During the Proterozoic era, oxygen produced by photosynthesizing ... Iron present in exposed rocks reacts with this oxygen, and rust colors the planet red. While oxygen-loving organisms evolve ...

The Proterozoic Eon, spanning from 2,500 million ... These ice ages, occurring between 720 and 635 million years ago, encased the planet in ice and drastically altered global ecosystems.

Earth surface processes in the Hadean and Archaean differ from those of the Proterozoic and, increasingly, the Phanerozoic. This occurs largely because of the impact of life on its environment, ...

Virginia Tech study unveils 2 billion years of evolution, highlighting the 'boring billion,' Snowball Earth, and ancient marine life.