[mobilejdral]

> Its what nature intends

A better question is if it is a fitness advantage to die. And it is. If you have two species and the first dies when something happens and the second doesn't the first will "win". The first species will have its old die out and so the young will be able to evolve faster without having to compete with everyone else that is alive, only the current generation.

We have this "kill switch" in our brains already. It is the PVN. Very much oversimplifying, but as bad things build up "inflammation", it kicks of production of cortisol to deal with it. The cortisol reduces neurogenesis and little by little our brain dies. The PVN also controls LH levels so sex hormones so rising cortisol downregulate CRH and the PVN. Puberty and menopause are just the speed changing of GnRH to match. Pain, wounds, immune system reaction, they all go through this. Imagine, at one time there was a species that wouldn't die of natural causes when it was in constant pain.

Vertebrates have the PVN, invertebrates don't. Vertebrates (nearly always) die, invertebrates generally don't.

There is a reason why all the stuff to increase life span is (generally) about healing or reducing inflammation.

I am skipping over a lot of details, but you get the point. Dieing is an evolutionary advantage, not to you, but to the species.

[vbsd]

You are invoking an argument that's called "group selection" [1], it's the idea that genes propagate based on whether they benefit the species as a whole. This argument has been heavily criticized and it is not used much in the mainstream evolutionary science. Perhaps group selection has some effect in some niche, limited circumstances but it doesn't seem to be a significant driving force of evolution.

You don't need to invoke group selection to explain dying though. Dying might be an evolutionary advantage, not to you, but to the genes that make you. Which is not the same as the species, at all [2]. Organisms die not to make space for others but because building the mechanisms to keep young indefinitely is not worth the price compared to spending these resources on reproduction mechanisms. Or because the right combination of genes that allow you to have free lunch just wasn't reached yet. If there was a magic mutation that prevents mammals from ageing without any other effects, I'm pretty sure that gene would spread. Quite possibly to the detriment of the species.

(Beware, not an evolutionary biologist, just somewhat interested in the topic.)

[1] https://en.wikipedia.org/wiki/Group_selection

[2] https://en.wikipedia.org/wiki/Gene-centered_view_of_evolutio...