notes-science-bio-evolutionOfHumans
potential reasons for bipedalism in humans:
http://en.wikipedia.org/wiki/Bipedalism#Evolution_of_human_bipedalism
theory that humans evolved to be especially good very long-distance runners, chasing a prey for days until it collapses from heat exhaustion; good sweat glands, and ability to track
theory that being in a wet environment is the best explanation for bipedalism, speech, loss of fur:
http://users.ugent.be/~mvaneech/Morgan.html
i once read an article that related, in a chain, opposable thumbs, large eye whites, and monogamy, but i forgot it