Learn more about a time period marked by an intense burst of evolution. 3 min read The Cambrian period, part of the Paleozoic era, produced the most intense burst of evolution ever known.

This animation created for Evolution: "Great Transformations" depicts creatures whose fossils were found at the Burgess Shale. As alien as these creatures seem, they are also surprisingly familiar.

There is considerable geological evidence for an extensive glaciation some 600 million years ago. Its end caused an alteration of climate that made possible the proliferation of animal life in ...

Since soon after our planet formed, Earth's 4.6 billion-year-long history was dominated by single-celled life. Something ...