First there was Adam. Then there was Eve. Then Eve broke the one rule and doomed all of humanity (yes, both of them!) for her transgression (well, once the omnipresent and omniscient God realized what had happened, which he deduced because they were trying to hide their nakedness rather than seeing it coming before he even created humanity because that’s how omniscience is supposed to work, or watching her talk to the serpent, eat the apple, and then offer one to Adam, which is how omnipresence is supposed to work) and we got kicked out of paradise into a place that sounds similar (as in it still has the animals and the plants and all that) but isn’t paradise. Then Adam and Eve had two sons, Cain and Able. Then Cain killed Able and was exiled for it. So technically there’s three people, all related, though only two of them have contact with one another.

Anyways, some time passes and all the people are wicked (possibly due to being so inbred), so obviously God wants to kill them, but there’s one dude that is ok, so he’s tasked with building a giant boat and filling it with just two of every single animal in existence (sorry animals, but the people (other than Noah and presumably his family, or maybe they get a pass because of how great Noah is) are wicked and God doesn’t want to do a high precision genocide). Then after he somehow succeeds in this task (nevermind different geographic areas, including ones Noah has no idea even existed, having completely different animals or local variants of the same animals), humanity and the entire animal kingdom are now back to square one for genetic diversity.

But for some reason people today are more worried about nuclear weapons that can potentially destroy the planet than people in the Bible were worried about angering an active and interactive God who would occasionally brutally and spectacularly demonstrate his power in a fit of rage. But I’m starting to digress from the genetic diversity topic.