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Location: UFOUpDatesList.Com > 2007 > Aug > Aug 1

Re: Binary/Convergent Evolution

From: Michael Tarbell <mtarbell.nul>
Date: Tue, 31 Jul 2007 11:11:01 -0600
Archived: Wed, 01 Aug 2007 09:54:45 -0400
Subject: Re: Binary/Convergent Evolution


>From: Bob Shell <bob.nul>
>To: ufoupdates.nul
>Date: Tue, 31 Jul 2007 08:56:10 -0400
>Subject: Re: Binary/Convergent Evolution

>>From: Michael Tarbell <mtarbell.nul>
>>To: ufoupdates.nul
>>Date: Thu, 26 Jul 2007 11:21:01 -0600
>>Subject: Re: Binary/Convergent Evolution


<snip>

>We really still don't know what killed off the dinosaurs, and
>until we do we can't really understand why some things lived
>through that extinction. Birds, fish, crocodilians, lizards,
>insects, small mammals, crustaceans,spiders, and many other
>groups of animals survived. I think the real question is not why
>did certain animals die out, but rather why did so many survive.
>This is the main weakness in the asteroid impact theory. If
>birds, which we now know are dinosaurs, survived, why not some
>other lines of dinosaurs? Why not dinosauroid evolution?


I'm not certain about this, but I seem to recall that size was
an important selection factor in the KT extinction... something
to the effect that no line of land animal larger than a dog
survived (correct me on that as necessary). This seems like a
plausible scenario in the case that the vast majority of the
browsable vegetation was destroyed (by fire?) and unable to re-
grow (sunlight blocked?). Large herbivores and their predators
died off quickly, leaving a few mating pairs of small animals
scraping by on what was left until normal plant growth resumed.

I would think that, even by that criterion, some dinosaur lines
(aside from birds) would have survived. Again I am not certain
here, but I believe that various species of roughly chicken-
sized non-avian dinosaurs were extant at the time of the KT
extinction. Perhaps the warm-vs.-cold-blooded distinction is
more critical at smaller sizes.

Mike






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