Later On

A blog written for those whose interests more or less match mine.

The fascinating story behind Ardi’s announcement

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ardipithecus-side-view440

Ardi has an entire issue of Science, and this post explains how that came about:

Meet Ardipithecus.

This introduction has been a long time coming. Some 4.4 million years ago, a hominid now known as Ardipithecus ramidus lived in what were then forests in Ethiopia. Fifteen years ago, Tim White of Berkeley and a team of Ethiopian and American scientists published the first account of Ardipithecus, which they had just discovered. But it was just a preliminary report, and White promised more details later, once he and his colleagues had carefully prepared and analyzed all the fossils they had unearthed. “Later,” it turned out, meant 15 years.

I’ve mentioned before how unfashionable this slow-cooked style of science can be. But sometimes, it’s the only way to do things right. Getting clues about HIV by observing sick chimpanzees in the wild takes years.  And so does reconstructing a fossil–particularly one as delicate as Ardipithecus happened to be. Today, the journal Science has handed many of its pages over to White and his colleagues, who have filled them with lots of details about Ardipithecus, plus a couple excellent articles by writer Ann Gibbons. Ardipithecus has gone from being an enigmatic collection of bones to a new touchstone for our early hominid ancestors.

To appreciate the importance of this new look of Ardipithecus, you have to step back into the history of hunting for hominid fossils. In the early 1970s, Tim White was part of a research team that found what was, at the time, the oldest hominid known: a 3.2 million year old fossil of Australopithecus afarensis. What made their discovery particularly spectacular was that they found a fair amount of a single A. afarensis individual, whom they named Lucy.

Combined with other A. afarensis fossils, paleonthropologists got a pretty decent picture of what hominids looked like. Lucy was a chimpanzee-sized ape with a brain that was only a little bigger than a chimp’s. She still had long arms and curving hands and other traits hinting that she could still climb in trees. But she also had feet with stiff, forward-facing toes, an adaptation for walking on the ground.

So things stood for about 20 years. But then …

Continue reading.  

Written by LeisureGuy

3 October 2009 at 10:02 am

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