[devoply]

> Evolution evolved to ensure the survival of the species, not the individual.

At some point in our evolutionary history the cells in our body made this choice. Evolution favors survival and potentially reproduction, because otherwise you are no longer in the game. So there was some evolutionary constraint that caused those genes not to regenerate parts.

It's possible we can change things so that those genes are active again. But we don't really understand these systems well enough to do that and won't anytime soon. But science carries on and I am sure you can make lab mice to test hypotheses of how this might work in mammals. And we probably will very soon, if not here then in China.

Evolution is perfectly fine even if you don't reproduce much, as long as you continue to survive in your environment. There are creatures out there that have changed very little and we know this because we have fossil records, and this is because they have been adapted to their environment and stayed adapted despite the environmental changes. And there are even immortal creature that die not because their bodies age and kill them but because they are eaten by other things, but still they don't change much over time. I guess you could say they are better evolved than other creatures that have to constantly change. They made better evolutionary decisions than other creatures very early on.

[tachyonbeam]

It doesn't have to be all about the evolutionary fitness of regenerating limbs. I think it might just be that losing a limb (and having the opportunity/time to regrow it) may have been a fairly unlikely event. Possibly, those genes mutated and were broken, right around the same time that some other genetic advantage evolved that caused a huge gain in evolutionary fitness.

The ability to regenerate limbs could have been lost in mammals simply because some old pre-mammal who happened to have broken regeneration genes was smarter and much better at finding food than the rest, and went on to pass his/her genes to all of us.

Furthermore, the evolutionary advantage of regenerating limbs may not be much in most animals. It's something we really would like to have, But imagine that some ancient primate species was able to regenerate limbs. Under what scenario do primate lose limbs? When some tiger chews them off? If that was ever to happen to a primate, it was basically fucked. Even if the tiger didn't eat it, it didn't fare very well lacking an arm for several months. The primate that is better at spotting tigers and avoiding them has much higher evolutionary fitness.

[piptastic]

You don't have to regenerate parts to live long enough to have offspring. You can do it at like 15 years old. So evolution isn't going to help in that regard much.

[toasterlovin]

Living for a long time after you have children is incredibly useful from the standpoint of genetic fitness. After all, grandparents play an important role in pretty much every human culture. And a grandparent with all their body parts is a whole lot more useful than one without.

[derefr]

The counterpoint being that in resource-scarce evolutionary environments, every grandparent (or even parent) that stays around is consuming resources that could instead go toward creating+maintaining an additional child.

[toasterlovin]

That's assuming that they consume more resources than they extract from the environment. And then there's also that grandparents can use the power and influence they've accumulated to benefit their grandchildren.

[devoply]

Often grandparents will starve to keep grandkids alive. Grandkids eat first.

[vacri]

There are plenty of species where the male dies during mating, and squillions more where the male isn't around after mating.

Evolution only requires that you get to reproduction, however that happens. It doesn't require that you're happy, sad, whatever, just that you reproduce.

[arcticfox]

> Evolution only requires that you get to reproduction, however that happens. It doesn't require that you're happy, sad, whatever, just that you reproduce.

It requires that your offspring actually survive as well. Humans are, at least historically, exceptionally well-equipped to influence the survival of their offspring.

[vacri]

Humans also take figuratively forever to be self-sufficient. Herd animals are born with the ability to walk, for example. Humans take about 10 years before they can be taught to be even somewhat self-sufficient, which is a ridiculously long time in comparison to others.

So, given that humans are sexually mature before they're fully self-sufficient, that enhanced ability to support their offspring is not all advantage - it's actually required for the propagation of the species. If older folks weren't taking care of the younger ones, none of them would reach reproductive age.

[devoply]

A 7 or 8 year old can hunt if you were to teach them to do so. An 8 year olds has conceived. So it's possible to do it at a much younger age if you have no choice.

[coldtea]

>Living for a long time after you have children is incredibly useful from the standpoint of genetic fitness. After all, grandparents play an important role in pretty much every human culture.

In the time scale that matters to evolution, grandparents played absolutely no role for the Homo Sapiens, and neither did culture.

[simonh]

I don't think that's at all likely. We've had fire and had the physiological adaptations enabling speech for well over a million years. We've been manufacturing complex tools such as spears with stone tips for about half a million years, to Homo heidelbergensis. Even Ergaster had lifespans allowing survival to an age where grandchildren could reach adulthood, allowing for skills transfer.

[toasterlovin]

Do you have children? Raising children is hard. And it's a lot less hard when you have other adults to help. Historically, those would be grandparents and aunts/uncles. But aunts/uncles would probably have children of their own.

[coldtea]

"Historically" is the keyword here. Evolutionary timespans are much much larger than recorded history and human culture as we know it.

[toasterlovin]

Nobody's saying that grandparents being alive are a prerequisite for grandchildren. But anybody with kids will tell you that grandparents are tremendously helpful in raising children.

Evolution is statistical in nature, not binary. Grandparents just have to be useful in raising grandchildren for them to be favored by natural selection. They don't need to be strictly necessary.

[aquadrop]

In many historic cultures, 'elders' were the ones who controlled the tribe.

[hyko]

I agree with you but don't forget the role of genetic drift.