[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]


On Mon, 21 May 2001, Ken Kinman wrote:

> ...raccoons and opossums 
> have no need to compete.

I think this was _my_ point.  Others are arguing that opossum radiation in
NA shows they are competitive with placentals.  But, if man has disturbed
the environment so much that competition doesn't occur, this argument is
nullified. (I reiterate that I would not be surprised if the opossum were
fully competitive or even superior in specific niches)

>       But getting back to more relevant matters, I was surprised at your 
> characterization of K-T as a low-end mass extinction.
> I wouldn't call ANY 
> global extinction "low-end".  A low-end mass extinction might be regional or 
> even continental, but a global event like K-T can hardly be called low-end.  
> And it wouldn't even come close to grading into background extinction.

This is all so undefined!  How about the idea that in some parts of the
planet, in some communities, that _locally_ it was a low-end, grading into
background extinction?  I'm not just being difficult.  As impressive
reproductive machines, if dinosaurs survived anywhere, they should have
been able to repopulate.  Short of global steralization, I think this is a

> And even fish didn't get by "unscathed".  Several whole orders of fish 
> went extinct, and I doubt that any fish order got through it without a 
> significant culling of genera.

But they were relatively unaffected compared to ammonites, say.  Why?

> One might charge that some people exaggerate 
> just how bad K-T was, but I think you are going to the other extreme, as if 
> to say "it wasn't so bad" if everything wasn't wiped out.

No, just that the pattern of survival is unexplained.  And I'm really just
goading for a definition.  Things that can't be defined may not exist.

> Maybe it wasn't 
> as bad as the end of the Permian, but it certainly was devastating on a 
> global scale.


>  Even if all the enantis had already gone extinct before K-T (which I 
> doubt), the neornithineans were still devastated.

Could you be more specific.
John Bois.