For the Sake of Science

I said my views on evolution are always evolving. This is a good example of that.

Modern humans may have left Africa thousands of years earlier than previously thought, turning right and heading across the Red Sea into Arabia rather than following the Nile to a northern exit, an international team of researchers says.

Stone tools discovered in the United Arab Emirates indicate the presence of modern humans between 100,000 and 125,000 years ago, the researchers report in Friday’s edition of the journal Science.

While science has generally accepted an African origin for humans, anthropologists have long sought to understand the route taken as these populations spread into Asia, the Far East and Europe. Previously, most evidence has suggested humans spread along the Nile River valley and into the Middle East about 60,000 years ago.

“There are not many exits from Africa. You can either exit” through Sinai north of the Red Sea or across the straits at the south end of the Red Sea, explained Hans-Peter Uerpmann of the Center for Scientific Archaeology of Eberhard-Karls University in Tuebingen, Germany.

“Our findings open a second way which, in my opinion, is more plausible for a massive movement than the northern route,” he said in a telephone briefing.

These findings are always interesting, but it takes so much evidence to come to any sort of conclusion that the theories put forth are always so tentative. We can say humans probably left Africa earlier than previously thought, but speculation on a new route is less solid.

One recent theory I recall hearing is that humans and Neanderthals once interbred. There is some evidence for it, and just last year some good DNA evidence was uncovered showing as much. In fact, I would go so far as to confidently proclaim that the evidence solidly shows humans interbred with Neanderthals very early in the human exit from Africa. Beyond that, I very much doubt there was interbreeding; the Neanderthals in all probability died out as a unique species, unable to breed with H. sapiens.

I mention this theory because the first thing that popped into my mind upon reading the first few paragraphs of the article was how long it would take until someone suggested Neanderthals may have been responsible for the toolmaking.

The techniques used to make the hand axes, scrapers and other tools found at Jebel Faya in Sharjah Emirate suggest they were produced by people coming from somewhere else, said Anthony E. Marks of Southern Methodist University in Dallas, adding that there are similar tools made about that time in East Africa.

“If these tools were not made by modern man, who might have made them?,” Marks asked. “Could Neanderthals have made them?”

Neanderthals were mainly in Europe and migrated into Russia but “there is no evidence for any Neanderthals south of that” zone at that time, he said. “To suggest one group of Neanderthals took a turn south and went several thousand kilometers … seems to me a very difficult explanation and one that doesn’t follow any reasonable logic.”

I have to agree with that assessment of the data. Humans moved towards Neanderthals, plausibly going through the areas of this recent discovery, not the other way around. Now that we have evidence left by our ancestors, this adds a new route humans took when leaving Africa. I find the scenario plausible, even likely. It still isn’t certain, but there is now some good evidence for it.

Filed under: Evolution | Tagged: Africa, Humans, Neanderthals, Tools | 5 Comments »