(ORDO NEWS) — Research in southern Ethiopia has shown how key phases of climate change have affected human evolution, dispersal and innovation.
An international team of scientists led by Verena Foerster from the University of Cologne (Germany) compiled a fairly detailed paleoclimatic record of East Africa, the region from which, according to modern ideas, Homo sapiens came out.
The authors compared the obtained data with the shifts in human evolution known to us.
Although the fossils of hominins in East Africa have been found by archaeologists for a long time, we still do not fully understand the process of evolution and settlement of modern humans and their ancestors in the Pleistocene.
The authors of the work, like many other scientists , believe that the development and migration of representatives of the genus Homo is a consequence of climate change.
The problem is that there was no even relatively detailed paleoclimatic record for East Africa. The researchers decided to fill this gap. They recovered two continuous 280-meter sediment cores from the Chow Bahr lake basin in southern Ethiopia.
It is located in close proximity to the Turkana region and Omo-Kibish , key paleoanthropological and archaeological sites in the region, near which the remains of ancient people have been found more than once.
After analyzing the cores, the scientists found that various anatomically diverse groups of hominins inhabited the area during a phase of a long and relatively stable humid climate, from about 620,000 to 275,000 years ago.
However, this climatic phase was disturbed several times by the wedging of sharp and extremely dry periods.
Most likely, this led to the splitting of the habitats of our ancestors into parts, a sharp reduction in their populations, and even to the extinction of some of them.
As a result, small, reproductively and culturally isolated groups had to adapt to dramatically changed local environments, which likely stimulated the emergence of many geographically and anatomically distinct groups of hominins and the separation of our modern human ancestors from their ancestral, archaic groups.
From 275,000 to 60,000 years ago, climate change became more frequent. Several times they led to a sharp change in the landscape: lush vegetation and deep freshwater lakes gave way to semi-desert with small brackish pools.
At the same time, local Homo gradually moved from Acheulian technologies (oval stone axes associated primarily with Homo ergaster/erectus ) to more complex technologies of the Middle Stone Age.
The ancestors of people are forced to somehow protect themselves from adverse conditions, change their lifestyle, and as a result of these changes, Homo sapiens appears in East Africa.
From about 60,000 to 10,000 years ago, sharp climate fluctuations again begin in the same region – and the driest phase in history begins. In order to survive, people had to change many things, including their place of residence.
Scientists believe that the brief overlap of wet periods in East Africa with wet periods in Northeast Africa and the Mediterranean was the key to opening migration routes from Africa to the Levant. And this, in turn, led to the global dispersal of Homo sapiens across the Earth.
While the authors are undeniably correct in associating human migrations with extreme climate fluctuations in East Africa, some of their conclusions may be ambiguous.
For example, the period of 10-60 thousand years ago, which they consider to have made a great contribution to the spread of Homo sapiens on the planet, began after the period when people of modern appearance had undoubtedly already left Eurasia.
The indigenous people of Australia reached their continent about 65 thousand years ago , and in general, geneticists date the exit of people from Africa to the Middle East about 70 thousand years ago.
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