Thursday, October 1, 2009

Some 200,000 generations ago

Some 200,000 generations ago, a woman affectionately named, Ardi, wandered through a grassy woodland with patches of denser forest and freshwater springs in what today is known as Ethiopia. Time Magazine article, Excavating Ardi: A New Piece for the Puzzle of Human Evolution, says of her:

"[She is an] interesting mosaic" with certain uniquely human characteristics: bipedalism, for one. Ardi stood 47 in. (120 cm) tall and weighed about 110 lb. (50 kg), making her roughly twice as heavy as Lucy. The structure of Ardi's upper pelvis, leg bones and feet indicates she walked upright on the ground, while still retaining the ability to climb. Her foot had an opposable big toe for grasping tree limbs but lacked the flexibility that apes use to grab and scale tree trunks and vines ("Gorilla and chimp feet are almost like hands," says Lovejoy), nor did it have the arch that allowed Australopithecus and Homo to walk without lurching side to side. Ardi had a dexterous hand, more maneuverable than a chimp's, that made her better at catching things on the ground and carrying things while walking on two legs. Her wrist, hand and shoulder bones show that she wasn't a knuckle walker and didn't spend much time hanging or swinging ape-style in trees. Rather, she moved along branches using a primitive method of palm-walking typical of extinct apes. "[Ardi is] a lovely Darwinian creature," says Penn State paleoanthropologist Alan Walker, who was not involved in the discovery."

Wow! 200 thousand generations ago. Does that go back further than the Eve of the Bible?

It is interesting to note that Ardi is not chimp-like, and therefore suggests that chimps were from an entirely different branch of the tree than humans. The article notes that many people 'envisioned Great-Great-Grandpa to have looked most nearly like a knuckle-walking, tree-swinging ape. But "[Ardi is] not chimp like," according to White, which means that the last common ancestor probably wasn't either. "This skeleton flips our understanding of human evolution..."

The apologists in the Creationism wing of the loony right have often scoffed at and held to ridicule the concept that we, the apes and chimps all came down the same ladder. Ardi mutes that nonsense altogether, yet it will not inhibit the 'true believers' in any way.

Here's to you, dear Ardi! You can't have imagined that your bones would mean to us, some 200,000 generations later.

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