This is an extremely interesting 32-minute lecture by Robert Sapolsky, who is a neurobiologist and baboonologist at Stanford, on how people differ from apes. In short, nearly everything we think of that is unique about us has come from ape precursers, but we just go off the deep end with it.
I leave him when he finds one area of actual uniqueness, which he frames in a Christian manner, the persistence of faith in the face of the impossible and the ability to simultaneously believe in contradictory things. Then he goes off the deep end himself, saying humans (which he seems to conflate with Christians, though I'm sure he doesn't really) believe in some stuff just because it is impossible, and that a moral imperative derives from it. If that's true, I suppose it is as biologically determined as religiosity, but I don't seem to have that allele.
I could believe there is a uniquely human ability to believe contradictory things (just as I could believe chimps do it, too), but I see no need to Christianize it or to derive a moral imperative from it. One day I'll post about where I think morals come from, but I deny any moral imperative from God, Kant, or the universe.
The lecture starts at 5:00 minutes. I came across it on Andrew Sullivan's blog.