Re: Inevitable simultaneous extinction?

[JAMES ARONIS <Apollo@MLink.net>]

Because an extraterrestrial origin for the demise of over 65% of life on earth
resulting in the termination of an entire geological era, is just too simplistic
for some to accept. But sometimes, the simple answers are the best ones :-)

Ken Kinman wrote:

>       Very imaginative, but his makes little sense to me.  Sorry, but this
> sounds like a Gaia hypothesis resulting from an overly imaginative view of
> how dinosaurs could have possibly affected CO2 levels to such an extent.
> There are just too many other variables in the storage and release of CO2.
>      Maybe we could think of some scenario that mosasaur extinction caused
> the demise of dinosaurs??   I really don't understand why people are so
> resistant to the bolide extinction of dinosaurs.
>                -------Ken
> ********************************************************
> >From: KELL00BELL@aol.com
> >Reply-To: KELL00BELL@aol.com
> >To: dinosaur@usc.edu
> >Subject: Inevitable simultaneous extinction?
> >Date: Fri, 27 Apr 2001 22:45:33 EDT
> >
> >           The extinction of the dinosaurs (for whatever reason) could have
> >triggered the demise of mosasaurus and other thermophilac sea life.  The
> >immediate aftermath of dinosaur extinction probably witnessed a major
> >increase in terrestrial plant biomass in the absence of megaherbivores to
> >suppress it.  An increase in vegetation could have caused a reduction in
> >atmospheris CO2, absorbed by plants, a reduced greenhouse effect, and
> >cooler
> >temperatures which, coupled with regression, could have dealt the coup de
> >grace to thermophilac marine reptiles.
> >      Since the Triassic, dinosaurs were probably the key element in a
> >warmer
> >Gaian regime they "invented" and maintained.  Suppressing vegetation with
> >their appetites, dinosaurs kept CO2 levels and global temperatures high,
> >which facilitated recuperative growth (especially after angiosperms
> >appeared)
> >and thus maximized the productivity of the land, supporting huge
> >dinosaurian
> >sizes and populations, even with elevated metabolic rates.
> >      If this view is correct, the existence of dinosaurs was essential to
> >the
> >maintenance of Mesozoic warmth.  Sea reptiles were beneficiaries of
> >dinosaurian dominance and could not survive without them.
> >      A very important point is that the near-simultaneous extinction of
> >dinosaurs and sea reptiles need not imply a common agency of extinction.
> >The
> >dinosaur extinction may have caused marine extinctions indirectly, made
> >them
> >inevitable.  Generally, it is assumed that the lack of a common biological
> >agency of extinction, on land and at sea, implies a common physical agency
> >e.g. an asteroid.  But a biological agency or agencies could have
> >extinguished the dinosaurs AND, indirectly, the sea creatures, for the
> >latter
> >may have needed the dinos.
> >      --Tim Donovan
> _________________________________________________________________
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