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Re: Theories on the extinction of dinosaurs

At 10:28 AM 11/14/99 -0800, dbensen wrote:
>That woulnd't work.  For instance, if all the dinosaurs in Asia were driven
>extinct by a meteor, then after the dust had cleared, the dinosaurs from other
>places would recolonize the continent. And remember pterosaurs, which can fly
>away from localized disasters.  Something would have to kill off _all_
>dinosaurs _everywhere_ for any mass extinction to take place.

Not necessarily.  Recolonization, especially over water, takes many, many
millennia at the least.  And that assumes substantial thriving populations
in the source areas.  In a world-wide stress situation the potential source
populations would NOT be thriving, and would thus not really be available
as sources for recolonization.

Extintion does not require simultaneous die off, just failure to recover
from successive disasters.  This is how a certain snail in the Atlantic
became extinct recently - not with a bang but a whimper.

May the peace of God be with you.         sarima@ix.netcom.com