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Re: The Drunken Sailor's Stumble (was Re: March of "progress")




Ken Kinman wrote:

    I'm not going to argue with you about Gould's ideas.  He's a bright
scientist, but some of his ideas are too simplistic in my view (Simon
Conway-Morris rightly criticizes some of these; see Crucible of Creation).

For once Ken, we're in agreement. :-) I find Gould's idea of drift being the major theme of evolution a little troubling. In fact, Gould's own discussion on the evolution horses in the book (which correctly rebuts the view that equid evolution was *not* governed by forward progress) tends to undermine his assertion that diversity is not due to adaptive advantage. "Full House" is an interesting read, but I highly recommend "Crucible of Creation".


The most troublesome is that the so-called Cambrian "explosion" was
supposedly a phyletic explosion of body-plans, when it is more realistically
regarded as an explosion of hard parts scattered here and there on an
already well-diversified Metazoan tree.

I respectfully disagree: I think the Cambrian explosion was real, not an artifact of preservation. But Gould (in "Wonderful Life") tends to overstate the diversity of Cambrian forms; some "unique" forms are now believed to be members of hitherto known forms (e.g. _Hallucogenia_ is likely to be a spine-backed onychophoran, not a "phylum" unto itself.) Also, Gould's notion that certain Cambrian lineages survived while others didn't was due to chance (Dumb Luck) is a little difficult to swallow, in my very humble opinion.



Tim

------------------------------------------------------------

Timothy J. Williams

USDA/ARS Researcher
Agronomy Hall
Iowa State University
Ames IA 50014

Phone: 515 294 9233
Fax:   515 294 3163

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