This is why evolutionary biology irks me. It assumes there is no greater utility than reproduction. They've been struggling with this question for awhile. While men can continue spawning offspring when they are grandfathers, what is the purpose of a grandmother?
While I understand their question and the arguments, it's dehumanizing. It's like the only value of a person is the ability to make more. But we are a social species. I don't think it's far-fetched for the 'purpose' of an individual (in this case, a collective of individuals, older women) be fore the greater good. We have lots of examples that show that the older a woman gets, the less likely she will be able to bear a healthy child, because all women are born with as many eggs as they'll ever have and they get beat up over the years. It may be in the best interest of the species that women over a certain age don't reproduce, so their offspring can survive.

But then the disheartening question becomes "Why do grandmothers live after being unable to produce children?"

Arg.

It's cuz it's time to get down to business! We've got important stuff to contribute and we can't be fettered by the roller coaster of hormones and emotions.

gentle my ass!! I wish I had an "on/off" switch.

In many social species, unrelated individuals help care for offspring. This benefits the reproductive success of the species as whole.

We are odd in that we live beyond our "reporductive years. It juts so happens that males keep producing sperm since they are "cheap" to make. An egg is a large investment.


If grandma can hang around and help her offspring as well as any others then a reproductive advantage is afforded.



When it comes down to it, evolutionarily speaking, it is all about reproduction.

I know. That's kinda what I said.

But that's what irritates me about evolution. Those that don't reproduce are thought to have no value. None. The implications of that... disturb me.

This is not the perceived notion by a long chalk.

The goal is survival. There are many different levels of survival, but they all centre around propagating the species - passing on DNA. Now as between you and I there is less than 0.1% then your survival is very close to mine. So even if I didn't reproduce but did something that allowed you to reproduce (such as fight off a sabre toothed tiger or share my food with you) then that would be akin to 99.9% of my DNA surviving.

So a grandparent or grandparent figure who did stuff that helped generations below survive is still part of the survival process - not written off. In contrast this is a very high value indeed.

Nature ascribes no values, that's a human idea, and as humans its up to us to assign value to an individual life.

Evolutionarily speaking, value is only in the number of offspring you produce. That may sound "cold", but as I said, value is a human idea in the sense that we're using the word.

That shouldn't be disturbing to anyone really. I have no children yet I greatly value my life as do my family and friends. In the sense of modified descent I am a dead end thus far, but so what.

Morality is a construct of man and should not be looked for in the mechanisms of nature.

:)

Sorry, sorry, I'm mixing some evolutionary psychology in with my evolutionary biology. That's where it gets muddy.

I remember reading articles about the quality of eggs and sperm over time - as a person ages, their risk of passing on defective genes increases. That may also play a part in why menopause takes place when it does.