What provides the moral for humanity's standard is evolution. Notice I said provides a standard, not a absolute.
They way I see it working is that "right" choices means survival for the species. Those that survive pass down through culture and genetics those correct choices. Those choices wrong enough to cause early demise don't get passed down. Over time, the human brain gets wired via culture and genetics to feel certain choices are correct and other choices are wrong. So we get an inherent feeling for what is right and what is wrong.
Now this is far from perfect since that only requirement is that it only requires it to be correct enough to allow survival until one is able to procreate.
In the past, these feeling of right and wrong get encoded into various religions. However not all religious morality comes from this evolutionary process. Individuals get inspired by whatever experiences they have and add to this religious moral code. Both ideas which are successful to survival and ideas which are not overly detrimental to survival get passed down to future generations.
There is a fairly wide range of what we as a species find as morally acceptable since as long as an idea is not overly detrimental to the survival of the species, it gets passed on.
I see my morals as partly evolved, partly inspired by my life experiences. Some even passed on to me by other people's concepts of God however there was no need for an actual God to declare absolute moral law.