Thursday, December 13, 2007

Amazing Evolution!

Just came across another example of superfluous invocations of evolution in this New York Times article:

Spines, Made Extra Curvy for Women by John Schwartz

Let me just start off by saying that, as you may know from reading this blog before, I really don't have a dog in the fight of the "Evolution Wars." Whether or not God used evolution or some other secondary cause to develop life seems in the big picture much less interesting to me than investigating the actual natures of organisms.

With that disclaimer, here's some of the article's text:

Anthropologists have long known that the lower spine in humans developed a unique forward curve to help compensate for the strains that arose when the primate ancestors began walking upright. Researchers looked for a mechanism that compensated for pregnancy’s additional burden as well.

What they found, said Katherine K. Whitcome, a post-doctoral fellow at Harvard and the lead author of the paper, was evidence that evolution had produced a stronger and more flexible lower spine for women.

I don't understand why (aside from personal piety) evolution has to be brought into the picture at all. Concretely speaking, is there any difference between saying that humans developed such-and-such feature and saying that they have such-and-such feature. What value does evolution actually add to the discussion?

Answer: absolutely zero. Judging from the Times article (and from previous similar instances), there's nothing in the science here particular to evolution. It's pretty old news that women are more flexible than men. Evolution is just a buzz word that sexes up an somewhat interesting but rather unremarkable observation.1

But then there's this paragraph:

As solutions go, the extra flexibility is only partly successful, Professor Shapiro said, since women still commonly complain of back trouble during pregnancy. And that is the difference between the way that evolution works and the way that actual designers do their job, Dr. Whitcome said: nature tinkers. For natural selection to favor one feature over another, “It doesn’t have to be an ideal solution,” she said. “It just has to be better.”

That's the standard claim: that evolution explains shortcomings in somatic form. But that claim treats an organism's traits as if they were independent from each other and not integrally related parts of a whole. How do we know that the "imperfection" in spine design is a "bug" and not a "feature" for some other reason? How do we know that the "imperfection" isn't necessary because "fixing" it would wildly upset another part of the organism?

Nature differs from human designers in that it works with the whole organism. Organisms are much more perfect, more integrated, than anything humans can every make on their own. We humans have trouble even comprehending all the interconnections between the different parts and metabolic pathways of an organism. That is why artificial genetic modification (as opposed to artificial breeding) is the height of arrogance.

It is also presumptuous to declare the shortcomings in the female human spine a defect. Years ago geneticists declared DNA that didn't code for proteins "junk DNA." Now we are learning that it is far from junk. The present case is just another instance in which scientists, failing to see the use of something, declare it useless.

When will we learn that nature holds much more wisdom than we can know?


1. It would be quite another thing if the scientists traced out an evolutionary pathway that resulted in the spine curvature. But that would involve genetic and biochemical work, and the journal article in which the findings are reported is by two anthropologists, so the chance of there being any such work here is nil.

John Schwartz, "Spines, Made Extra Curvy for Women" New York Times (December 13, 2007).

Katherine K. Whitcome, Liza J. Shapiro & Daniel E. Lieberman, "Fetal load and the evolution of lumbar lordosis in bipedal hominins," Nature 450 (13 December 2007), 1075-1078.

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