Creation and the Consequence of Satan's Fall

The Gap Theory shows evidence of the dinosaurs becoming extinct as the result of Satans fall and explores the origin of demons as being disembodied spirits of a pre-Adamic race, who were judged by God, as the result of Satans sin.Why was man commissioned by God in Genesis 1:28 to replenish the earth? Why did God use that word? Could this be a reference to a pre-Adamic race that was created in Genesis 1:1 and destroyed in Genesis 1:2 due to Satans fall, and which the human was to replace or replenish? Read where angels that sinned left their heavenly habitation and came down to earth to procreate with humans and whose children were called Mighty men, which were of old, men of renown, offspring that are the source of all the ancient secular myths that claim the gods came down to earth and married human women.