Cambrian

/ˈkæmbriən/

Other forms: Cambrians

The Cambrian is the first period of the Paleozoic era, spanning from 541 to 485 million years ago. It started with the "Cambrian Explosion," when most major groups of complex animals first appear in the fossil record.

During the Cambrian, life diversified dramatically, with many organisms evolving greater complexity, mobility, and features like shells, skeletons, and teeth. The Cambrian saw the rise of animals such as trilobites, early marine arthropods with three-part exoskeletons; some of the earliest ancestors of vertebrates; and large predators, like Anomalocaris, a three-foot-long, shrimp-like hunter with circular teeth. Because many Cambrian animals developed hard parts, they left behind a rich fossil record that provides key insights into early animal evolution.

Definitions of Cambrian

1. adjective

   of or relating to or characteristic of Wales or its people or their language
   synonyms: Welsh
2. noun

   a native or resident of Wales
   synonyms: Cymry, Welsh, Welshman

   type of:

   European

   a native or inhabitant of Europe
3. adjective

   relating to or denoting the period from about 541 to 485 million years ago
4. noun

   the period of geologic time from about 541 to 485 million years ago; the first period of the Paleozoic era
   synonyms: Cambrian period

   example of:

   geological period, period

   a unit of geological time during which a system of rocks formed