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Re: Copeing with mammals



But missing from the article is a discussion of why they move _out_
of the smaller niche.  I'm not sure why they ignore this question.

Probably they haven't thought of it, as we have to expect if they really believe so much in Cope's "rule".


Indeed, if tooth-length can be extrapolated to niche usage,
at no time do the two clades share a niche.

Which clearly shows that they never competed.

And it occurred to me that if a similar thing happened toward the end of
the Cretaceous...i.e., that small sub-clades of dinosaurs (birds) and
newly evolving mammal types squeezed other dinosaur and pterosaur out of
these niches and in effect pushed them into big-only niches...

This is even feasible without actual competition. It's enough if every time a species of the "old" clade dies out, a species of the "new" clade evolves into the empty niche because the "new" clade can somehow evolve faster in that direction.


that this is enough reason in itself to provide an extinction mechanism.

No, it's not, because it doesn't even try to explain why the biggest species of the "old" clades died out. Nothing dead or alive can compete with a pteranodontid or azhdarchid.


In other words, if a clade surrenders its small niche, it becomes extinct

...in the next mass extinction. Could be.

You can probably expect more on this issue when I'll start writing my diploma ( ~ Master's) thesis less than a year from now. :-° Probably I won't treat the K-Pg mass extinction all that much, however.