by Matthew Cobb
There’s an interesting report in Science magazine today [subscription needed] about a meeting held in Gibraltar earlier this month about human evolution. Most of the debate seems to have revolved around the classification of around 28 >500,000 year old fossil hominins from Sima in Spain. Some people argue they were Homo heidelbergensis, generally viewed as an ancestor of the Neandertals.
Science reports that Ian Tattersall, from the American Museum of Natural History, argued that “two or more hominin lineages must have existed side by side in Europe for several hundred thousand years before H. sapiens arrived from Africa. One line led to the Neandertals and may have included the Sima fossils; another, rightly called H. heidelbergensis, went extinct while the Neandertals lived on until at least 30,000 years ago.”
Equally fascinating was the discussion about *how* we came out of Africa, and how many times. We seem to have originated in Africa around about 200,000 years ago, and to have left to colonize the world about 50,000 years ago. But in the “Levant” there are clear signs of co-habitation between humans and neanderthals from 75-130,000 years ago. Some people call this “the failed dispersal”. At the Gibraltar meeting, paleontologist Mike Petraglia (Oxford) summarized archeological evidence – stone tools and so on – that suggests the “failed” dispersal was not such a failure as that.
He argued that human populations may have gone on from the Levant into India and thence to Australia, where we turned up about 40,000 years ago. The archeological evidence suggests we crept along the sea-shore, at about 1km a year… If we didn’t leave the stone tools, who did? Some people at the meeting were skeptical, pointing out that archeology was not biology – without human fossils, you can’t tie the tools to us. As always with scientific arguments, evidence will decide who’s right and who’s wrong.