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Re: Dinosaur ecology: hermetically sealed?




On Thu, 13 Apr 2000, Larry Dunn wrote:

> From what I recall, even the most enthusiastic "meteor
> people" admit that a calamity like such an impact
> would have pushed already-stressed populations over
> the brink rather than being the sole cause of their
> extinction.

I'm not sure this addresses my point regarding an actual mechanism, viz,
if there were prey available, how come they starved to death?  However, I
do agree there were likely many causative factors.  As you know, though, I
argue the smart bullet effect, the apparent targeting of dinosaurs alone
among terrestrial vertebrates is suggestive of predation rather than
scattershot of global physical effects.  I feel the subsequent
effectiveness of predation limiting the large egglaying lifestyle is also
suggestive of a coming-of-age of animals--mammals and birds--to a point
where they could have an effect on dinosaurs.

> How do you account for the
> extinction of many other species, particularly the
> marine reptiles?

I was talking about terrestrial species only.  And I'm not arguing that a
bolide didn't hit and didn't have global effects.  I just don't think it
does a good job--by itself, at least--of explaining dinosaur extinction.  
I don't know about marine species.  I do think the relative success of
fish despite the argued collapse of marine food chain, is a similarly
difficult challenge--apparently there was more hermetic sealing for the
sea lizards.