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Re: Dinosaurs versus mammals



> Date:          Fri, 23 May 1997 13:49:45 -0400 (EDT)
> Reply-to:      jbois@umd5.umd.edu
> From:          John Bois <jbois@umd5.umd.edu>
> To:            Stanley Friesen <sarima@ix.netcom.com>
> Cc:            dinosaur@usc.edu
> Subject:       Re: Dinosaurs versus mammals

> 
> > The basic idea that Jonathan is getting at here is the basic one we
> > ecologists call "competitive exclusion".  By observation we have noticed
> > that close competitors tend not to coexist, and that the incumbent has a
> > major advantage in nature, as in politics.
> 
> But again, why dinosaurs first, or second, or why not now.  Somewhere in
> here ought to be discussed the abilities of certain traits.  Also, the
> notion of competitive exclusion is very fuzzy.  The term "close
> competitors" needs definition.  Are zebra and wildebeests close.  How
> about cheetah/lion; how close do you believe early mammals were to early
> dinosaurs?
> 
Zebra migrate ahead of wildebeest and eat the upper part of the 
grass.  Wildebeest follow and crop closer to the ground.  So they 
don't compete which is why it works so well.  Cheetah take smaller 
prey than lion although they are about 70% successful.  Lions 
generally eat larger prey and are about 40% successful( someone 
mentioned 25% the other day and this is too low).  Therein lies the 
answer to your question.  Regional ecosystems work.  If they get out 
of balance things happen until they work again.  For some reason 
dinosaurs ascended to dominance because things worked better that 
way.  For awhile. (Quite awhile).

As always, this is only an opinion, subject to
retraction and recall without notice, and with 
due respect to others opinions.

Thanks,

Michael Teuton MD