Re: transitional fossils

> Dear Dr. Garrison,
>
> I have always assumed that the impetus for Gould and Eldredge's
> "punctuated
> equilibrium" hypothesis. That is, there would be no need for such a
> hyopothesis if there were an abundance of transitional fossils.
>
> God bless,
>
> Bill Green
> www.god4science.com

This is a very common misunderstanding of Gould. Punctuated
equilibrium is a model for speciation. It argues that morphological
change does not occur at a uniform rate, but is concentrated at
speciation events. This was presented as an extension of the
allopatric speciation model that proposed that evolutionary change is
accentuated during times when species lineages are in the process of
splitting due to the geographic isolation of small populations. There
are many good theoretical reasons based on population genetics why this
might be a common pattern.

Transitional forms are abundant in the fossil record and cross every
level of the taxonomic heirarchy from species to phyla.

Keith

Keith B. Miller
Research Assistant Professor
Dept of Geology, Kansas State University
Manhattan, KS 66506-3201
785-532-2250
http://www-personal.ksu.edu/~kbmill/
Received on Sat Dec 3 12:31:37 2005