We've known for some time that human being originated in Africa, but it's a big continent. Scientists have been trying to pinpoint exactly where Homo sapiens first appeared, and the more we learn, the muddier the search becomes. The theory of "mitochondrial Eve," in which one woman is the ancestor to all humans, indicates it was in East Africa, while the corresponding "genetic Adam" points to West Africa. The earliest evidence of art and symbolic thought come from South Africa. These discoveries have led some scientists to a fairly new pan-African theory: that modern humans evolved over a very large area.
Chris Stringer, of the Natural History Museum, London, explains. “The immediate predecessors of modern humans probably arose in Africa about 500,000 years ago and evolved into separate populations,” he says.
“When times were bad – for example, when the Sahara was arid, as it is now – you would get little isolated pockets of humans clinging on to existence. Some of these people would have gone extinct. Others managed to hang on.”
Later, when conditions improved – for instance, when the Sahara became green again and lakes and rivers formed – surviving populations expanded and came into contact with each other. When they did, they would have exchanged ideas – and genes. Then the climate would have turned grim again and they would have separated.
“This happened over and over again in different places for different reasons for the next 400,000 years,” adds Stringer. “The end product was Homo sapiens, the species that is more or less the version of modern humanity that now inhabits every continent on Earth.”
This idea hints that our very existence comes from our distant ancestors' willingness to travel and to connect with others. Read about the discoveries that led to this concept at the Guardian. -via Strange Company
(Image credit: Wapondaponda)
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