Re: [asa] AAAS Symposium on Human Origins

Today there was an excellent talk on human origins by Tim White, cofounder with Don Johannsen of the Lucy fossil. He gave high credit to yesterday's speakers but gave a different perspective.

White has been a major force behind the Middle Awash project http://middleawash.berkeley.edu/middle_awash.php which has been working since 1981 in the region near the Awash river in Ethiopia. This project has discovered 19,000 fossils including 290 hominid specimens spanning the last 6 million years.

White took issue with the tendency toward increasing numbers of hominid species. He referred to the book "The Last Humans" sponsored by the American Museum of Natural History which lists 22 species. He thinks it is less than half that. Specifically, he did not think the new species mentioned yesterday, H. Georgica and H. Antecessor, were unique species.

He noted that the Middle Awash region was unique in providing a single site with a continuous sedimentation and fossil column through the last 6 million years. He cited a real problem with comparing specimens from vastly different geographies and different times. This site allows a coherent fossil record. He listed the following hominid fossils that were all found in the same region, making it a continuous evolutionary trend:

Aduma; 80 kya; H. sapiens at about the time of the last out of Africa migration

Herto; 160 kya; the earliest known H. sapiens fossil

Bodo; 500 kya; intermediate between H. erectus and H. sapiens

Daka; 1 Mya; H. erectus

Bouri Hata; 2.5 Mya; most recent Australopithecus

Maka; 3.4 Mya; A. afarensis (Lucy species--he noted that Lucy wasn't typical for her species)

Asa Issie; 4.2 Mya; earliest Australopithecus (amenensis)

Sagantole Aramis; 4.4 Mya; fragments only

Adu asa; 5.8 Mya; Ardipithecus earliest known hominid fossil

This is really quite impressive to see this monotonical development in a single region. White thinks that the geometry of human evolution from its split with chimpanzees shouldn't be thought of as either a tree or a bush but as a saguaro. He also talked about H. floresiensis and said as we heard yesterday that it was quite a mystery.

I wish I could have written down all the Darwin quotes and the "what would Darwin have asked in 2009" speculation quotes. He had a lot of them and they were very good. It was a standing room only crowd. He's a terrific speaker.

Net: he doesn't see the human evolutionary pattern nearly as confusing as yesterday's speakers but his last few slides did point out where all the major gaps were in the fossil record and where it would be great to find more. But what we have found seems to fit remarkably well.

Randey

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Received on Sun Feb 15 00:25:04 2009