If all the world's a stage and all the species merely players, then their exits and entrances can be found in the rock record ...

The Proterozoic Eon is also called the Cryptozoic ("age of hidden life"). About 2.5 billion years ago, enough shield rock had formed to start recognizable geologic processes such as plate tectonics.

Proterozoic life was generally smaller and squishier -- like sea sponges that didn't develop mineral skeletons -- and left fewer traces to fossilize in the first place.

It is unclear why atmospheric oxygen remained trapped at low levels for more than 1.5 billion years following the Paleoproterozoic Great Oxidation Event. Here, we use models for erosion ...

Proterozoic Era (2,500-543 mya) During the Proterozoic era, oxygen produced by photosynthesizing bacteria collects in the oceans and then in the atmosphere.

1. Archean-Proterozoic. You should be able to: describe the differences between Archean and Proterozoic rocks, and what they tell us about changes in plate tectonic processes; use what you know about ...

Researchers have hypothesized that the mid-Proterozoic ocean may have lacked such large producers. Jochen J. Brocks and colleagues examined porphyrins, ...

Advanced tools and expanded fossil datasets have painted a clearer picture of the eukaryotic diversity of the Proterozoic eon, which has been hard to quantify. The findings show that Earth's ...

If Earth's history were a calendar year, humans would not appear until the last few minutes before midnight on Dec. 31. During the Proterozoic Eon—2.5 billion years to 543 million years ago ...

The paper shows that the Proterozoic climate was temperate until temperatures began to fall during the early Paleozoic, around 500 million years ago. This drop in temperature, ...