Catherine Woodgold  wrote or quoted:
> Tim Tyler (tim{at}tt1lock.org) writes:

> > It doesn't seem likely that evolution "saw" very many
post-menopausal
> > women during our species development - so it seems more likely that
> > it occurs as a side effect of developmental processes that occurred 
> > earlier on in our ancestor's lives.
> 
> It's not necessary for evolution to have "seen" many.
> The few who were seen had tremendous positive influence
> on their society, IMO.  Holding the family together,
> teaching, remembering, healing, etc.

The notion that they did that better through being infertile seems
highly questionable to me.

The notion that they did it *much* better seems even more suspect.

AFAICS, the most sensible hypothesis here is that the female
reproductive system simply craps out after a while - through
ordinary senescence.

This would be in no way adaptive to the individual female concerned -
or to the socitey as a whole.

Rather it would be a side effect of devoting a lot of resources to 
reproduction in youth - and relatively few to maintenance processes 
intended to preserve reproductive function.

There may be an effect whereby later pregnancy is not favoured -
since it's less likely to result in a viable offspring (due to
senescence) and is more likely to damage the mother (again, due to
senescence) - reuslting in her no longer being able to offer
parental care to her existing offspring.  That sort of selection
could actively favour the existence of a menopause.

Why does the male reproductive system last longer?  That's a
complex issue - but AFAIUI - it's partly a function of the effort
involved  (impregnating a female is a lot less demanding than bearing
a child), partly a function of the fact that fathers are usually older 
than mothers, partly a function of the fact that females provide more
parental care, partly due to sexual selection by men(!) favouring young 
mates - and partly to do with the fact that human males can be a lot more 
biologially successful than human females can ever hope to be - and thus 
an individual male potentially has a greater absoulte amount to lose if 
their reproductive system gives out.
-- 
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 |im |yler  http://timtyler.org/  tim{at}tt1lock.org  Remove lock to reply.
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