Battlepanda: Take that, Behe!


Always trying to figure things out with the minimum of bullshit and the maximum of belligerence.

Saturday, January 21, 2006

Take that, Behe!

I did a little happy dance inside when I saw this article. It describes how modern ears evolved from the gills of ancient lobe-finned fish. It was an idea I'd run across in Richard Dawkins' The Ancestor's Tale, and this new discovery seems to tie it up quite neatly. It's a good example of how science works: you observe a certain aspect of the world around you, formulate a hypothesis to explain that aspect that is consistent with the available data, then seek out additional evidence which could either confirm or invalidate that hypothesis.

It also helps knock down a bit of bad science. The modern creationist movement ( they call it "Intelligent Design" now) seems to love the idea of irreducible complexity; that is, biological systems which would cease to function if deprived of one of several substructures. The favorite is the eye, though many other examples exist. The odds, they assert, that each aspect of these subsystems emerging at the same time, in the right configuration to do their job are astronomically remote.

That is true. And that's why no one is proposing that that's what happens. The bulwark of irreducible complexity is exposed as a house of cards without strawmen to defend it. The panderichthys fossil is an elegant demonstration of what is often referred to as "scaffolding" or "cooption". That's when, in the course of evolutionary diversification, certain bits of biology might make incidental improvements on a certain system. A biological system which becomes useless or even a liability will be selected against, but parts of that system might hang around if they improve on another useful function. In this case, little bones from the jaw drift away, and while early tetrapods learn to breathe through lungs instead of gills, the bones remain to set the stage for something completely different.

No assembly required.