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Poor misunderstood Punctuated Equilibrium (was RE: Some thoughts on AVES )
> From: firstname.lastname@example.org [mailto:email@example.com]On Behalf Of
> Robert G. Tuck Jr.
> > Evolution occurs through the accumulation of minute changes, not the
> sudden appearance of radical changes
> Gould and company might take issue with this statement.
> Personally, I await
> more data and take no sides in the matter.
Actually, the punc eq model does NOT advocate the sudden appearance of
*radical* changes, despite the fact that it is sometimes characterized as
Instead it suggests that species remain stable for long periods of time, and
that speciation (primarily by allopatric speciation: peripheral isolates of
the main population) undergo change in a geologically short period of time.
However, those changes are not held to be *radical* changes (and is the
reason that punctuated equilibrium is not synonymous with Goldschmidt's
"Hopeful Monster" model). Instead these changes are largely the minutiae of
interspecific differences: possibly some proportional shape changer, or
perhaps some minor discrete change (such as number of ribs on a clam shell,
addition or loss of a lens in the compound eye of a trilobite).
So the punctuations in punc eq are not supposed to be sudden major
reworkings of the body plan.
Thomas R. Holtz, Jr.
Department of Geology Director, Earth, Life & Time Program
University of Maryland College Park Scholars
College Park, MD 20742
Phone: 301-405-4084 Email: firstname.lastname@example.org
Fax (Geol): 301-314-9661 Fax (CPS-ELT): 301-405-0796