From: kelley at pulpculture.org
At 02:10 PM 4/5/2004, Charles Brown wrote:
>Maybe we could get the Venezuelan Bolivarians to send the Greens some
>statutes of General Simon Bolivar, suggesting it become the Green Giant
>Party, for, ecologic is not self-actuating theory.
>
>Charles
I read this book review (9.28.02 issue of The New Yorker, H Allen Orr) and thought it was interesting. Haven't had a chance to read the book, though. According to the review, Gould ended up reassessing his claims about "punctuated equilibrium"--basically gutting it. Gould conceded that change happens all the time. So, why the appearance of a pattern in the fossil reccord? "only if species split do the resulting differences last long enough to have a shot at showing up as fossils". From what the reviewer has argued, PE has been gutted as a theory of change and resurrected as a theory of why the fossil record appears as it does. An excerpt from TSET, <http://www.stephenjaygould.org/library/gould_structure.html> :
^^^^^ CB: This quote from Gould is , to me ,a reiteration of punctuated equilibrium. The original pe _is_ that change happens all the time. So, it is not a concession by Gould to say change happens all the time. The change that happens _most_ of the time is "equilibrated", that is changes that are "circular" around a point of equilibrium. As Gould describes in one of the essays of _Dinosaurs in a Haystack_ there might be one parameter , say, shell size of a mollusk, and over long periods and many generations it vacillates in a range. That is change but , equilibrated. Then , rarely, this equilibrated change is punctuated by a leap, back from which there is no vacillation into the range. A new population is established.
Similarly with respect to the fossil record comment below. This is exactly how it arises in Darwin - socalled "gaps" in the fossil record, with no gradual stages of forms in the gaps. However, this fossil record _is_ the evidence of punctuated equilibrium.
I'm not sure what is meant by the "theory" being gutted. _The_ theory is Darwin's: the origin of species by natural selection. That is Gould's theory too. He didn't abandon it , I am pretty sure. What Gould and his colleague modified in Darwin, was the "pattern" of how the changes arise. Changes within species are the "equilibrated" change, gradual change. Darwin's position was that new species resulted from gradual, long term change (evolution). Gould's modification is that the gradual change that goes on most of the time is not the species originating change, rather the rare punctuations are, as I understand it ( dialectical , law of quantity turning into quality).
The issue of allopatric speciation, i.e. populations having to be in different territories sufficiently separated that they are completely separate gene pools long enough that there is no gene exchange ,is a principle I learned in basic population genetics. It isn't new, I don't think. In fact, Comrade J.S.B. Haldane was a founder of it ( Haldane's dilemma and all that). Allopatric populations as a mechanism of speciation was assumed by Gould and Aldridge.
Another thing about the discussion below is that it seems to imply that Gould in his punctuated equilibrium theory "left" Darwinism. This is not accurate. He expanded it or developed it while maintaining its fundamental principle. Gould often "pledges his allegiance" to Darwinism in his punctuated equilibrium theory. Punctuated equilibrium is a completely Darwinian theory in the natural selection as origin of species sense. It modifies Darwin's gradualism. I have numerous quotes of Gould declaring for Darwinism and natural selection, so that raises questions about the author below.
Even with the issue that Darwin had a organism selection model and Gould proposed both organism (individual)and species ( group) selection, still Darwin is talking about organism selection as a mechanism for origin of species, obviously. They are both discussing the origin of new species, whether by individual or group selection.
Cheerio,
CB
"The model of punctuated equilibria does not maintain that nothing occurs gradually at any level of evolution. It is a theory about speciation and its deployment in the fossil record. It claims that an important pattern, continuous at higher levels-the 'classic' macroevolutionary trend-is a consequence of punctuation in the evolution of species. It does not deny that allopatric speciation occurs gradually in ecological time (though it might not-see Carson, 1975), but only asserts that this scale is a geological microsecond."
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