Christopher Stringer [11.12.11] I'm thinking a lot about species concepts as applied to humans, about the "Out of Africa" model, and also looking back into Africa itself. I think the idea that modern humans originated in Africa is still a sound concept. Behaviorally and physically, we began our story there, but I've come around to thinking that it wasn't a simple origin. Twenty years ago, I would have argued that our species evolved in one place, maybe in East Africa or South Africa. There was a period of time in just one place where a small population of humans became modern, physically and behaviourally. Isolated and perhaps stressed by climate change, this drove a rapid and punctuational origin for our species. Now I don’t think it was that simple, either within or outside of Africa. http://edge.org/conversation/rethinking-out-of-africa
I also like the next part: Thank you for bringing this. It's great. These views will necessarily shift as new evidence emerges, but Dr. Stringer gives a great update, discussing the best conclusions thus far concerning human ancestry and evolution.
I wonder the two region or stock If it does not have any thing to do with Caucasian and Asian stick ?
He definitely connects archaic humans to Tanzania and Kenya, and Siberian Devonians to Australasians. That leaves just about everyone else with some Neanderthal DNA. These kinds of analyses seem to outweigh the smaller differences between races, but certainly that issue will prevail as well. As to the origin of races, he does give this:
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The epicanthic eye-fold is a very recent development. None of the New World people have it. That means it is less than 15,000 years old. All of these other species were extinct by then so it can't have anything to do with hybridization. (Well maybe not H. floresiensis but I don't think anyone postulates them as an ingredient in our gene pool.)
You mean to tell me that sitting bull didn't have an epicanthal fold? I always thought it looked like he did. So he just had really narrow, constantly angry eyes then? edit:Looking up the definition again for the first time in a while, I can see the difference.
I spent most of my life in the West. The Native Americans do not have what the OP calls "Oriental eyes." I don't know about the Eskimos. They arrived much later than the Paleoindians, around 3500BCE.
I'm not sure Stringer was advocating that. I may have caused a point of confusion, by posting a later subject from Stringer's talk, in response to arauca's reference to race. I think Stringer was making a general comment about sexual selection, including eyes, to differentiate the causes of racial divergence from his main thesis.
This is something I read several years ago so I can't cite the source. I spent about fifteen minutes looking for it today and from what I found, the epicanthic eye fold is not totally absent among the indigenous people of the New World, but it is far less common here than in Asia. The populations in which it occurs most often are those in the northern part of the hemisphere (the Eskimos use seafaring technology for hunting and so have probably not been completely isolated from their ancestral gene pool in Siberia), and some of the Arawak communities along the Amazon. The appearance is a composite of several distinct features, all of which are not necessarily present in any one individual.
Additional Info. I covered Jeffrey Rose's work most recently here. Together with his work on the Gulf Oasis, Jebel Faya, and the Skhul/Qafzeh hominids from the Levant, it now appears that modern humans were widely dispersed >100 thousand years ago in the Near East, possessing distinct lithic technologies. It is becoming increasingly impossible to reconcile this evidence with scenaria of Out-of-Africa after 70ka. The pre-100ka Near East was seemingly teeming with modern humans; it may have been possible to dismiss these as the Out-of-Africa that failed when the Skhul/Qafzeh hominids were the only players in the game, but populations stretching from the Levant to southern Arabia did not simply vanish and were replaced after 70ka. This leads to a conundrum: Either geneticists are in error when they date the L3/modern human expansion to 70 thousand years ago, or They are in error when they place its origin to Africa. As I have argued before, the archaeological and genetic evidence can be reconciled if the L3/modern human expansion occurred recently Out-of-Arabia, during the super-arid conditions of MIS 4, after having establishing themselves there in the good times that preceded it. From the paper: The Nubian Complex is a regionally distinct Middle Stone Age (MSA) technocomplex first reported from the northern Sudan in the late 1960 s [1], [2]. Archaeological sites belonging to the Nubian Complex (Fig. 1) have since been found throughout the middle and lower Nile Valley [3]–[6], desert oases of the eastern Sahara [7], [8], and the Red Sea hills [9], [10]. Numerical ages from Nubian Complex sites (Table 1) are constrained within Marine Isotope Stage 5 (MIS 5), although temporal differences have been observed among assemblages; as such, it is divided into two phases, an early and a late Nubian Complex [5], [11]. I had previously speculated about the origin of modern humans in a wet Sahara, followed by their expansion into West Asia during MIS 5. I don't know how tenable this scenario is archaeologically, but it certainly appears to be chronologically and genetically: modern mankind coming to its own in the wet Sahara, collapsing demographically as the desert reasserted itself; finding a secondary cradle in Arabia, and expanding as the Arabian desert reasserted itself. Is this the solution: a tale of two deserts, pumping humans from Africa to the Near East pre-100ka and from the Near East to the rest of the world post-70ka? http://dienekes.blogspot.com/2011/12/nubian-complex-in-southern-arabia-106.html
Why is that? Just because there are more than one site doesn't necessarily mean there were large numbers of humans in the area. There were many Neanderthal sites over an even broader range and yet their contribution to the genome is so minuscule that it was very difficult to detect. There is also evidence (though perhaps it will eventually be reevaluated) that there was the "genetic bottleneck" in the human species 70K years ago. If one believes that that was precipitated by something akin to the Toba Catastrophe, that would well explain why those older populations died out. Most humans did, across the face of Africa. It's no big stretch to say that most of them did across the face of Africa and parts of the Near East. Any theory will have to explain why there seems to be the bottleneck...and (unless it's disproven) that requires that large numbers of human lineages die out. I'm not saying you are necessarily incorrect, but without more explanation it seems entirely possible (and not even "improbable" as far as I can tell), that these early colonizers also came from Africa and mostly or entirely died out prior to 70K years ago (possibly as a result of the same forces that led to the human genetic bottleneck).
What I don't understand is the motive for the direction of "out of Africa". The initial migration appears during the last ice age and have the pre-humans moving northward toward the cold. t It would be like someone from Florida migrating north on foot during winter. It would have made more sense to go the other way, unless they were returning somewhere after being pushed southward by the beginning of the ice age about 2.5 million years ago.
I don't think there is anyone that is proposing there was some sort of mass migration. Populations spread due to several reasons. Imagine the hunting pressure is high in one area the population will tend to move to areas that have a higher concentration of animals. This may involve maybe a 50 mile movement over 3 generations. Doesn't seem like much but after 1000 years you have expanded the human habitation by 500 miles. After 10,000 years you have expanded your range over the continent.
There are a number of potential ways to explain it. First, they didn't move north from Africa directly. They moved east into Asia, where some slowly migrated north to central Asia. From there, groups migrated east again, eventually reaching Europe. The evidence is that they didn't pass through the modern holy land. If you move from central Asia into the Mediterranean region, that's a step up climatewise. But also remember that these groups may have been migrating a few dozen miles further each generation or two, and that would not have led to a noticeable difference in climate (other than arising from elevation differences when they hit mountains), so changes would have been subtle rather than gross. Plus they may have been moving either to get away from the competition at their backs, and in the direction they believed unexploited animals or other resources lay. That would push them into new territory to the extent livable.
A different way is they follower the cost of South Arabia the entered the Persian gulf which was fresh water ( non salty ) and continued into Mesopotamia . An other group followed the east coast of South Arabia, Were the Red sea was not a sea but a lake ( 20000 to 60000 years the sea level was at least 100 meter lower then now ) they would enter into Levant By the way this is incorrect "They moved east into Asia, where some slowly migrated north to central Asia. From there, groups migrated east again, eventually reaching Europe. " from Asia to Europa you go WEST
Cavalli-Sforza has performed exhaustive DNA analysis on humans from all over the planet. This is the definitive study of the subject. His results consistently support the out-of-Africa hypothesis. He has even been able to draw a rather detailed map showing the migration route and timing of each major ethnic group. He was so thorough that he actually found traces of the genetic markers that identify the Native Australians in populations along the south coast of Asia. This indicates that along the way a few of the San travelers decided to stop walking and set up housekeeping. Their clans survived until the next, larger wave of migration 10KY later, with whom they intermarried. This does not falsify any evidence of previous migrations. But it does imply that all of them were, in the long term, unsuccessful, and their bloodlines died out. This is similar to the occasional discovery of domesticated wolves in disparate locations, dated long before the subspeciation of dogs from wolves in Mesopotamia 12KYA. There's no doubt that these fossils are real and that humans and dogs experimented with living together in a multi-species community long ago. But these experiments were dead ends, and modern dogs do not have their DNA. Perhaps when times got tough the domesticated wolves decided they'd do better by reverting to the predatory ways of their ancestors. The same is, apparently, true of these earlier migrations of Homo sapiens out of Africa. They did it, but for various reasons they did not endure, and today's non-African populations have none of their DNA.
Research: Neanderthal demise due to many influences, including cultural changes Computer modeling shows interactions between Neanderthals and modern human ancestors TEMPE (Feb. 6, 2012) - As an ice age crept upon them thousands of years ago, Neanderthals and modern human ancestors expanded their territory ranges across Asia and Europe to adapt to the changing environment. In the process, they encountered each other. Although many anthropologists believe that modern humans ancestors "wiped out" Neanderthals, it's more likely that Neanderthals were integrated into the human gene pool thousands of years ago during the Upper Pleistocene era as cultural and climatic forces brought the two groups together, said Arizona State University Professor C. Michael Barton of the Center for Social Dynamics and Complexity and School of Human Evolution and Social Change. "The traditional story in textbooks doesn't fit well with what we know about hunter-gatherers. For the most part, they don't like to go far from home. It's dangerous," Barton said. Barton and Julien Riel-Salvatore of the University of Colorado Denver, present new research in the journal, Advances in Complex Systems, that the Neanderthals demise was due to a combination of influences, including cultural changes. The paper titled, Agents of Change: Modeling Biocultural Evolution in Upper Pleistocene Western Eurasia, appears online in January. It builds on work published last year in the journal Human Ecology and on recent genetic studies that show a Neanderthal contribution to the modern human genome. "How a culture's working knowledge is passed on is as important as biological information for human evolution," Barton said. "There is a perception that biological evolution determines culture during the Pleistocene era and that cultural influences predominate afterwards (including today). The reality is that the two forces have been working together and they were as important 50,000 years ago as they are today." The researchers used archaeological data to track cultural and socio-ecological changes in behavior in Western Eurasia during the past 120,000 years. As Neanderthals and early humans land-use patterns shifted during the last ice age, computer modeling showed that the two populations began to interact and mate, leading to the "extinction" of one of the groups due to hybridization, a well-recognized phenomenon in conservation biology. Neanderthals were limited to western Eurasia and usually it is the smaller population that becomes "extinct" in this way. Nevertheless, succeeding hybrid populations still carry genes from the regional group that disappeared, according to the researchers. To address the possibility that the two groups would not have seen one another as potential mates, the researchers also examined the possible impacts of social barriers to mating in their models. They found that unless social taboos were nearly 100 percent effective, it would have not made any difference in outcomes over time as the gene pools mixed, Barton said. "This is one of the first attempts to explicitly address the impact of various degrees of social avoidance on possible hybridization between the two groups," added Riel-Salvatore. "Other than the fact that they disappeared, there is no evidence that Neanderthals were any less fit as hunter-gatherers of the late Pleistocene than any other human ancestor living at that time. It looks like they were as capable as anyone else," Barton said. Barton and Riel-Salvatore studied the stone artifacts that were left behind by these ancient peoples to track the movement patterns among hunter-gatherers across western Eurasia during the Pleistocene era. "Stone technology is completely different than the kind of technology we have today," Barton said. "But it can tell us important things about land use, how people organized themselves and how they moved to access resources to live." These tools provide insight into Neanderthals' lives and gene sequencing tells the story of their legacy. "Recent sequencing of ancient Neanderthal DNA indicates that Neanderthal genes make up from 1 to 4 percent of the genome of modern populations—especially those of European descent," Riel-Salvatore said. "While they disappeared as a distinctive form of humanity, they live on in our genes. What we do in this study is propose one model of how this could have happened and show that behavioral decisions were probably instrumental in this process." The researchers suggest it's time to study variation and diversity among individuals rather than classify them into types or species. "Neanderthals' legacy lives on in our biological genome and possibly in our cultural knowledge," Barton added. "There may have been may other populations like Neanderthals who were integrated into a global human species in the Late Pleistocene. We're the results."
