Evolution explains how life arose from simple non-biological precursor

Are you sure about that?

Doesn't evolution explain how life arose from other life, and how speciation occurs, and how common descent can have happened? If the theory of evolution-proper is thought to incorporate, as well, the explanation of how "how life arose from *non-biological* precursors", it's news to me.

Seems to me for that, you need some additional hypothesis, such as "lightning + amino acid soup" (I don't actually know what the current consensus is). Another possible hypothesis might be "seeding from outer space". But whatever that hypothesis (about origins of life) it would not be essential to the theory of *evolution* per se. In other words, even if "lightning + amino acid soup" is a wrong explanation of how the first RNA/DNA formed, it wouldn't make *evolution* wrong.

That's because evolution is not *about* the origin of life from non-biological precursors. It's about "change in the gene pool of a population over time" (got this from your link). Right?

Ob. Disclaimers: I am not a "creationist". I agree that "creationism" is nonsense. I agree that evolution should be taught in schools. I see no sense in "teaching creationism" in schools. Nor in slapping "only a theory" on evolution (everything in science is "only" a theory; typically, very strong ones, and evolution is one such). IMHO those who push "creationism" are misguided and reactionary at best. I just see no sense in overplaying your hand like this.