</noinclude> <!-- c. Trilobite --> Trilobites are extinct arthropods that form the class Trilobita. They appeared in the 2nd Epoch (Series 2) of the Cambrian period and flourished throughout the lower Paleozoic era before beginning a drawn-out decline to extinction when, during the Late Devonian extinction, all trilobite orders, with the sole exception of Proetida, died out. [[File:Trilobite.jpg|thumb|200px|Trilobite]]
Catastrophism is the idea that Earth has been affected by sudden, short-lived, violent events that were sometimes worldwide in scope.
