Thursday, April 6, 2006

A gap closes

A thousand years from today, evolution will be like gravity, so commonplace as not to raise a murmur. Often, when science has met dogmatism, science has won. It is almost inevitable that it will: science largely rests on evidence, facts, observations (not always, of course; it is practised by humans, after all).

Those who want to believe that God "designed" animals the way they currently are find themselves considerably embarrassed by the existence of fossils of animals that are no longer with us. They weaselled out of that by suggesting that God created all sorts of life but did not expect or want it all to last forever. What he did not do, they insist, is allow it to evolve. Quite why they can't simply adapt their dogma to include evolution, I don't know. It would be a smart designer indeed who used evolution as his or her means to create abundant life.

A prop for the creationists has always been that the fossil record is patchy and has "gaps". These are an artefact of its being so unlikely for a fossil to survive, given the need for particular conditions at the time of the organism's death and for the fossil to survive for millions of years in a world that suffers upheaval and change.

The discovery of the "fishapod" closes one of those gaps. Here is one of those "transitional" fossils that the creationists demand, claiming that their lack is proof that evolution does not happen.

But it does. Fish walked out from the sea and became land animals. Tiktaalik roseae is a snapshot: one creature in that chain of creatures -- at one end fish, at the other tetrapods. Tiktaalik is neither one nor the other, precisely. It is a creature in transition. Of course, in its day, it was the end of the line. (We forget that about evolution, particularly when we write articles titled "Is Man Still Evolving?" Evolution is not a process with an endpoint, and we are not finished in any sense that T. roseae was not.)

It gives me a small thrill to realise that T. roseae might be an ancestor of mine (some would say the resemblance to a crocodile proves it). Our lives are meagre, insubstantial, soon forgotten, but the chain of being that we are part of stretches back billions of years to a molecule in a warm pond and will, if our genes are lucky and we don't manage to exterminate ourselves and all other life at some point, stretch into a future as deep as the past that was home to T. roseae.

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