The Proterozoic eon was the gathering up of oxygen in Earth's atmosphere, and the Phanerozoic eon coincides with the major diversification of animals, plants, and fungi.

This is exemplified by the well-known mass extinction events and associated environmental perturbations during the Phanerozoic Eon (538 Ma – present day). The Proterozoic Eon also saw ...

Approximately between 1.8 and 0.8 billion years ago, in the mid-Proterozoic Eon, Earth's oceans contained virtually no animal life. A complex ecosystem requires sufficiently large primary ...