This question has been bothering in the past few days. If all of us were born, or our species has pressed on based on our fitness, than where do moral take play? For example, lets say me and you were in a hunter-gathering tribe and we are in a location with no other animals. (perhaps by biotic factors) Because there are no other animals present for food, one of us will eat each other. If our goal in life is to live and evolution takes play, than me or you, depending on who is more fit, will die.
Natural selection still plays but when did we say it was wrong of us to kill each other? How can we live in peace without morals?