From this perspective, mechanisms that prolong life in favourable circumstances but curtail in difficult times, make sense.
I need a source on that, because for the most part that's not how evolution works.
At the point of reproduction, the moment genes are passed on, the paternal time of death isn't "known" to natural selection. Generally speaking, there really is no way to put pressure on death like you suggested. Except maybe for some group selection mechanics, where scientific consensus would be far from settled, and it wouldn't qualify for any statement on "all higher lifeforms", anyway.
What's true tho, evolution doesn't care too much about your survival after reproduction, either. So, eg. some early in life adaptations may increase your chances of death later in life - live fast, die young.
But that's really different than saying death has this evolutionary purpose like you suggested. Complicated things just fall apart at some point. That's so much a fact, that large animals like whales and elephants actually do need "anti-cancer" adaptations to bring their plenty of cells into reproductive age.
Also, I think people may be prone to an anachronistic fallacy in regard to dying here. See, 1 in 5 people will die because of cancer, it's a pretty "natural" thing in our lives, but.... human cancer rates are actually mostly down to environmental and lifestyle factors. Before civilization and industrialization cancer was rare. Yes, people live longer to see it happen, but for example lung cancer is almost always attributable to some hazard exposure. Smoking increases your risk by 2000% (!), yet most smokers won't get lung cancer - lung cancer is that rare!
Alcohol, houses on radon soil, highly processed food, VOCs, hexavalent chromium, heavy metals, estrogenic plasticizer, asbestos, sedentary lives, obesity, microplastic, nanoparticles, ... stress. We could have cashed in on maternal and child mortality to fix our stats, but hey: you win, you lose.
Before life, there was only death. At some point, something life-like sprung into existence, and soon died. And then it happened again. At some point it was able to reproduce, and then died.
Death is the default. It was always there. Some things managed to cheat it long enough to reproduce. Those things are alive.
This is why I don’t see that organisms evolved to die. The very first life-like things were dying, before they had the ability to reproduce.
Agreed, but..
> Dying is a prerequisite to evolution. If every individual were to survive, the gene pool would not converge towards more advantageous adaptations.
This is kinda wrong. Reproduction is the perquisite for evolution. Evolution does not care much about your "survival" as a whole, especially after you reproduced. In "Survival of the fittest", you can better think of survival on the level of genes, not individuals, for the most part.
I think we need to substantiate this more. Where does "higher" lifeform begin? And is this statement really true?
There are trees older than 4k years and some whales become 200 years old.