perforce small owing to the precious nature of hominid teeth, but it demonstrates the potential utility of the intra-tooth isotope profile method for extracting ontogenetic histories of human ancestors. PMID:26673156

  14. [Sierra of the Atapuerca, thinking about the evolution].

    Science.gov (United States)

    Carbonell, Eudald

    2007-01-01

    Homo sapiens walks to the future in a uncertain way. The fosil evidences from the lithosphere can help us to get into know the social and cultural evolution of all the species that have precede us and even our own. Atapuerca, with more than 1.2 MA old of fossilized history from the Pleistocene to the Holocene is throwing a scientific message through the study of all its archaeological sites. There are thousands of animal and human fossils in Trinchera del Ferrocarril, Cueva de Gran Dolina, Sima del Elefante and Galeria that yield information on the cultural cannibalism practices by Homo antecessor 900,000 years ago, and the hunting and gathering that Homo heidelbergensis developed 400,000 years ago. Finally in the Sima de los Huesos, with a similar chronology than at the H. heidelbergensis sites from the Trinchera del Ferrocarril, we find the first intentional accumulation of hominid bodies. These contributions are significant to the knowledge of the biological and cultural human evolution and permits to deepen it empirically. We hope that understanding the message we will be able to improve our species through the socialization of the scientific knowledge. PMID:18069605

  15. The Sima de los Huesos (Burgos, northern Spain): palaeoenvironment and habitats of Homo heidelbergensis during the Middle Pleistocene

    Science.gov (United States)

    García, Nuria; Arsuaga, Juan Luis

    2011-06-01

    Interpreting how environmental dynamics respond to global climate change and how this has affected human evolution and dispersal is an on-going topic of debate. During the early Middle Pleistocene (˜0.6-0.4 Ma), as compared to earlier, environmental conditions were relatively more stable, with longer climatic cycles alternating between open and forested landscapes. During this interval, humans spread successfully providing an important number of fossil sites where fossils or tools are reported. The Atapuerca-Sima de los Huesos (Burgos, northern Spain) site (Atapuerca-SH) is one of the earliest localities with hominin evidence in the European Middle Pleistocene, with the most important accumulation of Homo heidelbergensis so far. We have analyzed the abundant faunal record from Sima de los Huesos, which is mainly comprised of carnivores, in order to approach an interpretation of the palaeoenvironmental circumstances where these hominids inhabited within the Sierra. Other sites from Sierra de Atapuerca referred to the same Faunal Unit (FU 6), are roughly contemporaneous, and include important ungulates, which are here analyzed with Atapuerca-SH. Additional information provided by isotopic analysis helps elucidate the ancient ecology of taxa present in Sima de los Huesos allowing for an accurate portrayal of the setting in which humans lived. The timing of the spread of Homo heidelbergensis is dominated by a relative climatic and environmental stability and points to a landscape dominated by savannah-like open woodland.

  16. Direct Transcriptional Effects of Apolipoprotein E.

    Science.gov (United States)

    Theendakara, Veena; Peters-Libeu, Clare A; Spilman, Patricia; Poksay, Karen S; Bredesen, Dale E; Rao, Rammohan V

    2016-01-20

    A major unanswered question in biology and medicine is the mechanism by which the product of the apolipoprotein E ε4 allele, the lipid-binding protein apolipoprotein E4 (ApoE4), plays a pivotal role in processes as disparate as Alzheimer's disease (AD; in which it is the single most important genetic risk factor), atherosclerotic cardiovascular disease, Lewy body dementia, hominid evolution, and inflammation. Using a combination of neural cell lines, skin fibroblasts from AD patients, and ApoE targeted replacement mouse brains, we show in the present report that ApoE4 undergoes nuclear translocation, binds double-stranded DNA with high affinity (low nanomolar), and functions as a transcription factor. Using chromatin immunoprecipitation and high-throughput DNA sequencing, our results indicate that the ApoE4 DNA binding sites include ∼1700 gene promoter regions. The genes associated with these promoters provide new insight into the mechanism by which AD risk is conferred by ApoE4, because they include genes associated with trophic support, programmed cell death, microtubule disassembly, synaptic function, aging, and insulin resistance, all processes that have been implicated in AD pathogenesis. Significance statement: This study shows for the first time that apolipoprotein E4 binds DNA with high affinity and that its binding sites include 1700 promoter regions that include genes associated with neurotrophins, programmed cell death, synaptic function, sirtuins and aging, and insulin resistance, all processes that have been implicated in Alzheimer's disease pathogenesis.

  17. Optimum ratio of upper to lower limb lengths in hand-carrying of a load under the assumption of frequency coordination.

    Science.gov (United States)

    Wang, W J; Crompton, R H; Li, Y; Gunther, M M

    2003-02-01

    The ratio of the upper to lower limb lengths [or the intermembral index (IMI)] in the earliest human ancestors is closer to that of the living chimpanzees than to our own, although the former show undoubted adaptations to bipedality. What biomechanical factors could then have led to the phenomenon of genus Homo? This paper proposes and evaluates a relationship between IMI and hand-carrying. Assuming that coordination of limb swing frequencies of the upper and lower limbs would be the subject of positive selection, a mathematical expression was derived and can in part explain the changes in IMI. We found that AL-288-1 [3.6 million years old (MY)], the most complete skeleton of the early hominid Australopithecus afarensis, could only have carried loads equivalent to 15-50% of the upper limb weight while maintaining swing symmetry, but KNM WT-15000, Homo ergaster (1.8MY) and modern humans could both carry loads 3 times heavier than the upper limb while maintaining swing symmetry. The carrying ability of chimpanzees would be inferior to that of AL-288-1. The IMI of modern humans, at 68-70, is the smallest, and is optimal for hand-carrying under our criteria. Under reduced selection pressure for hand-carrying, but unreduced selection for mechanical effectiveness, we might expect humans to evolve a longer upper limb, to improve swing symmetry when unloaded. PMID:12547362

  18. An Early Pleistocene high-resolution paleoclimate reconstruction from the West Turkana (Kenya) HSPDP drill site

    Science.gov (United States)

    Stockhecke, Mona; Beck, Catherine; Brown, Erik T.; Cohen, Andrew; Deocampo, Daniel M.; Feibel, Craig S.; Pelletier, Jon D.; Rabideaux, Nathane M.; Sier, Mark

    2016-04-01

    The Hominin Sites and Paleolakes Drilling Project (HSPDP), and the related Olorgesailie Drilling Project (ODP), recovered ~2 km of drill core since 2012. At the HSPDP West Turkana Kaitio (WTK) site a 216 m-long core that covers the Early Pleistocene time window (1.3 to 1.87 Ma) during which hominids first expanded out of Africa and marine records document reorganization of tropical climate and the development of the strong Walker circulation. WTK carries particular interest for paleoclimate and paleoenvironmental reconstructions as it is located only 2.5 km from the location of one of the most complete hominin skeletons ever recovered (Nariokotome Boy). XRF core scanning data provide a means of evaluating records of past environmental conditions continuously and at high resolution. However, the record contains complex lithologies reflecting repeated episodes of inundation and desiccation along a dynamic lake margin. Here we present a methodological approach to address the highly variable lithostratigraphy of the East African records to establish comprehensive paleoclimate timeseries. The power spectrum of the presented hydroclimate record peaks at Milankovitch cycles, qualifying HSPDP drill cores from the Turkana Basin to be used as high-resolution Early Pleistocene paleoclimate archive. Comparing these data with marine climate reconstructions sheds light into athmospheric processes and continental climate dynamics.

  19. USER principle as relating the human environmental management

    International Nuclear Information System (INIS)

    The environmental variable can be understood as the resulting biosphere space that has suffered the occurrence of pre-biotic, biotic and anthropic processes. This necessary expansion of the environmental frontier allows understand clearly the magnitude the great complexity of the process immersed in the current environmental problematic. This, taking into account the analysis of the reference systems used by the different species to face their interaction with the nature. Hence, it is necessary to evaluate the human referential process of reality, as a responsible specie of the derange shown by the Environmental Mother Eve. The latest hominid development of an Artificial Reference System (ARS) (linguistic symbols), points to the constitution of the casual factor that triggers such an environmental problematic. The expansive dynamics accomplished by the ARS has not always made reference to the natural ambience that created them. The formulation of the Unprivilegeness of Symbolic Endogenous Referents (USER) Principle (Kernakis 1986, 1997), as a necessary epistemological consequence of the Special Relativity from Einstein, entails to the reversion of the local privileges created by the ARS, stating a referential crisis as alternative to a potential environmental collapse. AII these could lead to the most intra-specific understanding with the nature, antonomastical fragmented by the privileges of the ARS. Such integration species-nature would allow to make possible an spontaneous natural-cultural arranging of the environmental balance

  20. Sex differences in impulsive and compulsive behaviors: a focus on drug addiction.

    Science.gov (United States)

    Fattore, Liana; Melis, Miriam

    2016-09-01

    Sex differences in inhibition and self-regulation at a behavioral level have been widely described. From an evolutionary point of view, the different selection pressures placed on male and female hominids led them to differ in their behavioral strategies that allowed our species to survive during natural selection processes. These differences reflect changes in neural and structural plasticity that might be the core of sex differences, and of the susceptibility towards one psychiatric condition rather than another. The goal of the present review is to summarize current evidence for such a dichotomy in impulsive and compulsive behavior with a focus on drug addiction. Sex-dependent differences in drug abuse and dependence will be examined in the context of pathophysiological regulation of impulse and motivation by neuromodulators (i.e. gonadal hormones) and neurotransmitters (i.e. dopamine). Advances in the understanding of the sex differences in the capability to control impulses and motivational states is key for the determination of efficacious biologically based intervention and prevention strategies for several neuropsychiatric disorders where loss of impulse control and compulsivity are the core symptoms. PMID:26935237

  1. Voyages Through Time: Everything Evolves

    Science.gov (United States)

    Fisher, Jane; Tarter, Jill; Devore, Edna; Pendleton, Yvonne; O'Sullivan, Kathleen; Burke, Meg

    2004-06-01

    The SETI Institute, the California Academy of Sciences, NASA Ames Research Center, and San Francisco State University have developed standards-based curriculum materials for a one-year high school integrated science course centered on the unifying theme of evolution. Scientists, teachers, curriculum writers, and media specialists are currently finalizing six modules that integrate astronomical, geological, and biological sciences as well as the history of science and technology. The sequence of lessons in each module is designed to promote students' understanding and skills as defined by the National Science Education Standards and Benchmarks for Science Literacy. The modules cover: Cosmic Evolution, Planetary Evolution, Origin of Life, Evolution of Life, Hominid Evolution, and the Evolution of Technology. The core lessons for all six modules are provided via CD-ROM, including instructional guidelines, science background information, and additional resources (print, audiovisual, software, WWW sites, and databases). These products will be published as a complete set for use as a yearlong science course and will also be available as individual modules for use in discipline-based courses. Evolutionary change is a powerful framework for studying our world and our place therein. It is a story of epic size, capable of inspiring awe and of expanding our sense of time and place. This story is the basis of Voyages Through Time.

  2. Evaluating methods used for fission track dating of tephras: examples from the Afar Depression, Ethiopia, and the Denali fault zone, Alaska

    Science.gov (United States)

    Blythe, A. E.; Warfel, T. S.; Phillips, D. J.

    2015-12-01

    Although fission track geochronology has been successfully used to date volcanic glasses and tephras in several studies, a variety of approaches have been used (see Westgate et al., 2013), and no consensus for a standardized methodology has emerged. As a result, this technique is rarely employed, despite having the potential to date tephras and glasses that cannot be dated by other methods, such as K-Ar dating. We have been evaluating the various approaches used to address the technical issues in fission track dating of tephras, by applying them to standards of known ages, including Moldavite tektite, and Huckleberry and Bishop Tuffs. Some of these issues include track etching and counting protocol, and corrections for the effects of track fading at low temperatures. Track etching is generally done in 24% HF for 75 or more seconds, but the time necessary for optimal etching appears to vary according to sample composition and grain size. To correct for track fading, we are using the diameter correction technique of Sandhu and Westgate (1995). We have obtained tephra samples from two regions, the Afar Depression in Ethiopia, an area with significant early hominid fossils, and the Denali fault zone in Alaska, an area with a complicated tectonic evolution. For both of these regions, we have samples that have been dated by other methods for calibration purposes, and we will explore the application of a Zeta correction to the technique. This underutilized technique can provide powerful constraints on studies of timing in diverse geologic environments.

  3. 河南灵井许昌人遗址普通马(Equus caballus)化石居群的死亡年龄曲线%Mortality Curves for Horses(Equus Caballus) from the Lingjing Site, Henan Province

    Institute of Scientific and Technical Information of China (English)

    李占扬; 张双权; 张乐; 高星

    2011-01-01

    普通马(Equus caballus)是河南灵井许昌人遗址动物群中的一个优势属种.本文基于这一动物属种牙齿材料的测量与分析,初步完成了普通马个体死亡年龄的计算及其化石居群的生命表构建,并与世界范围内多个动物群的相关材料进行了对比研究.该动物群普通马化石材料的死亡年龄曲线反映了这一时期古人类以普通马居群中的壮年个体为主要狩猎目标的选择性生存策略和狩猎能力.%Horse (Equus caballus) is one of the dominant species of the faunal assemblage from the Lingjing site, Henan Province. Based on dental remains of this animal, this paper tabulated the death ages of various individuals and further constructes the life tables for the populations of this species. Some comparative studies were also conducted between fossil materials from the site and other related faunal assemblages from around the world. The mortality curves for horses from the Lingjing Site clearly indicate that adult horses were preferentially hunted by the hominids who frequented the site.

  4. Anthracothere dental anatomy reveals a late Miocene Chado-Libyan bioprovince.

    Science.gov (United States)

    Lihoreau, Fabrice; Boisserie, Jean-Renaud; Viriot, Laurent; Coppens, Yves; Likius, Andossa; Mackaye, Hassane Taisso; Tafforeau, Paul; Vignaud, Patrick; Brunet, Michel

    2006-06-01

    Recent discovery of an abundant and diverse late Miocene fauna at Toros-Ménalla (Chad, central Africa) by the Mission Paléoanthropologique Franco-Tchadienne provides a unique opportunity to examine African faunal and hominid evolution relative to the early phases of the Saharan arid belt. This study presents evidence from an African Miocene anthracotheriid Libycosaurus, particularly well documented at Toros-Ménalla. Its remains reveal a large semiaquatic mammal that evolved an autapomorphic upper fifth premolar (extremely rare in Cenozoic mammals). The extra tooth appeared approximately 12 million years ago, probably in a small northern African population isolated by climate-driven fragmentation and alteration of the environments inhabited by these anthracotheriids [Flower, B. P. & Kennett, J. P. (1994) Palaeogeogr. Palaeoclimatol. Palaeoecol. 108, 537-555 and Zachos, J., Pagani, M., Sloan, L., Thomas, E. & Billups, K. (2001) Science 292, 686-693]. The semiaquatic niche of Libycosaurus, combined with the distribution and relationships of its late Miocene species, indicates that by the end of the Miocene, wet environments connected the Lake Chad Basin to the Libyan Sirt Basin, across what is now the Sahara desert.

  5. Theories of bipedal walking: an odyssey.

    Science.gov (United States)

    Vaughan, Christopher L

    2003-04-01

    In this paper six theories of bipedal walking, and the evidence in support of the theories, are reviewed. They include: evolution, minimising energy consumption, maturation in children, central pattern generators, linking control and effect, and robots on two legs. Specifically, the six theories posit that: (1) bipedalism is the fundamental evolutionary adaptation that sets hominids--and therefore humans--apart from other primates; (2) locomotion is the translation of the centre of gravity along a pathway requiring the least expenditure of energy; (3) when a young child takes its first few halting steps, his or her biomechanical strategy is to minimise the risk of falling; (4) a dedicated network of interneurons in the spinal cord generates the rhythm and cyclic pattern of electromyographic signals that give rise to bipedal gait; (5) bipedal locomotion is generated through global entrainment of the neural system on the one hand, and the musculoskeletal system plus environment on the other; and (6) powered dynamic gait in a bipedal robot can be realised only through a strategy which is based on stability and real-time feedback control. The published record suggests that each of the theories has some measure of support. However, it is important to note that there are other important theories of locomotion which have not been covered in this review. Despite such omissions, this odyssey has explored the wide spectrum of bipedal walking, from its origins through to the integration of the nervous, muscular and skeletal systems.

  6. Direct radiocarbon dates for prehistoric paintings at the Altamira, El Castillo and Niaux caves

    International Nuclear Information System (INIS)

    Among things that most strikingly distinguish modern humans from other hominids and the rest of the animal kingdom is the ability to represent things and events pictorially. Complex paintings of the type discovered in the Altamira, El Castillo, Niaux and Lascaux caves represent an important stepping stone in the cultural evolution of humankind. Until now dates were derived from style or dated remains left by prehistoric visitors and could be biased by prolonged occupation or visits unrelated to painting activity. Here we report the first radiocarbon dates for the charcoal used to draw stylistically similar bisons in these caves: 14,000 ± 400 yr BP in the Spanish caves of Altamira, 12,990 ± 200 yr BP in El Castillo, and 12,890 ± 160 yr BP for a bison of different style in the French Pyrenean cave of Niaux. Our results demonstrate the imprecise nature of stylistic dating and show that painting dates derived from remains of human activities should be used with caution. (Author)

  7. Out of Africa: modern human origins special feature: human origins: out of Africa.

    Science.gov (United States)

    Tattersall, Ian

    2009-09-22

    Our species, Homo sapiens, is highly autapomorphic (uniquely derived) among hominids in the structure of its skull and postcranial skeleton. It is also sharply distinguished from other organisms by its unique symbolic mode of cognition. The fossil and archaeological records combine to show fairly clearly that our physical and cognitive attributes both first appeared in Africa, but at different times. Essentially modern bony conformation was established in that continent by the 200-150 Ka range (a dating in good agreement with dates for the origin of H. sapiens derived from modern molecular diversity). The event concerned was apparently short-term because it is essentially unanticipated in the fossil record. In contrast, the first convincing stirrings of symbolic behavior are not currently detectable until (possibly well) after 100 Ka. The radical reorganization of gene expression that underwrote the distinctive physical appearance of H. sapiens was probably also responsible for the neural substrate that permits symbolic cognition. This exaptively acquired potential lay unexploited until it was "discovered" via a cultural stimulus, plausibly the invention of language. Modern humans appear to have definitively exited Africa to populate the rest of the globe only after both their physical and cognitive peculiarities had been acquired within that continent.

  8. Human origins: Out of Africa

    Science.gov (United States)

    Tattersall, Ian

    2009-01-01

    Our species, Homo sapiens, is highly autapomorphic (uniquely derived) among hominids in the structure of its skull and postcranial skeleton. It is also sharply distinguished from other organisms by its unique symbolic mode of cognition. The fossil and archaeological records combine to show fairly clearly that our physical and cognitive attributes both first appeared in Africa, but at different times. Essentially modern bony conformation was established in that continent by the 200–150 Ka range (a dating in good agreement with dates for the origin of H. sapiens derived from modern molecular diversity). The event concerned was apparently short-term because it is essentially unanticipated in the fossil record. In contrast, the first convincing stirrings of symbolic behavior are not currently detectable until (possibly well) after 100 Ka. The radical reorganization of gene expression that underwrote the distinctive physical appearance of H. sapiens was probably also responsible for the neural substrate that permits symbolic cognition. This exaptively acquired potential lay unexploited until it was “discovered” via a cultural stimulus, plausibly the invention of language. Modern humans appear to have definitively exited Africa to populate the rest of the globe only after both their physical and cognitive peculiarities had been acquired within that continent. PMID:19805256

  9. Cosmic evolution, life and man

    International Nuclear Information System (INIS)

    Among the most basic problems confronting science are those regarding the origin of the universe, the origin of life and the origin of man. This general overview starts (1) with a brief introduction addressed primarily to the Cyril Ponnamperuma Memorial. Then, the thesis is presented that the appearance of life and intelligence on our planet can be understood as the result of a number of cosmic and biological evolutionary processes, including (2) the stellar thermonuclear synthesis of the biogenic elements other than hydrogen (C, N, O, P and S), their dispersal into space, and their combination into circumstellar and interstellar molecules. (3) The formation of the Solar System and the Earth-Moon System. (4) The role of comets and carbonaceous chondrites in contributing organic matter to the primitive Earth. (5) The prebiotics synthesis of amino acids, purines, pyrimidines, fatty acids, and other biochemical monomers. (6) The prebiotic condensation reactions leading to the synthesis of oligomers such as oligonucleotides and oligopeptides, with replicative and catalytic activities. (7) The synthesis of amphiphilic lipids, and their self-assembly into liposomes with bi-layered membranes. (8) The formation of protocellular structures. (9) The activation of protocells into a functioning Darwin's ancestral cell. (10) Early evolution of life. (11) The K-T boundary event and the disappearance of dinosaurs. (12) Evolution of hominids leading to Homo sapiens. (13) The rapid development of civilization. (14) The exploration of the Solar System. (15) Life beyond our planetary system. (16) Epilogue. Peace from cosmic evolution? (Abstract only)

  10. Ancient hunters and their modern representatives: William Sollas's (1849-1936) Anthropology from disappointed bridge to trunkless tree and the instrumentalisation of racial conflict.

    Science.gov (United States)

    Sommer, Marianne

    2005-01-01

    During the first decades of the 20th century, many anthropologists who had previously adhered to a linear view of human evolution, from an ape via Pithecanthropus erectus (today Homo erectus) and Neanderthal to modern humans, began to change their outlook. A shift towards a branching model of human evolution began to take hold. Among the scientific factors motivating this trend was the insight that mammalian evolution in general was best represented by a branching tree, rather than by a straight line, and that several new fossil hominids were discovered that differed significantly in their morphology but seemed to date from about the same period. The ideological and practical implications of imperialism and WWI have also been identified as formative of the new evolutionary scenarios in which racial conflict played a crucial role. The paper will illustrate this general shift in anthropological theory for one particular scientist, William Sollas (1849-1936). Sollas achieved a synthesis of human morphological and cultural evolution in what I will refer to as an imperialist model. In this theoretical framework, migration, conflict, and replacement became the main mechanisms for progress spurred by 'nature's tyrant,' natural selection.

  11. Nut-like oil seeds: food for monkeys, chimpanzees, humans, and probably ape-men.

    Science.gov (United States)

    Peters, C R

    1987-07-01

    The hypothetical hyperrobust australopithecine gnathic nutcracker adaptation is reexamined in light of ecobotanical information on edible wild nuts provided by the flora of tropical and subtropical Africa. The nut producing species are tree-forms. Those of the forest region do not as a rule produce fruits with edible mesocarps. In contrast, the woodland savanna species (particularly in the Zambezian region) characteristically provide an important whole fruit, i.e., a nutritious mesocarp in addition to edible oil-rich nut seeds. These fruits drop from the tree before they are fully mature and go through the final ripening phase on the ground. They are important seasonal foods for a variety of vertebrates, including primates, elephants, and antelope. Altogether the nuts exhibit a broad range of toughness values, measured here as strength under compression. The woodland nuts are not as tough (177-934 kg force, breaking load) as those of the tropical forest (192-1,673 kg force). The seed-predators of the woodland species include squirrels, baboons, warthogs, and parrots. Paleoecological analyses indicate that it was the woodland nuts that were probably available to Australopithecus boisei and A. robustus. Preliminary estimates of adult male gnathic nut-cracking capabilities suggest that A. boisei could have orally cracked a significant portion of the woodland nuts. In spite of this, ecobotanical data indicate that we can probably reject the hypothesis that these hominids were year-round gnathic nut-cracking specialists. Both the indirect and direct evidence support this conclusion. PMID:3113265

  12. Differential resource utilization by extant great apes and australopithecines: towards solving the C4 conundrum.

    Science.gov (United States)

    Sponheimer, Matt; Lee-Thorp, Julia A

    2003-09-01

    Morphological and biogeochemical evidence suggest that australopithecines had diets markedly different from those of extant great apes. Stable carbon isotope analysis, for example, has shown that significant amounts of the carbon consumed by australopithecines were derived from C(4) photosynthesis in plants. This means that australopithecines were eating large quantities of C(4) plants such as tropical grasses and sedges, or were eating animals that were themselves eating C(4) plants. In contrast, there is no evidence that modern apes consume appreciable amounts of any of these foods, even in the most arid extents of their ranges where these foods are most prevalent. Environmental reconstructions of early australopithecine environments overlap with modern chimpanzee habitats. This, in conjunction with the stable isotope evidence, suggests that australopithecines and great apes, even in similar environments, would utilize available resources differently. Thus, the desire or capacity to use C(4) foods may be a basal character of our lineage. We do not know, however, which of the nutritionally disparate C(4) foods were utilized by hominids. Here we discuss which C(4) resources were most likely consumed by australopithecines, as well as the potential nutritional, physiological, and social consequences of eating these foods. PMID:14527627

  13. Growth changes in internal and craniofacial flexion measurements.

    Science.gov (United States)

    May, R; Sheffer, D B

    1999-09-01

    Growth changes in both internal and craniofacial flexion angles are presented for Pan troglodytes, Gorilla gorilla, and modern humans. The internal flexion angle (IFA) was measured from lateral radiographs, and the craniofacial flexion angle (CFA) was calculated from coordinate data. Stage of dental development is used as a baseline for examination of growth changes and nonparametric correlations between flexion angles and dental development stage are tested for significance. In Gorilla, the IFA increases during growth. The IFA is relatively stable in Pan and modern humans. Pan and Gorilla display an increase in the CFA. However, this angle decreases during growth in modern humans. Flexion angles were derived from coordinate data collected for several early hominid crania. Measurements for two robust australopithecine crania indicate strong internal flexion. It has been suggested that cerebellar expansion in this group may relate to derived features of the posterior cranial base. In general, australopithecine crania exhibit craniofacial flexion intermediate between great apes and modern humans. The "archaic" Homo sapiens specimen from Kabwe is most similar to modern humans. PMID:10490467

  14. Growth changes in measurements of upper facial positioning.

    Science.gov (United States)

    May, R; Sheffer, D B

    1999-03-01

    Growth changes in the position of the midline upper face are examined for samples of Pan troglodytes, Gorilla gorilla, and modern humans. Horizontal and vertical distances between nasion and the anterior end of the cribriform plate are plotted against stage of dental development. Kendall's nonparametric correlations between facial positioning and stage of dental development are tested for significance. In African apes, the upper face becomes more projecting and positioned higher relative to the anterior cranial base. The extent of this horizontal and vertical separation reflects primarily facial size. In modern humans, the upper face becomes more projecting but is relatively stable in its vertical position. Comparison of Pan and modern human crania in the youngest dental age category indicates that the upper face of modern humans is positioned lower early in postnatal life. The position of the upper face (glabella) relative to the anterior and posterior cranial base is presented for several fossil hominid crania. The fossil crania are similar to Pan and modern humans in facial projection relative to the anterior cranial base. However, glabella is positioned low in the fossil crania. Total facial projection (relative to hormion) for Sts 5 is similar to the mean for Gorilla. Fossil Homo and robust australopithecine crania display very projecting upper faces. We suggest that the upper face of Homo is projecting due to the length of the anterior cranial fossa, while robust australopithecines possess a thick frontal bone. PMID:10096679

  15. Lucy's lower limbs: long enough for Lucy to be fully bipedal?

    Science.gov (United States)

    Wolpoff, M H

    The recent attempt to show that the Hadar australopithecine female 'Lucy' (AL 288-1) had hindlimbs too short to allow a modern pattern of striding bipedal gait has important implications for understanding the origin of bipedalism, if not for the more general problem of hominid origins. Combined with previous claims that Lucy had a forelimb unusually long in proportion and ape-like in morphology, the additional contention of a relatively short hindlimb would suggest a very different pattern of gait from the norm of today because the effectiveness of the pendulum action of the lower limb during stride is a function of the amount of mass in the limb, and because a short hindlimb would necessitate a short stride length. Yet, these contentions seem contradicted by the analyses of Lucy's pelvis (and the innominates of other australopithecines) that indicate a similar pattern of muscle use and imply a lack of significant gait differences. Are Lucy's legs too short to allow an effective stride, or is there a different solution to this contradiction? I propose here that there is. PMID:6408483

  16. Biomechanics of cross-sectional size and shape in the hominoid mandibular corpus.

    Science.gov (United States)

    Daegling, D J

    1989-09-01

    Mandibular cross sections of Pan, Pongo, Gorilla, Homo, and two fossil specimens of Paranthropus were examined by computed tomography (CT) to determine the biomechanical properties of the hominoid mandibular corpus. Images obtained by CT reveal that while the fossil hominids do not differ significantly from extant hominoids in the relative contribution of compact bone to total subperiosteal area, the shape of the Paranthropus corpora indicates that the mechanical design of the robust australopithecine mandible is fundamentally distinct from that of modern hominoids in terms of its ability to resist transverse bending and torsion. It is also apparent that, among the modern hominoids, interspecific and sexual differences in corpus shape are not significant from a biomechanical perspective. While ellipse models have been used previously to describe the size, shape, and subsequent biomechanical properties of the corpus, the present study shows that such models do not predict the biomechanical properties of corpus cross-sectional geometry in an accurate or reliable manner. The traditional "robusticity" index of the mandibular corpus is of limited utility for biomechanical interpretations. The relationship of compact bone distribution in the corpus to dimensions such as mandibular length and arch width may provide a more functionally meaningful definition of mandibular robusticity. PMID:2508480

  17. The first australopithecine 2,500 kilometres west of the Rift Valley (Chad)

    Science.gov (United States)

    Brunet, M; Beauvilain, A; Coppens, Y; Heintz, E; Moutaye, A H; Pilbeam, D

    1995-11-16

    The first sites with Pliocene and Pleistocene mammals west of the Rift Valley in Central Africa in northern Chad were reported in 1959 (ref. 1), and documented the presence of mixed savannah and woodland habitats. Further sites and a probable Homo erectus cranio-facial fragment were subsequently discovered. In 1993 a survey of Pliocene and Pleistocene formations in the Borkou-Ennedi-Tibesti Province of Chad (B.E.T.) led to the discovery of 17 new sites in the region of Bahr el Ghazal (classical Arabic for River of the Gazelles) near Koro Toro. One site, KT 12 (15 degrees 58'10"N, 18 degrees 52'46"E) yielded an australopithecine mandible associated with a fauna biochronologically estimated to be 3.0-3.5 Myr old. Australopithecine species described since 1925 are known from southern Africa and from sites spread along the eastern Rift Valley from Tanzania to Ethiopia (Fig. 1). This new find from Chad, which is most similar in morphology to Australopithecus afarensis, documents the presence of an early hominid a considerable distance, 2,500 km, west of the Rift Valley. PMID:7477344

  18. Paleopediatrics: or when did human infants really become human?

    Science.gov (United States)

    Conroy, G C; Kuykendall, K

    1995-10-01

    Modern human children take about twice as long as their closest biological relative, the chimpanzee, to mature. One standard explanation for the evolution of "delayed maturation" at an early stage of human evolution is that it provided the time necessary for immature individuals to learn complex skills, most notably those relating to tool-making abilities. However, after comparing dental maturational profiles of early hominids from South Africa (who apparently did make and use stone tools) (Susman [1994] Science 265:1570-1573) to those of extant humans and chimpanzees, we find no evidence to document an association between "delayed maturation" and tool-making abilities in the early stages of human evolution. This also suggests that the assumed association between prolonged childhood dependency and other behaviors often associated with the advent of tool-making such as cooperative hunting, food sharing, home bases, sexual division of labor, etc., is also suspect. Instead, we must look for other, or additional, selective pressures for the evolution of "delayed maturation," which may postdate the australopithecine radiation. PMID:8644874

  19. Life history effects on the molecular clock of autosomes and sex chromosomes.

    Science.gov (United States)

    Amster, Guy; Sella, Guy

    2016-02-01

    One of the foundational results in molecular evolution is that the rate at which neutral substitutions accumulate on a lineage equals the rate at which mutations arise. Traits that affect rates of mutation therefore also affect the phylogenetic "molecular clock." We consider the effects of sex-specific generation times and mutation rates in species with two sexes. In particular, we focus on the effects that the age of onset of male puberty and rates of spermatogenesis have likely had in hominids (great apes), considering a model that approximates features of the mutational process in mammals, birds, and some other vertebrates. As we show, this model can account for a number of seemingly disparate observations: notably, the puzzlingly low X-to-autosome ratios of substitution rates in humans and chimpanzees and differences in rates of autosomal substitutions among hominine lineages (i.e., humans, chimpanzees, and gorillas). The model further suggests how to translate pedigree-based estimates of human mutation rates into split times among extant hominoids (apes), given sex-specific life histories. In so doing, it largely bridges the gap reported between estimates of split times based on fossil and molecular evidence, in particular suggesting that the human-chimpanzee split may have occurred as recently as 6.6 Mya. The model also implies that the "generation time effect" should be stronger in short-lived species, explaining why the generation time has a major influence on yearly substitution rates in mammals but only a subtle one in human pedigrees.

  20. Culture, Urbanism and Changing Human Biology

    Science.gov (United States)

    Schell, L.M.

    2014-01-01

    Anthropologists have long known that human activity driven by culture changes the environment. This is apparent in the archaeological record and through the study of the modern environment. Perhaps the largest change since the paleolithic era is the organization of human populations in cities. New environments can reshape human biology through evolution as shown by the evolution of the hominid lineage. Evolution is not the only process capable of reshaping our biology. Some changes in our human biology are adaptive and evolutionary while others are pathological. What changes in human biology may be wrought by the modern urban environment? One significant new change in the environment is the introduction of pollutants largely through urbanization. Pollutants can affect human biology in myriad ways. Evidence shows that human growth, reproduction, and cognitive functioning can be altered by some pollutants, and altered in different ways depending on the pollutant. Thus, pollutants have significance for human biologists and anthropologists generally. Further, they illustrate the bio-cultural interaction characterizing human change. Humans adapt by changing the environment, a cultural process, and then change biologically to adjust to that new environment. This ongoing, interactive process is a fundamental characteristic of human change over the millennia. PMID:25598655

  1. The fossil record as a tool in cyclo stratigraphy: the incidence of Milankovitch-scale palaeoenvironmental changes on palaeocommunities

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Tovar, F. J.

    2013-06-01

    Cyclo stratigraphic analysis at the Milankovitch scale has to date mainly been approached through the sedimentary record, although palaeontological data (the fossil record) is known to provide useful evidence of orbital-scale cycles of precession, obliquity and eccentricity. Orbit ally induced marine and terrestrial palaeoenvironmental changes determine variable responses on the part of the resident communities. Aside from the disruption of communities, complex evolutionary responses including stasis, speciation and extinction phenomena may take place. Cyclic variations in the marine past-biota at the community level, or in some particular taxa, have often been associated with orbit ally induced changes in palaeoenvironmental parameters. Cyclo stratigraphic research into foraminifera, radiol aria and nanno fossil data, mainly from Cretaceous sediments, may contribute significantly to our understanding of the planktonic community's response, whereas the response of the benthic community, deriving mainly from benthic foraminifera and trace fossils, has been studied to a lesser extent. Recognition of Milankovitch cycles from terrestrial palaeocommunities is relatively scarce and based mainly on the study of Pliocene-Miocene pollen assemblages. Astronomical forced climate changes determine well known variations in the distribution of terrestrial vegetation, but can also affect the terrestrial animal community, including hominid populations (migration, dispersion and colonisation). (Author)

  2. Possible brucellosis in an early hominin skeleton from sterkfontein, South Africa.

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    Ruggero D'Anastasio

    Full Text Available We report on the paleopathological analysis of the partial skeleton of the late Pliocene hominin species Australopithecus africanus Stw 431 from Sterkfontein, South Africa. A previous study noted the presence of lesions on vertebral bodies diagnosed as spondylosis deformans due to trauma. Instead, we suggest that these lesions are pathological changes due to the initial phases of an infectious disease, brucellosis. The macroscopic, microscopic and radiological appearance of the lytic lesions of the lumbar vertebrae is consistent with brucellosis. The hypothesis of brucellosis (most often associated with the consumption of animal proteins in a 2.4 to 2.8 million year old hominid has a host of important implications for human evolution. The consumption of meat has been regarded an important factor in supporting, directing or altering human evolution. Perhaps the earliest (up to 2.5 million years ago paleontological evidence for meat eating consists of cut marks on animal remains and stone tools that could have made these marks. Now with the hypothesis of brucellosis in A. africanus, we may have evidence of occasional meat eating directly linked to a fossil hominin.

  3. Land - Ocean Climate Linkages and the Human Evolution - New ICDP and IODP Drilling Initiatives in the East African Rift Valley and SW Indian Ocean

    Science.gov (United States)

    Zahn, R.; Feibel, C.; Co-Pis, Icdp/Iodp

    2009-04-01

    The past 5 Ma were marked by systematic shifts towards colder climates and concomitant reorganizations in ocean circulation and marine heat transports. Some of the changes involved plate-tectonic shifts such as the closure of the Panamanian Isthmus and restructuring of the Indonesian archipelago that affected inter-ocean communications and altered the world ocean circulation. These changes induced ocean-atmosphere feedbacks with consequences for climates globally and locally. Two new ICDP and IODP drilling initiatives target these developments from the perspectives of marine and terrestrial palaeoclimatology and the human evolution. The ICDP drilling initiative HSPDP ("Hominid Sites and Paleolakes Drilling Project"; ICDP ref. no. 10/07) targets lacustrine depocentres in Ethiopia (Hadar) and Kenya (West Turkana, Olorgesailie, Magadi) to retrieve sedimentary sequences close to the places and times where various species of hominins lived over currently available outcrop records. The records will provide a spatially resolved record of the East African environmental history in conjunction with climate variability at orbital (Milankovitch) and sub-orbital (ENSO decadal) time scales. HSPDP specifically aims at (1) compiling master chronologies for outcrops around each of the depocentres; (2) assessing which aspects of the paleoenvironmental records are a function of local origin (hydrology, hydrogeology) and which are linked with regional or larger-scale signals; (3) correlating broad-scale patterns of hominin phylogeny with the global beat of climate variability and (4) correlating regional shifts in the hominin fossil and archaeological record with more local patterns of paleoenvironmental change. Ultimately the aim is to test hypotheses that link physical and cultural adaptations in the course of the hominin evolution to local environmental change and variability. The IODP initiative SAFARI ("Southern African Climates, Agulhas Warm Water Transports and Retroflection

  4. Field-mapping and petrographic analysis of volcanoes surrounding the Lake Natron Homo sapiens footprint site, northern Tanzania

    Science.gov (United States)

    Hewitt, S. M.; Zimmer, B.; Liutkus, C.; Carmichael, S. K.; McGinnis, K.

    2010-12-01

    The Lake Natron Homo sapiens footprint site is located in northern Tanzania along the East African Rift escarpment. The site is positioned south of Lake Natron within an ephemeral channel of the Engare Sero River. The hominid footprints are preserved in a tuff, which originated from one of the volcanic centers surrounding the site. Two large volcanoes in the surrounding region, including the active carbonatite producing Oldoinyo L’engai and the now extinct Kerimasi are possible sources. This area also contains over 30 smaller tuff cones and tuff rings that have been poorly mapped and not analyzed in detail. The site is significant as it is the oldest modern human trackway in East Africa and one of the largest collections of hominid footprints in the world. Determining the source of the footprinted volcanic ash requires detailed field mapping, and both petrographic and geochemical analyses. Extensive field-mapping of the region revealed multiple regional beds that stratigraphically overlay the footprinted layer. Age dating as well as geochemical analysis is being conducted to relate these beds to the footprinted layer. Field-mapping showed that the footprinted tuff is over 35 cm thick, suggesting a large, sustained eruption. The bulk of the tuff cones examined in the field visibly varied in composition to the footprinted tuff and, based on proximity to the footprint site, are too small to produce the requisite volume of ash. Field analysis of samples collected from Oldoinyo L’engai reveal the most similar mineral assemblages to the footprinted layer, and the large volcano provides a source substantial enough to create a thick ash bed 10 km north of the summit. Preliminary research reveals that the footprinted tuff is a phonolite, characterized by silica depletion and the presence of sanidine, augite, and annite with interstitial calcite. XRD analysis of samples collected from Oldoinyo L’engai reveal a nepheline-rich phonolite with zeolites (ie. phillipsite

  5. The inverted bowl

    Science.gov (United States)

    Cole, G. H. A.

    ch. 1. Planets orbiting the sun and other stars. 1.1. General features of the solar system. 1.2. The terrestrial planetary bodies. 1.3. The characteristics of a planetary body. 1.4. Maximum and minimum conditions. 1.5. Planetary bodies: cold bodies. 1.6. Methods used to detect bodies of planetary mass. 1.7. Observed exo-planets. 1.8. Relevance for the occurrence of advanced life. 1.9. Summary -- ch. 2. The dynamic earth. 2.1. The geological divisions. 2.2. The formation and isothermal structure of the earth. 2.3. Internal thermal balance. 2.4. Geochronology: measurement of rock radioactivity. 2.5. Measurement of remanent magnetisation. 2.6. The land surfaces - the development of continents. 2.7. The surface temperature. 2.8. The climate. 2.9. The atmosphere. 2.10. Energy absorbed from solar radiation. 2.11. Astronomical factors affecting the atmosphere. 2.12. Effects of volcanoes. 2.13. Ice ages. 2.14. External impacts. 2.15. Summary -- ch. 3. Life in water: the precambrian. 3.1. Constructing the very early times. 3.2. Life begins. 3.3. Life develops. 3.4. ATP: a biological battery. 3.5. Life expands. 3.6. Oxygen and internally differentiated cells. 3.7. Complex cells. 3.8. Sex arrives - genetic diversity and stability. 3.9. Primitive senses. 3.10. Some images from the middle cambrian burgess shale -- ch. 4. Life develops in the phanerozoic. 4.1. Invasion of the land. 4.2. The seed and the amniotic egg. 4.3. Creatures come and go: some fly away. 4.4. The role of extinctions. 4.5. Evolution of eyes. 4.6. Brief comment on climate. 4.7. Summary -- ch. 5. Hominids - homo sapiens. 5.1. Nomenclature. 5.2. Development of more modern forms. 5.3. Hominids diversify. 5.4. The line homo sapiens. 5.5. The future of homo sapiens sapiens? 5.6. Summary -- ch. 6. A universe of exo-life? 6.1. Preliminary information. 6.2. A stellar time scale. 6.3. Abiogenisis - how did life form? 6.4. Where did life form - in situ or panspermia? 6.5. Where can life live?. 6.6. Suitable exo

  6. Les Rhinocerotidae (Mammalia, Perissodactyla miocènes et pliocènes des Tugen Hills (Kénya

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    Guérin, C.

    2011-12-01

    Full Text Available More than 70 determinable and usable rhinoceros remains belonging to nine species were yielded by 26 Miocene and Pliocene sites from the Tugen Hills (Kenya, namely Cheboit, Kapsomin, Kipsaraman and Tabarin. Such a material allows a better knowledge of the anatomy of these species. It is now possible to distinguish the postcranial skeleton of Aceratherium acutirostratum from that of Dicerorhinus leakeyi. The cranial and dental anatomy of Paradiceros mukirii is better known. The temporal extension of Chilotheridium pattersoni and Paradiceros mukirii are increased. Ceratotherium praecox is the most frequent rhino from the Uppermost Miocene onwards. Diceros bicornis is known since 6 My, about at the same time the first C. praecox. Diceros cf. pachygnathus is identified in the Lukeino and Mabaget Formations, and the geographical extension of this group of species is much increased. The Hominid Orrorin tugenensis is associated with rhinoceroses in four sites of the Lukeino Formation; Ceratotherium praecox is present in three of them, alone in Kapcheberek, associated one time (Tabarin with D. bicornis and in another one (Cheboit with Brachypotherium lewisi; at Aragai the sole rhino is Diceros cf. pachygnathus. All these rhinos contribute to assign to Orrorin a variable but mostly open and rather wet palaeoenvironment.

    [fr] Plus de 70 restes déterminables appartenant à neuf espèces de Rhinocerotidae ont été recueillis dans 26 gisements miocènes et pliocènes des Tugen Hills, les plus riches étant Cheboit, Kapsomin, Kipsaraman et Tabarin. Ce matériel permet d’accroître sensiblement nos connaissances sur l’anatomie de ces espèces. Il est désormais possible de distinguer le squelette post-crânien de Aceratherium acutirostratum de celui de Dicerorhinus leakeyi; l’anatomie crânienne et dentaire de

  7. Estudios pioneros en torno al origen del lenguaje natural

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    Martínez Contreras, Jorge

    2011-02-01

    Full Text Available It has being an ancient desire to ask apes what their natural lives are. De la Mettrie was the first to propose, in the 18th C., that the sign language of deaf adults could be used with them since they do not speak. We enhance here some of the pioneering projects of the two strategies for this endeavor: the use of ASL and the utilization of lexigrams and computers. Besides the ancient communicative quest with them, the evolutionist’s perspective has seen in these studies a way to find out how the natural language (NL emerged in hominids. If it is clear that apes do no possess totally the NL, the linguistic turn in primatology has left way, as in philosophy, to more complex field and laboratory cognitive studies of less anthropocentric nature.

    Tratar de hablar con los simios y preguntarles cosas sobre su vida natural es un viejo deseo. De la Mettrie propone, en el s. XVIII, que se les enseñe el lenguaje de los sordos en vista de que no pueden hablar. Resaltamos aquí algunos estudios pioneros en relación con las dos estrategias llevadas a cabo para tratar de hablar con los simios: el uso del lenguaje americano de sordos (ASL y el de los lexigramas y computadoras. Además del viejo interés interrogativo humano hacia ellos, la perspectiva evolucionista ha visto en estos estudios un medio de investigar cómo surgió el lenguaje natural (LN en homínidos. Si queda claro que los simios no poseen totalmente el LN, el giro lingüistico en primatología ha cedido, como en filosofía, el paso a estudios cognitivos más complejos, de campo y de laboratorio, de orientación menos antropomórfica.

  8. Evidence for linkage to psychosis and cerebral asymmetry (relative hand skill) on the X chromosome.

    Science.gov (United States)

    Laval, S H; Dann, J C; Butler, R J; Loftus, J; Rue, J; Leask, S J; Bass, N; Comazzi, M; Vita, A; Nanko, S; Shaw, S; Peterson, P; Shields, G; Smith, A B; Stewart, J; DeLisi, L E; Crow, T J

    1998-09-01

    The hypothesis that psychosis arises as a part of the genetic diversity associated with the evolution of language generates the prediction that illness will be linked to a gene determining cerebral asymmetry, which, from the evidence of sex chromosome aneuploidies, is present in homologous form on the X and Y chromosomes. We investigated evidence of linkage to markers on the X chromosome in 1) 178 families multiply affected with schizophrenia or schizoaffective disorder with a series of 16 markers spanning the centromere (study 1), and 2) 180 pairs of left-handed brothers with 14 markers spanning the whole chromosome (study 2). In study 1, excess allele-sharing was observed in brother-brother pairs (but not brother-sister or a small sample of sister-sister pairs) over a region of approximately 20 cM, with a maximum LOD score of 1.5 at DXS991. In study 2, an association between allele-sharing and degree of left-handedness was observed extending over approximately 60 cM, with a maximum lod score of 2.8 at DXS990 (approximately 20 cM from DXS991). Within the overlap of allele-sharing is located a block in Xq21 that transposed to the Y chromosome in recent hominid evolution and is now represented as two segments on Yp. In one of two XX males with psychosis we found that the breakpoint on the Y is located within the distal region of homology to the block in Xq21. These findings are consistent with the hypothesis that an X-Y homologous determinant of cerebral asymmetry carries the variation that contributes to the predisposition to psychotic illness.

  9. Dragon's paradise lost: palaeobiogeography, evolution and extinction of the largest-ever terrestrial lizards (Varanidae.

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    Scott A Hocknull

    Full Text Available BACKGROUND: The largest living lizard species, Varanus komodoensis Ouwens 1912, is vulnerable to extinction, being restricted to a few isolated islands in eastern Indonesia, between Java and Australia, where it is the dominant terrestrial carnivore. Understanding how large-bodied varanids responded to past environmental change underpins long-term management of V. komodoensis populations. METHODOLOGY/PRINCIPAL FINDINGS: We reconstruct the palaeobiogeography of Neogene giant varanids and identify a new (unnamed species from the island of Timor. Our data reject the long-held perception that V. komodoensis became a giant because of insular evolution or as a specialist hunter of pygmy Stegodon. Phyletic giantism, coupled with a westward dispersal from mainland Australia, provides the most parsimonious explanation for the palaeodistribution of V. komodoensis and the newly identified species of giant varanid from Timor. Pliocene giant varanid fossils from Australia are morphologically referable to V. komodoensis suggesting an ultimate origin for V. komodoensis on mainland Australia (>3.8 million years ago. Varanus komodoensis body size has remained stable over the last 900,000 years (ka on Flores, a time marked by major faunal turnovers, extinction of the island's megafauna, the arrival of early hominids by 880 ka, co-existence with Homo floresiensis, and the arrival of modern humans by 10 ka. Within the last 2000 years their populations have contracted severely. CONCLUSIONS/SIGNIFICANCE: Giant varanids were once a ubiquitous part of Subcontinental Eurasian and Australasian faunas during the Neogene. Extinction played a pivotal role in the reduction of their ranges and diversity throughout the late Quaternary, leaving only V. komodoensis as an isolated long-term survivor. The events over the last two millennia now threaten its future survival.

  10. The Divergence of Neandertal and Modern Human Y Chromosomes.

    Science.gov (United States)

    Mendez, Fernando L; Poznik, G David; Castellano, Sergi; Bustamante, Carlos D

    2016-04-01

    Sequencing the genomes of extinct hominids has reshaped our understanding of modern human origins. Here, we analyze ∼120 kb of exome-captured Y-chromosome DNA from a Neandertal individual from El Sidrón, Spain. We investigate its divergence from orthologous chimpanzee and modern human sequences and find strong support for a model that places the Neandertal lineage as an outgroup to modern human Y chromosomes-including A00, the highly divergent basal haplogroup. We estimate that the time to the most recent common ancestor (TMRCA) of Neandertal and modern human Y chromosomes is ∼588 thousand years ago (kya) (95% confidence interval [CI]: 447-806 kya). This is ∼2.1 (95% CI: 1.7-2.9) times longer than the TMRCA of A00 and other extant modern human Y-chromosome lineages. This estimate suggests that the Y-chromosome divergence mirrors the population divergence of Neandertals and modern human ancestors, and it refutes alternative scenarios of a relatively recent or super-archaic origin of Neandertal Y chromosomes. The fact that the Neandertal Y we describe has never been observed in modern humans suggests that the lineage is most likely extinct. We identify protein-coding differences between Neandertal and modern human Y chromosomes, including potentially damaging changes to PCDH11Y, TMSB4Y, USP9Y, and KDM5D. Three of these changes are missense mutations in genes that produce male-specific minor histocompatibility (H-Y) antigens. Antigens derived from KDM5D, for example, are thought to elicit a maternal immune response during gestation. It is possible that incompatibilities at one or more of these genes played a role in the reproductive isolation of the two groups.

  11. Historical evidence of the 1936 Mojokerto skull discovery, East Java.

    Science.gov (United States)

    Huffman, O Frank; Shipman, Pat; Hertler, Christine; de Vos, John; Aziz, Fachroel

    2005-04-01

    To resolve ambiguities in the literature, we detail the discovery history of the Mojokerto child's skull (Perning 1), employing letters, maps, photographs, reports, and newspaper accounts not previously used for this purpose. Andoyo, an experienced vertebrate-fossil collector with the Geological Survey of the Netherlands Indies, found the skull on February 13, 1936, while collecting for Johan Duyfjes, who had mapped the field area geologically. On February 18-19 Andoyo sent the fossil and a 1:25,000-topographic map showing the discovery point to Survey headquarters. The locality lies between Perning and Sumbertengu villages, approximately 10km northeast of Mojokerto city, East Java. G.H. Ralph von Koenigswald, Survey paleontologist, identified the specimen as Pithecanthropus and then named it Homo modjokertensis (it is now accepted as Homo erectus). Unfortunately he confused the discovery record in a March 28 newspaper article by characterizing the skull as a "surface find" [Dutch: oppervlaktevondst] while also attributing it to ancient beds. von Koenigswald probably had insufficient basis for either assertion, having not yet talked to Andoyo or Duyfjes. Eugene Dubois challenged von Koenigswald on the "surface-find" issue, Andoyo was consulted, and Duyfjes went to the site. Duyfjes and von Koenigswald then published scientific papers stating that the skull was unearthed 1m deep from a hill-slope outcrop of conglomeratic sandstone in Duyfjes' Pucangan formation. A cross section by Andoyo, which may show the Mojokerto site, also indicates a skull at 1m depth in conglomeratic sandstone. Photographs taken in 1936-1938 show a shallow pit at a single field location that fits Duyfjes' site description and is identified as the Mojokerto-skull site in 1940-1943 publications. By WWII the scientific community accepted the skull as an early hominid. Although von Koenigswald's "surface-find" comment remains a source of doubt in the record, we consider in situ discovery for the

  12. Brain size and thermoregulation during the evolution of the genus Homo.

    Science.gov (United States)

    Naya, Daniel E; Naya, Hugo; Lessa, Enrique P

    2016-01-01

    Several hypotheses have been proposed to explain the evolution of an energetically costly brain in the genus Homo. Some of these hypotheses are based on the correlation between climatic factors and brain size recorded for this genus during the last millions of years. In this study, we propose a complementary climatic hypothesis that is based on the mechanistic connection between temperature, thermoregulation, and size of internal organs in endothermic species. We hypothesized that global cooling during the last 3.2 my may have imposed an increased energy expenditure for thermoregulation, which in the case of hominids could represent a driver for the evolution of an expanded brain, or at least, it could imply the relaxation of a negative selection pressure acting upon this costly organ. To test this idea, here we (1) assess variation in the energetic costs of thermoregulation and brain maintenance for the last 3.2 my, and (2) evaluate the relationship between Earth temperature and brain maintenance cost for the same period, taking into account the effects of body mass and fossil age. We found that: (1) the energetic cost associated with brain enlargement represents an important fraction (between 47.5% and 82.5%) of the increase in energy needed for thermoregulation; (2) fossil age is a better predictor of brain maintenance cost than Earth temperature, suggesting that (at least) another factor correlated with time was more relevant than ambient temperature in brain size evolution; and (3) there is a significant negative correlation between the energetic cost of brain and Earth temperature, even after accounting for the effect of body mass and fossil age. Thus, our results expand the current energetic framework for the study of brain size evolution in our lineage by suggesting that a fall in Earth temperature during the last millions of years may have facilitated brain enlargement.

  13. Sexual division of labor: energetic and evolutionary scenarios.

    Science.gov (United States)

    Panter-Brick, Catherine

    2002-01-01

    This article examines comparative energetic data on hunter-gatherers in the context of evolutionary scenarios of the sexual division of labor, with respect to both specific task allocation and overall levels of daily physical activity. The division of labor between men and women, well marked in contemporary foraging societies, was once posited as the "true watershed" for the evolution of the genus Homo. Some research on brain-wiring even links sex differences in cognitive and spatial abilities to sex-specific foraging activities. Most recent evolutionary arguments posit that men focus on hunting and women on gathering activities to realize potentially conflicting mating and parenting goals. A range of cooperative strategies (male/female and female/female) for child provisioning is also under investigation. Attention to energetic and reproductive trade-offs has usefully challenged the proposition that women are excluded from big-game hunting due to constraints of foraging ecology and reproduction. Simplistic assumptions about gender roles are thus increasingly questioned in anthropology, as well as in archaeology. Current models in behavioral ecology explore ways in which foraging practices vary with ecological circumstances, aiming to derive testable hypotheses from fine-grained data on the behavior of contemporary hunter-gatherers. Data on overall physical activity levels (PAL) can also serve to evaluate relative male/female workloads in modern groups, reconstruct hominid energy requirements and activity profiles, and examine changes with subsistence intensification. Male/female PAL ratios show that a task-specific division of labor does not readily extrapolate to 24-hour energy expenditure and that male/female differences in workloads were not necessarily reduced with the transition to agriculture. With respect to gender roles and PAL, a shift away from facile stereotypes of human behavior is evident. The challenge is to incorporate a range of behavioral

  14. Los fósiles humanos de Ibeas (Sierra de Atapuerca, Burgos. Inventario y determinación del número mínimo de individuos

    Directory of Open Access Journals (Sweden)

    Aguirre, E.

    1986-12-01

    Full Text Available During 1983-1986 excavations carried out in some Middle Pleistocene sites of the Sierra de Atapuerca (Burgos, a total of 141 human remains were recovered in the Sima de los Huesos site, one of the cavities of the Cueva Mayor-Cueva del Silo karst system. These findings come to be added to the ones, occurred in 1976 in the same site, which were attributed to hominids of the so called «anteneandertalians- group. Aa. offer in this paper the inventory of all the human fossils recovered up to the present in the Sima de los Huesos site. The mandibular remains and the isolated teeth show that at least ten individuals of different sexes and ages are represented in the Atapuerca hypodigm.

    Durante las campañas de excavación de 1983-1986, llevadas a cabo en diversos yacimientos mesopleistocenos de la Sierra de Atapuerca (Burgos, se han recuperado un total de 141 restos humanos en la Sima de los Huesos, una de las cavidades del Sistema kárstico de Cueva Mayor-Cueva del Silo. Estos hallazgos se suman a los realizados en 1976 en el mismo yacimiento, que fueron atribuidos a homínidos del denominado grupo de los «anteneandertales», Presentamos en este trabajo el inventario de todos los fósiles humanos recuperados hasta el momento en la Sima de los Huesos. Los restos mandibulares y los dientes aislados demuestran que al menos diez individuos de diferentes sexos y edades están representados en el hipodigma de Atapuerca.

  15. A ~600 kyr duration Early Pleistocene record from the West Turkana (Kenya) HSPDP drill site: elemental XRF variability to reconstruct climate change in Turkana Boy's backyard

    Science.gov (United States)

    Stockhecke, M.; Beck, C. C.; Brown, E. T.; Cohen, A.; Deino, A. L.; Feibel, C. S.; Sier, M.

    2015-12-01

    Outcrops in the Kenyan and Ethiopian rift valleys document repeated occurrences of freshwater lakes and wooded landscapes over the past 4 million years at locations that are currently seasonally-dry savanna. Studies of the rich fossil records, in combination with outcropping lacustrine sequences, led to major breakthroughs in our knowledge of driving factors in human evolution. However, study of continuous drill core from ancient lake basins provides a basis for to unravel East African climate dynamics in an unseen fashion. The Hominin Sites and Paleolakes Drilling Project (HSPDP), and the related Olorgesailie Drilling Project, recovered ~2 km of drill core since 2012. A major project goal is characterization of East African paleoclimate in order to evaluate its impact on hominin evolution. XRF core scanning data provide a means of evaluating records of past environmental conditions continuously and at high resolution. However, the HSPDP records contain complex lithologies reflecting repeated episodes of inundation and desiccation of the lake basins. Nevertheless, careful data evaluation based on detailed lithostratigraphy, which includes smear-slide microscopic analyses and X-radiographic images, allows disentanglement of complex signals and robust identification of continuous sequences for any cyclostratigraphic and statistical analysis. At the HSPDP Turkana Basin site a 175.6 m-long core the covers the Early Pleistocene time window during which hominids first expanded out of Africa and marine records document reorganization of tropical climate and the development of the strong Walker circulation. This drill site carries particular interest as it is located in only 2.5 km from the location of one of the most complete hominin skeletons ever recovered (Turkana Boy). Here we present a methodological approach to address the highly variable lithostratigraphy of the East African records to establish comprehensive and environmentally meaningful paleoclimate timeseries

  16. Emergence of a Homo sapiens-specific gene family and chromosome 16p11.2 CNV susceptibility.

    Science.gov (United States)

    Nuttle, Xander; Giannuzzi, Giuliana; Duyzend, Michael H; Schraiber, Joshua G; Narvaiza, Iñigo; Sudmant, Peter H; Penn, Osnat; Chiatante, Giorgia; Malig, Maika; Huddleston, John; Benner, Chris; Camponeschi, Francesca; Ciofi-Baffoni, Simone; Stessman, Holly A F; Marchetto, Maria C N; Denman, Laura; Harshman, Lana; Baker, Carl; Raja, Archana; Penewit, Kelsi; Janke, Nicolette; Tang, W Joyce; Ventura, Mario; Banci, Lucia; Antonacci, Francesca; Akey, Joshua M; Amemiya, Chris T; Gage, Fred H; Reymond, Alexandre; Eichler, Evan E

    2016-08-11

    Genetic differences that specify unique aspects of human evolution have typically been identified by comparative analyses between the genomes of humans and closely related primates, including more recently the genomes of archaic hominins. Not all regions of the genome, however, are equally amenable to such study. Recurrent copy number variation (CNV) at chromosome 16p11.2 accounts for approximately 1% of cases of autism and is mediated by a complex set of segmental duplications, many of which arose recently during human evolution. Here we reconstruct the evolutionary history of the locus and identify bolA family member 2 (BOLA2) as a gene duplicated exclusively in Homo sapiens. We estimate that a 95-kilobase-pair segment containing BOLA2 duplicated across the critical region approximately 282 thousand years ago (ka), one of the latest among a series of genomic changes that dramatically restructured the locus during hominid evolution. All humans examined carried one or more copies of the duplication, which nearly fixed early in the human lineage--a pattern unlikely to have arisen so rapidly in the absence of selection (P < 0.0097). We show that the duplication of BOLA2 led to a novel, human-specific in-frame fusion transcript and that BOLA2 copy number correlates with both RNA expression (r = 0.36) and protein level (r = 0.65), with the greatest expression difference between human and chimpanzee in experimentally derived stem cells. Analyses of 152 patients carrying a chromosome 16p11. rearrangement show that more than 96% of breakpoints occur within the H. sapiens-specific duplication. In summary, the duplicative transposition of BOLA2 at the root of the H. sapiens lineage about 282 ka simultaneously increased copy number of a gene associated with iron homeostasis and predisposed our species to recurrent rearrangements associated with disease. PMID:27487209

  17. Learning by heart: cultural patterns in the faunal processing sequence during the middle pleistocene.

    Directory of Open Access Journals (Sweden)

    Ruth Blasco

    Full Text Available Social learning, as an information acquisition process, enables intergenerational transmission and the stabilisation of cultural forms, generating and sustaining behavioural traditions within human groups. Archaeologically, such social processes might become observable by identifying repetitions in the record that result from the execution of standardised actions. From a zooarchaeological perspective, the processing and consumption of carcasses may be used to identify these types of phenomena at the sites. To investigate this idea, several faunal assemblages from Bolomor Cave (Valencia, Spain, MIS 9-5e and Gran Dolina TD10-1 (Burgos, Spain, MIS 9 were analysed. The data show that some butchery activities exhibit variability as a result of multiple conditioning factors and, therefore, the identification of cultural patterns through the resulting cut-marks presents additional difficulties. However, other activities, such as marrow removal by means of intentional breakage, seem to reflect standardised actions unrelated to the physical characteristics of the bones. The statistical tests we applied show no correlation between the less dense areas of the bones and the location of impacts. Comparison of our experimental series with the archaeological samples indicates a counter-intuitive selection of the preferred locus of impact, especially marked in the case of Bolomor IV. This fact supports the view that bone breakage was executed counter-intuitively and repetitively on specific sections because it may have been part of an acquired behavioural repertoire. These reiterations differ between levels and sites, suggesting the possible existence of cultural identities or behavioural predispositions dependant on groups. On this basis, the study of patterns could significantly contribute to the identification of occupational strategies and organisation of the hominids in a territory. In this study, we use faunal data in identifying the mechanics of

  18. The Divergence of Neandertal and Modern Human Y Chromosomes

    Science.gov (United States)

    Mendez, Fernando L.; Poznik, G. David; Castellano, Sergi; Bustamante, Carlos D.

    2016-01-01

    Sequencing the genomes of extinct hominids has reshaped our understanding of modern human origins. Here, we analyze ∼120 kb of exome-captured Y-chromosome DNA from a Neandertal individual from El Sidrón, Spain. We investigate its divergence from orthologous chimpanzee and modern human sequences and find strong support for a model that places the Neandertal lineage as an outgroup to modern human Y chromosomes—including A00, the highly divergent basal haplogroup. We estimate that the time to the most recent common ancestor (TMRCA) of Neandertal and modern human Y chromosomes is ∼588 thousand years ago (kya) (95% confidence interval [CI]: 447–806 kya). This is ∼2.1 (95% CI: 1.7–2.9) times longer than the TMRCA of A00 and other extant modern human Y-chromosome lineages. This estimate suggests that the Y-chromosome divergence mirrors the population divergence of Neandertals and modern human ancestors, and it refutes alternative scenarios of a relatively recent or super-archaic origin of Neandertal Y chromosomes. The fact that the Neandertal Y we describe has never been observed in modern humans suggests that the lineage is most likely extinct. We identify protein-coding differences between Neandertal and modern human Y chromosomes, including potentially damaging changes to PCDH11Y, TMSB4Y, USP9Y, and KDM5D. Three of these changes are missense mutations in genes that produce male-specific minor histocompatibility (H-Y) antigens. Antigens derived from KDM5D, for example, are thought to elicit a maternal immune response during gestation. It is possible that incompatibilities at one or more of these genes played a role in the reproductive isolation of the two groups. PMID:27058445

  19. The neural basis of human tool use.

    Science.gov (United States)

    Orban, Guy A; Caruana, Fausto

    2014-01-01

    In this review, we propose that the neural basis for the spontaneous, diversified human tool use is an area devoted to the execution and observation of tool actions, located in the left anterior supramarginal gyrus (aSMG). The aSMG activation elicited by observing tool use is typical of human subjects, as macaques show no similar activation, even after an extensive training to use tools. The execution of tool actions, as well as their observation, requires the convergence upon aSMG of inputs from different parts of the dorsal and ventral visual streams. Non-semantic features of the target object may be provided by the posterior parietal cortex (PPC) for tool-object interaction, paralleling the well-known PPC input to anterior intraparietal (AIP) for hand-object interaction. Semantic information regarding tool identity, and knowledge of the typical manner of handling the tool, could be provided by inferior and middle regions of the temporal lobe. Somatosensory feedback and technical reasoning, as well as motor and intentional constraints also play roles during the planning of tool actions and consequently their signals likewise converge upon aSMG. We further propose that aSMG may have arisen though duplication of monkey AIP and invasion of the duplicate area by afferents from PPC providing distinct signals depending on the kinematics of the manipulative action. This duplication may have occurred when Homo Habilis or Homo Erectus emerged, generating the Oldowan or Acheulean Industrial complexes respectively. Hence tool use may have emerged during hominid evolution between bipedalism and language. We conclude that humans have two parietal systems involved in tool behavior: a biological circuit for grasping objects, including tools, and an artifactual system devoted specifically to tool use. Only the latter allows humans to understand the causal relationship between tool use and obtaining the goal, and is likely to be the basis of all technological developments. PMID

  20. GEOLOGY OF THE HOMO-BEARING PLEISTOCENE DANDIERO BASIN (BUIA REGION, ERITREAN DANAKIL DEPRESSION

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    ERNESTO ABBATE

    2004-12-01

    Full Text Available This paper deals with the geological context of the northernmost site in the East Africa Rift system which has yielded Homo erectus-like remains. They are dated ca. 1 Ma and have been found in the deltaic deposits of the Alat Formation belonging to the Dandiero group. This newly defined group crops out extensively in an elongated belt from the Gulf of Zula to the North to the Garsat area to the south. In the Buia-Dandiero area it ranges in age from the Early to the Middle Pleistocene, and incorporates six formations, from bottom up: the fluvial Bukra Sand and Gravel, the deltaic and lacustrine Alat Formation, fluvial Wara Sand and Gravel, the lacustrine Goreya Formation, the fluvio-deltaic Aro Sand and alluvial Addai Fanglomerate. This succession is bounded by two major unconformities, which separate it from the Neoproterozoic basement and from the overlaying Boulder Beds fanglomerate, and has been designated the Maebele Synthem. The latter is the result of two lacustrine transgression and regressions evidenced by two depositional sequences. The unconformities bounding the Maebele Synthem are related to the tectonic history of the basin fill and its substrate. The development of the two sequences was, instead, mainly controlled by lake level fluctuations and, hence, by climatic variations connected with the weakening and strengthening of the monsoons in the northwestern Indian ocean. The environment where the Buia Homo lived was a savannah with some scattered water pools. This environment probably extended farther north along the western coastal plain of the Red Sea, and was a preferential pathway for the dispersal of the hominids from East Africa toward Eurasia. 

  1. The neural basis of human tool use

    Directory of Open Access Journals (Sweden)

    Guy A Orban

    2014-04-01

    Full Text Available In this review, we propose that the neural basis for the spontaneous, diversified human tool use is an area devoted to the execution and observation of tool actions, located in the left anterior supramarginal gyrus (aSMG. The aSMG activation elicited by observing tool use is typical of human subjects, as macaques show no similar activation, even after an extensive training to use tools. The execution of tool actions, as well as their observation, requires the convergence upon aSMG of inputs from different parts of the dorsal and ventral visual streams. Non semantic features of the target object may be provided by the posterior parietal cortex (PPC for tool-object interaction, paralleling the well-known PPC input to AIP for hand-object interaction. Semantic information regarding tool identity, and knowledge of the typical manner of handling the tool, could be provided by inferior and middle regions of the temporal lobe. Somatosensory feedback and technical reasoning, as well as motor and intentional constraints also play roles during the planning of tool actions and consequently their signals likewise converge upon aSMG.We further propose that aSMG may have arisen though duplication of monkey AIP and invasion of the duplicate area by afferents from PPC providing distinct signals depending on the kinematics of the manipulative action. This duplication may have occurred when Homo Habilis or Homo Erectus emerged, generating the Oldowan or Acheulean Industrial complexes respectively. Hence tool use may have emerged during hominid evolution between bipedalism and language.We conclude that humans have two parietal systems involved in tool behavior: a biological circuit for grasping objects, including tools, and an artifactual system devoted specifically to tool use. Only the latter allows humans to understand the causal relationship between tool use and obtaining the goal, and is likely to be the basis of all technological developments.

  2. Recent evolution of the NF-κB and inflammasome regulating protein POP2 in primates

    Directory of Open Access Journals (Sweden)

    Harton Jonathan A

    2011-03-01

    Full Text Available Abstract Background Pyrin-only protein 2 (POP2 is a small human protein comprised solely of a pyrin domain that inhibits NF-κB p65/RelA and blocks the formation of functional IL-1β processing inflammasomes. Pyrin proteins are abundant in mammals and several, like POP2, have been linked to activation or regulation of inflammatory processes. Because POP2 knockout mice would help probe the biological role of inflammatory regulation, we thus considered whether POP2 is common in the mammalian lineage. Results BLAST searches revealed that POP2 is absent from the available genomes of not only mice and rats, but those of other domestic mammals and New World monkeys as well. POP2 is however present in the genome of the primate species most closely related to humans including Pan troglodytes (chimpanzees, Macaca mulatta (rhesus macaques and others. Interestingly, chimpanzee POP2 is identical to human POP2 (huPOP2 at both the DNA and protein level. Macaque POP2 (mqPOP2, although highly conserved is not identical to the human sequence; however, both functions of the human protein are retained. Further, POP2 appears to have arisen in the mammalian genome relatively recently (~25 mya and likely derived from retrogene insertion of NLRP2. Conclusion Our findings support the hypothesis that the NLR loci of mammals, encoding proteins involved in innate and adaptive immunity as well as mammalian development, have been subject to recent and strong selective pressures. Since POP2 is capable of regulating signaling events and processes linked to innate immunity and inflammation, its presence in the genomes of hominids and Old World primates further suggests that additional regulation of these signals is important in these species.

  3. Ancient mtDNA sequences from the First Australians revisited.

    Science.gov (United States)

    Heupink, Tim H; Subramanian, Sankar; Wright, Joanne L; Endicott, Phillip; Westaway, Michael Carrington; Huynen, Leon; Parson, Walther; Millar, Craig D; Willerslev, Eske; Lambert, David M

    2016-06-21

    The publication in 2001 by Adcock et al. [Adcock GJ, et al. (2001) Proc Natl Acad Sci USA 98(2):537-542] in PNAS reported the recovery of short mtDNA sequences from ancient Australians, including the 42,000-y-old Mungo Man [Willandra Lakes Hominid (WLH3)]. This landmark study in human ancient DNA suggested that an early modern human mitochondrial lineage emerged in Asia and that the theory of modern human origins could no longer be considered solely through the lens of the "Out of Africa" model. To evaluate these claims, we used second generation DNA sequencing and capture methods as well as PCR-based and single-primer extension (SPEX) approaches to reexamine the same four Willandra Lakes and Kow Swamp 8 (KS8) remains studied in the work by Adcock et al. Two of the remains sampled contained no identifiable human DNA (WLH15 and WLH55), whereas the Mungo Man (WLH3) sample contained no Aboriginal Australian DNA. KS8 reveals human mitochondrial sequences that differ from the previously inferred sequence. Instead, we recover a total of five modern European contaminants from Mungo Man (WLH3). We show that the remaining sample (WLH4) contains ∼1.4% human DNA, from which we assembled two complete mitochondrial genomes. One of these was a previously unidentified Aboriginal Australian haplotype belonging to haplogroup S2 that we sequenced to a high coverage. The other was a contaminating modern European mitochondrial haplotype. Although none of the sequences that we recovered matched those reported by Adcock et al., except a contaminant, these findings show the feasibility of obtaining important information from ancient Aboriginal Australian remains. PMID:27274055

  4. The Divergence of Neandertal and Modern Human Y Chromosomes.

    Science.gov (United States)

    Mendez, Fernando L; Poznik, G David; Castellano, Sergi; Bustamante, Carlos D

    2016-04-01

    Sequencing the genomes of extinct hominids has reshaped our understanding of modern human origins. Here, we analyze ∼120 kb of exome-captured Y-chromosome DNA from a Neandertal individual from El Sidrón, Spain. We investigate its divergence from orthologous chimpanzee and modern human sequences and find strong support for a model that places the Neandertal lineage as an outgroup to modern human Y chromosomes-including A00, the highly divergent basal haplogroup. We estimate that the time to the most recent common ancestor (TMRCA) of Neandertal and modern human Y chromosomes is ∼588 thousand years ago (kya) (95% confidence interval [CI]: 447-806 kya). This is ∼2.1 (95% CI: 1.7-2.9) times longer than the TMRCA of A00 and other extant modern human Y-chromosome lineages. This estimate suggests that the Y-chromosome divergence mirrors the population divergence of Neandertals and modern human ancestors, and it refutes alternative scenarios of a relatively recent or super-archaic origin of Neandertal Y chromosomes. The fact that the Neandertal Y we describe has never been observed in modern humans suggests that the lineage is most likely extinct. We identify protein-coding differences between Neandertal and modern human Y chromosomes, including potentially damaging changes to PCDH11Y, TMSB4Y, USP9Y, and KDM5D. Three of these changes are missense mutations in genes that produce male-specific minor histocompatibility (H-Y) antigens. Antigens derived from KDM5D, for example, are thought to elicit a maternal immune response during gestation. It is possible that incompatibilities at one or more of these genes played a role in the reproductive isolation of the two groups. PMID:27058445

  5. Evolution of the Genus Homo

    Science.gov (United States)

    Tattersall, Ian; Schwartz, Jeffrey H.

    2009-05-01

    Definition of the genus Homo is almost as fraught as the definition of Homo sapiens. We look at the evidence for “early Homo,” finding little morphological basis for extending our genus to any of the 2.5-1.6-myr-old fossil forms assigned to “early Homo” or Homo habilis/rudolfensis. We also point to heterogeneity among “early African Homo erectus,” and the lack of apomorphies linking these fossils to the Asian Homo erectus group, a cohesive regional clade that shows some internal variation, including brain size increase over time. The first truly cosmopolitan Homo species is Homo heidelbergensis, known from Africa, Europe, and China following 600 kyr ago. One species sympatric with it included the >500-kyr-old Sima de los Huesos fossils from Spain, clearly distinct from Homo heidelbergensis and the oldest hominids assignable to the clade additionally containing Homo neanderthalensis. This clade also shows evidence of brain size expansion with time; but although Homo neanderthalensis had a large brain, it left no unequivocal evidence of the symbolic consciousness that makes our species unique. Homo sapiens clearly originated in Africa, where it existed as a physical entity before it began (also in that continent) to show the first stirrings of symbolism. Most likely, the biological underpinnings of symbolic consciousness were exaptively acquired in the radical developmental reorganization that gave rise to the highly characteristic osteological structure of Homo sapiens, but lay fallow for tens of thousands of years before being “discovered” by a cultural stimulus, plausibly the invention of language.

  6. Nonocclusal dental microwear analysis of 300,000-year-old Homo heilderbergensis teeth from Sima de los Huesos (Sierra de Atapuerca, Spain).

    Science.gov (United States)

    Pérez-Pérez, A; Bermúdez De Castro, J M; Arsuaga, J L

    1999-04-01

    Casts of nonocclusal enamel surfaces of 190 teeth from the Middle Pleistocene site of Sima de los Huesos have been micrographed by scanning electron microscopy. Microscopic analyses of striation density and length by orientation show distinct patterns of intrapopulation variability. Significant differences in the number and length of the striations by orientation are found between maxillary and mandibular teeth. This probably reflects differences in the mechanical forces involved in the process of chewing food. Significant differences are present between isolated and in situ teeth that could be caused by postdepositional processes differentially affecting the isolated teeth. In addition, a distinct and very unusual striation pattern is observed in a sample of teeth that can be explained only by a strong nondietary, most probably postmortem abrasion of the enamel surfaces. These teeth have a very high density of scratches, shorter in length than those found on other teeth, that are not indicative of dietary habits. No known depositional process may account for the presence of such postmortem wear since heavy transportation of materials within the clayish sediments has been discarded for the site. Despite this, a characteristic dietary striation pattern can be observed in most of the teeth analyzed. Most likely the diet of the Homo heidelbergensis hominids from Sima de los Huesos was highly abrasive, probably with a large dependence on hard, poorly processed plant foods, such as roots, stems, and seeds. A highly significant sex-related difference in the striation pattern can also be observed in the teeth analyzed, suggesting a differential consistency in the foods eaten by females and males. PMID:10229388

  7. Landmark-based shape analysis of the archaic Homo calvarium from Ceprano (Italy).

    Science.gov (United States)

    Bruner, Emiliano; Manzi, Giorgio

    2007-03-01

    The Ceprano calvarium represents one of the most important sources of information about both the dynamics of the earliest hominid dispersal toward Europe and the evolution of the genus Homo in the early-to-middle Pleistocene. In this paper, the midsagittal vault profile and the 3D frontal bone morphology of Ceprano are investigated comparatively, using landmark coordinates and Procrustes superimposition. In fact, despite the fact that the skull appears partially distorted by diagenetic pressures (thus precluding a comprehensive landmark-based analysis), some aspects of the overall morphology are suitable for consideration in terms of geometric morphometrics. The midsagittal profile shows an archaic shape, comparable with the H. ergaster/erectus range of variation because of the fronto-parietal flattening, the development of the supraorbital and nuchal structures, and the occurrence of a slightly larger occipital bone. By contrast, the frontal bone displays a derived 3D shape that, mostly because of the widening of the frontal squama, appears comparable with the Afro-European variation of the Middle Pleistocene (i.e., H. heidelbergensis/rhodesiensis). Taking into account the unique morphological pattern displayed by Ceprano, its role as a link between early Homo and the Middle Pleistocene populations of Europe and Africa is not falsified. Thus, when aspects of the Ceprano's morphology are described within the analytical framework provided by geometric morphometrics, the relationships between Ceprano and the subsequent Afro-European fossil record are emphasized, suggesting the occurrence of an ancestral stock of H. heidelbergensis/rhodesiensis that is properly represented by the Italian specimen. PMID:17177181

  8. The evolution of human speech: the role of enhanced breathing control.

    Science.gov (United States)

    MacLarnon, A M; Hewitt, G P

    1999-07-01

    Many cognitive and physical features must have undergone change for the evolution of fully modern human language. One neglected aspect is the evolution of increased breathing control. Evidence presented herein shows that modern humans and Neanderthals have an expanded thoracic vertebral canal compared with australopithecines and Homo ergaster, who had canals of the same relative size as extant nonhuman primates. Based on previously published analyses, these results demonstrate that there was an increase in thoracic innervation during human evolution. Possible explanations for this increase include postural control for bipedalism, increased difficulty of parturition, respiration for endurance running, an aquatic phase, and choking avoidance. These can all be ruled out, either because of their evolutionary timing, or because they are insufficiently demanding neurologically. The remaining possible functional cause is increased control of breathing for speech. The main muscles involved in the fine control of human speech breathing are the intercostals and a set of abdominal muscles which are all thoracically innervated. Modifications to quiet breathing are essential for modern human speech, enabling the production of long phrases on single expirations punctuated with quick inspirations at meaningful linguistic breaks. Other linguistically important features affected by variation in subglottal air pressure include emphasis of particular sound units, and control of pitch and intonation. Subtle, complex muscle movements, integrated with cognitive factors, are involved. The vocalizations of nonhuman primates involve markedly less respiratory control. Without sophisticated breath control, early hominids would only have been capable of short, unmodulated utterances, like those of extant nonhuman primates. Fine respiratory control, a necessary component for fully modern language, evolved sometime between 1.6 Mya and 100,000 ya. PMID:10407464

  9. Brains, tools, innovation and biogeography in crows and ravens

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    Jønsson Knud A

    2012-05-01

    Full Text Available Abstract Background Crows and ravens (Passeriformes: Corvus are large-brained birds with enhanced cognitive abilities relative to other birds. They are among the few non-hominid organisms on Earth to be considered intelligent and well-known examples exist of several crow species having evolved innovative strategies and even use of tools in their search for food. The 40 Corvus species have also been successful dispersers and are distributed on most continents and in remote archipelagos. Results This study presents the first molecular phylogeny including all species and a number of subspecies within the genus Corvus. We date the phylogeny and determine ancestral areas to investigate historical biogeographical patterns of the crows. Additionally, we use data on brain size and a large database on innovative behaviour and tool use to test whether brain size (i explains innovative behaviour and success in applying tools when foraging and (ii has some correlative role in the success of colonization of islands. Our results demonstrate that crows originated in the Palaearctic in the Miocene from where they dispersed to North America and the Caribbean, Africa and Australasia. We find that relative brain size alone does not explain tool use, innovative feeding strategies and dispersal success within crows. Conclusions Our study supports monophyly of the genus Corvus and further demonstrates the direction and timing of colonization from the area of origin in the Palaearctic to other continents and archipelagos. The Caribbean was probably colonized from North America, although some North American ancestor may have gone extinct, and the Pacific was colonized multiple times from Asia and Australia. We did not find a correlation between relative brain size, tool use, innovative feeding strategies and dispersal success. Hence, we propose that all crows and ravens have relatively large brains compared to other birds and thus the potential to be innovative if

  10. Multi-detector row CT scanning in Paleoanthropology at various tube current settings and scanning mode.

    Science.gov (United States)

    Badawi-Fayad, J; Yazbeck, C; Balzeau, A; Nguyen, T H; Istoc, A; Grimaud-Hervé, D; Cabanis, E- A

    2005-12-01

    The purpose of this study was to determine the optimal tube current setting and scanning mode for hominid fossil skull scanning, using multi-detector row computed tomography (CT). Four fossil skulls (La Ferrassie 1, Abri Pataud 1, CroMagnon 2 and Cro-Magnon 3) were examined by using the CT scanner LightSpeed 16 (General Electric Medical Systems) with varying dose per section (160, 250, and 300 mAs) and scanning mode (helical and conventional). Image quality of two-dimensional (2D) multiplanar reconstructions, three-dimensional (3D) reconstructions and native images was assessed by four reviewers using a four-point grading scale. An ANOVA (analysis of variance) model was used to compare the mean score for each sequence and the overall mean score according to the levels of the scanning parameters. Compared with helical CT (mean score=12.03), the conventional technique showed sustained poor image quality (mean score=4.17). With the helical mode, we observed a better image quality at 300 mAs than at 160 in the 3D sequences (P=0.03). Whereas in native images, a reduction in the effective tube current induced no degradation in image quality (P=0.05). Our study suggests a standardized protocol for fossil scanning with a 16 x 0.625 detector configuration, a 10 mm beam collimation, a 0.562:1 acquisition mode, a 0.625/0.4 mm slice thickness/reconstruction interval, a pitch of 5.62, 120 kV and 300 mAs especially when a 3D study is required. PMID:16211320

  11. Darwin’s legacy in South African evolutionary biology

    Directory of Open Access Journals (Sweden)

    S. D. Johnson

    2010-02-01

    Full Text Available In the two decades after publication of the Origin of Species, Charles Darwin facilitated the publication of numerous scientific papers by settler naturalists in South Africa. This helped to establish the strong tradition of natural history which has characterised evolutionary research in South African museums, herbaria and universities. Significant developments in the early 20th century included the hominid fossil discoveries of Raymond Dart, Robert Broom, and others, but there was otherwise very little South African involvement in the evolutionary synthesis of the 1930s and 1940s. Evolutionary biology developed into a distinct discipline in South Africa during the 1970s and 1980s when it was dominated by mammalian palaeontology and a vigorous debate around species concepts. In the post-apartheid era, the main focus of evolutionary biology has been the construction of phylogenies for African plants and animals using molecular data, and the use of these phylogenies to answer questions about taxonomic classification and trait evolution. South African biologists have also recently contributed important evidence for some of Darwin’s ideas about plant–animal coevolution, sexual selection, and the role of natural selection in speciation. A bibliographic analysis shows that South African authors produce 2–3% of the world’s publications in the field of evolutionary biology, which is much higher than the value of about 0.5% for publications in all sciences. With its extraordinary biodiversity and well-developed research infrastructure, South Africa is an ideal laboratory from which to advance evolutionary research.

  12. Remote sensing, paleoecology, and the archaeology of human migration during the Pleistocene in central Asia and western China

    Science.gov (United States)

    Glantz, Michelle M.; Todd, Lawrence

    2003-07-01

    Remote sensing used in the context of global information systems has enormous applications within archaeology. This technology enables the discovery of new archaeological features and promotes an understanding of the relationship between ecosystem and cultural dynamics. Archaeologists are able to add a time dimension to 'creeping environmental changes' that other areas of scientific inquiry concerned with climate change often lack. Remote sensing and other aerial prospecting has been used successfully to model land use and population expansions during relatively recent archaeological eras, such as the Bronze and Iron Ages. Although satellite image databases exist for numerous areas of the New and Old World, very little research has been conducted in Central Asia or western China. This region is historically significant because of its position along the important trading route called the Silk Road. The purpose of the present research is to investigate another poorly understood period of human history that would benefit from the application of remote sensing and associated ground truthing techniques. The migration of hominids out of Africa during the late Pliocene/early Pleistocene and their subsequent colonization of north-central, east, and south-east Asia is relatively well documented in the archaeological record and marks the beginning of the long-term process of human impacts on the region. However, the trajectory of dispersal of Homo erectus, Neandertals, and early modern humans and the ways by which ecosystem vagaries affected this dispersal across Eurasia is unknown. Our purpose is to summarize what is currently known about the geological indicators of ecosystem changes that remote sensing techniques provide and how ecosystem variables may allow us to model human migration as that of an invasive species through this important geographic crossroads of the Old World.

  13. Paranthropus boisei: an example of evolutionary stasis?

    Science.gov (United States)

    Wood, B; Wood, C; Konigsberg, L

    1994-10-01

    Of the presently recognised early hominid species, Paranthropus boisei is one of the better known from the fossil record and arguably the most distinctive; the latter interpretation rests on the numbers of apparently derived characters it incorporates. The species as traditionally diagnosed is distributed across approximately one million years and is presently confined to samples from East African sites. The hypodigm has been examined for evidence of intraspecific phyletic evolution, with particular emphasis on the areas best represented in the fossil record, namely the teeth and mandible. The results of this examination of 55 mandibular and dental variables which uses the gamma test statistic for the detection of trend, and nonparametric spline regression (Loess regression) for investigating pattern and rate of temporal change, show that within Paranthropus boisei sensu stricto most evidence of temporally related morphological trends relates to the morphology of the P4 crown. There is little or no evidence of any tendency to increase in overall size through time. Fossils from the Omo Shungura Formation and West Turkana which have been recovered from a time period earlier than the P. boisei sensu stricto hypodigm resemble the latter taxon in some features, but differ from it in aspects of cranial morphology. There is insufficient fossil evidence of the earlier taxon to tell whether it changes through time, but when trends of 47 mandibular and dental variables are assessed across the combined East African "robust" australopithecine sample, there is evidence for a relatively abrupt change around 2.2-2.3 Myr in approximately 25% of the dental and mandibular remains. Some of these changes correspond with the temporal trends within P. boisei sensu stricto, but others, such as mandible height, do not. If the earlier material is ancestral to P. boisei sensu stricto, evidence from the teeth and jaws is consistent with a punctuated origin for the latter taxon. PMID:7802091

  14. A quantitative and qualitative reanalysis of the endocast from the juvenile Paranthropus specimen l338y-6 from Omo, Ethiopia.

    Science.gov (United States)

    White, D D; Falk, D

    1999-12-01

    Based on an analysis of its endocast, Holloway (1981 Am J Phys Anthropol 53:109-118) attributed the juvenile Omo L338y-6 specimen to Australopithecus africanus (i.e., gracile australopithecines) rather than to Paranthropus (Australopithecus) boisei (robust australopithecines) favored by other workers (Rak and Howell [1978] Am J Phys Anthropol 48:345-366). Holloway's attribution was based on the specimen's (1) low cranial capacity, (2) gracile-like meningeal vessels, (3) gracile-like cerebellar hemispheres, and (4) absence of an enlarged occipital/marginal (O/M) sinus system. Recent work, however, has shown that criteria 1 and 2 are not useful for sorting gracile from robust australopithecines (Culotta [1999] Science 284:1109-1111; Falk [1993] Am J Phys Anthropol 92:81-98). In this paper, we test criterion 3 by quantifying the endocranial cerebellar and occipital morphology reproduced on the Omo L338y-6 endocast, and comparing it to seven endocasts from South and East African early hominids. Our preliminary results show that metric analysis of this specimen cannot be used to sort it preferentially with either robust or gracile australopithecines. Finally, we demonstrate that, contrary to previous reports, the Omo L338y-6 endocast reproduces an enlarged left occipital sinus (criterion 4). This observation is consistent with the original attribution of the Omo specimen to robust australopithecines (Rak and Howell [1978] Am J Phys Anthropol 48:345-366). Furthermore, if Omo L338y-6 was a robust australopithecine, this discovery extends the occurrence of an enlarged O/M sinus system to one of the earliest known paranthropines. Am J Phys Anthropol 110:399-406, 1999. PMID:10564571

  15. Comparative morphometric study of the australopithecine vertebral series Stw-H8/H41.

    Science.gov (United States)

    Sanders, W J

    1998-03-01

    Lower spinal structure correlates well with positional behavior among mammals. Nonetheless, the functional morphology of the axial post-crania of australopithecines has received less attention than their appendicular skeletons. This paper presents a detailed description and comparative morphometric analysis of the australopithecine thoracolumbar vertebral series Stw-H8/H41, and examines spinal mechanics in early hominids. Stw-H8/H41 is an important specimen, as the australopithecine vertebral sample is small, and vertebral series are more useful than isolated elements for the interpretation of spinal function. Results of the study support the interpretation that australopithecine species are highly sexually dimorphic. The study also reveals a considerable amount of morphometric variation other than size among australopithecine vertebrae, though the sample is too small and incomplete to ascertain whether this indicates significant interspecific differences in spinal function. Most importantly, structural and metric observations confirm that the morphology of the lower spine in australopithecines has no modern analogue in its entirety. Aspects of zygapophyseal structure, numerical composition of the lumbar region, and centrum wedging suggest that the australopithecine vertebral column was adapted to human-like intrinsic lumbar lordosis and stable balance of the trunk over the pelvis in sustained bipedal locomotion. However, relative centrum size in australopithecines indicates that either they had a different mechanism for channeling vertical forces through the vertebral column than humans, or differed behaviorally from humans in ways that produced smaller increments of compression across their centra. These findings have important implications for hypotheses of australopithecine positional behavior, and demonstrate that larger samples and more complete vertebral series are needed to improve our understanding of australopithecine spinal function. PMID:9547457

  16. Biomechanical reasons for the divergent morphology of the knee joint and the distal epiphyseal suture in hominoids.

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    Preuschoft, H; Tardieu, C

    1996-01-01

    The obliquity of the femoral diaphysis accounts for the valgus position of the human knee joint and reduces bending moments in the frontal plane. A high angle of obliquity is considered a hallmark of hominid bipedality, but its functional importance has rarely been identified correctly. A biostatic investigation of the knee joint in various realistic positions unveils resultant joint forces which do not deviate greatly from the long axis of the femoral shaft. This is due to the length of the femur and to the shortness of the human foot. The flat epiphyseal suture is more or less perpendicular to these joint forces, and the equal size of the femoral condyles reflects the even distribution of forces between them. In great apes the resultant forces acting in the knee joint vary considerably in dependence on the degree of flexion and rotation of the knee joint. The resultant joint force may be line with the femur shaft or diverge. The epiphyseal surfaces offer facets to all joint forces found in the course of the study. Due to the pronounced varus position of the knee joint, the joint itself and the adjacent part of the femur are under medially concave bending moments, which lead to higher compressive forces at the medial than at the lateral condyle. The enlarged medial condyle allows the distribution of medially displaced joint forces over a relatively large area, and the elliptic cross-section yields high bending resistance in the frontal plane. A human-like angle of obliquity is present in the early australopithecines, the values being mostly within the range of variation of children. The valgus position of the australopithecine knee joint is considered to be a functional, and epigenetic consequence of habitual bipedality. It is particularly pronounced because of the short length of the femur and the great bitrochanteric width. PMID:8953752

  17. Les hominoïdes fossiles : une aide pour l’éducation en Afrique Fossil hominoids: an educational help in Africa

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    Brigitte Senut

    2009-10-01

    Full Text Available L’Afrique est un continent privilégié pour décrypter notre histoire partagée avec celle des grands singes et comprendre l’émergence de notre famille en rapport avec l’environnement. Aujourd’hui de nombreuses expéditions  internationales mènent des recherches sur le continent et plus spécialement dans les pays d’Afrique orientale. Le riche patrimoine fossile découvert dans des endroits souvent isolés est transféré dans les musées nationaux, (créés le plus souvent par des expatriés et situés dans les capitales où l’accès y est plus facile pour les chercheurs internationaux, mais souvent difficile voire impossible pour les gens qui habitent près des sites fossilifères. Que se passe-t-il au niveau local ? Le plus souvent, les populations ont été marginalisées, des sentiments de frustration sont apparus, notamment en raison de la grande médiatisation des découvertes de laquelle les locaux sont souvent exclus. Or, ce sont ces populations locales qui sont les gardiennes du patrimoine. Les choses changent progressivement et aujourd’hui, de plus en plus de chercheurs de terrain s’impliquent dans la vie locale et les besoins locaux. Notre engagement de scientifique en tant que citoyen est fondamental : l’éducation est un droit pour tous, comme cela est signalé dans la déclaration universelle des droits de l’homme. Dans le cadre des travaux entrepris en Afrique avec l’équipe, des grands singes et des hominidés fossiles ont été découverts dans trois pays africains sur lesquels cet article est focalisé : l’Ouganda, le Kenya et la Namibie ; ces données montrent que l’évolution des grands singes ne s’est pas déroulée exclusivement en Afrique orientale, mais bien sur l’ensemble du continent, comme cela a été confirmé plus récemment par des découvertes en Afrique centrale et occidentale. Ces découvertes ont été réalisées avec des citoyens de chacun de ces pays et ont donné lieu

  18. Evolution of human IgH3'EC duplicated structures: both enhancers HS1,2 are polymorphic with variation of transcription factor's consensus sites.

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    Giambra, Vincenzo; Fruscalzo, Alberto; Giufre', Maria; Martinez-Labarga, Cristina; Favaro, Marco; Rocchi, Mariano; Frezza, Domenico

    2005-02-14

    the 17-bp external element in hominids. The relevance of the polymorphisms in the HS1,2 enhancers is due to the variable number of binding sites for the transcription factors: NF-kappaB, CMYB, BSAP1/2, AP1/4, E47, MyoD and muE5 and thus to the possible influence of these variations on switch, production of Ig and on maturation of B cells.

  19. Delineation of separate brain regions used for scientific versus engineering modes of thinking

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    Patterson, Clair C.

    1994-08-01

    Powerful, latent abilities for extreme sophistication in abstract rationalization as potential biological adaptive behavioral responses were installed entirely through accident and inadvertence by biological evolution in the Homo sapiens sapiens species of brain. These potentials were never used, either in precursor species as factors in evolutionary increase in hominid brain mass, nor in less sophisticated forms within social environments characterized by Hss tribal brain population densities. Those latent abilities for unnatural biological adaptive behavior were forced to become manifest in various ways by growths in sophistication of communication interactions engendered by large growths in brain population densities brought on by developments in agriculture at the onset of the Holocene. It is proposed that differences probably exist between regions of the Hss brain involved in utilitarian, engineering types of problem conceptualization-solving versus regions of the brain involved in nonutilitarian, artistic-scientific types of problem conceptualization-solving. Populations isolated on separate continents from diffusive contact and influence on cultural developments, and selected for comparison of developments during equivalent stages of technological and social sophistication in matching 4000 year periods, show, at the ends of those periods, marked differences in aesthetic attributes expressed in cosmogonies, music, and writing (nonutilitarian thinking related to science and art). On the other hand the two cultures show virtually identical developments in three major stages of metallurgical technologies (utilitarian thinking related to engineering). Such archaeological data suggest that utilitarian modes of thought may utilize combinations of neuronal circuits in brain regions that are conserved among tribal populations territorially separated from each other for tens of thousands of years. Such conservation may not be true for neuronal circuits involved in

  20. Catarrhine primate divergence dates estimated from complete mitochondrial genomes: concordance with fossil and nuclear DNA evidence.

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    Raaum, Ryan L; Sterner, Kirstin N; Noviello, Colleen M; Stewart, Caro-Beth; Disotell, Todd R

    2005-03-01

    Accurate divergence date estimates improve scenarios of primate evolutionary history and aid in interpretation of the natural history of disease-causing agents. While molecule-based estimates of divergence dates of taxa within the superfamily Hominoidea (apes and humans) are common in the literature, few such estimates are available for the Cercopithecoidea (Old World monkeys), the sister taxon of the hominoids in the primate infraorder Catarrhini. To help fill this gap, we have sequenced the entire mitochondrial DNA (mtDNA) genomes from a representative of three cercopithecoid tribes, Cercopithecini (Chlorocebus aethiops), Colobini (Colobus guereza), and Presbytini (Trachypithecus obscurus), and analyzed these new data together with other catarrhine mtDNA genomes available in public databases. Molecular divergence date estimates are dependent on calibration points gleaned from the paleontological record. We defined criteria for the selection of good calibration points and identified three points meeting these criteria: Homo-Pan, 6.0 Ma; Pongo-hominines, 14.0 Ma; hominoid/cercopithecoid, 23.0 Ma. Because a uniform molecular clock does not fit the catarrhine mtDNA data, we estimated divergence dates using a penalized likelihood and a Bayesian method, both of which take into account the effects of rate differences on lineages, phylogenetic tree structure, and multiple calibration points. The penalized likelihood method applied to the coding regions of the mtDNA genome yielded the following divergence date estimates, with approximate 95% confidence intervals: cercopithecine-colobine, 16.2 (14.4-17.9) Ma; colobin-presbytin, 10.9 (9.6-12.3) Ma; cercopithecin-papionin, 11.6 (10.3-12.9) Ma; and Macaca-Papio, 9.8 (8.6-10.9) Ma. Within the hominoids, the following dates were inferred: hylobatid-hominid, 16.8 (15.0-18.5) Ma; Gorilla-Homo+Pan, 8.1 (7.1-9.0) Ma; Pongo pygmaeus pygmaeus-P. p. abelii, 4.1 (3.5-4.7) Ma; and Pan troglodytes-P. paniscus, 2.4 (2.0-2.7) Ma. These

  1. Chromosomal evolution of the PKD1 gene family in primates

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    Krawczak Michael

    2008-09-01

    Full Text Available Abstract Background The autosomal dominant polycystic kidney disease (ADPKD is mostly caused by mutations in the PKD1 (polycystic kidney disease 1 gene located in 16p13.3. Moreover, there are six pseudogenes of PKD1 that are located proximal to the master gene in 16p13.1. In contrast, no pseudogene could be detected in the mouse genome, only a single copy gene on chromosome 17. The question arises how the human situation originated phylogenetically. To address this question we applied comparative FISH-mapping of a human PKD1-containing genomic BAC clone and a PKD1-cDNA clone to chromosomes of a variety of primate species and the dog as a non-primate outgroup species. Results Comparative FISH with the PKD1-cDNA clone clearly shows that in all primate species studied distinct single signals map in subtelomeric chromosomal positions orthologous to the short arm of human chromosome 16 harbouring the master PKD1 gene. Only in human and African great apes, but not in orangutan, FISH with both BAC and cDNA clones reveals additional signal clusters located proximal of and clearly separated from the PKD1 master genes indicating the chromosomal position of PKD1 pseudogenes in 16p of these species, respectively. Indeed, this is in accordance with sequencing data in human, chimpanzee and orangutan. Apart from the master PKD1 gene, six pseudogenes are identified in both, human and chimpanzee, while only a single-copy gene is present in the whole-genome sequence of orangutan. The phylogenetic reconstruction of the PKD1-tree reveals that all human pseudogenes are closely related to the human PKD1 gene, and all chimpanzee pseudogenes are closely related to the chimpanzee PKD1 gene. However, our statistical analyses provide strong indication that gene conversion events may have occurred within the PKD1 family members of human and chimpanzee, respectively. Conclusion PKD1 must have undergone amplification very recently in hominid evolution. Duplicative

  2. The Carbon Crisis: An Evolutionary Perspective

    Science.gov (United States)

    Peacock, K.

    2013-12-01

    By the 'carbon crisis' I mean the coupled crises of the depletion of the highest-EROI sources of fossil fuels and the global warming caused by our use of those fossil fuels. (EROI means 'energy return on energy investment'; Hall 2011.) While global warming is arguably more urgent, either of these factors would sooner or later be sufficient by itself to call a halt to our global-scale, energy-intensive, high technology economy. In lethal combination, they threaten to drastically reduce the capacity of the planet to support 7+ billion talking hominids. I will pull the camera back for a very long view and characterize the carbon crisis and our possible responses to it from an evolutionary and ecological perspective. It remains unclear why sapiens emerged rather suddenly as the most successful member of the family Homo about 50 to 60 kya; some argue that this neurological explosion could be due to our ancestors having survived the rigors of the Toba population bottleneck, which presumably would have favoured high adaptability (Ambrose 1998). Whatever the cause, Paleolithic humans deployed an unprecedented combination of technological and social ingenuity (the capacity for adaptive social organization; Homer-Dixon 2001). Aided by the relatively benign climate of the Holocene and ultimately by our increasing ability to tap into the resources of the 'found' ecology, especially the vast stores of hydrocarbons bequeathed by the Paleozoic and Mesozoic eras, our population has grown exponentially to its present unsteady pinnacle of (possibly) temporary reproductive success. The question now is what happens next. It was human ingenuity that got us through the ice age, put footprints on the Moon, and brought us to this crisis point; now, only human ingenuity (both social and technical) can get us past it. Our species will finally achieve a sustainable mode of existence on this planet when (in E. Odum's words; 1973) 'the present-day concept of ';unlimited exploitation of

  3. New dates reignite human evolution debate

    International Nuclear Information System (INIS)

    Australian research into the Asian fossil record is unearthing controversial evidence with implications for the evolution of humans. Dr Jian-xin Zhao and Prof Ken Collerson from the University of Queensland's Department of Earth Sciences have been studying the fossil record in East Asia for clues to the early migration of hominids out of Africa in collaboration with Chinese archaeologists Dr Kai Hu of Nanjing University and Hankui Xu of Nanjing Institute of Palaeontology, Academia Sinica. Together they have been studying the remains of Nanjing Man, the name given to two Homo erectus skulls and the tooth of a third individual discovered in Tangshan Cave 250 km north-west of Shanghai. Dr Zhao and Prof Collerson have now employed more accurate dating techniques and materials, using a mass spectrometer to analyse the amounts of thorium-230 and uranium-234 in a calcite flowstone above the Nanjing Man fossil bed. Unlike fossil teeth, uranium and thorium became locked into the flowstone's crystal lattice when the calcite became crystallised. Because of this, the U-series decay in the calcite reliably records when the calcite crystallised. Taking into account the half-lives of uranium-234 and thorium-230, Dr Zhao and Prof Collerson determined the age of the calcite flowstone to be 577,000 years old (+44,000/-34,000 years). As the flowstone overlies the fossil bed, this date only defines the minimum age of the Nanjing Man fossil bed. For comparison, the dentine and enamel components of one fossil deer tooth collected from the Nanjing Man fossil bed yielded discordant mass spectrometric U-series ages of 388,000 and 130,100 years, respectively. Dr Zhao says that this 'strongly demonstrates the unreliability of fossil teeth as a chronometer'. Other evidence in the sediments surrounding the fossils has been the presence of flora and fauna that are typical of a glacial period. Dr Zhao therefore believes that the skulls could have been deposited during a glacial period

  4. Macromammalian faunas, biochronology and palaeoecology of the early Pleistocene Main Quarry hominin-bearing deposits of the Drimolen Palaeocave System, South Africa.

    Science.gov (United States)

    Adams, Justin W; Rovinsky, Douglass S; Herries, Andy I R; Menter, Colin G

    2016-01-01

    The Drimolen Palaeocave System Main Quarry deposits (DMQ) are some of the most prolific hominin and primate-bearing deposits in the Fossil Hominids of South Africa UNESCO World Heritage Site. Discovered in the 1990s, excavations into the DMQ have yielded a demographically diverse sample of Paranthropus robustus (including DNH 7, the most complete cranium of the species recovered to date), early Homo, Papio hamadryas robinsoni and Cercopithecoides williamsi. Alongside the hominin and primate sample is a diverse macromammalian assemblage, but prior publications have only provided a provisional species list and an analysis of the carnivores recovered prior to 2008. Here we present the first description and analysis of the non-primate macromammalian faunas from the DMQ, including all 826 taxonomically identifiable specimens catalogued from over two decades of excavation. We also provide a biochronological interpretation of the DMQ deposits and an initial discussion of local palaeoecology based on taxon representation.The current DMQ assemblage consists of the remains of minimally 147 individuals from 9 Orders and 14 Families of mammals. The carnivore assemblage described here is even more diverse than established in prior publications, including the identification of Megantereon whitei, Lycyaenops silberbergi, and first evidence for the occurrence of Dinofelis cf. barlowi and Dinofelis aff. piveteaui within a single South African site deposit. The cetartiodactyl assemblage is dominated by bovids, with the specimen composition unique in the high recovery of horn cores and dominance of Antidorcas recki remains. Other cetartiodactyl and perissodactyl taxa are represented by few specimens, as are Hystrix and Procavia; the latter somewhat surprisingly so given their common occurrence at penecontemporaneous deposits in the region. Equally unusual (particularly given the size of the sample) is the identification of single specimens of giraffoid, elephantid and aardvark

  5. Do olympic athletes train as in the Paleolithic era?

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    Boullosa, Daniel A; Abreu, Laurinda; Varela-Sanz, Adrián; Mujika, Iñigo

    2013-10-01

    Every 4 years, approximately 10,000 athletes participate in the Olympic Games. These athletes have dedicated several years of physical training to achieve the best possible performance on a given day. Their preparation has been supported by expert coaches and an army of sport scientists, whose overall responsibility is to ensure that the athletes are in peak condition for their event. Although every athlete prepares specifically for the unique physiological challenges of their event, all athletes have one common characteristic: they are Homo sapiens. They share a unique genome, which is the result of evolutionary forces beyond their individual control. Although studies on the influence of different genetic polymorphisms on selected athletic events have been proven to be of limited utility, a body of evidence--from molecular biology to whole-body measures--suggests that training adaptations are enhanced when the stimulus closely resembles the activity pattern of human ancestors. Because genetic evolutionary changes occur slowly in Homo sapiens, and the traditional physical activity and dietary patterns of Homo sapiens have undergone rapid and dramatic changes in previous centuries, we propose that modern humans are physiologically better adapted to training modes and nutritional strategies similar to the ones that their hominid ancestors evolved on, rather than those supported by modern societies. Such an ancestral pattern was mainly characterized by the prevalence of daily bouts of prolonged, low-intensity, aerobic-based activities interspersed with periodic, short-duration, high-intensity bursts of activity. On some occasions, such activity patterns were undertaken with low carbohydrate availability. Specific activities that enhanced strength and power were typically performed after aerobic activities. We present scientific evidence to support the appropriateness of this model, and we propose that future studies should address this hypothesis in a multitude of

  6. On the nature and evolution of the neural bases of human language.

    Science.gov (United States)

    Lieberman, Philip

    2002-01-01

    the brains of human beings and other species provides insight into the evolution of the brain bases of human language. The neural substrate that regulated motor control in the common ancestor of apes and humans most likely was modified to enhance cognitive and linguistic ability. Speech communication played a central role in this process. However, the process that ultimately resulted in the human brain may have started when our earliest hominid ancestors began to walk.

  7. Contribution to the speleology of Sterkfontein cave, Gauteng province, South Africa.

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    Martini Jacques E. J.

    2003-01-01

    Full Text Available The authors present more data about the speleological aspect of the Sterkfontein Cave, famous for its bone breccia which yielded abundant hominid remains. They also briefly review the previous voluminous studies by numerous authors, which are mainly dealing with the paleontology, stratigraphy and sedimentology of the breccia. The present investigations were oriented to hitherto poorly investigated aspects such as detail mapping of the cave, its country rock stratigraphy and recording the underground extension of the basal part of the breccia body. The cave consists of a complex network of phreatic channels, developed along joints in Neoarchaean cherty dolostone over a restricted surface of 250x250m. The combined length of all passages within this area amounts to 5,23km. The system extends over a height of about 50m and the dry part of it is limited downwards by the water-table appearing as numerous static pools. The fossiliferous breccia (= Sterkfontein Formation forms an irregular lenticular mass 75x25m horizontally by 40m vertically, which is included within the passage network. It crops out at surface and in the cave, and resulted from the filling of a collapse chamber, which was de-roofed by erosion. The present investigation confirmed that the cave and the Sterkfontein Formation are part of a single speleogenetic event. The breccia resulted from cavity filling by sediments introduced from a pit entrance, whereas many of the phreatic passages around it, which are developed at the same elevation, were only partly filled or remained entirely open up to present. This filling took place mainly in a vadose environment. Taking into account the age of the Sterkfontein Formation (>3,3-1,5 My, from base to top, the geomorphic evolution of the landscape and the context of other caves in the region, it seems that the cave might have started to form 5 My ago. It has been continuously developing up to present as a result of a slow drop of the water-table.

  8. The environmental context of human evolutionary history in Eurasia and Africa.

    Science.gov (United States)

    Elton, Sarah

    2008-04-01

    This review has three main aims: (1) to make specific predictions about the habitat of the hypothetical last common ancestor of the chimpanzee/bonobo-human clade; (2) to outline the major trends in environments between 8-6 Ma and the late Pleistocene; and (3) to pinpoint when, and in some cases where, human ancestors evolved to cope with the wide range of habitats they presently tolerate. Several lines of evidence indicate that arboreal environments, particularly woodlands, were important habitats for late Miocene hominids and hominins, and therefore possibly for the last common ancestor of the chimpanzee/bonobo-human clade. However, as there is no clear candidate for this last common ancestor, and because the sampling of fossils and past environments is inevitably patchy, this prediction remains a working hypothesis at best. Nonetheless, as a primate, it is expected that the last common ancestor was ecologically dependent on trees in some form. Understanding past environments is important, as palaeoenvironmental reconstructions provide the context for human morphological and behavioural evolution. Indeed, the impact of climate on the evolutionary history of our species has long been debated. Since the mid-Miocene, the Earth has been experiencing a general cooling trend accompanied by aridification, which intensified during the later Pliocene and Pleistocene. Numerous climatic fluctuations, as well as local, regional and continental geography that influenced weather patterns and vegetation, created hominin environments that were dynamic in space and time. Behavioural flexibility and cultural complexity were crucial aspects of hominin expansion into diverse environments during the Pleistocene, but the ability to exploit varied and varying habitats was established much earlier in human evolutionary history. The development of increasingly complex tool technology facilitated re-expansion into tropical forests. These environments are difficult for obligate bipeds to

  9. Speleološki objekti planinskih masiva SZ Hrvatske

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    Šincek, Dubravko

    2011-06-01

    Full Text Available Geological structure of NE Croatia is characterized with big differences in lithological texture, intensity of tectonical upending, continuance and range of continental phases, same as transgression, thick and superposition of rocks and other geostructural elements.Even carbonate rocks in this region doesn’t occupied important surface, they are important due to development of karst with important number of karst features.Two carbonate units are karstified here: older, Triassic, mostly build by dolomite rocks, and younger Upper Baden unit, build by calcite. Four types of karst have been found here: deep Triassic, shallow Triassic, Triassic-Upper Baden and Upper Baden. Most expressed Karst features have been presented on mountains: Ravna gora Mt., Strahinjščica Mt., Ivanščica Mt., Kalničko gorje Mt., Varaždinsko- toplička gora Mt., Strugača Mt., Koštrun Mt., Kuna gora Mt., Cesargradska gora Mt. and Medvednica Mt.Using of speleological objects start already long before civilization, supported by rests of Neanderthal hominids, found on several locations in region. First literature reference dated in 1801 and scientific speleological researches started at the end of 19th Century and continued during 20. Century.Since 2003 systematic research of region is organized by Croatian Biospeleological Society (CBSS: Veternica cave (2003-2004, Medvednica Mt. (2004-2005, Ravna gora Mt. (2006-2007, Ivanščica Mt. (2008 and Strahinjščica Mt., Cesargrad Mt. and Kuna Mt. (2009.Speleological data base with 165 speleological objects on NW Croatia is established including many data of each object as: exact name and position, dimensions, geological, geomorphological, hydrological, elements; climatic and ecological data; list of animal taxa; paleontological and archaeological potential, but also eventual endanger and necessarily of protection. Speleological data base include also topographic plan of each object, photo documentary material, same as list of

  10. Hypoglossal canal size in living hominoids and the evolution of human speech.

    Science.gov (United States)

    Jungers, William L; Pokempner, Amy A; Kay, Richard F; Cartmill, Matt

    2003-08-01

    The relative size of the hypoglossal canal has been proposed as a useful diagnostic tool for the identification of human-like speech capabilities in the hominid fossil record. Relatively large hypoglossal canals (standardized to oral cavity size) were observed in humans and assumed to correspond to relatively large hypoglossal nerves, the cranial nerve that controls motor function of the tongue. It was suggested that the human pattern of tongue motor innervation and associated speech potential are very different from those of African apes and australopithecines; the modern human condition apparently appeared by the time of Middle Pleistocene Homo. A broader interspecific analysis of hypoglossal canal size in primates conducted in 1999 has rejected this diagnostic and inferences based upon it. In an attempt to resolve these differences of opinion, which we believe are based in part on biased size-adjustments and/or unwarranted assumptions, a new data set was collected and analyzed from 298 extant hominoid skulls, including orangutans, gorillas, chimpanzees, bonobos, siamang, gibbons, and modern humans. Data on the absolute size of the hypoglossal nerve itself were also gathered from a small sample of humans and chimpanzee cadavers. A scale-free index of relative hypoglossal canal size (RHCS) was computed as 100 x (hypoglossal canal area(0.5)/oral cavity volume(0.333)). No significant sexual dimorphism in RHCS was discovered in any species of living hominoid, but there are significant interspecific differences in both absolute and relative sizes of the hypoglossal canal. In absolute terms, humans possess significantly larger canals than any other species except gorillas, but there is considerable overlap with chimpanzees. Humans are also characterized by large values of RHCS, but gibbons possess an even larger average mean for this index; siamang and bonobos overlap appreciably with humans in RHCS. The value of RHCS in Australopithecus afarensis is well within both

  11. Organization of the lithic production and use-wear analysis from Middle Paleolithic site of Abric Romaní. Level Ja (Capellades, Barcelona, Spain

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    Martínez, Kenneth

    2001-06-01

    Full Text Available The fieldwork from layer Ja at Abric Romaní provides some interesting insights on the examination of patterns of late premodern hominid behavior The reconstruction of châine opératoire and use-wear analysis point out planning in the consumption of raw materials and in the design of stone tools for specific tasks. The archaeological record shows complexity in the settlement system and intrasite context, likewise, the land use depends mainly on the curation of tools through transport of cores, like reserve of tools, and retouched tools. The flakes were versatile tools; working wood, hide and participating in butchering activities and denticulates were used mainly on wood, probably to make points. So far, this work seeks to understand Middle Paleolithic way of life in its own right without comparing it with a hypothetical model of modern behavior.

    La intervención arqueológica del nivel Ja del Abric Romaní ha aportado una información muy valiosa para comprender los patrones conductuales de los últimos homínidos arcaicos. La reconstrucción de la organización de la producción lítica y los análisis funcionales indican una planificación a la hora de gestionar la materia prima y en el diseño de los útiles según tareas específicas. El registro arqueológico muestra una estructuración compleja de las ocupaciones en el interior del abrigo, así como una organización a escala regional de las ocupaciones. La explotación del entorno dependía principalmente de una gestión cuidada de la materia prima mediante el desplazamiento por el territorio de núcleos, como reserva de útiles, y de objetos retocados. Las lascas fueron útiles versátiles, trabajaron tanto madera como piel, y también participaron en actividades de carnicería. Por su parte, los denticulados fueron utilizados para trabajar madera, probablemente para elaborar puntas en este material. Por tanto, el presente artículo intenta comprender el modo de vida de

  12. The first hominin from the early Pleistocene paleocave of Haasgat, South Africa.

    Science.gov (United States)

    Leece, A B; Kegley, Anthony D T; Lacruz, Rodrigo S; Herries, Andy I R; Hemingway, Jason; Kgasi, Lazarus; Potze, Stephany; Adams, Justin W

    2016-01-01

    Haasgat is a primate-rich fossil locality in the northeastern part of the Fossil Hominid Sites of South Africa UNESCO World Heritage Site. Here we report the first hominin identified from Haasgat, a partial maxillary molar (HGT 500), that was recovered from an ex situ calcified sediment block sampled from the locality. The in situ fossil bearing deposits of the Haasgat paleokarstic deposits are estimated to date to slightly older than 1.95 Ma based on magnetobiostratigraphy. This places the hominin specimen at a critical time period in South Africa that marks the last occurrence of Australopithecus around 1.98 Ma and the first evidence of Paranthropus and Homo in the region between ∼2.0 and 1.8 Ma. A comprehensive morphological evaluation of the Haasgat hominin molar was conducted against the current South African catalogue of hominin dental remains and imaging analyses using micro-CT, electron and confocal microscopy. The preserved occlusal morphology is most similar to Australopithecus africanus or early Homo specimens but different from Paranthropus. Occlusal linear enamel thickness measured from micro-CT scans provides an average of ∼2.0 mm consistent with Australopithecus and early Homo. Analysis of the enamel microstructure suggests an estimated periodicity of 7-9 days. Hunter-Schreger bands appear long and straight as in some Paranthropus, but contrast with this genus in the short shape of the striae of Retzius. Taken together, these data suggests that the maxillary fragment recovered from Haasgat best fits within the Australopithecus-early Homo hypodigms to the exclusion of the genus Paranthropus. At ∼1.95 Ma this specimen would either represent another example of late occurring Australopithecus or one of the earliest examples of Homo in the region. While the identification of this first hominin specimen from Haasgat is not unexpected given the composition of other South African penecontemporaneous site deposits, it represents one of the few hominin

  13. On the nature and evolution of the neural bases of human language

    Science.gov (United States)

    Lieberman, Philip

    2002-01-01

    the brains of human beings and other species provides insight into the evolution of the brain bases of human language. The neural substrate that regulated motor control in the common ancestor of apes and humans most likely was modified to enhance cognitive and linguistic ability. Speech communication played a central role in this process. However, the process that ultimately resulted in the human brain may have started when our earliest hominid ancestors began to walk.

  14. Virtual Exploration of Earth's Evolution

    Science.gov (United States)

    Anbar, A. D.; Bruce, G.; Semken, S. C.; Summons, R. E.; Buxner, S.; Horodyskyj, L.; Kotrc, B.; Swann, J.; Klug Boonstra, S. L.; Oliver, C.

    2014-12-01

    Traditional introductory STEM courses often reinforce misconceptions because the large scale of many classes forces a structured, lecture-centric model of teaching that emphasizes delivery of facts rather than exploration, inquiry, and scientific reasoning. This problem is especially acute in teaching about the co-evolution of Earth and life, where classroom learning and textbook teaching are far removed from the immersive and affective aspects of field-based science, and where the challenges of taking large numbers of students into the field make it difficult to expose them to the complex context of the geologic record. We are exploring the potential of digital technologies and online delivery to address this challenge, using immersive and engaging virtual environments that are more like games than like lectures, grounded in active learning, and deliverable at scale via the internet. The goal is to invert the traditional lecture-centric paradigm by placing lectures at the periphery and inquiry-driven, integrative virtual investigations at the center, and to do so at scale. To this end, we are applying a technology platform we devised, supported by NASA and the NSF, that integrates a variety of digital media in a format that we call an immersive virtual field trip (iVFT). In iVFTs, students engage directly with virtual representations of real field sites, with which they interact non-linearly at a variety of scales via game-like exploration while guided by an adaptive tutoring system. This platform has already been used to develop pilot iVFTs useful in teaching anthropology, archeology, ecology, and geoscience. With support the Howard Hughes Medical Institute, we are now developing and evaluating a coherent suite of ~ 12 iVFTs that span the sweep of life's history on Earth, from the 3.8 Ga metasediments of West Greenland to ancient hominid sites in East Africa. These iVFTs will teach fundamental principles of geology and practices of scientific inquiry, and expose

  15. Petrology of the Oldoinyo Lengai volcano and the origin of the Lake Natron Footprint Tuff (northern Tanzania)

    Science.gov (United States)

    Balashova, A.

    2015-12-01

    During its evolution the Oldoinyo Lengai volcano (northern Tanzania) has erupted magmas with a compositional range from nephelinites to phonolites and carbonatites. Intrusive, metasomatic and cumulate enclaves are commonly found in all silicate products of the volcano. New and detailed geochemical and mineralogical study of 132 samples of fresh volcanic silicate material from four debris avalanches, and the volcanic edifice, indicates that phonolites and nephelinites associated with carbonatites were generated via different evolutionary paths. Temporally, the first stage of evolution included the phonolitic path, whereas the second, modern stage includes the production of combeite-wollastonite-bearing nephelinites, associated with carbonatites. Our data supports the two-stage evolutionary model previously presented by Klaudius and Keller (2006). The modern stage is characterised by the mildly explosive natrocarbonatitic activity, which is alternating with highly explosive, nephelinitic eruptions. Distal products of these nephelinitic eruptions cover a wide area around the volcano, however only the recent eruptions have been documented. In this context, special emphasis was paid to the origin of the Lake Natron Footprint Tuff which has preserved hominid footprints that received considerable interest within the anthropological community in recent years. The so-called Footprint tuff is the most significant volcaniclastic horizon in the area around Oldoinyo Lengai. Based on the geochemical, mineralogical and magnetic data we collected from this site, we can deduce that the footprint-bearing horizon was deposited during one or several big eruptions of the Oldoinyo Lengai volcano (corresponding to the late nephelinitic stage of volcanism) and was slightly reworked by water. The material that comprises the upper horizon, which covers the footprints, was derived as aeolian sediments from the Lake Natron - Engaruka Monogenetic Volcanic Field (i.e., melilititic in

  16. The Taung endocast: a reply to Holloway.

    Science.gov (United States)

    Falk, D

    1983-04-01

    specimen for the lateral end of L, and the pongid-like sulcal pattern of Taung is reaffirmed. Thus, we do not yet know when human-like sulcal patterns first appeared in the hominid fossil record. PMID:6405623

  17. [The anatomical and functional origin of the first bipedalism].

    Science.gov (United States)

    Coppens, Y

    1991-10-01

    This communication is the synthesis of ten years of researchers of comparative anatomy done by the author or under his control on fossil Hominids, three million years old, found by his expeditions in Eastern Ethiopia. It brings, for the first time, the odd picture of a skeleton adapted to arboricolism and bipedalism together. The rachis has already the curves of an erect being but with at least a thoraco-lumbar cyphosis a bit more elongated than in our own rachis; the pelvis is wide and shallow like the pelvis of a biped but with many particular features like the width of the iliac wings, a great biacetabular diameter, the small size of the coxo-femoral joints; the femur is short with a special long neck, a very oblique diaphysis like in Man and an intercondylar fossa, deep and wide like in chimp; the tibia is also short, its spines very tight in such a way that the knee shows a great laxity. The foot is short and flat, with an abducted hallux and long curved toes; the scapular, elbow and wrist joints show, at the opposite of the knee joint, a great solidity, but both characteristics of the hind and fore-limb joints are not in contradiction: they are, as in chimpanzees again, functionally adapted to climbing and moving in the trees where are needed firm grip of the hands as well as mobility of the knee and of the foot. It seems that the early Australopithecine' bipedalism was original, different from ours and quite instable: short steps were necessary to maintain equilibrium as well as a strong rotation of the pelvis around the vertebral axis (50 to 60 degrees on each side). This analysis is then demonstrating a real evolution of bipedalism which was not at all, at once, the bipedalism of Homo sapiens, as it has been claimed. This paper is also showing that bipedalism anatomic organization is taking place from the pelvis to the foot and not the other way round. At last, as we have found, also in Ethiopia, stone-tools more than three million years old in association

  18. Muscle-specific integrins in masseter muscle fibers of chimpanzees: an immunohistochemical study.

    Directory of Open Access Journals (Sweden)

    Gianluigi Vaccarino

    2010-05-01

    Full Text Available Most notably, recent comparative genomic analyses strongly indicate that the marked differences between modern human and chimpanzees are likely due more to changes in gene regulation than to modifications of the genes. The most peculiar aspect of hominoid karyotypes is that human have 46 chromosomes whereas gorillas and chimpanzees have 48. Interestingly, human and chimpanzees do share identical inversions on chromosome 7 and 9 that are not evident in the gorilla karyotype. Thus, the general phylogeny suggests that humans and chimpanzees are sister taxa; based on this, it seems that human-chimpanzee sequence similarity is an astonishing 99%. At this purpose, of particular interest is the inactivation of the myosin heavy chain 16 (MYH16 gene, most prominently expressed in the masticatory muscle of mammals. It has been showed that the loss of this gene in humans may have resulted in smaller masticatory muscle and consequential changes to cranio-facial morphology and expansion of the human brain case. Powerful masticatory muscles are found in most primates; contrarily, in both modern and fossil member Homo, these muscles are considerably smaller. The evolving hominid masticatory apparatus shifted towards a pattern of gracilization nearly simultaneously with accelerated encephalization in early Homo. To better comprehend the real role of the MYH16 gene, we studied the primary proteins present in the muscle fibers of humans and non-humans, in order to understand if they really can be influenced by MYH16 gene. At this aim we examined the muscle-specific integrins, alpha 7B and beta 1D-integrins, and their relative fetal isoforms, alpha 7A and beta 1A-integrins, analyzing, by immunohistochemistry, muscle biopsies of two components of a chimpanzee's group in captivity, an alpha male and a non-alpha male subjects; all these integrins participate in vital biological processes such as maintenance of tissue integrity, embryonic development, cell

  19. Estrategias de subsistencia en los momentos finales del Pleistoceno medio: el nivel XII de la Cova del Bolomor (La Valldigna, Valencia

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    Ruth BLASCO

    2009-08-01

    los homínidos de la Cova del Bolomor y contribuir al conocimiento de los modos de vida de los grupos humanos del Pleistoceno medio final.ABSTRACT: Bolomor Cave, located in Tavernes de la Valldigna (Valencia, offers one of the best faunal records in the second half of the Middle Pleistocene in the Iberian Peninsula. The cavity contains a sedimentary deposit composed of seventeen stratigraphical levels ranging from OIS 9 to OIS 5e. This wide chronological sequence allows to deal with different issues related to human groups this period and their relationship with the environment. Specifically, from zooarchaeological study of level XII (OIS 6, we have reconstructed the anthropic sequence of obtaining and processing of faunal resources. Thus, different subsistence strategies carried out by hominids to obtain the animals were identified. These practices range from scavenging to the hunting and include the supply of small prey such as birds (Cygnus olor or leporids (Oryctolagus cuniculus. This variability of strategies could be interpreted as the great adaptability that possesses these groups to take advantage of the opportunities the environment offers. It was also noted the existence of systematic patterns well both in the utilization of faunal external resources (skin, meat, tendons and the obtaining of internal resources (marrow. Many of the diagnostic elements that demonstrate the anthropic breakage at level XII show systematization both in areas and in specific anatomical parts. The existence of morphologies repeated in some skeletal elements indicates a high degree of standardization at the time of bone breakage. This reiteration could imply the existence of learning mechanisms or transmission of information within the group in this chronological period. Overall, this study aims to provide data about the subsistence strategies of hominids in Bolomor Cave and contribute to knowledge about the way of life of human groups in the Last Middle Pleistocene.

  20. Communicating Climate Change: An Evolutionary Perspective

    Science.gov (United States)

    Peacock, K. A.; Byrne, J. M.; McDaniel, S.

    2012-12-01

    The most effective way to communicate the scientific "big picture" is to appeal to the intelligence and imagination of that large number of people who really want to know what science has to say, and who really would be likely to support enlightened policies if they were given an unflinching picture of the present human predicament. Staff writers at Life Magazine used to be told, "Never overestimate readers' information; never underestimate their intelligence." In the long run, whatever communications channels may be employed, the best hope of moving forward is to appeal to the intelligence of the public. (Media such as wikis, which invite participation, could be one of the best ways to do that.) There are two salient "big picture" facts to be communicated. The first is the ecological unsustainability of the present human condition. There is not the slightest possibility of a long-term future for a planetary-scale, technologically-intensive society of over 7 billion talking hominids that gets most of its free energy from the combustion of a one-time-only store of biotic waste products laid down in the strata hundreds of millions of years ago. Not only is this limited fuel supply running out, but its waste products are rapidly destabilizing the very climatic conditions that favoured the growth of our complex culture. As Homer-Dixon puts it, we are on the "cusp of a planetary-scale emergency"—obvious to earth scientists, but not obvious to all of even the best-intentioned members of the public. The second crucial fact is that our species' capacity to innovate (technologically, linguistically, socially), unique in the history of life on this planet, has up to now been our most effective survival tool and still remains our best chance for pulling through the present crisis. Herbert Spencer said that the most important adaptive trait is what he called "sagacity"—intelligent adaptability. But our sagacity now faces its toughest test, tougher than the harsh Ice Age in

  1. Language comprehension in ape and child.

    Science.gov (United States)

    Savage-Rumbaugh, E S; Murphy, J; Sevcik, R A; Brakke, K E; Williams, S L; Rumbaugh, D M

    1993-01-01

    required the ability to reverse work order as they did on sentences that did not require this capacity. These results are discussed in light of a model of the evolution of language that suggests that the potential for language comprehension preceded the appearance of speech by several million years at minimum. The onset of speech is linked to the appearance of fully adapted bipedalism, which necessitated reorientation of the laryngeal tract and made closure of the soft palate possible. For the first time, such closure permitted mammals to easily produce sounds that could be interpreted by the mammalian auditory system in a categorical manner. When these sounds were paired with the previously extant capacity to produce vowels, it became possible to form "bounded vowels" or sound units that could readily be discriminated as units by the auditory system. It is suggested that this physical adaptation allowed the extant cognitive capacity of the hominids to embark on a speech-like mode of communication. PMID:8366872

  2. Messiniense: compleja y grave crisis ecologica

    Directory of Open Access Journals (Sweden)

    Aguirre, E.

    2003-08-01

    Full Text Available The «Messinian» is the last stratigraphic stage of the Miocene, lasting between 6.616.5 and 5.3 MaBP. Its redefinition and stratotype designation were problematic in the 1960s, in the frame of the IUGS International Commission on Stratigraphy (ICS revision works and the Project 110.25 of the International Geological Correlation Program (IGCP in the following decades. The interpretation of the regional Mediterranean stratigraphic sequence was debated. Many fossil mammal sites in Spain and other peri-Tethic regions, showing relevant events and intercontinental exchanges within that time span, add pressing questions to the essential need of correlating the continental bio,stratigraphic divisions to the marine based stratigraphic scale. Recent discovery of fossil hominids with early evidence of bipedal adaptation in East-and Central Africa with referred ages of nearly 6 MaBP, or more, makes the study of that age still more exciting. In the same time span, major palaeogeographic, geodynamic, palaeoclimatic and palaeoenvironmental events have been dated, that started been investigated 40 years ago also in connection to the late Miocene Mediterranean «Salinity Crisis»: isolation from the Atlantic Ocean, global sea leve1 lowering, continental accretion and orogeny, glaciation and vegetal cover deterioration. Severa1 models of sequenced interactions have been proposed. A comprehensive scenario is here attempted of these major events in the History of Earth and History of Life, with a calibration of nearly hundred thousand years.La división final del Mioceno, piso «Messiniense» -entre 6,5/6,6 Ma y 5,3 Ma-, presentó problema para su redefinición y la interpretación de sus secuencias estratigráficas en la década de 1960. Fue objeto de estudios profundos y diversos en el marco de programas de la Comisión Internacional de Estratigrafía (ICS y del Programa Internacional de Correlación Geológica en las décadas siguientes. Numerosos

  3. Morfología comparada de los dientes humanos fósiles de Ibeas (Sierra de Atapuerca, Burgos

    Directory of Open Access Journals (Sweden)

    Bermúdez de Castro, J. M.

    1987-08-01

    Full Text Available This paper contains a morphological and comparative study of 68 human fossil teeth recovered from the "Sima de los Huesos" site of the Cueva Mayor-Cueva del Silo karst system (Sierra de Atapuerca, Ibeas de Juarros, Burgos. The morphology of the Ibeas teeth conforms with a pattern of expansion of the anterior dentition characterizing all the Middle Pleistocene human populations, and with a pattern of structural reduction of the posterior teeth characterizing the European population of that period. The Ibeas teeth share several morphological traits with those of other European, North African and Asian Middle Pleistocene fossils. However, the tooth morphology of the European group, in which the Ibeas fossils are included, shows remarkable differences with that of the other groups. This fact permits to reinforce the thesis that a distinctive hominid lineage was established in Europe during the Middle Pleistocene. On the other hand, the Ibeas teeth bring forward new evidence to support the hypothesis of a close filogenetic relationship between the Middle Pleistocene European population and the Nearderthals and, accordingly, of a local evolution during that period and the Early Upper Pleistocene.Este trabajo contiene el estudio morfológico comparado de un total de 68 dientes humanos fósiles recuperados en la Sima de los Huesos, yacimiento situado en el sistema kárstico Cueva Mayor-Cueva del Silo (Sierra de Atapuerca, Ibeas de Juarros, Burgos. La morfología de los dientes de Ibeas se ajusta a un modelo de expansión de la dentición anterior que caracteriza a todas las poblaciones humanas del Pleistoceno medio, y a un modelo de reducción estructural de la dentición posterior que caracteriza a la población europea de dicho periodo. Los dientes de Ibeas comparten diversos rasgos morfológicos con los dientes de otros fósiles mesopleistocenos de Europa, norte de Africa y este de Asia. Sin embargo, el grupo europeo, en el que se incluyen los f

  4. Recollections of a Journey Through a Psychotic Episode: Or, Mental Illness and Creativity

    Directory of Open Access Journals (Sweden)

    Anonymous

    2007-01-01

    alluded as how I needed help. By now, my parents had seen enough and decided to drive me into the Capital District Psychiatric Centre. On the way there I had the horrible perception that I had taken the next step in the evolution of humanity and that the first action of this new subspecies of humanity was to wipe out the existing human race, as had been the case with previous hominids. When this realization hit me, I became hysterical and started crying uncontrollably and ordered my mother to stop the car. Then in a very soothing tone of voice she said, "If you really are the next step in the evolution of mankind, you will have the wisdom to assimilate rather than destroy the human race." This calmed me down. The rest of the trip was uneventful. That is the first phase of the experience. [Abstract not available.

  5. Olduvai Gorge, Shaded Relief and Colored Height

    Science.gov (United States)

    2004-01-01

    Three striking and important areas of Tanzania in eastern Africa are shown in this color-coded shaded relief image from the Shuttle Radar Topography Mission. The largest circular feature in the center right is the caldera, or central crater, of the extinct volcano Ngorongoro. It is surrounded by a number of smaller volcanoes, all associated with the Great Rift Valley, a geologic fault system that extends for about 4,830 kilometers (2,995 miles) from Syria to central Mozambique. Ngorongoro's caldera is 22.5 kilometers (14 miles) across at its widest point and is 610 meters (2,000 feet) deep. Its floor is very level, holding a lake fed by streams running down the caldera wall. It is part of the Ngorongoro Conservation Area and is home to over 75,000 animals. The lakes south of the crater are Lake Eyasi and Lake Manyara, also part of the conservation area. The relatively smooth region in the upper left of the image is the Serengeti National Park, the largest in Tanzania. The park encompasses the main part of the Serengeti ecosystem, supporting the greatest remaining concentration of plains game in Africa including more than 3,000,000 large mammals. The animals roam the park freely and in the spectacular migrations, huge herds of wild animals move to other areas of the park in search of greener grazing grounds (requiring over 4,000 tons of grass each day) and water. The faint, nearly horizontal line near the center of the image is Olduvai Gorge, made famous by the discovery of remains of the earliest humans to exist. Between 1.9 and 1.2 million years ago a salt lake occupied this area, followed by the appearance of fresh water streams and small ponds. Exposed deposits show rich fossil fauna, many hominid remains and items belonging to one of the oldest stone tool technologies, called Olduwan. The time span of the objects recovered dates from 2,100,000 to 15,000 years ago. Two visualization methods were combined to produce the image: shading and color coding of

  6. Number of ancestral human species: a molecular perspective.

    Science.gov (United States)

    Curnoe, D; Thorne, A

    2003-01-01

    Despite the remarkable developments in molecular biology over the past three decades, anthropological genetics has had only limited impact on systematics in human evolution. Genetics offers the opportunity to objectively test taxonomies based on morphology and may be used to supplement conventional approaches to hominid systematics. Our analyses, examining chromosomes and 46 estimates of genetic distance, indicate there may have been only around 4 species on the direct line to modern humans and 5 species in total. This contrasts with current taxonomies recognising up to 23 species. The genetic proximity of humans and chimpanzees has been used to suggest these species are congeneric. Our analysis of genetic distances between them is consistent with this proposal. It is time that chimpanzees, living humans and all fossil humans be classified in Homo. The creation of new genera can no longer be a solution to the complexities of fossil morphologies. Published genetic distances between common chimpanzees and bonobos, along with evidence for interbreeding, suggest they should be assigned to a single species. The short distance between humans and chimpanzees also places a strict limit on the number of possible evolutionary 'side branches' that might be recognised on the human lineage. All fossil taxa were genetically very close to each other and likely to have been below congeneric genetic distances seen for many mammals. Our estimates of genetic divergence suggest that periods of around 2 million years are required to produce sufficient genetic distance to represent speciation. Therefore, Neanderthals and so-called H. erectus were genetically so close to contemporary H. sapiens they were unlikely to have been separate species. Thus, it is likely there was only one species of human (H. sapiens) for most of the last 2 million years. We estimate the divergence time of H. sapiens from 16 genetic distances to be around 1.7 Ma which is consistent with evidence for the earliest

  7. Book Reviews

    Directory of Open Access Journals (Sweden)

    Danker H. Schaareman

    1980-01-01

    . xvi + 329 pages. Maps, tables, plates, figures, index. - A. de Ruijter, S.F. Moore, Secular Ritual. Van Gorcum, Assen, 1977. 293 pp., B.G. Myerhoff (eds. - A. Ploeg, L.M. Serpenti, Cultivators in the swamps. Social structure and horticulture in a New Guinea society, Second edition. Van Gorcum, Assen, 1977, 308 pp., maps, tables, figures, glossary. - A. de Ruijter, R. Needham, Symbolic classifications. Goodyear Publishing Company Inc. Santa Monica, California. 1979. 78 pp. - Danker H. Schaareman, Urs Ramseyer, The art and culture of Bali. Oxford 1977: Oxford University Press. 265 pp., 405 pp., ill. - Anthony Shelton, E. Schwimmer, The Yearbook of Symbolic anthropology, London: C. Hurst and Co., 1978; pp. 230. - H. Steinhauer, M.A. Chlenov, Naselenie Molukkskix Ostrovov [The population of the Moluccas], Moscow 1976, 285 pp. - P. van de Velde, M.G. Leakey, The fossil hominids and an introduction to their context, 1968-1974, Oxford: Clarendon Press, 1978. Volume 1 of R.E. Leakey & G.Ll. Isaac (general editors: Koobi Fora - researches into geology, palaeontology, and human origins. 191 pages; 28 plates and numerous figures; tables; index., R.E. Leakey (eds. - Leontine E. Visser, P.A. Stott, Nature and man in South East Asia, 1978, S.O.A.S., London, 183 pp., fig., phot., subject index. - J.J. de Wolf, F. Bovenkerk, Toen en thans: De sociale wetenschappen in de jaren dertig en nu. Onder redactie van F. Bovenkerk, H.J.M. Claessen, B. van Heerikhuizen, A.J.F. Köbben, N. Wilterdink. 1978 Ambo, Baarn., H.J.M. Claessen, B. van Heerikhuizen (eds.

  8. Morphological Comparison of the ZKD 3 and 5 Skulls and the Probable Population Isolation as Reflected by Evolutionary Rates%周口店直立人3号与5号头骨形态特征对比及其演化速率所反映的群体隔离

    Institute of Scientific and Technical Information of China (English)

    邢松; 张银运; 刘武

    2012-01-01

    In 1941, Pere Teilhard de Chardin emphasized the morphological stability of Homo erectus from Zhoukoudian throughout the 50 meters of sediments of Locality 1. He believed that not a single anatomical difference could be detected between the skull remains found at the very bottom of the deposit and those collected at the very top. This morphological stability was evidence of a slowness that characterized biological evolution whenever not obscured, disturbed or accelerated by the intrusive immigration of foreign elements. The present study employs both traditional metrics and recently developed 3D scanning techniques to explore the morphological variations of skulls between the probable first and last inhabitants, represented by ZKD 3 and 5. Also these variations are scaled by those between NJ 1 and 2 skulls, whose owners probably spent the same duration as ZKD 3 and 5. After comparison, the skull of the latest (or top) inhabitant at Zhoukoudian Locality 1 was found to have increased in every direction related to the earliest (or bottom) inhabitant, while the shape seems to be relatively stable though the hundreds of thousand years that passed in the interim. In the present study, evolutionary rates of Homo erectus from Zhoukoudian were determined using 11 cranial measurements. The results show that biological evolutionary rate is very slow, compared with that of hominid from Nanjing. The Homo erectus crania from Zhoukoudian may represent an isolated population, and as a result, lacked evidence of gene flow from outside populations.%德日进认为周口店直立人保持着形态上的稳定性;这种进化上的缓慢性表明周口店直立人进化过程中无论何时都未曾发生过外来移民的闯入,从而打乱、干扰或推进其进化过程.本项研究采用三维结构重叠和精确测量数据的方式对比了周口店第一地点晚期代表周口店直立人(ZKD)5号头骨相对于早期代表ZKD3的形态特征演化

  9. Datación por ESR del yacimiento arqueológico del Pleistoceno inferior de Vallparadís (Terrassa, Cataluña, España

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    García, Joan

    2011-06-01

    Full Text Available Excavated between 2005 and 2007, the site of Vallparadís (Terrassa, Spain has given an abundant and diversified fauna associated with a rich Mode 1 industry. In order to complete the chronostratigraphic framework, we performed ESR and combined US-ESR dating applied to quartz grains extracted from sediments and fossil teeth, respectively. The results obtained are very significant, giving a weighted mean ESR age of 0.83 ± 0.13 Ma (2σ for the reference archaeological level of the site (level 10 and another of 0.79 ± 0.23 Ma (2σ for the archaeological level 12 of the Vallparadís sequence. These ESR results are in total agreement with the ones derived from biochronology and paleomagnetism. This whole dataset allows the elaboration of a reliable and consistent chronostratigraphic framework which chronologically places Vallparadís site in the late Early Pleistocene period, i.e. within a time range comprised between Jaramillo and Brunhes geomagnetic events. Consequently, as well as Gran Dolina-TD6 and Sima del Elefante- TE9 sites, in Atapuerca, Burgos, Vallparadís can be therefore considered as a key site for the study of early hominid settlements in Europe.Excavado entre 2005 y 2007, el yacimiento de Vallparadís (Terrassa, España ha aportado una fauna rica y diversa en asociación con un importante conjunto lítico de Modo 1. Con el objetivo de completar el marco cronoestratigráfico, se hicieron dataciones por los métodos de Resonancia Paramagnética Electrónica (Electron Spin Resonance, ESR y ESR combinada con uranio-torio sobre algunas muestras de granos de cuarzo extraídos de sedimentos y dientes fósiles, respectivamente. Los resultados obtenidos son muy significativos, ofreciendo edades ESR promedias de 0,83 ± 0,13 Ma (2σ para el nivel arqueológico de referencia del yacimiento (nivel 10 y de 0,79 ± 0,23 Ma (2σ para el nivel arqueológico 12 de la secuencia de Vallparadís. Dichos resultados por ESR concuerdan con los obtenidos a

  10. Hacia una nueva conceptualización evolutiva de la comunicación «cultural» Communicating Culture: An Evolutionary Explanation

    Directory of Open Access Journals (Sweden)

    James James Lull

    2011-03-01

    together by communication links. Can the information-sharing behavior of our species ever be brought into broader perspective and eventually foster greater harmony for all humankind? The authors argue that the answer to this question is «yes». Culture provides the necessary space for social negotiation and change. Advanced communication ability is the means by which this necessary cultural work is perpetually accomplished. A non-deterministic understanding of culture must be acknowledged from the outset. Cultural life differs greatly from biological conditions. Even under repressive conditions, culture is not determined the same way viral infections ravage biological bodies or computers. Technological advances in communication do not simply reinforce and intensify top-down, dominant cultural messages as theories of imperialism, memetic transmission, or social contagion contend. The pace of cultural development over the past 10,000 years has been particularly fast compared to any other time since hominids split from our common ancestor with chimpanzees millions of years ago. Our species’ unique skill as communicators in the dynamic technological and cultural environment of today offers real hope for retrieving the primordial affinities that unite us all.

  11. Variability of knapping methods and technological change in the Middle Palaeolithic of the Abric Romani (Capellades, Barcelona

    Directory of Open Access Journals (Sweden)

    Vaquero, Manuel

    1999-12-01

    Full Text Available Lithic reduction sequences are a fundamental topic in palaeolithic research, since they provide data on the behavioural capabilities of early hominids. This paper studies the variability of lithic reduction strategies in the Abric Romaní (Capellades, Barcelona. This site has an extensive stratigraphic sequence, dated between 40 and 70 ka BP. In this sequence, mostly formed by travertine deposits, 27 archaeological levels have been identified, most of them corresponding to the Middle Palaeolithic. The Middle Palaeolithic levels so far excavated (B-L are dated between 40 and 52 ka BP, and suggest a reconstruction of the behavioural patterns of the Neanderthal groups preceding the early Upper Palaeolithic. The variability of the reduction sequences in a synchronous level and the changes over time are presented in the framework of the operative field concept. The results suggest that the technological changes in the Middle Palaeolithic can be explained by technical criteria that are reflected in different domains of analysis; these criteria are related to the degree of technical knowledge invested in lithic production and the range of technical options envisaged in each archaeological level.

    Las secuencias de talla lítica constituyen un tema fundamental en la investigación del Paleolítico, ya que proporcionan datos sobre las capacidades conductuales de los primeros homínidos. Este artículo estudia la variabilidad de las estrategias de talla en el Abric Romaní (Capellades, Barcelona, yacimiento que cuenta con una amplia secuencia estratigráfica datada entre los 40 y los 70 ka BP. En dicha secuencia, formada en su mayor parte por depósitos travertínicos, se han reconocido 27 niveles de ocupación, la mayor parte de los cuales atribuidos al Paleolítico Medio. Los niveles del Paleolítico Medio excavados hasta el momento (B-L, datados entre los 40 y los 52 ka BP, han permitido una reconstrucción de los patrones conductuales de los

  12. Paternal inheritance of mitochondrial DNA in the sheep (Ovine aries)

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Xingbo

    2001-01-01

    fertilization of honeybee (Apis mellifera L.) eggs, Curr. Genet., 1993, 24(6): 539-543.[13]Sutherland, B., Stewart, D., Kenchington, E. R. et al., The fate of paternal mitochondrial DNA in developing female mus-sels, Mytilus edulis: implications for the mechanism of doubly uniparental inheritance of mitochondrial DNA, Genetics, 1998, 148(1): 341-347.[14]Hiendleder, S., Lewalski, H., Wassmuth, R. et al., The complete mitochondrial DNA sequence of the domestic sheep (Ovis aries) and comparison with the other major ovine haplotype, J. Mol. Evol., 1998, 47(4): 441-448.[15]Zardoya, R., Villalta, M., Lopez-Perez, M.J. et al., Nucleotide sequence of the sheep mitochondrial DNA D-loop and its flanking tRNA genes, Curr. Genet., 1995, 28(1): 94-96.[16]Caetano-Anolles, G., Gresshoff, P. M., Staining nucleic acids with silver, Promega Notes, 1994, 45, 15-18.[17]Cummins, J. M., Wakayama, T., Yanagimachi, R. et al., Fate of microinjected spermatid mitochondria in the mouse oocyte and embryo, Zygote, 1998, 6(3): 213-222.[18]Lopez, J. V., Yuhki, N., Masuda, R. et al., Numt, a recent transfer and tandem amplification of mitochondrial DNA to the nuclear genome of the domestic cat, J. Mol. Evol., 1994, 39: 174-190.[19]Wallace, D. C., Stugard, C., Murdock, D. et al., Ancient mtDNA sequences in the human nuclear genome: A potential source of errors in identifying pathogenic mutations, Proc. Natl. Acad. Sci. USA, 1997, 94: 14900-14905.[20]Eyre-Walker, A., Smith, N. H., Smith, J. M., How clonal are human mitochondria? Proc. R. Soc. Lond. B Biol. Sci., 1999, 266(1418): 477-483.[21]Hagelberg, E., Goldman, N., Lin, P. et al., Evidence for mitochondrial DNA recombination in a human population of is-land Melanesia, Proc. R. Soc. Lond. B Biol. Sci., 1999, 266(1418): 485-492.[22]Awadalla, P., Eyre-Walker, A., Smith, J. M., Linkage disequilibrium and recombination in Hominid mitochondrial DNA, Science, 1999, 286(5449): 2524-2525.

  13. Diet, evolution and aging--the pathophysiologic effects of the post-agricultural inversion of the potassium-to-sodium and base-to-chloride ratios in the human diet.

    Science.gov (United States)

    Frassetto, L; Morris, R C; Sellmeyer, D E; Todd, K; Sebastian, A

    2001-10-01

    Theoretically, we humans should be better adapted physiologically to the diet our ancestors were exposed to during millions of years of hominid evolution than to the diet we have been eating since the agricultural revolution a mere 10,000 years ago, and since industrialization only 200 years ago. Among the many health problems resulting from this mismatch between our genetically determined nutritional requirements and our current diet, some might be a consequence in part of the deficiency of potassium alkali salts (K-base), which are amply present in the plant foods that our ancestors ate in abundance, and the exchange of those salts for sodium chloride (NaCl), which has been incorporated copiously into the contemporary diet, which at the same time is meager in K-base-rich plant foods. Deficiency of K-base in the diet increases the net systemic acid load imposed by the diet. We know that clinically-recognized chronic metabolic acidosis has deleterious effects on the body, including growth retardation in children, decreased muscle and bone mass in adults, and kidney stone formation, and that correction of acidosis can ameliorate those conditions. Is it possible that a lifetime of eating diets that deliver evolutionarily superphysiologic loads of acid to the body contribute to the decrease in bone and muscle mass, and growth hormone secretion, which occur normally with age? That is, are contemporary humans suffering from the consequences of chronic, diet-induced low-grade systemic metabolic acidosis? Our group has shown that contemporary net acid-producing diets do indeed characteristically produce a low-grade systemic metabolic acidosis in otherwise healthy adult subjects, and that the degree of acidosis increases with age, in relation to the normally occurring age-related decline in renal functional capacity. We also found that neutralization of the diet net acid load with dietary supplements of potassium bicarbonate (KHCO3) improved calcium and phosphorus balances

  14. 巨猿牙齿釉质厚度及对食性适应与系统演化的意义%Enamel Thickness of Gigantopithecus blacki and Its Significance for Dietary Adaptation and Phylogeny

    Institute of Scientific and Technical Information of China (English)

    张立召; 赵凌霞

    2013-01-01

    or extant primates,while Paranthropus,early Homo and Ouranopithecus macedoniensis possess relatively closer values with it.With considerations of body and tooth size,the enamel measurements indicate that G.blacki belongs to a category of“thick-enamel” primate along with modem humans,Cebus,Australopithecus,East African Early Homo,Asian Homo erectus and some Miocene fossil apes (eg Proconsul nyanzae and Afropithecus turkanensis),but thinner than South African early Homo,Paranthropus and Ouranopithecus macedoniensis.The extremely thick enamel of G.blacki molars are evidently well used for grinding and crushing for a long period.The dietary proclivities may primarily focus on tough or fibrous vegetation.Human ancestors probably have thick enamel.G.blacki may be a side branch of hominids during the evolution.Meanwhile,G.blacki can be also evolved from one branch of Miocene fossil ape whose teeth enamel is thick.The thick enamel,common characteristic of G.blacki and human,is the result of parallel evolution.

  15. 山西晚新生代古地理环境变迁与新构造运动响应%Evolution of Late Cenozoic Geography and Environment in Shanxi Province and the Neotectonic Response

    Institute of Scientific and Technical Information of China (English)

    闫小兵; 李自红; 郭瑾; 赵晋泉; 陈文; 扈桂让; 苏宗正

    2014-01-01

    large-scale rift lake because of the intense tectonic movement.The neighboring mountains were uplifted significantly.From then on,the basic geomorphological pat-tern was consistent with that of the current basin.In the late Pliocene,the rift basin subsided sig-nificantly,the climate became cooler,and large lakes began to appear in the rift basin.The early Pleistocene is characterized by wide-spread lakes in rift basins.In general,the climate at this time was a temperate forest and grassland monsoon climate alternating between wet and dry.It was moister and cooler than the Pliocene period,warm and humid in the earlier part,and cool and hu-mid later.Loess deposition began,but mainly in the west of the Luliang Mountain watershed;the Yellow River developed in the early Pleistocene,during which five terraces formed.In the middle Pleistocene the lakes in the first basins began to recede,and loess deposits up to 200 m thick were deposited throughout the province,indicating a fairly arid climate.During this time,large-scale ba-salt flooding and eruptions occurred in the Datong Basin,caused by Himalayan orogenic move-ments.In the middle Pleistocene the climate was temperate humid and semi-arid forest steppe, warm and humid in the early part of this interval,cold and drought-prone later,and in general col-der and drier than the early Pleistocene.Middle Pleistocene hominid cultural sites have been found at the He River in Ruicheng,containing mainly stone and also burned bones.In the Middle Pleis-tocene,loess was deposited almost throughout the province which formed the thickest deposits are still preserved today.The most prominent event in the late Pleistocene was the demise of the lakes,and the geography became much closer to its current form.During this time,the mountains were being uplifted and undergoing erosion and sedimentation occurred in the rift basin,with ac-cumulation of thick lacustrine,fluvial-lacustrine and fluvial-alluvial deposits,which formed the present-day plain

  16. Secretion expression of recombinant glucagon in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    WEN; Chongwei

    2001-01-01

    [1]Cann, R. L., Stoneking, M., Wilson, A. C., Mitochondria DNA and human evolution, Nature, 1987, 325: 31-36.[2]Vigilant, L., Stoneking, M., Harpending, H. et al., African populations and the evolution of human mitochondrial DNA, Science, 1997, 253: 1503-1507.[3]Cavalli-Sforza, L. L., Piazza, M. P., The History and Geography of Human Genes, Princeton: Princeton University Press, 1994.[4]Brooks, A. S., Wood, B., Paleoanthropology, The Chinese side of the story, Nature, 1990, 344: 288-289.[5]Li, T., Etler, D. A., New middle Pleistocene hominid crania from Yunxian in China, Nature, 1992, 357: 404-407.[6]Wu, X. Z., Poirier, F. E., Human Evolution in China, Oxford: Oxford University Press, 1995.[7]Etler, D. A., The fossil evidence for human evolution in Asia, Annu. Rev. Anthropol., 1996, 25: 275-301.[8]Wolpoff, M. H., Interpretations of multiregional evolution, Science, 1996, 274: 704-707.[9]Stringer, C. B., Andrew, P., Genetic and fossil evidence for the origin of modern humans, Science ,1988, 239: 1263-1268.[10]Wilson, A. C.,Cann, R. L., The recent African genesis of humans, Scientific American, 1992, (4): 68-75.[11]Weng, Z., Yuan, Y., Du, R., Analysis of the genetic structure of human populations in China, Acta Anthropol. Sin. (in Chi-nese)1989, 8: 261-268.[12]Zhao, T., Zhang, G., Zhu, Y. et al., The distribution of immunoglobulin Gm allotypes in forty Chinese populations, Acta Anthropol. Sin. (in Chinese), 1986, 6: 1-8.[13]Chu, J. Y., Huang, W., Kuang, S. Q. et al., Genetic relationship of populations in China, Proc. Natl. Acad. Sci., 1998, 95: 11763-11768.[14]Jobling, M. A., Tyler-Smith, C., Fathers and sons: the Y chromosome and human evolution, Trends in Genetics,1995, 11: 449-455.[15]Oefner, P. J., Underhill, P. A., Comparative DNA sequencing by denaturing high-performance liquid chromatography (DHPLC), Am. J. Hum. Genet., 1995, 57: A266.[16]Oefner, P. J., Underhill, P. A., DNA mutation detection

  17. Y-chromosome haplotype distribution in Han Chinese populations and modern human origin in East Asians

    Institute of Scientific and Technical Information of China (English)

    KE; Yuehai

    2001-01-01

    [1]Cann, R. L., Stoneking, M., Wilson, A. C., Mitochondria DNA and human evolution, Nature, 1987, 325: 31-36.[2]Vigilant, L., Stoneking, M., Harpending, H. et al., African populations and the evolution of human mitochondrial DNA, Science, 1997, 253: 1503-1507.[3]Cavalli-Sforza, L. L., Piazza, M. P., The History and Geography of Human Genes, Princeton: Princeton University Press, 1994.[4]Brooks, A. S., Wood, B., Paleoanthropology, The Chinese side of the story, Nature, 1990, 344: 288-289.[5]Li, T., Etler, D. A., New middle Pleistocene hominid crania from Yunxian in China, Nature, 1992, 357: 404-407.[6]Wu, X. Z., Poirier, F. E., Human Evolution in China, Oxford: Oxford University Press, 1995.[7]Etler, D. A., The fossil evidence for human evolution in Asia, Annu. Rev. Anthropol., 1996, 25: 275-301.[8]Wolpoff, M. H., Interpretations of multiregional evolution, Science, 1996, 274: 704-707.[9]Stringer, C. B., Andrew, P., Genetic and fossil evidence for the origin of modern humans, Science ,1988, 239: 1263-1268.[10]Wilson, A. C.,Cann, R. L., The recent African genesis of humans, Scientific American, 1992, (4): 68-75.[11]Weng, Z., Yuan, Y., Du, R., Analysis of the genetic structure of human populations in China, Acta Anthropol. Sin. (in Chi-nese)1989, 8: 261-268.[12]Zhao, T., Zhang, G., Zhu, Y. et al., The distribution of immunoglobulin Gm allotypes in forty Chinese populations, Acta Anthropol. Sin. (in Chinese), 1986, 6: 1-8.[13]Chu, J. Y., Huang, W., Kuang, S. Q. et al., Genetic relationship of populations in China, Proc. Natl. Acad. Sci., 1998, 95: 11763-11768.[14]Jobling, M. A., Tyler-Smith, C., Fathers and sons: the Y chromosome and human evolution, Trends in Genetics,1995, 11: 449-455.[15]Oefner, P. J., Underhill, P. A., Comparative DNA sequencing by denaturing high-performance liquid chromatography (DHPLC), Am. J. Hum. Genet., 1995, 57: A266.[16]Oefner, P. J., Underhill, P. A., DNA mutation detection