“Was North Africa the Launch Pad for Modern Human Migrations?”
http://www.sciencemag.org/content/331/6013/20 [abstract; subscription required for full access]
by Michael Balter
Science, January 7, 2011
[Balter notes: Since I am a Contributing Correspondent at Science (and former Paris bureau chief) and have been writing for the publication for 20 years, most of my pitches tend to be fairly informal emails. But I did put in some extra effort last year when I was trying to convince them to do a major feature on North Africa as a possible launching pad for Out of Africa migrations.]
Most researchers agree that the major migration of modern humans out of Africa and into Eurasia took place between 50-70,000 years ago, with some limited, earlier migration into the Levant around 100,000 years ago. Where did these colonizers come from? Since they didn’t have trains or airplanes, the only reasonable answer is North Africa. Yet in recent years most of the attention on modern human origins has been focused on south and east Africa, for two main reasons: Genetics indicates those regions as the origins of Homo sapiens, and a number of celebrated sites, such as Blombos and Pinnacle Point in South Africa, have shown evidence of early symbolic activity, a hallmark of modern human cognition.
But over the past several years, researchers working in North Africa have been coming up with increasing evidence that this part of the continent was not just a brief way-station on the way out of Africa, but a major center of modern human habitation, cultural evolution, and probably physical evolution as well. In brief, North Africa appears to have been teeming with hominins, and not just right before the out of Africa migrations. Very new work and new dating at sites in Morocco, for example, have shown that the major culture of the region–the Aterian, characterized by sophisticated stone tools not see elsewhere in Africa –had a continuity of tens of thousands of years, stretching as far back as 120,000 years or more. Similar evidence for longstanding hominin residency is coming from Libya, Egypt, and Ethiopia; indeed, one research group thinks it has evidence that the Ethiopian highlands was the staging ground for the out
of Africa exodus. This picture is supported by new paleoclimatic studies showing that the Sahara Desert was much wetter than today, with river corridors, oases, and high rainfall in regions that correspond with human presence.
Finally, in addition to the environmental and archaeological work cited above, paleoanthropologists have been taking a new look at old and new modern human fossils from the region and coming up with evidence that the moderns who lived in North Africa were
undergoing an evolutionary process from archaic to modern forms, ie, North Africa may have been a cauldron of modern human evolution. Shara Bailey and Chris Stringer key people here
Most of this work has been going on with little attention and little fanfare, but it is crucial to our understanding of the evolution of our species. The peg for the story would be the July Cambridge meeting I attended where much of this work was presented, but that would just be the starting point for a feature that would pull together all of the major work in the area and its exciting implications.