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Re: Olshevsky's Rule, the Critical Response (was Re: "Cope's Rule" Put to the...



In a message dated 97-01-23 03:07:16 EST, znc14@ttacs1.ttu.edu (Jonathan R.
Wagner) writes:

<< Perhaps George has never heard of the hummingbird, which is quite a
 bite smaller than the earliest known tetrapod, smaller the the earliest
 known aminotes, smaller than any dinosaurian outgroup, indeed quite a bit
 smaller than _Archaeopteryx_. >>

None of which is necessarily the ancestor of the hummingbird, by the way,
which dulls your point a bit.

The real point is that there are far more large birds than there are
hummingbirds. As I just indicated in two previous posts, Cope's Rule is not a
rule, merely a tendency whose truth is supported by the evolutionary history
of practically every vertebrate group. Simply FINDING vertebrate groups whose
earliest members are significantly larger than the majority of their later
members is difficult, and even in such cases you would have the devil of a
time demonstrating that the larger earlier members actually did evolve into
the smaller later members.