That's not what I'm saying at all. Their are many species in which females
remain fertile until they die except when their lives are extended in a
laboratory setting. Human females in primitive societies regularly live to
the age of menopause which is an event specified by the genes, not a
product of cellular decay.
> > Fertility is already in decline by that period (probably due
> > to other agents already discussed) so being able to give birth would
not
> > result in a great success for the genes.
>
> That seems like another circular argument. If the genes weren't reducing
> fertility then they'd have a greater chance of success.
That's where those other factors come in. Things like cellular decay and
tissue breakdown might not be programmed into genes. They could be the
result of the high cost of maintaining an individual. If it takes more
energy to keep an individual alive than it takes to ensure gene survival
through other methods the individual will be allowed to die. In the case
of human females it would take more energy than is justified by gene
welfare to keep them fertile. It takes very little energy to make sure
that she does not give birth when the chances of the child and her
surviving the event are much lower than usual. Therefore, in the years she
has left before the effects that helped in youth but will hurt in old age
result in death the most useful function she can do from a gene's point of
view is help her genes survive in other relatives through either assisting
in gathering or giving knowledge to the tribe.
> > It
> > is a fallacy to think that genes don't "care" about a person after they
> > have reproduced. Genes care about a person as long as the existence of
> > that person is a benefit to the genes.
>
> Of course it's some kind of compromise between all these factors.
Which is why calling the above argument circular is uncalled for. Genes
cannot be considered one group. Some genes helped in youth and cause (or
allow to occur) a decline in fertility in old age. A gene coding for
menopause came along and it was very successful in promoting its survival
in other carriers. It's just taking advantage of a pre-existing situation.
The "menopause gene" does not cause the decline in fertility. It simply
turns the decline towards its best advantage.
Dan Hook
guldann@ix.netcom.com