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Re: GRACILITY IN TETRAPODS



ornstn@inforamp.net (Ronald Orenstein) writes:

>One thing to think about: what are the different selective factors leading
>to gracility as opposed to simply smaller size?  If, for example, food
>becomes limiting so there is an advantage to reducing body weight, eithr
>gracility or dwarfism would do the trick - yet on islands, for example,
>dwarfism seems the commoner result.  

Actually, it's just the opposite...
Gracility arises in "boom times", a response to a sudden increase in the
availability of resourcess, NOT a reduction of resources.  Gracility
is also accompanied by such changes as early sexual maturity, and in
some cases, larger litters/more eggs.  A good discussion of
gracile vs. robust species variants can be found in the excellent
book:

        Calvin, William, "The Ascent of Mind", 1990 Bantam Books.

Although in the book Calvin is talking about early hominids, most
of the concepts are transferrable to dinosaur species.

-----------
Achut Reddy                     So many fossils... so little time!
achut@sun.com