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Re: Theories on the extinction of dinosaurs



At 01:15 PM 11/4/99 -0800, Betty Cunningham wrote:
Patrick Norton wrote:
> What is your evidence for claiming that dinosaurs did not adapt to changing
> circumstances very well?

they're extinct?

Patrick said dinosaurs make up a major percentage of *extant* vertebrate species. (There are actually more extant bird than mammal species aren't there?)

A couple of other things John Clavin said that I wondered about...

My personal opinion is that each contributed significantly to change the
climatic patterns, which combined with other ecological pressures
(alteration in the dominant flora, mammalian expansion etc.) to make the
latter half of  the Cretaceous a pretty damn difficult time to be alive.

I know there is widely believed to have been a decline in dinosaur diversity before the _coup de grace_, but it wasn't for the whole *latter half* of the Cretaceous was it?

Especially for a group of creatures that don't adapt to changing
circumstances very well.

They *did* adapt -- They grew feathers and learned to fly!

Besides, wasn't there a similar ecological crisis that wiped
out many species at the end of the Jurassic?  (The dinosaurs --
even the non-flying ones -- weathered *that* storm okay.)



                                  -- Dave