Those are great models for local adaptations. They won't grow a leg with extricate mechanical properties we have trouble modeling in state-of-art robotics/mechanics.

I didn't say it had to simulate real physics. Have you ever tried *a* genetic algorithm? They grow legs all the time in their toy universes, if that helps them increase their objective function.

All genetic algorithms are created by conscious intelligent beings. So I'm more interested in how a genetic algorithm develops by chance, with what probability. I guess typing monkeys wouldn't create genetic algorithms in the existing universe's timeframe even if the monkeys themselves have some (also random) fitness function that by chance has the ability to replace dumb monkeys with smarter ones.

Genetic algorithms are everywhere. Every time (1) something copies itself with mistakes, and (2) ....... actually there's just (1), no (2). Every time things copy themselves imperfectly, you have a genetic algorithm, and the fitness function is how much they copy themselves in the long run.

The current best hypothesis is that RNA randomly developed and evolved. Some if it happened to be self-copying. If there are self-copying things, there will be lots of self-copying things - that's common sense. And a genetic algorithm fitness function. In an ocean with RNA, sometimes it will happen to bump into other bits of RNA and swap over. Sometimes they randomly get better at copying. Zillions of molecules and hundreds of millions of years is a long time for small chances to happen. We want genetic algorithms to run in seconds on a PC. Ones that run for millions of years in the Earth's whole ocean don't have to be nearly as good.

The Miller-Urey experiment demonstrated that chemicals we know as building blocks of life can come into existence by themselves in early Earth conditions. What we don't know yet is exactly how they got from there to cells, since we don't have a time machine to go and look. Scientists keep finding plausible stepping stones, though.

my favourite far out there version of chemical evolution is the one where the entire Hubble volume was in the goldilocks zone for a few million years! sadly we may never be able to confirm it with samples, as there will always be the worry of contamination from earth.