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Re: DINO EXTINCTIONS
Jonathan's point is important to note - what survived and how is as
important if not more important than what didn't make it. (Except that
might be off-list :-))
Also, please note that some of the death by bolide scenarios that have
been mentioned in these discussions seem to me to show the worse-case
scenario as THE ONE. I certainly do not support the extreme versions of
these ideas. I think that for the size of the event, the immediate effects
were close to minimal and extended for only a short period of time. To me
the bolide impact was the event that triggered a SERIES of bad times for
dinosaurs and the other species that went extinct.
One point that I'd like to re-iterate - Hibernation. When I first had
to write an outline for a class on dino extinction that I was teaching, I
added hibernation as a possible means of survival of for those animals that
made it past the extinction event (K/T boundary). At the time (1987), I had
not seen any papers or news articles that talked about hibernation as a
factor in survival of the K/T event. I reasoned that since most of the
survivors could hibernate, maybe the extinct animals could not hibernate.
(My idea at the time was that dinosaurs, having evolved in a mostly warm,
mostly moist, hardly seasonal climate; did not need to hibernate, but that
some earlier and some later genera did need to hibernate). (By the way,
since I produced that outline, it has been taught to around 75-125 dinosaur
docents, with little change - these are the volunteers that teach the public
about dinosaurs in the exhibits at the Academy of Natural Sciences - Mickey
can probably find a copy of my notes on extinction to verify.
From: Jonathon Woolf <firstname.lastname@example.org>
To: PTJN@aol.com <PTJN@aol.com>
Cc: email@example.com <firstname.lastname@example.org>; email@example.com
Date: Thursday, August 13, 1998 6:10 AM
Subject: Re: DINO EXTINCTIONS
>> This is an important point. The perceived selectivity of the K/T
>> may be more a function of the ability of a species to recover from an
>> environmentally induced population crash than a profile of what lived and
>> did not live through the event itself.
>True. But you'll agree, I hope <g>, that a species which has some members
>does better at survival than a species that has no members survive.
>IMHO, even if the extinction was gradual (on a human scale -- say, fifty
>years or so), there is still some insight to be gained form looking at what
>survive and recover vs. what didn't.
>-- Jon W.