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You could say that this is the ultimate price of science, to discover when, where and why humans have evolved.
For a long time, the evidence was overwhelming that Homo sapiens evolved in Africa and then spread out of the continent to colonize the rest of the planet.
But is the story of our origins really as simple as it looks? Published today, a new comment written by British and German scientists does not suggest it.
Too easy, but then …
A few years ago, it seemed too easy. The case has been settled. Homo sapiens evolved in the East African Rift Valley about 200,000 years ago and emerged from the mother continent to colonize the remaining planet about 60,000 years ago.
But after decades of reflection, In solving this ultimate riddle, the story of our origins begins to be revised for a long time.
A series of recent discoveries has pushed our origins back to Africa more than 315,000 years ago – and suggested sapiens Almost 194,000 years ago, Africa left the country. Africa to travel to southern China soon after, perhaps 139,000 years ago.
And to add more complexity, this first "Out-of-Africa" seems to have been followed by one or more subsequent movements, by different populations sapiens who settled in remote places like Australia by about 65,000 years ago.
We have also begun to find humans whose physical features do not correspond to our preconceived notions about what sapiens should look like, like the Iwo Eleru, Nazlet Khater and the later Red Deer Cave survivors in various parts of Africa and Asia.
Would they be hybrids that we asked ourselves? Because, after decades of scientists on the subject, geneticists have finally proven that our ancestors mated with Neanderthals, Denisovians and other archaic humans, even in Africa.
Change in the wind
Of course, regularly updated, with new discoveries changing what we think we know and sometimes even expanding knowledge into new places.
But as someone who has kept a close eye on developments and, in fact, on active research, our evolution, it is clear to me that something is happening here. Change is in the wind
So deep is the current change in the science of human origins that we see the unusual gait of a team of 23 researchers (led by Eleanor Scerri from the US). Oxford University) publishes new synthesis of evidence. and by doing so embrace the emerging image of complexity and abandon old simplistic ideas. Among their ranks are archaeologists, anthropologists, geneticists and climate scientists.
It reads like a manifesto and describes the main new directions of research that archeology should follow to solve our confusing origins. A key message is that none of these disciplines alone is able to do it and go it alone. This approach only leads us to look for simple answers to complex questions
Big problems on the line
There are a number of major problems here. Among the most important, there is the recognition that the physical variation that characterizes our species around the planet today seems to have emerged only 100,000-40,000 years ago. This has made the identification of our ancestors and traced their evolutionary history extremely difficult.
Herto's skull in Ethiopia is an excellent example of a very ancient person who was undoubtedly a member of our species, but who does not really fit the variation characterizing any living group.
How would this happen? ? It seems that the first centuries of our history saw our African ancestors living in very small and geographically isolated populations that evolved more or less independently of one another. one or more populations of living people, some of whom have left Africa, and no clear evidence of how all this has happened.
This brings us to another, and perhaps most important of all. How do we define Homo sapiens in the first place? How will this process provide useful criteria for recognizing our species in the African fossil record 200,000, 300,000 or even 400,000 years ago?
Define Homo sapiens
The Smithsonian Institution has provided a summary of the main characteristics that we use to define our species, but unfortunately, many can not easily be found on the skulls of our African ancestors .
Does this mean that they are not our ancestors? Not necessarily, just that our current approach is quite limited and we must keep in mind that our early ancestors would have looked, well, ancestral!
Finally, the complex links between climate change in the ice age and environmental changes in Africa acting as key factors in natural selection and genetic drift are increasingly understood. These forces have shaped how we behave and continue to influence our biology today.
Despite all the progress we have made over the past decade to dismember our origins, Scerri's manifesto and his team has more than a hint of "coming back to the future" about it.
As audacious and ambitious as he is, he leaves me with many more questions than answers, and a lingering feeling that the problems are much more complicated than we were willing to admit. until now
This article was originally published on The Conversation and is republished here with permission. Read the original article.
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