Discovery Institute barking mad over Australopithecus sediba’s diet

By Paul Braterman

I don’t normally bother with the Creationist newssheet, Evolution News and Views, but the recent article there by David Klinghoffer goes beyond what I am willing to suffer in silence. Klinghoffer himself, of course, is a senior fellow of the Discovery Institute, and the author of How Would God Vote? Why the Bible Commands You to Be a Conservative. I do not know his academic credentials – I seem to remember that he is a lawyer, but neither his biography on the Discovery Institute website, nor his Wikipedia entry (which follows that biography rather closely), give any details, and I hope that some readers can tell us more about this.

I also think it worth noting that Klinghoffer’s article has nothing to do with Intelligent Design, misguided though that may be. Like so much Discovery Institute material, it is an attack on the well-established facts of common ancestry. In other words, what is being advocated is, in the strictest and narrowest sense of the word, creationism. And not even creationism as a philosophical or religious position, but as an interpretation of the facts of biology, in a manner that has been intellectually unsustainable since around 1830.

Anyway, to business: in my own recent posting here I describe why, when announcing their finding in 2010, the discoverers of Au. sediba chose, on reflection, to include it in the genus Australopithecus rather than in the genus Homo. That 2010 account does, however, give a long list of ways in which Au. sediba is closer than Australopithecus to modern humans, and the title I chose for my piece (An Almost Human Tragedy) reflects this. I also described the most recent, rather surprising, finding; that the diet of Au. sediba ignored available grasses, in favour of woodland products such as tree bark.

Now here is what Klinghoffer has to say about this same finding:

Another Human “Ancestor” Bites the Dust Bark

…Sure enough, the cooling trend [concerning the importance of Au. sediba] is now plainly in evidence, with Nature reporting that the creatures had a very notable characteristic in common with chimps, not humans, that had not previously been recognized: their diet, highlighted by tree bark and wood. This was found thanks to an analysis of tooth enamel and dental tartar and microwear. The NY Times lets its readers down softly:

“Dr. Berger was an author of the new journal report. Few other paleoanthropologists agree with Dr. Berger’s contention that the new species is the most plausible known ancestor of archaic and modern humans. [Emphasis added by Klinghoffer]. Dr. [Amanda G.] Henry’s group said that studies of additional fossils from the Malapa caves “will provide a better understanding of the dietary ecology of Au. sediba.””

Actually, the New York Times account amplifies an earlier one, which said

The discoverer of the fossils, Lee Berger of the University of Witwatersrand in Johannesburg, says the new species, known as Australopithecus sediba, is the most plausible known ancestor of archaic and modern humans. Several other paleoanthropologists, while disagreeing with that interpretation, say the fossils are of great importance anyway, because they elucidate the mix-and-match process by which human evolution was shaped.

And the original paper in Science actually said, in the Abstract,

Combined craniodental and postcranial evidence demonstrates that this new species shares more derived features with early Homo than any other australopith species and thus might help reveal the ancestor of that genus

…and, in the body of the paper (p 203, column 3),

We can conclude that combined craniodental and postcranial evidence demonstrates that this new species shares more derived features with early Homo than does any other known australopith species, and thus represents a candidate ancestor for the genus, or a sister group to a close ancestor that persisted for some time after the first appearance of Homo[my added emphasis].

The situation is exactly as I described it, with no great claim to originality, in my earlier account:

The problem is no longer one of finding a missing link, but one of tracing an individual branch (the one that led to us) through a densely forking bush. It is always notoriously difficult to distinguish closely related species, because of individual differences. Even when we can, we have no way of being sure which extinct species lie on our direct ancestral line; it is difficult to tell the difference between our great-grandfather and our great-great-uncle, or between one great-great-uncle and another.

In short, then, on the basis of newspaper accounts and apparently without having read the original literature, Klinghoffer gleefully demotes Au. sediba from a position that most workers in the field had never even claimed for it, in the belief that the evolutionary account is thereby in some way undermined. Actually, the boot is on the other foot; the loser is the religious doctrine of separate creation. For if the 20 or so known distinct australopithecine and other early hominin species are not related by common descent, and were therefore doomed to extinction without progeny, why were they ever created in the first place?

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