The writers of Genesis might have been on to something, but their science-deficient brains could not imagine two ancient microscopic organisms 'getting together.' Thus the myth of Adam and Eve and all of the other hogwash therein.
Two prokaryotes got together and here we are. Not only we animals but those mutant cousins, the plants. ScienceDaily explains:
Lake has discovered the first exclusively prokaryote endosymbiosis.
And the rest, as they say, is history. In fact about 2.5 billion years. Our microscopic Adam and Eve kept on 'doing it' for billions of years and, abracadabra, here I am writing about our collective genealogy and our plant cousins, once-removed.