The period of Earth's history that began 2.5 billion years ago and ended 543 million years ago is known as the Proterozoic. Many of the most exciting events in the history of the Earth and of life occurred during the Proterozoic -- stable continents first appeared and began to accrete, a long process taking about a billion years. Also coming from this time are the first abundant fossils of living organisms, mostly bacteria and archaeans, but by about 1.8 billion years ago eukaryotic cells appear as fossils too.
With the beginning of the Middle Proterozoic comes the first evidence of oxygen build-up in the atmosphere. This global catastrophe spelled doom for many bacterial groups, but made possible the explosion of eukaryotic forms. These include multicellular algae, and toward the end of the Proterozoic, the first animals.
Click on the buttons below to learn more about the Proterozoic.
The chart at left shows the three major subdivisions of the Proterozoic Era. These divisions are somewhat arbitrary, and we have not attempted to prepare exhibits on each of them. We do have a nice exhibit on the Vendian, the last portion of the Neoproterozoic.
Visit Joe Meert's Paleomagnetism Home Page for the latest information on Precambrian continent reconstructions. Caltech Paleomagnetics Laboratory presents a summary of research into Neoproterozoic paleogeography.
Read about the Llano uplift in central Texas, which is also of Proterozoic age.
Find out more about the Precambrian paleontology and geology of North America at the Paleontology Portal.