From: Darrell Parfitt (eng5dgp@titan.vcu.edu)
Date: Fri Sep 19 1997 - 09:17:44 MDT
On Fri, 19 Sep 1997, Joao Pedro wrote:
> Hi!
>
> I wrote:
> > >...................
> > >'basic ones'? If aging was a result of 'basic' errors, evolution would
> > >soon had found a way to prevent aging which is not the case for our
> > >species.
> > >...................
>
Evolution is not kind to the elderly. Evolution encourages as many
generations as possible and the most offspring as practical. Evolution
favors traits that improve the chance of the young growing to reproductive
age at the expense of early death after replication has been successful.
Our cells contain instructions which limit the speed of division more and
more with passing years. Anytime cells divide there is a chance of
cancer, which can eliminate the young and fertile just as well as the
aged. Curiously enough, sharks don't get cancer, and they don't die of
natural causes. For all we know there could be thousand year old sharks
swimming around in the Atlantic. If we could genetically engineer humans
to not get cancer and then released them in a pastoral world, eventually
they would likely evolve to have greatly increased lifespans, since there
would no longer be any evolutionary pressure against the maintanence
functions which would eliminate aging. Aging really isn't a flaw, it is
just that genes don't have the same motives as single organisms do. It is
similar to the way that my body as a whole will set immune system
defenses off to kill a precancerous cell, even though that cell is a part
of me and "wants" to keep living and dividing.
Darrell Parfitt
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