The Ordovician period, which lasted from about 485 to 444 million years ago, is a significant era in Earth's history, marked by a rich diversity of marine life and notable mass extinction events.

These first steps toward life on land were cut short by the freezing conditions that gripped the planet toward the end of the Ordovician. This resulted in the second largest mass extinction of all ...

although it’s unclear if whether that amounts to a sixth mass extinction. The Ordovician-Silurian mass extinction event may have wiped out some 85 percent of species, including many of the ...

Ordovician-Silurian Extinction (about 443 million years ago): Around 85% of species went extinct, likely due to a combination of a drop in sea levels and glaciation, followed by rising sea levels ...

although it’s unclear if whether that amounts to a sixth mass extinction. The Ordovician-Silurian mass extinction event may have wiped out some 85 percent of species, including many of the ...