The age of innocence = when humans lived contently as animals amidst animals, in paradise = nature.
The apple = some form of a psychedelic plant, most likely psilocybin mushrooms, that held within the "knowledge of God".
Evolution through psychedelics = glossolalia + synesthesia = language (The Stoned Ape-hypothesis by Terence McKenna).
Result = separation from other animals and ultimately even nature = the fall of man.