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Re: Theories on the extinction of dinosaurs
On Fri, 19 Nov 1999 Dinogeorge@aol.com wrote:
> the impact not happened. Perhaps there would have been a general decline in
> dinosaur diversity through the Cenozoic paralleling a general rise in small
> mammal diversity.
> Perhaps a few new dinosaur groups would have evolved, and
> there might have been a greater diversity of large flightless predatory birds
> (the "new theropods").
Then you need an explanation why for this didn't happen. In
almost every case of extant large flightless birds, predation by
_much_ smaller mammals appears the principal limiting factor. Competition
with mammals is seldom observed. My question is: Why would this not
happen in any case to limit the "new theropods"?
> Doubt that anything like humans would have appeared
> among the mammals.
Well, humans are so far down stream of 65 mya, such speculation is
meaningless. A more useful statement might be: Primates would not have
evolved were it not for the extinction of non-avian dinosaurs. But this
would be hard to justify sincethe two groups may never have come into
contact with each other.