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Re: Extinction scenarios



In a message dated 98-08-19 16:58:48 EDT, jdaniel@aristotle.net writes:

<< But the point here is that neither the disease nor the bolide are
sufficient to
 wipe out all those species in and of themselves, it was the combination of
both
 that did the job, at least if this hypothesis is correct.>>

Sorry, but the action of the disease is contingent on the action of the
bolide, so it's the bolide that is the ultimate cause of the extinction.

<<  so you can't say, yes
 the bolide killed them because it did not, according to this view. it would
merely
 have drastically reduced their populations.>>

This is what extinction is all about: the drastic reduction of a population to
the point where it can no longer sustain itself. The cause of death of the
last individual is not particularly relevant, and could well be quite random.

<<  The disease by itself would not have
 done so, either so obviously the disease is not the culprit.  Putting it all
on
 the bolide's shoulders is an oversimplification.  Without the pathogen, the
bolide
 would not have wiped them out, so then it becomes the cold that killed the
last
 passenjer pigeon in your example. >>

Let's put it this way: in the case of the passenger pigeon with the cold,
overhunting was more than 99.999% responsible, and the cold was less than
0.001% responsible.