X-Message-Number: 17353
Date: Wed, 22 Aug 2001 14:15:40 +0000
From: Kennita Watson <>
Subject: Oxygen surfeit?

Yvan Bozzonetti wrote:
> The question is: what is the optimum O2 level? it must come from an 
> adaptative process, so I would say it is the atmospheric level in african 
> pains (the origin domain of man). Now, evolution has a fair amount of
> inertia and O2 level has not always been what it is now. At some epoch it
> peaked at near 30 per cent... Because actual level is rather low on the
> historical scale, I would guess we are adapted to an optimum higher than
> the current partial pressure in the atmosphere. This was my basic logic
> for testing atmospheric content with more O2.

Note that, by that logic, we are also adapted to an optimum life span 
of 20-30 years.  The 02 level is low on the historical scale; life span
is high.  I won't claim a direct correlation, but it is worth considering.

Note also that the evolutionary processes that gave rise to humans had no
reason to optimize our oxygen metabolism; it was good enough.  As far as
that goes, maybe more oxygen _is_ better for reproduction -- running 
from tigers. toiling in fields, nourishing fetuses, etc.  I don't think 
it follows that it's better for longevity. 

-- 
May you live long and prosper,
Kennita
--
Kennita Watson          | Way Cool Internet Radio: http://www.live365.com
     |      
http://www.kennita.com  |    Great Minds Think Alive! -- Lee Corbin

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