climate and finches

Alex Duncan (
13 Nov 1995 13:17:03 GMT

In article <> Paul Crowley, writes:

>This is crazy. Where did *you* learn your evolutionary theory?
>The first finches that got to the Galapagos benefitted from an environ-
>mental change(EC). Were the 13(?) other speciations also the result of
>EC? Are all the billions of species the result of EC? OK, you can
>always go back a stage and find a change. You could always say that
>they are all the result of the Big Bang. (That was some EC!) But if
>you do that you are just into tautology. *Without* going back a
>stage, only a very small proportion of species arise from EC.

A note about the Galapagos finches. Some recent work there has been done
that noted some divergent selection in a finch species (into large-billed
and small-billed populations -- and not even geographically isolated).
If selection had continued in the manner in which it had been occuring,
two new species would likely have appeared, where there had only been one
before. What was the mediating factor? Climatic change. I don't have
the reference for this right on the top of my head, but I'll find it for

Alex Duncan
Dept. of Anthropology
University of Texas at Austin
Austin, TX 78712-1086