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by Jonathan Witt
Neo-Darwinism leads us to expect more than just change over time in the fossil record. It anticipates a fossil pattern of very, very gradual evolution of new forms -- evolution by tiny steps. On Darwinian grounds we should expect to find this pattern even given our highly incomplete fossil record. Instead the pattern we find is sudden appearance and stasis, sudden appearance and stasis, and precious little transition. Charles Darwin himself admitted that this pattern, particularly in the Cambrian explosion, posed a serious challenge to his theory.
More than a century and a half later, the problem -- and the pattern -- persists.
Stephen Meyer details all this in Darwin's Doubt. As he notes, Stephen J. Gould tried to patch up the problem of an uncooperative fossil record with his idea of punctuated equilibrium, according to which evolution moves by relatively quick bursts followed by long periods of status. But even the quick bursts proposed by Gould's model require many millions of years to get major new forms. That's because natural selection working on beneficial genetic mutations still must do the primary creative work, and that can only happen one small step at a time.
Why not big jumps? Big random mutations don't improve fitness; they maim and kill. This is well established experimentally, and the reasons for it are discernible from an analysis of engineering constraints at the molecular biological level. (See Chapter 16 of Darwin's Doubt for why evo-devo and other patches offer no escape from the problem either.)
So if intelligent design isn't allowed a foot in the door, we should expect extraordinarily gradual and incremental change in the fossil record from one form to a subsequent and dramatically different form. But the fossil record fails to cooperate, whether in the Cambrian explosion, in the appearance of birds and land animals, or elsewhere in the fossil record…
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