FWIW I'm a biologist, though I've only done a little bit of work on aging. > For example, if there was a human or animal genetic pattern that made the organism

FWIW I'm a biologist, though I've only done a little bit of work on aging. > For example, if there was a human or animal genetic pattern that made the organism not age, wouldn't that organism have created many offspring (in its long life) and the mutation have spread? First, aging is extremely complex and caused by a host of factors. No single gene or regulatory sequence could cause or prevent all of those things. Take DNA damage, for example. Read through this wikipedia article and notice how just within this single issue how many things can go wrong: https://en.wikipedia.org/wiki/DNA_damage_theory_of_aging https://en.wikipedia.org/wiki/DNA_damage_theory_of_aging > Does the fact that we don't (appear to) observe any ageless vertebrates or humans mean that it's probably not a genetic problem? The right way to think of this is that there's no genetic solution, or that one hasn't evolved yet in humans. > is life on Earth already so old that everything that will exist has likely already evolved? Evolution isn't linear. It just optimizes for whatever the current situation is. New genes are still being created (on evolutionary timescales anyway). Until very recently, the average lifespan for a human was in the 20-30 year range. Even if lifespan-enhancing genetic changes did occur in some individuals, those people were dying of bacterial infections or starvation or whatever, so they never got the chance to live 300 years and have 280 children and thus "take over" the population. Also, as others have pointed out, genes that confer longevity may come at a cost. Humans are just so complex that every change is a tradeoff.