re: How do we know...Earth wasn't colonized simply to provide entertainment?
As in Garden of the Gods??
Something up there is watching us (I think they call 'em the "Watchers") but they don't seem too anxious to intervene in our coming destruction. Mother Nature will inevitably shake the poisonous creatures off her planet and let the oceans cleanse her lands once again.
I don't buy the Bible's interpretation that Eve was spawned from Adam's rib. Without a woman, Adam wouldn't be here in the first place.
Unless there's a literal interpretation of some selective cloning going on from planet-faring "gods".......which is my guess.
Did they ever find the missing link?