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Re: Evolution of sleep



Apparently it is better evolutionarily to be rested 6 hour and alert for 18 hours a day than be frizzzled for 24/7. A lot of nappers are guarded in cooperative behavior, ie. deer always have someone on guard. This can be extrapolated to cover dinos or mammals and everything in between I suspect. Is there any vertebrate creature that doesn't sleep?
Frank Bliss
MS Biostratigraphy
Weston, Wyoming


On Mar 17, 2005, at 2:40 PM, don ohmes wrote:

To expand the question:
Assuming sleep correlates with sharply reduced
alertness/awareness, what is the across-the-board
selective advantage of unconsciousness that prevents
at least some vertebrate animals from evolving always
on status relative to mental awareness? Or if there
are some, why are they rare?

Is it a systemic weakness that selection cannot
overcome? I can rest w/out sleeping, but sleep I will,
even in the face of certain death.

Don

--- K and T Dykes <ktdykes@arcor.de> wrote:
<<REM sleep is much more common. Crocodiles and very
young birds show it,
and I forgot what else.>>

I wouldn't be surprised about that, David.  However,
the question concerned
only mammals.

<<Sleep per se is common to all... vertebrates?>>

This must be another interesting question, because I
don't know the answer
either.  Happily, there's a good chance somebody
else will be able to
enlighten us both.  That's the great thing about
ignorance.  It leaves
plenty of
room for learning new stuff.
Cheers
Trevor

Mesozoic Eucynodonts
http://home.arcor.de/ktdykes/meseucaz.htm
The Mesozoic - more than just the dinosaur.