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Re: extinction by suffocation?!



There is a really good article on this subject in J. Exp. Biol. 201,1043-1050 
(1998),
Atmospheric Oxygen, Giant Paleozoic Insects And The Evolution Of Aerial 
Locomotor
Performance by Robert Dudley.

Dudley reports that oxygen peaked at 35% at the very end of the Carboniferous 
and
declined precipitously into and through the Permian, with a double minimum in 
the
Jurassic and early Triassic, then rose to another, lower maximum at the end of 
the
Cretaceous and early Tertiary, before declining gradually to the present day 
levels.
It's interesting to note that spontaneous combustion of the biosphere might be 
possible
at 35% oxygen concentration. Wonder where all those coal deposits came from? 
Also, the
higher oxygen partial pressures might allow oxygen and carbon dioxide exchange 
in the
trachea of long-necked animals.  Both thoughts are highly speculative.  Take 
them with a
grain of salt, if at all.
JimC

Richard W Travsky wrote:

> On Tue, 22 Dec 1998 Ccookk@aol.com wrote:
> >       I just happened to see a partial of what you are talking about. 
> > Evidently
> > some gas trapped in amber was analyzed to be approximately 35% oxygen. This
> > was from the time of the dino's, Jurassic I beleive. So the theory goes that
>
> I saw most of this, and I'm pretty sure they said cretaceous. (Oh dear...)
>
> > [...]
> >       I can see how some of this may be viable as a concept, but really 
> > need to get
> > more info on this. One thing is may explain, is how the large sauropods were
> > able to get enought oxygen through those large necks. A greater percent of
>
> I've been curious whether or not any absorption through the skin was
> possible (I doubt it, tho).
>
> > [...]
>
> rich