What are Some Ordovician Organisms?
Ordovician organisms lived during the Ordovician period, which lasted between approximately 488.3 to 443.7 million years ago. It began with a mass extinction called the Cambrian-Ordovician extinction events, which wiped out 50% of all multicellular organisms in the fossil record. At the time, all known multicellular organisms were exclusively marine. The number of known fossils from the Ordovician numbers about 500, substantially more than the 200 or so available from the Cambrian before it. The Ordovician period featured episodes of adaptive radiation and diversification only exceeded by the so-called Cambrian explosion, which occurred about 60 million years earlier. The end-Cambrian mass extinctions seriously impacted brachiopods (a stationary shelled organism superficially resembling bivalves), trilobites (which were never the same again), and early jawless fishes called conodonts. During the Ordovician, other animals, such as articulate brachiopods, cephalopods (sophisticated mollu
