Richard Dawkins explains the flatfish's evolutionary history as:
"... bony fish as a rule have a marked tendency to be flattened in a vertical direction.... It was natural, therefore, that when the ancestors of [flatfish] took to the sea bottom, they should have lain on one side.... But this raised the problem that one eye was always looking down into the sand and was effectively useless. In evolution this problem was solved by the lower eye 'moving' round to the upper side."
Storyteller: Richard Dawkins in the Blind Watchmaker
Story Research: National Geographic Finds Opportunity to Conflate Intelligent Design with Creationism while Misreporting Fish Fossil
Flatfish Evolution revealed
Peer Reviewed Paper: Neo-Darwinism falsified
5 hours ago