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Re: bauplan convergence
At 07:48 PM 6/16/00 -0700, Ken Kinman wrote:
I see no big problems with such a sequence, but I believe
protofeathers first evolved for either display or insulation, not both at
the same time.
The problem I have with this is that natural selection does not act on
functions or uses, nor even, really, on individual organisms. It is a
population process. This means that there is rarely a clean separation of
functional effects with regard to selection.
In short: separate selection for one of a set of function is *very*
rare. Selection for an amalgam of functions within the context of the
local ecological situation is the general rule.
Significant changes *rarely* happen for just one reason.
Thus display and insulation are not separable features with respect to the
evolution of proto-feathers.
Nor are brood insulation and display separable with respect to proto-wings
(aka extended feathers attached to arms).
May the peace of God be with you. email@example.com