Posted on 04/21/2012 7:01:51 AM PDT by SunkenCiv
Nest thing you know, this topic will descend into a pun war.
Which is a good thing.
First the dinosaurs were giant cold-blooded reptiles. Now, they’re giant warm-blooded birds. A hundred years from now school children will laugh to think that adults thought the obviously mammalian dinosaurs were birds.
The dividing line (warm-blooded vs cold-blooded) has itself been superseded as a consequence of the study of more species.
So are we seeing greater speciation today with larger distinctions between species?
Not much — there’s no speciation going on today, as far as has been observed. In the fossil record there’s a broad diversity of critter types, same as now, with unknown numbers not preserved, or poorly represented (no complete type specimen). This suggests that there’s not much difference in the sheer number and diversity now as there ever has been — but it’s apparent that whole taxa vanished at the various paleontological boundaries.
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