Multi regional continuity the fossil evidence

This species arose in Africa two million years ago as H.

Multi regional continuity the fossil evidence

One of the most hotly debated issues in paleoanthropology the study of human origins focuses on the origins of modern humans, Homo sapiens. The nature of this transformation is the focus of great deliberation between two schools of thought: one that stresses multiregional continuity and the other that suggests a single origin for modern humans. BBC Shop sells products online, by phone, post. But in , Alan Templeton published a genetic analysis involving other loci in the genome as well, and this showed that some variants that are present in modern populations existed already in Asia hundreds of thousands of years ago. Neanderthals are distinguished by a unique set of anatomical features, including: a large, long, low cranial vault with a well-developed double-arched browridge a massive facial skeleton with a very projecting mid-face, backward sloping cheeks, and large nasal aperture, with large nasal sinuses an oddly shaped occipital region of the skull with a bulge or bun molars with enlarged pulp chambers, and large, often very heavily worn incisors a mandible lacking a chin and possessing a large gap behind the last molar a massive thorax, and relatively short forearms and lower legs although short in stature they possessed robustly built skeletons with thick walled limb bones long clavicles and very wide scapulas Homo sapiens is a separate species from Neanderthals and other hominids By , years ago, following a prolonged period of independent evolution in Europe, Neanderthals were so anatomically distinct that they are best classified as a separate species — Homo neanderthalensis. In the s, paleontologist W. It is, therefore, highly likely that modern humans do not carry Neanderthal genes in their DNA. A possible problem with this view is that recent dating of late surviving Homo erectus in Indonesia suggests that they survived here until 50, years ago, which is potentially when fully modern humans may have arrived in the region from Africa. Neanderthals were apparently no match for the technologically advanced fully modern humans who invaded Europe and evidence for interbreeding of these two types of hominids is equivocal. Better geological dating and more complete specimens are needed to more fully assess this possibility. The exact timing and pathways outside of Africa are still under debate, perhaps out of East Africa, perhaps along with a southern route from South Africa. However, the mitochondrial and Y chromosome data could not be explained by the same modern human expansion out of Africa; the Y chromosome expansion would have involved genetic mixing that retained regionally local mitochondrial lines.

The Multiregional Continuity Model15 contends that after Homo erectus left Africa and dispersed into other portions of the Old World, regional populations slowly evolved into modern humans. Whatever precise trajectory demand takes, all forms of energy will be required to meet rising demand, with fossil fuels remaining an essential part of the energy mix for decades.

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out of africa vs multiregional essay

Understanding the issue Multiregional theory: homo erectus left Africa 2 mya to become homo sapiens in different parts of the world.

These arguments still had to be tied directly to the growing fossil record: again, no genetic data was available. Amsterdam: Elsevier.

Out of africa theory vs multiregional theory pdf

They concluded that the diversity of these recent humans could not "result exclusively from a single late Pleistocene dispersal", and implied dual ancestry for each region, involving interbreeding with Africans. The presence of Neanderthals at two other caves in Israel, Amud and Kebara, dated to roughly 55, years means that Neanderthals and Homo sapiens overlapped in this region for at least 55, years. Neanderthals and modern humans coexisted in some parts of the world for thousands of years. Amsterdam: Elsevier. Overview[ edit ] The Multiregional hypothesis was proposed in by Milford H. They see an evolutionary link between ancient Homo erectus in Java right through to Australian aborigines. Weidenreich himself in wrote: "I may run the risk of being misunderstood, namely that I believe in polyphyletic evolution of man". Wolpoff stresses that regional continuity works in conjunction with genetic exchanges between populations. By these mechanisms, surviving local varieties of the species evolved into modern humans, retaining some regional adaptations but with many features common to all regions. In the s, paleontologist W. Although in its infancy, such genetic studies support the view that Neanderthals did not interbreed with Homo sapiens who migrated into Europe. The Tianyuan 1 specimen unearthed in in Tianyuan Cave , Zhoukoudian, and Carbon 14 dated to kya exhibits a series of typical modern human features such as a distinct chin. Studies of contemporary DNA, especially mitochondrial DNA mtDNA which occurs only in the cellular organelles called mitochondria, reveal that humans are astonishingly homogeneous, with relatively little genetic variation. If RAO was right, there should be very few alleles older than the origins of anatomically modern humans in Eurasia, and a decrease in genetic diversity as you get away from Africa.

This is theoretically unlikely since Neanderthal traits would have been genetically swamped by the Homo sapiens genes over such a protracted period of time. Stringer C. Using the genetic distance between African populations and others as a measure of time, they furthermore suggested that Homo sapiens arose betweenandyears ago in Africa.

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They see an evolutionary link between ancient Homo erectus in Java right through to Australian aborigines.

assimilation model

If RAO was right, there should be very few alleles older than the origins of anatomically modern humans in Eurasia, and a decrease in genetic diversity as you get away from Africa.

Genetic evidence Investigation of the patterns of genetic variation in modern human populations supports the view that the origin of Homo sapiens is the result of a recent event that is consistent with the Out of Africa Model.

Multiregional hypothesis evidence

Any hominin lineage that branched off from the modern human species prior to , years ago did not leave any mtDNA in modern humans. Long-term regional continuity in certain morphological traits is explained by Alan Thorne 's "Centre and Edge" [30] population genetics model which resolves Weidenreich's paradox of "how did populations retain geographical distinctions and yet evolve together? Combinations of features are "unique" in the sense of being found in only one region, or more weakly limited to one region at high frequency very rarely in another. Encyclopedia of Quaternary Science Second Edition. Cast of anatomically modern human Kow Swamp 1 skull from Australia with a face to vault angle matching that of Sangiran The Tianyuan 1 specimen unearthed in in Tianyuan Cave , Zhoukoudian, and Carbon 14 dated to kya exhibits a series of typical modern human features such as a distinct chin. The presence of Neanderthals at two other caves in Israel, Amud and Kebara, dated to roughly 55, years means that Neanderthals and Homo sapiens overlapped in this region for at least 55, years. A possible problem with this view is that recent dating of late surviving Homo erectus in Indonesia suggests that they survived here until 50, years ago, which is potentially when fully modern humans may have arrived in the region from Africa. Since this study other studies have been done using much more data see Phylogeography. This is theoretically unlikely since Neanderthal traits would have been genetically swamped by the Homo sapiens genes over such a protracted period of time. In the midth century, when Darwin wrote Origin of Species , the only lines of evidence of human evolution he had were comparative anatomy and a few fossils. Wolpoff had expected the skull to match that of the Homo erectus specimens from China like the Dali skull , but instead, the face to vault angle seemed to be retained regionally over time, even while the fossils in the two regions showed parallel increases in brain case size and parallel reductions in masticatory structures over the intervening approximately , years. They concluded that the diversity of these recent humans could not "result exclusively from a single late Pleistocene dispersal", and implied dual ancestry for each region, involving interbreeding with Africans.
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Ancient History/Human Evolution/Multiregional Origin