Ordovician

is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 million years ago to the start of the Silurian Period 443.8 Mya.

flora
the first terrestrial plants arose in Ordovician e.g moss and Psilophytopsida

animals
in Ordovician cephalopods began to dominate. see this article→ ordovician animals

and this is a list of the Cambrian animals that survived to Ordovician:


 * wiwaxia
 * trilobite

and this is a list of Cambrian animals that did not survive to Ordovician or evolved into other animals


 * myllokuminga
 * cambroraster
 * anomalocaris
 * opabina
 * pikaia
 * hallucigenia