Everything is downstream of fortuitous mistakes.

Every living thing is downstream of billions of fortunate mistakes that just so happened to have been useful and be conserved.

For example, a minor genetic mutation, or an accidental experiment.

Most mistakes go away quickly:

If they are actively harmful, they are immediately selected out.

If they aren't actively useful, they erode and fade back into the background noise, averaging away into nothing.

Useful things are conserved

This is true no matter how they originally came to be.

Useful just means they help out the entity that is making the selection decisions.

In artificial selection, it's for example the farmer doing the animal husbandry.

In natural selection, it's the ground truth of natural selection.

Natural selection is fully emergent; it must be so.

Things that are more likely to survive or replicate are more likely to be more prevalent in the next time step, on a fundamental level.