What is the source for our morals?

[JuliaL]

Morals come about from the differential success of groups exhibiting those 'moral' behaviors.  The winners get to define moral behavior and they uniformly consider themselves as behaving correctly.  Clearly this had to be the case, it worked for them.

There are some unfortunate results of this:
One revolves around its short time horizon and bias towards individual success.
Homo Sap. has developed a useful brain appendage, our frontal lobes, whose function is to model our surroundings and make short term predictions as to probable future conditions.  It is good at predicting, say, the trajectory of a thrown rock and deciding which way to duck.  It is not so good at predicting more complex future events, say, the global effects of large scale burning of fossil fuels.  In groups and on extended time scales, we're simply more stupid.  Immediately after the oil shocks of the 1970s, we in the U.S. collectively believed ourselves acting optimally by ramping up coal production to burn it in electrical generation and in conversions to vehicular fuels.  If God exists, He has a nasty sense of humor.
I'm more inclined to believe that it isn't a divine joke. It's just that our (moral) communities cannot adequately predict future conditions.  This is  because our successes are always based on our insufficient ability to extrapolate from past events, the only ones available to us.

A second, related issue involves our inability to see morality from any perspective but our own.
This is a crippling blindness that limits investigation into alternative courses of action.
Slavery and oppression of women is currently considered 'bad' by many of us.
It was not always thus but we in the relatively liberal West cannot understand on a visceral level how that could be.  For us, it's just evil.
This causes conflict with those communities for whom the old ways, the ones that worked for our ancestors, are still true.

There are other selective pressures at less complex, individual, levels that lead to group success: sex is good, children are a good and should be protected.  But up at the level of 'morals,' the common factor is the short term prosperity of the societies which exhibit and define moral behavior, even if it eventually leads to biodiversity destruction, ecological collapse and the death of those moral communities.