Date: Wed, 24 Apr 1996 20:44:06 -0500 From: rahul-AT-peaches.ph.utexas.edu (Rahul Mahajan) Subject: Punctuated equilibria Lisa, I agree with your and Dawkins's view that the theory of punctuated equilibria is well within the pre-existing framework of understanding. Gould himself has always said that he is talking about ordinary speciation by natural selection, although he has perhaps overplayed the significance of the idea. What seems new to me is not the idea that rates of change can vary greatly, which anyone without an a priori prejudice could see immediately, but rather that our picture that gradual change within species occurs over millions of years (in addition to whatever more rapid change/speciation may occur) is either wrong or much less universal than we supposed. In effect, they posit a stability of species to small deformations and present a picture of long periods of almost complete genetic stasis (in the adaptive sense, of course; nonadaptive genetic drift continues at a near-constant rate). This, if true, is interesting, but I have seen little that directly addresses this question, perhaps because it's difficult to address experimentally. What would be especially interesting would be to look at the persistence and prevalence of stasis broken down by complexity of organism. We already know that the more complex an organism is, the less potential for radical change it has (viz. the evidence of the Burgess Shale and other post-Cambrian Explosion sites). This would add another piece to that picture. Rahul --- from list marxism2-AT-lists.village.virginia.edu ---
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