Hey, steamin'...I did not say it was the cause of ALL life on Earth! I said it might have played some part in affecting life on Earth in various ways...by seeding some new species here...by introducing genetic changes to some organisms here...etc.

I agree that Noah and the Ark is not a believable story...if taken literally. If, however, it is an exaggerated legend based upon some real incident(s) of great floods and of survivors in the remote past...and Noah is a simplified and much embellished symbolic version of what really happened, a version that the Israelites came up with in order to put themselves at the center of the story...then it is, like many other legends, based on something that really occurred in the past, but was then turned into a story that was culturally adapted to suit the ideas of some people at a later time.

That sort of thing has happened over and over again. People shape a story to fit their own cultural viewpoint and their own social concerns.