Convoluted human evolution:late tree newly described (Introduction)

by David Turell @, Tuesday, September 19, 2017, 20:30 (369 days ago) @ David Turell

The timing as to how Neanderthals and Denisovans appeared is changed according to this article:

https://www.quantamagazine.org/genetics-spills-secrets-from-neanderthals-lost-history-2...

"Approximately 750,000 years ago, according to Rogers, the forerunners of Neanderthals and Denisovans left the ancestors of modern humans behind in Africa to make their way across Eurasia’s expansive territory. Once on their own, something nearly wiped them out entirely; the genetic data shows the population passed through a severe bottleneck, never observed in previous studies. But whatever caused that brush with disaster, the archaic humans bounced back from it, and just a few thousand years later — by 744,000 years ago — they separated into two separate lineages, the Neanderthals and the Denisovans. The former then split further into the smaller regional groups that so fascinated Rogers.

"The dating of that schism between the Neanderthals and the Denisovans is surprising because previous research had pegged it as much more recent: a 2016 study, for instance, set it at only 450,000 years ago. An earlier separation means we should expect to find many more fossils of both eventually. It also changes the interpretation of some fossils that have been found. Take the large-brained hominid bones belonging to a species called Homo heidelbergensis, which lived in Europe and Asia around 600,000 years ago.

"Paleoanthropologists have disagreed about how they relate to other human groups, some positing they were ancestors of both modern humans and Neanderthals, others that they were a nonancestral species replaced by the Neanderthals, who spread across Europe.
Rogers’ findings imply that the H. heidelbergensis had to have been an early Neanderthal. “The separation time we estimate is so early that a European hominid from 600,000 years ago pretty much has to be a Neanderthal,” he said, “at least genetically, even if they didn’t look entirely like Neanderthals yet.”

"Coincidentally or otherwise, this new reconstruction of the Neanderthals’ complicated early history closely resembles what we learned about the populations of anatomically modern people who first spread into Europe and Asia. Nearly 50,000 years ago, Eurasians separated from Africans, experienced a bottleneck period during which their population was very low, and then splintered into regional populations throughout Eurasia — the so-called out-of-Africa theory of human migration. “It looks like the same thing happened 600,000 or 700,000 years ago” with the Neanderthals and Denisovans, Rogers said. “There was another out-of-Africa diaspora that no one had previously suspected.”

"It’s no secret that the Neanderthals struggled: The glacial periods they endured and the fragmentation of their population left them unable to support robust social or technological growth. “But the one misconception people have is that we represent progress, that modern humans are the best and Neanderthals beneath us,” Hawks said. “When it comes to being hunters, being reliant on high-energy food resources in marginal environments, Neanderthals were the extreme.” He added, “They solved problems we don’t face today. How did they live at such low population densities for hundreds of thousands of years? That’s something we never managed.”

Comment: The point that Neanderthals had to deal with glaciation and survived them indicates they were quite capable folks. It is obvious we are still learning about our antecedents.


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