[knodi123]

> It seems logical to me that something in which is part of, the environment a species evolved to, would tend to have positive effects.

Not to me. Now, "tend not to have a negative effect on reproduction", sure.

But there's no reason evolution should make it beneficial, nor even neutral to those past breeding years.

For instance, if radiation caused humans to die younger than otherwise due to cancer, but still to live long enough to crank out a litter of babies and raise them to adulthood.... then evolution probably wouldn't care. Hell, evolution would love the way it gets rid of the chaff and frees up resources for the breeders.

[Tossrock]

Well, the grandmother hypothesis actually suggests that among humans, living healthily into old age to help rear one's grandchildren has evolutionary benefits, even if one stops reproducing.