I’m curious as to what level we’ve discovered what drives the instinct to survive. I know that all living things down to single cell organisms have that instinct and a big part of how it is achieved is through homeostasis, but “why”? I don’t mean in the existential sense, but rather from a pure biochemical POV.
I have a double major in biology and microbiology with a good bit of interest in evolutionary biology.
I’m not sure what the “instinct to survive” is exactly, as much as I do understand it, I would argue that it is not the root drive of life. Life reproduces. Evolution is all about making viable offspring that can go make their own viable offspring in turn. Survivorship is only important to get those viable offspring out into the world.
Salmon swim upstream as their bodies go through intense changes so they can spawn and die.
Male angler fish get absorbed by the female fish until they are nothing but gonads pumping spermatozoon.
Male black widows and praying mantises get eaten by their mates.
As to some sort of hypothetical drive to survive, I doubt there is a single biochemical pathway.
Bacteria don’t have instincts or thoughts or drives and they are alive.
Viruses are simpler biochemically and they may or may not be alive.
Viruses are much different than us, but we both reproduce.
Scientists do think about the first life and what sort of traits it might have, but that’s more along the lines of RNA World or metabolism first, or looking at possible lipid bilateral evolution.