RE: "But What About The..." arguments (long!)

["Allan Edels" <edels@msn.Com>]

My view is that the bolide was the killing blow, not necessarily the
ONLY reason so many genera and families went extinct.  I think that
without the bolide strike, most of the extinctions would not have
occurred.  Certainly, some extinctions may have been inevitable; but not
necessarily a lot of them. 

If ONLY all the non-avian dinosaurs went extinct at the time of the
bolide strike, then it would be more difficult to believe that the
bolide was the causal agent.  

However, with so many extinctions occurring nearly simultaneously
(geologically speaking :-) ) - It is more parsimonious that the bolide
strike was a major causative agent in most of the extinctions.  In some
cases, the bolide strike was the coup de gras (my French spelling is
atrocious); in other cases it was the only cause; and in other cases an
extinction was occurring without any extra help (the bolide) needed.

Some animals were just plain unlucky; and others were in the wrong side
of a decline when the strike occurred, and were also unlucky (doubly
so).  Some animals were very lucky and were mostly spared (at least
sufficiently enough to survive).

My comments are prefixed by "===>", after the following:

-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu] On Behalf
Of John Bois
Sent: Tuesday, June 04, 2002 9:43 PM
To: philidor11
Cc: david.marjanovic@gmx.at; The Dinosaur Mailing List
Subject: Re: "But What About The..." arguments (long!)



On Tue, 4 Jun 2002, philidor11 wrote:

>> <I do think that when there's that huge impact, there should be a
huge
>> catastrophic mass extinction. Such a mass extinction is present. So
it
>> should IMNSHO be the null hypothesis that everything that dies out
then
does
>> so because of the impact, and the burden of proof is on those that
want
to
>> take something out of this picture, as HP John Bois apparently tries
to.>

> Your hypothesis might be restated as:  nothing but the bolide caused
the KT
> extinctions.  If any factor other than the bolide produced a
substantial
> portion of the extinctions, then your hypothesis would be falsified.

Things the bolide "null" hypothesis has yet to refute: Neornithine birds
outcompeted enantiornithine birds; marsupial extinctions were due to
competition/predation from eutherian invaders; pterosaurs were barely
hanging on (i.e., diversity was lowest ever _before_ K/T); marine
extinctions happened at a different time from terrestrial
extinctions; some non-avian dinosaurs lived past the K/T and should have
had to re-establish populations.  I'm sure there are others.

===> In the above paragraph, HP John Bois brings up several of the
problems that mean that the bolide was not the all powerful killer of
nearly everything, as it is often painted (I mean this in the sense of
description, as opposed to pigment on a surface [and other methods :-)]
).   

The last two items I haven't heard/read anything that would indicate
these were true.  I know that there are some marine extinctions that
predated the K-T - so these were not affected by the bolide; and some
the occurred just after the K-T - but it may be that some marine
extinctions lag behind for some reason.  

I would like to see that some non-avian dinosaurs lived past the K-T and
managed to re-establish a viable population.  This has not been shown
yet (AFAIK).  Actually, finding a re-established non-avian dinosaur
population after the K-T would strengthen the theory that those groups
that survived the multiple effects of the bolide strike were lucky!    

As I have stated before, there is no need for the bolide (and its
various effects) to be the all powerful killer.  It merely needed to be
a SUFFICIENT killer.

More wood for the fire! 

Allan Edels