[bhuga]

> survival of the species is not aligned with the survival of an individual

The unit of survival is not the individual or the species, but the gene. Genes maximize their survival by combining via sexual reproduction with other genes over time. Any one combination of genes will be out-competed over time.

The reason for honest aging signals is that a gene survives longer by getting out of the way of its offspring's combinations with other, newer genes. Sexual reproduction is the only way to get access to new phenotype features.

It's not service for the collective. Hanging around in one individual is the genetic version of vendor lock-in.

[ttoinou]

Why would women survive so long after menopause then ?

[nonameiguess]

I think it can be instructive to look at other social mammals that range over large areas, like Orca and Elephants. They tend to lean heavily on elder females as the purveyors of tribal knowledge and inter-generational memory to remember where to go and how to get there as environmental conditions vary from year to year and decade to decade. It doesn't matter as much in humans since we have writing and maps now, but this kind of wisdom of those who remember similar lean times from 60 years ago could have been very important to the survival of human communities.

[mrkstu]

Happy accident at first, though there are some possibilities around grandparents increasing survival rates of younger children, so that would ultimately feed back into the gene pool.

[wizzwizz4]

Kin selection. Parents, and community in general, are kinda important for the survival of a child.

[whythre]

Clearly living longer after viable reproductive age offers something. Having grandmothers around to nurture the second generation offspring is certainly a benefit.

[tarkin2]

To help her offspring propogate her genes is one theory I've read, coming from observing post menopausal sharkes

[ysofunny]

better curated memes

which are an expression of the concept of gene over the field of informatics, instead of the field of biology (unit cells vs unit bits)

[lloeki]

> the genetic version of vendor lock-in

All models are wrong but this one is mine, IANA biologist, yadda yadda.

- there are only so many resources to sustain individuals

- ergo there's a cap of the number of individuals

- ergo some individuals will die, if not from age, from attrition

- if age is not factored in, there are more old individuals, genetic competition between young individuals is reduced as they have to compete for resources with old individuals

- ergo age which kills old individuals irrespective of available resources allows more young individuals to exist in such a pool

- ergo ageing a) promotes competition between young individuals b) increases mixing of the gene pool

- ergo it promotes quicker turnaround on mutations

- ergo ageing is a significant asset in species adaptability to change

IOW vendor lock-in sucks in face of changing conditions as one is suddenly stuck with a suboptimal solution and competitors have a harder time emerging to challenge the status quo.

conversely the benefits of short term ageing are counterbalanced by social effects, where elders, even when not reproductive anymore but still otherwise in good health and thus autonomous as well as minimally consuming resources, are able to provide support for their chain of descendants, freeing energy for parents-to-be to reproduce, then parents to gather more resources that are then directed to support their younglings. The lack of reproductiveness of elders is advantageous to the species as it removes them from the direct gene mixing pool, instead promoting the younger ones.

IOW for its individual lives to be longer, a species goes increasingly social, channeling more support and thus energy towards their younger members, but ageing is still key otherwise the species ability to face quick change (at evolutionary scales) is severely hampered.

The deeper question for me is whether ageing is a specific primary process (a literal clock, which a technique such as the paper would attempt to skew backwards) that emerged from evolution or if it is a secondary effect from entropy corrupting other processes (e.g there's constant degradation + a ton of error correction but at some point degradation is too high and error correction cannot cope, triggering a catastrophic cascading effect leading to the sudden inability for an organism to sustain its own life, which the paper would delay by introducing younger cells, thus less errors, thus error correction can cope for longer)