WATER - First animals oxygenated the ocean

The evolution of the first animals may have oxygenated the earth's oceans -- contrary to the traditional view that a rise in oxygen triggered their development. New research contests the long held belief that oxygenation of the atmosphere and oceans was a pre-requisite for the evolution of complex life forms. The study builds on the recent work of scientists in Denmark who found that sponges -- the first animals to evolve -- require only small am ...

http://www.sciencedaily.com/releases/2014/03/140309150540.ht