Sunday, May 30, 2010

A Toss of the Bones

At intervals of a decade or so, drawings of hairy ape-like precursors of humanity appear in the papers. They are older and older in origin, but, you might say, perpetually young. Today I turned the page of the Free Press and there was Ardi in frontal view, stark naked, the arms reaching down so that her fingertips could touch her knee (mine are much shorter). Her feet have “thumbs” you might say. Her small face has an assertive sort of look as if to say, “You’ve got a problem with that?” No, Ardi, I don’t—but I do wonder, every decade or so.

Ardi is Ardipithecus ramidus, discovered in 1992, but it took two decades plus for the drawing to appear. Ardi is thought to have lived 4.4 million years ago, thus to be an earlier fossil than her rival Lucy (Australopithecus afarensis), thought to have lived 3.2 million years ago.

Images like this always make me wonder: How do they know? What did the digging anthropologists actually see? The newspapers, informed by a laudable motive to engage the reader in wonder and admiration, almost never treat us to the rawer sorts of data—although these data are, of course available to the more intensely curious. Herewith then I present photos of the bones actually found for both of these very ancient ladies:

As is quite evident, in the field of reconstructing the origins of humanity, imagination, huge leaps of faith, and lots of fanciful theory play a much greater role than simple observation. Thus, for instance, in both of these cases, the scientists inferred from the bones you see before you here that Lucy and Ardi must both have walked upright. Movement on two limbs, rather than four, is taken to be proof of human origin—provided, of course, that the forelimbs aren’t wings; lots of birds walk on two feet too. When I begin to delve into the details of this field—which is something I rather enjoy doing—I always feel in very good company. Novelists, especially science fiction writers, have a lot in common with fossilists. Both are obliged to stick to the broad patterns of observable reality in their inventions, but, within those boundaries, hey, the sky’s the limit. Thus one nods with fascination over such inferences as the one, for instance, that smaller canine teeth means more muted male rivalry over female favors, the emergence of pair-bonding, and more intense devotion to child care—as suggested in an October 2, 2009 article in Science which comments on Ardi. It occurs to me that the artist, commissioned to render Ardi, got her facial expression wrong. Maybe Ardi looked much more loving, like Lucy. Plenty to ponder on my Sunday walk.
Picture credits Science except for the skeleton of Lucy, which is from Wikipedia.

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