Step Aside, Lucy; Your Distant Ancestor Walked Upright, Researchers Claim
Penn State researchers are trying to scoop the coveted title of “discoverers of the first upright-walking hominid” with a CT scan of their champion, Orrorin (see 02/23/2001 headline). They have the ball and socket joint of the specimen (thought to be like a chimpanzee) and a bit of the bony neck that connects the ball to the upper thighbone, and part of the upper thigh. They claim that CT scans show a slight thickening in the neck that is intermediate between those of apes and humans. This is enough to convince them that their specimen walked upright, according to the report in EurekAlert. If so, they win the prize, because they date their specimen at 6 million years old, whereas Donald Johanson had dated his iconic specimen Lucy at only 3 million.
Skeptics are not sure the CT scans were accurate enough to make such a determination, and whether Orrorin, if it walked upright at all, did it habitually (even pygmy chimps and some monkeys walk upright sometimes; see 07/22/2004 headlines). But already the imaginations are getting into gear: “Bipedalism probably does represent a fundamental first step in human evolution,” claims Chris Stringer of the Natural History Museum in London, according to the report in National Geographic News. “As Darwin recognized, walking on two legs frees up the arms and hands for tasks like carrying, tool making, and tool use. And much of what happened in human evolution later on stemmed from it.”
What magnificent returns in storytelling emerge from such a trifling investment of fact. A tiny ratio difference in thickness on one bone from one specimen, based on CT scans of questionable accuracy, assuming no modifications by the fossilization process (see 03/28/2003 headline), dated with evolutionary assumptions, and they can convert a chimpanzee fossil into an upright walking human ancestor. Six million years later, its descendants are designing spacecraft and deciphering the human genome. How ever did the noble enterprise of science stoop to such pitiful grandstanding? Don’t think Johanson’s group, or any of the other rival teams, is going to take this upset without a challenge.