Продолжение...
Интересные факты по эволюции гоминид,
установленные в последние годы (1997-2004)
11. Nature. 1998 May 7;393(6680):62-6.
New specimens and confirmation of an early age for Australopithecus anamensis.
Leakey MG, Feibel CS, McDougall I, Ward C, Walker A.
The discovery of Australopithecus anamensis fossils from strata lying between tephra dated at 4.17 and 4.12 million years ago, and from slightly higher strata not well constrained in age by overlying dated units, provoked the claim that more than one species might be represented: it was suggested that the stratigraphically higher fossils, which include the important tibia, humerus and a large, presumed male, mandible (KNM-KP 29287), might belong to a later, more derived hominid. We have recovered new fossils from Kanapoi and Allia Bay, Kenya, during field work in 1995-1997 that confirm the primitive status of Australopithecus anamensis, the earliest species of Australopithecus. Isotope dating confirms A. anamensis' intermediate age as being between those of Ardipithecus ramidus and Australopithecus afarensis. New specimens of maxilla, mandible and capitate show that this species is demonstrably more primitive than A. afarensis. A lower first deciduous molar (dm 1) is intermediate in morphology between that reported for Ardipithecus ramidus and A. afarensis. Single-crystal 40Ar-39Ar age determinations on the Kanapoi Tuff show that, except for a large mandible, all of the hominid fossils from Kanapoi are from sediments deposited between 4.17+/-0.03 and 4.07+/-0.02 million years ago.
12. J Hum Evol. 2004 May;46(5):605-22.
Dental topography and diets of Australopithecus afarensis and early Homo.
Ungar P.
Diet is key to understanding the paleoecology of early hominins. We know little about the diets of these fossil taxa, however, in part because of a limited fossil record, and in part because of limitations in methods available to infer their feeding adaptations. This paper applies a new method, dental topographic analysis, to the inference of diet from fossil hominin teeth. This approach uses laser scanning to generate digital 3D models of teeth and geographic information systems software to measure surface attributes, such as slope and occlusal relief. Because it does not rely on specific landmarks that change with wear, dental topographic analysis allows measurement and comparison of variably worn teeth, greatly increasing sample sizes compared with techniques that require unworn teeth. This study involved comparison of occlusal slope and relief of the lower second molars of Australopithecus afarensis (n=15) and early Homo (n=8) with those of Gorilla gorilla gorilla (n=47) and Pan troglodytes troglodytes (n=54). Results indicate that while all groups show reduced slope and relief in progressively more worn specimens, there are consistent differences at given wear stages among the taxa. Early Homo shows steeper slopes and more relief than chimpanzees, whereas A. afarensis shows less slope and relief than any of the other groups. The differences between the two hominin taxa are on the same order as those between the extant apes, suggesting similar degrees of difference in diet. Because these chimpanzees and gorillas differ mostly in fallback foods where they are sympatric, results suggest that the early hominins may likewise have differed mostly in fallback foods, with A. afarensis emphasizing harder, more brittle foods, and early Homo relying on tougher, more elastic foods.
13. J Hum Evol. 2003 May;44(5):581-97.
The carbon isotope ecology and diet of Australopithecus africanus at Sterkfontein, South Africa.
van der Merwe NJ, Thackeray JF, Lee-Thorp JA, Luyt J.
The stable carbon isotope ratio of fossil tooth enamel carbonate is determined by the photosynthetic systems of plants at the base of the animal's foodweb. In subtropical Africa, grasses and many sedges have C(4)photosynthesis and transmit their characteristically enriched 13C/(12)C ratios (more positive delta13C values) along the foodchain to consumers. We report here a carbon isotope study of ten specimens of Australopithecus africanus from Member 4, Sterkfontein (ca. 2.5 to 2.0Ma), compared with other fossil mammals from the same deposit. This is the most extensive isotopic study of an early hominin species that has been achieved so far. The results show that this hominin was intensively engaged with the savanna foodweb and that the dietary variation between individuals was more pronounced than for any other early hominin or non-human primate species on record. Suggestions that more than one species have been incuded in this taxon are not supported by the isotopic evidence. We conclude that Australopithecus africanus was highly opportunistic and adaptable in its feeding habits.
14. Nutr Health. 2002;16(4):267-89.
Wading for food the driving force of the evolution of bipedalism?
Kuliukas A.
Evidence is accumulating that suggests that the large human brain is most likely to have evolved in littoral and estuarine habitats rich in naturally occurring essential fatty acids. This paper adds further weight to this view, suggesting that another key human trait, our bipedality might also be best explained as an adaptation to a water-side niche. Evidence is provided here that extant apes, although preferring to keep dry, go into water when driven to do so by hunger. The anecdotal evidence has suggested that they tend to do this bipedally. Here, a new empirical study of captive bonobos found them to exhibit 2% or less bipedality on the ground or in trees but over 90% when wading in water to collect food. The skeletal morphology of AL 288-1 ("Lucy") is shown to indicate a strong ability to abduct and adduct the femur. These traits, together with a remarkably platypelloid pelvis, have not yet been adequately explained by terrestrial or arboreal models for early bipedalism but are consistent with those expected in an ape that adopted a specialist side-to-side 'ice-skating' or sideways wading mode. It is argued that this explanation of A. afarensis locomotor morphology is more parsimonious than others which have plainly failed to produce a consensus. Microwear evidence of Australopithecus dentition is also presented as evidence that the drive for such a wading form of locomotion might well have been waterside foods. This model obtains further support from the paleo-habitats of the earliest known bipeds, which are consistent with the hypothesis that wading contributed to the adaptive pressure towards bipedality.
15. J Hum Evol. 2000 Dec;39(6):565-76.
The hunters and the hunted revisited.
Lee-Thorp J, Thackeray JF, van der Merwe N.
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. Copyright 2000 Academic Press.
16. Science. 1999 Jan 15;283(5400):368-70.
Isotopic evidence for the diet of an early hominid, Australopithecus africanus.
Sponheimer M, Lee-Thorp JA.
M. Sponheimer, Department of Anthropology, Rutgers University, New Brunswick NJ 08901-1414, USA.
Current consensus holds that the 3-million-year-old hominid Australopithecus africanus subsisted on fruits and leaves, much as the modern chimpanzee does. Stable carbon isotope analysis of A. africanus from Makapansgat Limeworks, South Africa, demonstrates that this early hominid ate not only fruits and leaves but also large quantities of carbon-13-enriched foods such as grasses and sedges or animals that ate these plants, or both. The results suggest that early hominids regularly exploited relatively open environments such as woodlands or grasslands for food. They may also suggest that hominids consumed high-quality animal foods before the development of stone tools and the origin of the genus Homo.
17. Asia Pac J Clin Nutr. 2004;13(Suppl):S17.
Paleolithic nutrition: what can we learn from the past?
Mann NJ.
Department of Food Science, RMIT University, Melbourne, 3001, Australia.
Background - Anthropologists and some nutritionists have long recognised that the diets of Paleolithic and recent hunter-gatherers (HG) may represent a reference standard for modern human nutrition and a model for defense against certain western lifestyle diseases. Boyd Eaton of Emory University (Atlanta) has spent over 20 years reconstructing prehistoric diets from anthropological evidence and observations of surviving HG societies, put this succinctly: "We are the heirs of inherited characteristics accrued over millions of years, the vast majority of our biochemistry and physiology are tuned to life conditions that existed prior to the advent of agriculture some 10,000 years ago. Genetically our bodies are virtually the same as they were at the end of paleolithic some 20,000 years ago. The appearance of agriculture and domestication of animals some 10,000 years ago and the Industrial Revolution some 200 years ago introduced new dietary pressures for which no adaptation has been possible in such a short time span. Thus an inevitable discordance exists between our dietary intake and that which our genes are suited to". This discordance hypothesis postulated by Eaton, could explain many of the chronic "diseases of civilisation". But what did hunter-gatherer populations actually eat? Review - The lines of investigation used by anthropologists to deduce the evolutionary diet of hominids include the study of: (i) changes in cranio-dental features, (ii) isotopic chemical tracer methods, including carbon isotope (13C/12C), strontium isotope (87Sr/86Sr) and trace element Sr/Ca ratios in enamel and bone of fossils,(iii) comparative gut morphology of modern humans and other mammals, (iv) the energetic requirements of a developing a large brain:body size ratio, (v) optimal foraging theory and food selection, (vi) the study of dietary patterns of surviving hunter-gatherer societies. Findings show clear cranio-dental changes including, a decrease in molar teeth size, jaws/skull became more gracile and front teeth became well-buttressed, all indicative of less emphasis on grinding course foliage and more on biting and tearing. Carbon isotope studies indicate the dietary intake of C4 grasses, undoubtedly in the form of herbivorous animals, at a level which increased substantially during the progression of our genus from A. aferensis to H. sapiens. Even as far back as 3.5 million years, the Sr/Ca ratio falls in between those typical for herbivores and carnivores. Gut morphology studies indicate a closer structural analogy with carnivores than the folivorous or frugivorous mammals. Energetic requirements of a relatively enlarged brain have been balanced by reduction in size and energy requirement of the digestive system, a phenomena requiring a high quality diet. Investigation of food procurement habits of hunter-gatherer societies indicates the advantage of hunting of game animals compared with plant foraging in terms of energy gain versus expenditure. Study of macronutrient energy proportions in the diet of HG societies (n=229) show a relatively high protein intake 19-35%, highly variable fat intake 28-47% and low carbohydrate level 22-40%. Conclusions - It is postulated that changes in food staples and food processing procedures introduced during the Neolithic and Industrial era have fundamentally altered seven crucial nutritional characteristics of our ancestral diet: (i) glycaemic load, (ii) fatty acid balance, (iii) macronutrient balance, (iv) trace nutrient density, (v) acid-base balance, (vi) sodium-potassium balance, (vii) fiber content.
18. J Hum Evol. 2004 Feb;46(2):119-62.
Patterns of resource use in early Homo and Paranthropus.
Wood B, Strait D.
CASHP and Department of Anthropology, The George Washington University, 2110 G St. NW, Washington, DC 20052, USA.
Conventional wisdom concerning the extinction of Paranthropus suggests that these species developed highly derived morphologies as a consequence of specializing on a diet consisting of hard and/or low-quality food items. It goes on to suggest that these species were so specialized or stenotopic that they were unable to adapt to changing environments in the period following 1.5 Ma. The same conventional wisdom proposes that early Homo species responded very differently to the same environmental challenges. Instead of narrowing their niche it was the dietary and behavioral flexibility (eurytopy) exhibited by early Homo that enabled that lineage to persist. We investigate whether evidence taken across eleven criteria supports a null hypothesis in which Paranthropus is more stenotopic than early Homo. In six instances (most categories of direct evidence of dietary breadth, species diversity, species duration, susceptibility to dispersal, dispersal direction, and non-dietary adaptations) the evidence is inconsistent with the hypothesis. Only one line of indirect evidence for dietary breadth-occlusal morphology-is unambiguously consistent with the null hypothesis that Paranthropus' ability to process tough, fibrous food items (e.g., leaves) was reduced relative to early Homo. Other criteria (habitat preference, population density, direct and indirect evidence of dietary breadth related to incisor use) are only consistent with the hypothesis under certain conditions. If those conditions are not met, then the evidence is either inconsistent with the hypothesis, or ambiguous. On balance, Paranthropus and early Homo were both likely to have been ecological generalists. These data are inconsistent with the conventional wisdom that stenotopy was a major contributing factor in the extinction of the Paranthropus clade. Researchers will need to explore other avenues of research in order to generate testable hypotheses about the demise of Paranthropus. Ecological models that may explain the evolution of eurytopy in early hominins are discussed.
19. J Hum Evol. 2002 Sep;43(3):291-321.
Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge.
Kimura Y.
Institute of History and Anthropology, University of Tsukuba, 1-1-1 Ten'noudai, Tsukuba, Ibaraki, Japan 305-8571.
ykimura@histanth.tsukuba.ac.jp
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.
20. Am J Phys Anthropol. 2002 Oct;119(2):192-7.
Revised age estimates of Australopithecus-bearing deposits at Sterkfontein, South Africa.
Berger LR, Lacruz R, De Ruiter DJ.
Palaeoanthropology Unit for Research and Exploration, Bernard Price Institute for Palaeontology, University of the Witwatersrand, Johannesburg 2050, South Africa.
106lrb@cosmos.wits.ac.za
The Sterkfontein fossil site in South Africa has produced the largest concentration of early hominin fossils from a single locality. Recent reports suggest that Australopithecus from this site is found within a broad paleontological age of between 2.5-3.5 Ma (Partridge [2000] The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 100-125; Partridge et al. [2000a], The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 129-130; Kuman and Clarke [2000] J Hum Evol 38:827-847). Specifically, the hominin fossil commonly referred to as the "Little Foot" skeleton from Member 2, which is arguably the most complete early hominin skeleton yet discovered, has been magnetostratigraphically dated to 3.30-3.33 Ma (Partridge [2000] The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 100-125; Partridge et al. [2000a], The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 129-130). More recent claims suggest that hominin fossils from the Jacovec Cavern are even older, being dated to approximately 3.5 Ma. Our interpretation of the fauna, the archeometric results, and the magnetostratigraphy of Sterkfontein indicate that it is unlikely that any Members yet described from Sterkfontein are in excess of 3.04 Ma in age. We estimate that Member 2, including the Little Foot skeleton, is younger than 3.0 Ma, and that Member 4, previously dated to between 2.4-2.8 Ma, is more likely to fall between 1.5-2.5 Ma. Our results suggest that Australopithecus africanus should not be considered as a temporal contemporary of Australopithecus afarensis, Australopithecus bahrelghazali, and Kenyanthropus platyops. Copyright 2002 Wiley-Liss, Inc.
21. Nature. 2004 Apr 29;428(6986):936-9.
Surprisingly rapid growth in Neanderthals.
Ramirez Rozzi FV, Bermudez De Castro JM.
UPR 2147, Dyamique de l'Evolution Humaine, CNRS, 44, Rue de l'Amiral Mouchez, 75014 Paris, France.
ramrozzi@ivry.cnrs.fr
Life-history traits correlate closely with dental growth, so differences in dental growth within Homo can enable us to determine how somatic development has evolved and to identify developmental shifts that warrant species-level distinctions. Dental growth can be determined from the speed of enamel formation (or extension rate). We analysed the enamel extension rate in Homo antecessor (8 teeth analysed), Homo heidelbergensis (106), Homo neanderthalensis ('Neanderthals'; 146) and Upper Palaeolithic-Mesolithic Homo sapiens (100). Here we report that Upper Palaeolithic-Mesolithic H. sapiens shared an identical dental development pattern with modern humans, but that H. antecessor and H. heidelbergensis had shorter periods of dental growth. Surprisingly, Neanderthals were characterized by having the shortest period of dental growth. Because dental growth is an excellent indicator of somatic development, our results suggest that Neanderthals developed faster even than their immediate ancestor, H. heidelbergensis. Dental growth became longer and brain size increased from the Plio-Pleistocene in hominid evolution. Neanderthals, despite having a large brain, were characterized by a short period of development. This autapomorphy in growth is an evolutionary reversal, and points strongly to a specific distinction between H. sapiens and H. neanderthalensis.
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