History Of The Ordovician Period

The Ordovician Period, which is best known for its diverse marine invertebrates, began 488.3 million years ago and ended 443.7 million years ago. As mentioned, this period is famous for its variety of marine life but also for the major Cambrian-Ordovician extinction event and Ordovician-Silurian mass extinction which began and ended the Ordovician Period. These extinction occurred nearly 488 million years ago and 443 million years ago and eliminated many brachiopods, conodonts, and intensely lowered the number of trilobite species. Although there is not a lot of information on how these extinctions came to be, it may have had something to do with previous extinctions since they so closely preceded these.
In general, the climate of the Ordovician
Period was milder. The weather was warm and the atmosphere was typically full of moisture. Water covered most areas which was a big reason for this. The weather of this period allowed for the first primitive plants to begin to appear on land. At this time sea levels were rising above those of today. When Gondwana finally settled on the South Pole however, huge glaciers formed causing the shallow seas to drain and sea levels to drastically drop.
During the Ordovician Period, life was mainly in the sea. There was an abundant amount of diverse marine invertebrates. A typical marine community included most all the organisms flourising in the sea at this time. Mollusks, which are invertebrates of a large category that include snails, slugs, mussels, and octopuses, dominated this time period. Fish and corals were also very common.