Re: Stereotypes and reputations

From: David C Campbell <amblema@bama.ua.edu>
Date: Mon Aug 01 2005 - 13:29:14 EDT

>What we see in the fossil record is consistent with evolution by common
descent. Monkeys arose prior to the splitting of Pangea and are found
both in Africa and South America.<

Actually, the monkeys arose after the split but seem to have gotten
across a (rather narrower than present) South Atlantic either by island
hopping or drifting on something. Same for the South American rodents.
 However, the South American groups are quite different from the
African ones-once they got across, they evolved in place.

>Lemurs are found only on the island of Madagascar.<

Lemur-like fossils occur elsewhere, but they only survived in
Madagascar, probabaly because the monkeys did not get there. There are
other primitive primates, not true lemurs, living in Africa and south
Asia (tarsier, etc.)

Although mammals are the most frequently invoked example of the
biogeographic patterns that fit with evolution, in fact all sorts of
organisms show geographic relationships that accord well with
evolutionary expectations. There are some oddball groupings that may
reflect differential extinction or poorly known past geographic
patterns (e.g., eastern North American crayfish form a group most
closely related to the group of Asian crayfish, and western North
American ones are linked to European ones, but species within a region
are most closely related to each other).

----------------------------------------
Dr. David Campbell
425 Scientific Collections
University of Alabama, Box 870345
Tuscaloosa AL 35487
"James gave the huffle of a snail in
danger But no one heard him at all" A.
A. Milne
Received on Mon Aug 1 13:30:36 2005

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