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Re: Bakker says



John Bois wrote:

> I think Bakker is correct in looking for a biological contributor in order
> to explain the _pattern_ of extinction, not extinction _per se_.
> But diseases don't do it for me.  First, diseases have never been known to
> wipe out whole taxa.  For starters bacteria and virus are usually
> species-specific, secondly diseases even within a single species don't
> usually knock out the entire species.

Most bacteria and viruses are species-specific, but not all.  Look at the
pathogen called Rinderpest -- spread from domestic cattle to wild African
antelope, and wiped them out by the thousands, across several different
species.  Look at rabies, which can infect almost any mammal species known.  A
pathogen as lethal and cross-contagious as rabies that was transmitted by air
could do a heckuva job on a fauna.  And some ecosystems don't need to lose all
that many species before they become unstable.

Also, I've heard some reports recently of Central American frogs -- several
species, in several genera -- getting hammered by a fungal skin disease.
Fungi and other external pathogens don't always have the same compatibility
problem between species that internal pathogens do.

-- Jon W.