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Real location of 'Garden of Eden' cast into doubt by oldest Homo sapiens fossils ever found

Modern humans evolved about 100,000 years earlier than previously thought, researchers say

Ian Johnston
Science Correspondent
Thursday 08 June 2017 12:39 BST
Earliest Homo sapiens fossils discovered in Morocco

Modern humans evolved about 100,000 years earlier than previously thought and may not have first emerged in a “Garden of Eden” in east Africa, scientists have said after dating fossils found in the mountains of Morocco.

Until now, it was believed Homo sapiens developed about 200,000 years ago in what is now Ethiopia.

But the dating of finds at Jebel Irhood, about 60 miles west of Marrakesh, to about 300,000 years ago suggests our species evolved in a more complex way.

In addition to being the oldest known remains of modern humans, the fossils, which include skulls, corroborate a fragment found in South Africa that had been tentatively dated to 260,000 years ago.

This suggests that Homo sapiens evolved from a variety of different types of Hominins which once existed across Africa.

The finds at Jebel Irhood, a well-known site first exposed by mining operations in the 1960s, also indicate that the Stone Age people who lived there were prolific hunters, living on a diet of gazelles, zebras, buffalos and wildebeests.

Professor Jean-Jacques Hublin, a palaeoanthropologist at the Max Planck Institute for Evolutionary Anthropology in Germany, said: “In the last 20 years, the consensus has been that very likely our species emerged somewhere around 200,000 years ago and probably the first forms of what we call early modern humans were represented in East Africa.

“There is this notion that somewhere in sub-Saharan Africa there is this sort of ‘Garden of Eden’ where our species first developed, then spread inside Africa and outside of Africa.

“Our results challenge this picture.”

The Moroccan fossils, coupled with those in East Africa and South Africa, suggest that Homo sapiens “spread across the entire African continent around 300,000 years ago”, he said.

“Long before the out-of-Africa dispersal of Homo sapiens, there was dispersal within Africa,” he added.

The researchers said they were trying to work out why the world came to be dominated by one “extremely successfully” type of human, when once there had been a number of different types, such as Neanderthals, Denisovans and the recently discovered “hobbits”, living alongside each other in Africa, Europe and Asia.

“What made our species so special, that this species expanded out of Africa at some point and replaced other groups of Hominins?” Professor Hublin said.

The fossils found at Jebel Irhood show the people had a modern-looking face and teeth. They also had a large braincase, but its shape had similarities with earlier types of humans.

However, writing in the journal Nature, the researchers said the fossils displayed the “early stages of the Homo sapiens clade in which key features of modern morphology were established”.

The site was discovered during mining operations in the 1960s and initially the fossils were not thought to be anywhere near as old. But modern techniques dated fire-heated flint artefacts found alongside them to about 315,000 years ago and a tooth from one individual to about 286,000 years ago, both estimates had a margin of error of more than 30,000 years.

Professor Rainer Grün, who helped date the fossils, described how quickly our understanding of human evolution had changed over the last few decades.

“If we look at the history of human evolution, until the mid-80s it was thought model humans evolved in Africa and shortly after migrated to Europe at around 40,000 years. In the late 80s there were the first results of anatomically modern humans in Israel at about 100,000 years,” he said.

“In the 90s there were a few sites found in Ethiopia dated to 200,000 years and now with these results the origins of modern humans are further pushed back to 300,000 years.”

But the Jebel Irhoud finds meant “we now have to rethink a number of principles within human evolution”, he added.

One reason why understanding early human evolution has been so difficult is that Homo sapiens do not appear to have buried their dead around this time.

Professor Grün, director of the leading Australian Research Centre for Human Evolution, said: “The finds in Jebel Irhoud are one of the few places we’ve found modern skulls. That’s why our understanding of human evolution is very patchy because we find so few human remains.

“In contrast, Neanderthals buried their dead but they ate them as well, leading to bone accumulations in caves.”

Among the remains were animal bones with tell-tale cuts made by human butchery techniques. Some bones were broken open so the people could eat the nutritious marrow.

Most of the bones were from gazelles but the remains of hartebeests, wildebeests, zebras, buffalos, porcupines, hares, tortoises, freshwater molluscs, snakes and ostrich egg shells were also identified.

Small game made up only a small percentage of the bones.

“It really seemed like people were fond of hunting,” said Professor Teresa Steele, of University of California, Davis, who analysed animal fossils at Jebel Irhoud.

Commenting on the research, Professor Robert Foley, an expert in human evolution at Cambridge University, told The Independent that the researchers had made “an important contribution to understanding modern human origins”.

“While we have abundant evidence for the existence of modern humans in and around Africa around 100,000 years ago, the early stages are very poorly known – only two fossil sites, both from Eastern Africa,” he wrote in an email. “While we have known about Jebel Irhoud for a long time, the new material is important and the new date extremely interesting.

“The morphology confirms what we see also in Herto and Omo Kibbish [sites in East Africa], namely that the earliest modern humans show some key derived features, but also retain more archaic ones,” he said.

“Combine this observation with the existence in other parts of Africa from 350,000 to 150,000 years ago of more archaic populations, then we have to think of Africa at this time as a mosaic of Hominin populations, a network of gene flow and isolation, from which, in the end, tens of thousands of years later, one form becomes predominant.

“Unravelling how that happened remains a big challenge. While this does not necessarily indicate a particular region of origin, it shows that similar populations were widely distributed across Africa.”

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