During the Proterozoic era, oxygen produced by photosynthesizing ... While oxygen-loving organisms evolve in these changing conditions, oxygen-intolerant anaerobes survive only in airless pockets.

The Proterozoic Eon, spanning from 2,500 million to 539 ... reshape our understanding of early biodiversity. Eukaryotes, organisms with nuclei in their cells, are the ancestors of modern ...

Proterozoic Eon: Covers catastrophic global glaciations known as the Snowball Earth, the appearance of eukaryotes, as well as first plants and animals. It also tells about mysterious organisms ...