Evolutionary mechanisms

Curtis Clark jcclark at CSUPOMONA.EDU
Mon Apr 7 23:26:03 CDT 2003

At 22:32 2003-04-07, Bob Mesibov wrote:
>"Punctuated equilibrium is the result of peripatric speciation (what you  have
>referred to as "paraphyletic speciation", iirc)."
>I don't understand this assertion and would be grateful for a clarification.

Eldredge and Gould were pretty specific, iirc, that punctuated equilibrium
was an extension of Mayr's peripatric speciation model to the fossil
record: new species (in that model) form initially as small peripheral
populations and are very unlikely to be fossilized. As the successful ones
expand their range, they may ecologically replace the ancestral species,
resulting in an abrupt change in the fossil record (the "punctuated" part).
As Eldredge pointed out, the punctuated part is fundamentally less
interesting than the "equilibrium", the persistence of species for long
periods of time with little change.

Curtis Clark                                     jcclark at csupomona.edu
Biological Sciences                              Voice +1 909 869-4062
California State Polytechnic University, Pomona    Fax +1 909 869 4078
Pomona CA 91768 USA                 http://www.csupomona.edu/~jcclark/

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