Science evolves

Science evolves

I missed this piece in Edge from Chris Stringer in November, Rethinking “Out of Africa”. He sums up his current thinking at the end:

We’ve got the lineage of the hobbit, ‘Homo floresiensis’ (in quotation marks because its human status in not yet clear), perhaps diverging more than two million years ago, evolving in isolation in southeast Asia, and apparently going extinct about 17,000 years ago.

We’ve got Homo erectus, most likely originating in Africa, giving rise to lineages which continue in the Far East in China and Java, but which eventually go extinct. In Europe, it perhaps gave rise to the species Homo antecessor, “Pioneer Man,” known from the site of Atapuerca in Spain. Again, going extinct.

In the western part of the Old World, we get the development of a new species, Homo heidelbergensis, present in Europe, Asia and Africa. We knew heidelbergensis had gone two ways, to modern humans and the Neanderthals. But we now know because of the Denisovans that actually heidelbergensis went three ways—in fact the Denisovans seem to represent an off-shoot of the Neanderthal lineage.

North of the Mediterranean, heidelbergensis gave rise to the Neanderthals, over in the Far East, it gave rise to the Denisovans. In Africa heidelbergensis evolved into modern humans, who eventually spread from Africa about 60,000 years ago, but as I mentioned, there’s evidence thatheidelbergensis populations carried on in Africa for a period of time. But we now know that the Neanderthals and the Denisovans did not go genetically extinct. They went physically extinct, but their genes were input into modern humans, perhaps in western Asia in the case of the Neanderthals. And then a smaller group of modern humans picked up DNA from the Denisovans in south east Asia.

We end up with quite a complex story, with even some of this ancient DNA coming back into modern humans within Africa. So our evolutionary story is mostly, but not absolutely, a Recent African Origin.

Now, I know that Milford Wolpoff has still not totally buried the hatchet with Stringer, but their views are actually converging a great deal. What does that tell us? Well, paleoanthropology most definitely is a science, reality and results are dictating to the intellectual antagonists.

(Via Ruchira Paul)

Razib Khan