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Re: Extinction scenarios

>I certainly don't contest Tom's superior biological expertise in this area.
>But as someone with some background in Anthropology, I will note that viral
>pandemics have been identified as _stong_ and _ contributing_ factors to
>massive populations declines of Paleo-Indian populations in the North America
>in the 16th and 17th centuries.  Perhaps those diseases would not, by
>themselves, have delivered a death blow to those cultures, but by eliminating
>a substantial percentage of the population they certainly dramatically
>increased their susceptibility to outside influences that they may otherwise
>have been able to resist. 

I would also note that pandemics have been blamed for at least the
near-extinction of some southern African ungulates (eg rinderpest) and for the
extinction of some Hawaiian birds (avian malaria and pox).  And let's not
forget diseases of plants, which could wreak havoc with food supply (eg the
American chestnut blight).  I certainly agree that disease alone is
unlikely to
have wiped out much (its usual result is to contribute to the evolution of
resistant hosts) but if it created a genetic bottleneck by greatly reducing
population it could have lowered, as the quote above notes, that population's
ability to resist other factors.
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
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Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@inforamp.net