RE: Extinction scenarios

["Augustus T. White" <augwhite@neosoft.com>]

-----Original Message-----
From:   Dinogeorge@aol.com [SMTP:Dinogeorge@aol.com]
Sent:   Tuesday, August 18, 1998 3:36 PM
To:     augwhite@neosoft.com; jwoolf@erinet.com; @usc.edu
Cc:     dinosaur@usc.edu
Subject:        Re: Extinction scenarios

<<Nevertheless, these are all extinctions caused by the asteroid impact. 
When
the bullet hits the bystander, only the coroner worries about whether the
bystander died from a direct wound to the heart or bled to death from a 
wound
to the thigh.>>

George:

No.  It makes a significant difference.  We hear constantly that the impact 
theory is flawed because it cannot explain selective extinction. 
 Therefore, we're told, we have to hypothsize some mysterious force that 
sounds (to me) very much like the discredited notion of genetic senescence. 
 The point is that the critics are looking at the wrong sort of causation. 
 Even the proponents of the bolide seem only to come up with bigger, 
stranger and more devastating methods of tranferring astronomic kinetic 
energy to living tissue.  The fact reamins that getting hit with a rock 
kills rather unselectively.  Ecological succession, on the other hand, can 
be a very finely tuned selector and can operate in a very short period of 
time.  I don't know if this concept of the extinction can be crafted into a 
testable hypothesis.  However, it is at least one reason not to asssume 
that selectivity undercuts the astronomical explanation for the KT 
extinction.

  --Toby White