This whole Alpha/Beta/Omega thing -- what's up with it?

A while back, I noticed these stories start appearing. I've tried looking it up on google to find out where it came from, but I always end up just either ending up at places with fic recs or with people talking about the 'alpha, beta, omega' psych profile types which is...entirely different.

The way that it's spread all over the place makes me think it came from something that was very widely-read or watched but, like I said, I haven't had any luck finding the origin.