Re: longevity

From: CurtAdams@aol.com
Date: Sun Nov 21 1999 - 17:25:34 MST


In a message dated 11/21/99 3:41:09 PM Pacific Standard Time, jr@shasta.com
writes:

> Does that imply that Evolution selects for
> shorter life-spans under certain circumstances?

It never selects for shorter lifespan per se. Shorter lifespan may evolve
because
it comes as part of a beneficial package-deal or because longer lifespan is to
hard to select for.

> I still find it difficult to
> fathom why a population that reproduces or completes its life cycle in
half
> the time of a competing population does not garner an advantage for itself
in
> that it can adapt to changing environmental conditions twice as fast.

The *population* garners an advantage (assuming the
environment is changing). But, *all* alleles in the
population get the same benefit. Alleles for extended
survival (hypothetically with no other effect) are
effectively "cheaters" and oust competing alleles for
short lifespan because they also get the benefit of
their carriers reproducing longer.



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