Subject:  Re: pigs could fly -Reply
Date: Thu, 23 May 1996 19:19:31 -0400 (EDT)


I suggest looking at some of the work of Adolph Seilacher or just
browsing through some issues of Paleobiology for examples of the
practical applications of the critique of adaptationism.  Seilacher's
"construction morphology" emphasizes how phylogeny, function, and
adaptation contribute to morphology: phylogeny, the genetic heritage
of the organism, constrains what is possible, as does function, which
includes the constraints that result from physical reality, for example,
those that can be explained by the laws of mathematics, physics, chemistry,
etc.  For example, many of the forms of molluscan shells have been 
explained as the result of various adaptations, but Raup (if I remember
right) showed how differential equations explain the narrow range of forms
the shells can take, and Seilacher showed how the chemical properties of
shell materials explain certain characteristics previously explained
as adaptations.

In general, I'm inclined to think of macroevolution and population
genetics as separate issues.  The idea of species selection is one
possible way they are decoupled.  As a result, I'm inclined not to
attribute any evolutionary change to adaptation  without a lot of 
evidence.

Paul


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