Earlier quoted context omitted.
Depends on how much your children need you actually. I've read somewhere that part of the reason women lose ability to bear children past around 40 is so they can take care of their grand children because that is usually more important at that point from an evolutionary point of view. It might have been a mere speculation but it kind of makes sense. Rather than take the time to bare and raise one child, that time is…
I dislike these kinds of explanations because they seem like ex post facto rationalizations. An explanation that could have gone both ways explains nothing: * Women stop having children after 40 because it's more important to raise the children you already have. * Women don't stop having children after 40 because bearing more offspring increases your chances of survival. Your explanation barely makes sense even on it…
To talk about what nature "wants" is probably not very helpful. I can't speak for the idea that menopause exists because it is useful for old women nurture their grandchildren, but tendencies like it exist simply because they are helpful enough in an evolutionary sense.
I mean, why should we want to have sex without reproducing? If nature "wanted" us to have children, why not make that coincide exactly with our sex drive? It's because no one designs these things or thinks of logical solutions. Having a sex drive regardless of individually wanting to have children works to a genetically beneficial end either way.
> Is it to their evolutionary advantage to care for the children they didn't have?
Their evolutionary advantage? How can an individual gain an evolutionary advantage in itself? When I'm dead, I'm dead. Nothing can be an advantage or a disadvantage to me as an individual at that point. The process of evolution stretches across generations and concerns things that do sustain for several generations, like genes.
Why would a spider want to mate if it almost always gets eaten immediately after doing so? How is it to their individual advantage to be eaten? Why would bees be born without reproductive capabilities? It's because these are genetically beneficial traits, not because the individuals themselves will gain from it.