[keepamovin]

I think it's interesting to consider in evolutionary terms: "what's the tradeoff?"

Why is there the proportion of Methuselan species that there are? Why not more, or less?

One simple take is old age is adaptive: the longer you live, the more chances to mate, the more offpsring, the more likely that your genes survive, perpetuating it.

One simple counter take is old age is not adaptive: the longer you live, the more your learned skills (or "maturity bequeathed survival" in the species where it's hard to say they are learning something), permit you to steal resources from the young, lessening the chances of survival of all offspring, on average. (you may take issue with that implication but you can also see how it is true, or better yet come up with another counter take!).

A second simple counter take is each generation lives longer so there's less evolution.

I think that in a species that learns, has a big brain, and is already adaptive, it makes sense that it will try to live longer because it's primary survival advantage comes not from its evolutionary legacy but from its accrued learnings (one may dispute that, or get pedantic and say "but without the original evolution you couldn't have the accrued culture", but you can also see how it's true), so even tho it's not "evolutionary"-based adaption, it's "self tinkering"-based adaptation. The longer you live, the more you learn, the better your chance of survival. Even if not evolutionary, you "Beat the gene", and make your culture, (and yourself, and all Methusalan individuals in it) more likely to be alive...rather obviously I guess.

So if we do come across aliens from such a species (like us, or orcas, or other big-brained, learning species, but more advanced), then it's likely they live a looong time. Unless they got fussy about some ethical issue with doing so, and decided against it. But any ethics involved seems unlikely to be proscribed by a constraint on energy capture / resource usage...as that would likely be one of the other characteristics of such a civilization, by virtue of us having been able to encounter them, it seems they were already able to master that. So it's highly likely that they live a long time.

So maybe, those "longevity gap" situations that people are so fond of agonizing and preaching about...are already the case on a cosmic scale, and the present race of humans are currently the beneficiary of the "less fortunate position".

Interesting to think tho, has the first child been born that will be the last generation to face death?

I'm reminded of two verses:

Old age should burn and rave at close of day;

and

Age shall not weary them, nor the years condemn.

[michaelmrose]

Arguably longevity may not be very meaningfully beneficial if you have a slim chance of getting old in the first place. You also must consider human reproductive design where eggs aren't produced on demand.

[keepamovin]

Ah, that's a good one, yeah. So you need a lack of natural predators and stable environment. That's true about reproduction as well, so evolutionary fitness of longevity favors males, but not, necessarily females after menopause. Part of human longevity may also be to extend female fertility...if women want that!

[perilunar]

Menopause and longevity are not necessarily at odds: see the Grandmother hypothesis.

https://en.wikipedia.org/wiki/Grandmother_hypothesis

[keepamovin]

Aaaah, that's cool! That makes sense.

It's amazing what you can explain with evolution. I wonder how much of it is real and how much of it is, "well, it sounds like it makes sense."

But this definitely makes sense.

I'm not sure how you could explain "career woman" tho, who chooses not to have kids. Tho I'm sure there's like a civilizational advantage to that behavior (aside from the obvious "economic" ones).

I suppose an argument could be made that, people prefer other people who share similar genes, so a powerful woman who rises in the business world, can then favor those with whom she shares genes (and increase their reproductive fitness, if not her own directly), thereby increasing the survivability of their offspring. The same could be said for a man, however. I don't think that makes a difference. In a sense, those who eschew their direct line to accrue worldly power may end up benefiting their "genes" in a different way to those who reproduce conventionally.

Not to take a negative slant at all, but humorously, a sort of post-modernist "deconstructed" nepotism, I suppose, haha!

What was Fukuyama's argument in end of history, again? I don't know, but I suppose at some point you get an "end of evolution" where civilization takes over and there's no obvious "reproductive fitness" any more to explain behaviors, it's more like "civilizational fitness". But, looking at the above, it seems that our genes may run rings around such suppositions already! Our clever genes! So very selfish!

One note in your link: I saw It also fails to explain the detrimental effects of losing ovarian follicular activity but I disagree, I think that physical decline provides opportunities for relatives to provide care, which likely increases social bonds, and enhances the Grandmother's "genetic nurturing" Effect. So if we assume the original hypothesis is true, physical decline would be a development that supports and enhances that effect, and so likely to occur. A truly noble sacrifice, on the part of the Grandmother, and all at the hands of the selfish genes, haha!