So morality is a common set of values agreed to by a group and enforced on any who disagree by threat of punishment. Until that group changes or is compelled to change by a stronger group. Might makes Right. Majority Rules. Morality is a shifting sand without any absolutes. In other words morality is a fiction.
Those who believe in evolution should cooperate with the group only when it is to their advantage. To do otherwise is foolish.