At the time of Adam and Eve, the human brain and mind had evolved to where the human brain/mind began to supersede genetics in terms of human evolution. Adam and Eve are symbolic of that change as the human mind went over the hump into free will.
An example of this is, if you are cold, you can put on clothes to keep yourself warm. We do not have to wait for the DNA, evolution and selective advantage to give humans fur. That could take thousands of years. The brain can leave the slow boat of biological evolution and make changes in real time, such as using clothing, to provide selective advantages. This is called free will. Animals are still under the DNA, as the primary of their evolution and instincts, since their brains are not able to constantly leave the cycle of evolution and alter its path via willpower.
The mythology of religions was a natural part of this change. Since mythology is not in touch with the cause and effect of nature, as science points out, mythology allowed the human mind to more easily leave the DNA, evolution and instincts. The DNA, evolution and instincts are in touch with the cause and effects of nature via our sensory systems. Mythology allowed the brain to leave the natural path toward pathes connected to alternate reality. These were places where the natural instincts could not follow, naturally, since it was not sensory in nature.
The instincts and the DNA will continue to pull the other way, via physical sensory cause and effect, with the DNA and evolution still slowly working toward its natural future. But the mind is pulling in its own way, trying to figure out how to resolve the constant internal conflict between these two opposing directions (free will/mythology and science/DNA). That is religion in a nutshell.
I can use will power to burn the candle at both ends (party all the time), due to an Epicurian abstraction. This choice will not be in harmony with natural instinct and the genetic limits of my body. My body can get run down, internal organs can suffer, and I might become sick. I will need to find a better balance, since the DNA and body is not design for this amount ofo free will partying. Also, I can not wait thousands of years for the slow boat of the DNA to arrive with the needed physical improvements to give me party selective advantage. Religion tries to strike the balance between God (free will) and the real time DNA, with the mythology keeping the alterate path always open (where DNA can not go).