You know, I've recently wondered quite a bit about aging and how any of it makes sense. What has perplexed me is the notion of honest signals[1] in a world governed by natural selection and the survival of the fittest. Why wouldn't cheating exclusively emerge as the only strategy? Why wouldn't a species evolve a mechanism to survive longer and longer till it completely dominates? Then it dawned on me that the surviva…
The selfish genes control, and their survival is not perfectly aligned with either the individual or the species. If aging becomes too slow, adaptation slows, and successful genes become more rare and their propagation slows. Genes are replicators, replicators need turn-over to replicate, and greater age means slower turn-over.
It may be that the advent of cultural replicators have decreased the optimal turn-over rate of genetic replicators, but they don't know that.