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Re: Bakker says




On Mon, 20 Jul 1998, Dave L. Hardenbrook wrote:

> At 05:06 PM 7/19/98 -0400, John Bois wrote:
> >But diseases don't do it for me.  First, diseases have never been known to
> >wipe out whole taxa.  
> 
> I don't think Bakker has ever suggested that all dinosaurs were wiped
> out by one virus...

I didn't mean to suggest that.
> He merely theorizes that the migration of species led
> to the introduction of viruses into alien environs, sort of the way the first
> Europeans in the Americans brought with them new diseases that the Native
> Americans had no defense against, and the Europeans brought back diseases 
> from America that *they* no immunity to.

But still all populations are fine.  And look at the time scale.  A
pathogenic crisis would be expected to work itself out in an ecological 
time span, whereas dinosaur diversity was apparently falling over some 7
million years (in Nth. America, at least).  Also, note the incredible mass
introductions of species to novel habitats over the last 500 years.  I
believe most extinctions have been caused by predation and competition;
very few by disease (some exceptions, of course).

> (Dr. Bakker has always emphasized that he sees the big mystery
> as not why the Late Creatceous dinos died out -- because *all* species die
> out -- but why no new dinosaur species evolved to take their place.)

Yes.  That _is_ the issue!  Something unique about non-avian dinosaurs
singled them out for harsh treatment.  But all God's creatures get sick.