"I knew you were going to say that"
You know me pretty well, Aurino. :)
"The thing is, either you believe morality has an evolutionary basis or you believe it comes from God. In either case you must realize that some form of morality is at the core of any creature's behaviour."
I would say that morality is a side effect of society. Not totally, as there is some need for individual morality, but individual morality is an artifact of more intelligent species in my opinion. So, let's stick with societal morality. Any kind of moral code a dividing strand of DNA in a pool has is so far from morality as we think of it that it might as well not exist. The first organisms could only learn through trial and error, so trials that result in error are bad, trials that result in sucess are good. These organsisms had absolutely no knowledge of others' presences, very little conscious awareness, no method of communication with each other, so I would say that any concept of morality they had is so far and away from the typical definition of morality that we only say it exists for the sake of argument. Sure, that first life contained the code that eventually led to Puritans, but for the sake of this discussion I'd say "Single-Cells: No Morality."
Now, when society becomes a neccesary survival trait, morality is used for the society to function. I think apatosaurs moved in herds to defend themselves jointly from predators. So, if one apatosaur said to himself "Screw this, I'm gonna kill 'em all" and started attacking his own herd, the integral morality to that society would kick into gear and the herd would fend of or kill the transgressor.
When society becomes neccesary for survival, some kind of adhesive is needed for that sociey's, and therefore that species' survival. That adhesive is morality.
"If you think "thou shalt not kill" is not essentially the same thing as "help your own species thrive", I'd suggest you think again."
Of course they're the same. The ten commandments is just moving morality from an institutional structure (law) to a universal one (God.) It's a more effecient means of transmitting your message, saying "God says so" has worked many times throughout time. :)