Morality as a result of biological evolution is a decent enough hypothesis, as long as you stipulate that the universe created itself. Now, if GOD really said, “Let there be light,” that would be the Big Bang. It happened a LOOOOOOONG time ago, 13.78 billion years or so, but either GOD did that or there isn’t a GOD.
So if GOD exists, then listen to Him define morality. Also pay close attention; being GOD, he has earned that right as your Maker.
And if not, then morality is just a construct with interesting properties.