Pulling fossilized heads from the sand -- and burying live ones in it

Almost 17 years ago, a paleoanthropologist was walking in the desert outside the town of Aramis, Ethiopia, and caught a glint of something among the pebbles and sand. That glinting object turned out to be the root of a fossilized molar, polished by the elements. Further digging turned up yet more bones -- a jaw, hands, a pelvis, feet, and a skull. The bones were hominin, like those of "Lucy," the world-famous Australopithecus afarensis skeleton discovered in Ethiopia in the 1970s. But these bones were about a million years older than Lucy's, extremely brittle, and in poor condition. A team of scientists and researchers spent nearly two decades using advanced technology to restructure the fossil fragments of this chimpanzee-sized creature called Ardipithecus ramidus, or "Ardi" for short.

That's the story told by the latest issue of Science (registration required), which devotes a huge chunk of the magazine to the long-awaited unveiling of Ardi, a primitive hominin female that spent part of her day climbing trees like a chimpanzee, and the other part walking upright like a human (or something close to it). She was able to perform this trick thanks to her feet, which had the stiffness required for bipedal motion, but also an opposable big toe used to grasp branches; and her pelvis, the upper parts of which are suitable for upright motion, but the lower parts of which are more ape-like. Researchers suspect that Ardi is an ancestor of Lucy -- who spent the entire day going about on two legs -- but have not yet confirmed that suspicion. Ardi's importance as a key to understanding human evolution, however, cannot be denied. As Science put it, Ardi is one of those discoveries that "reveals a whole chapter of our prehistory all at once."

Aside from the natural significance of Ardi's grand debut, it's fortuitous that she was unveiled just one month before the 150th anniversary of the first publication of Charles Darwin's On the Origin of Species. It's fortuitous because the copious documentation of the years-long scientific investigation into Ardi's bones stands in stark contrast to the cheap theatrics being employed by conservative activists looking to use the anniversary of Darwin's seminal work to reignite the "debate" over evolution.

Take, for instance, Ray Comfort, the New Zealand-born minister with no scientific training and a firm belief that bananas prove the existence of God. Comfort has decided to exploit both the public-domain status of On the Origin of Species and the gullibility of his fellow man by republishing his own edition of Darwin's tract that includes a 50-page introduction that connects Darwin to Hitler, exposes the "hoaxes" of evolution, and makes the case for "intelligent design." Next month, he and Kirk Cameron (the eldest son from the 1980s sitcom Growing Pains) are going to try and distribute 50,000 free copies of this Frankenstein edition of On the Origin of Species at 50 college campuses across America.

Comfort's cause has been heartily embraced by WorldNetDaily's Joe Farah, who also published Comfort's newest book, and whose disbelief in evolution is matched only by his disbelief in President Obama's citizenship. For a taste of Farah's scientific acumen, consider this passage from his column on Friday hyping Comfort's Darwin stunt: "Today, it is virtually impossible to escape being indoctrinated with evolutionary theory. I don't mean that evolution is taught as a theory. Just the opposite. It is taught as scientific doctrine, despite the fact that it is non-observable, non-testable and, frankly, nonsensical." Farah here is making an error common among evolution deniers -- that the word "theory" means conjecture and should be set apart from "scientific doctrine." When used in the scientific sense, "theory" means something that has been observed, tested, and affirmed, such as gravitational theory, cell theory, and, yes, evolutionary theory.

And that is why Ardi is so important -- she is another key piece of evidence upholding evolutionary theory, one of the many "transitional fossils" that Farah and his ilk insist don't exist. As Dr. C. Owen Lovejoy and his colleagues explained (registration required):

The pelvis, femur, and preserved thoracic elements of Ar. ramidus establish that adaptations to upright walking in these regions were well established by 4.4 Ma, despite retention of a capacity for substantial arboreal locomotion. Ar. ramidus thus now provides evidence on the long-sought locomotor transition from arboreal life to habitual terrestrial bipedality.

Translation: Ardi's bones show us how hominins went from swinging on tree branches to walking on two legs along the ground.

What will likely happen is that Comfort and Cameron will get a little bit of media buzz for their stunt, and the annoying hand-wringing and equivocating over the "two sides" of the evolution "debate" will begin anew. But the key thing to remember is that a few brittle bones pulled from the Ethiopian desert make a far more compelling case than 50 pages of Creationist drivel soldered to the front of one of humanity's greatest scientific achievements.