You are using an allegory in which a flood of water corresponds to something that I cannot be bothered to learn going on with Noah's nervous system, which in turn is some part of the story of man's evolution.
OH...
I assumed you were referring to our present discussion of the genealogy and the one-to-one corrspondence with the paleontology reported in the latest book on that subject.
In regard to the Flood story, I am reasoning that the Bible writer would have had no other alternative in telling the actual story we know that follows after the 22 evolutions but to use metaphor.
They woulkd have had to "liken" the population explosion Out-of-Africa to a virtual Flood of peoplke who after a total extinction of Neanderthal man would have populated the whole earth up to the mountain tops.
That the metaphor itself was an impossible report on the face of it, such an interpretation is warranted since it parallels the actual events.
This view that the Flood was metaphor was also used by the scientist who discovered the we are all related to just one man who lived 40,000 years ago when Modern man actually did migrate around the world, Out-of-Africa:
SCIENCE:
Christopher Stringer and Peter Andrews proposes that modern humans evolved from archaic Homo sapiens 200,000-150,000 years ago only in Africa and then some of them migrated into the rest of the Old World replacing all of the Neanderthals and other late archaic Homo sapiens beginning around 100,000 years ago.
If this interpretation of the fossil record is correct, all people today share a relatively modern African ancestry. All other lines of humans that had descended from Homo erectus presumably became extinct.
From this view, the regional anatomical differences that we see among humans today are recent developments--evolving mostly in the last 40,000 years.