Von Ur-Ozean und Snowball-Earth

Primal Ocean and Snowball Earth

Did the primal ocean originally cover the entire planet? What happened to organic life during and after the great ice age, which is sometimes called the "snowball earth"? How did the diverse species develop which, like in the Garden of Eden, originally coexisted in the depths of the ocean? And finally: How did the principle of "eat and be eaten" come about as a result of this?