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Fwd: A Little Brain Teaser

Forwarded message:
>From:  theropod@garnet.berkeley.edu (John R. Hutchinson)
To:     Dinogeorge@aol.com
Date: 95-10-24 11:50:41 EDT

>I've given this a little thought over the years, and I'm satisfied that
>herbivory derived from strict carnivory is rare indeed. Since herbivory
>requires some kind of specialized gastric flora to digest the cellulose, I
>can see how it could derive much more easily from insectivory of
>insects: the bugs that digest plants inside the bugs remain in the digestive
>tract of the insectivore, and eventually a symbiotic relationship develops.
>So small, arboreal insectivorous archosaurs could evolve without too much
>trouble into plant-eating dinosaurs. But we would have a lot more trouble
>evolving a herbivorous therizinosaur from a carnivorous tetanuran...

        Too true! The whole deal with guts and teeth (carnivores have
simple, unspecialized guts and dentitions generally - Carnivora excluded)
further complicates the issue. Omnivores certainly would have an easier
time going either way (to strict carnivory/herbivory). It's a very
intriguing issue....

                        John R. Hutchinson
                  Evolving Evolutionary Biologist
                 Department of Integrative Biology
                University of California - Berkeley
                        Berkeley, CA 94720
                          (510) 643-2109

        "Thus, the student of adaptation has to sail a perilous course
between a pseudoexplanatory reductionist atomism and stultifying
nonexplanatory holism."         --E. Mayr, "How to carry out the
adaptationist program?"