We evolved, trait by trait
Modern humans did not originate from a single region in East Africa, as we used to think. Traits that are typical for humans today appeared one at a time throughout Africa over a period of hundreds of thousands of years.
team of anthropologists headed by Eleanor Scerri from the University of Oxford in the UK introduced the theory of “African multiregionalism”, according to which the specific characteristics that now define Homo sapiens originated little by little over hundreds of thousands of years in small groups of people throughout most of Africa. The first individuals of the Homo sapiens species were much more different from each other than humans are today – in spite of our variation of height, weight, and skin colour. The major differences were due to the fact that groups of people developed individually over periods of tens of thousands of years.
If it were possible to travel back in time and visit all of them, we would realize that none of them were exactly like us. Some had sturdy jaws and teeth, others a heavy occipital bun, to which robust neck muscles were attached, and others had a sloping forehead and a massive brow ridge above the eyes, which can be observed in our early ancestors. But scientists still consider them to be Homo sapiens, as they had several modern human traits such as a narrow pelvis, a large brain in a ball-shaped skull, slender teeth, and a narrow jaw.
Today, African multiregionalism is the theory that, according to many scientists, offers the best explanation of the fact that the 315,000-year-old Jebel Irhoud man and other almost just as old African discoveries have modern anatomical characteristics, whereas the same traits are absent in some much younger finds.
Moreover, the theory puts a stop to the search for what scientists call a modern human autapomorphy - one single characteristic that makes it possible to differ between “us” and“them”, as it exists in all modern humans, but not in any of the species to which we are most closely related. Such a trait does not exist, if Homo sapiens developed in the way in which Eleanor Scerri believes it did.
If Scerri is right, it will also be impossible to determine the exact boundary between our species and the species we developed from – probably African individuals of Homo heidelbergensis. According to the most likely theory, it is somewhere between 315,000 and 400,000 years ago, as discoveries from earlier dates only include hints of modern traits.
Equipped with the new history of Homo sapiens in Africa, scientists are reconsidering when our ancestors took the leap from their