GLOSSARY To return to the original page you were on, click on the defined word that brought you here.

Endothermy - an organism that relies primarily on metabolism as a source of body heat.

Eocene - in geological time, an epoch within the Cenozoic dating from 35 to 58 million years ago.

Homeothermic - an organism able to maintain a constant optimal range of body temperature despite fluctuation in the environment. Also referred to as warm-blooded.

Icthyosaur - a dolphin-sized aquatic reptile group that lived from Middle Triassic to the end of the Cretaceous.

Mitochondrial B-cytochrome - a protein found in mitochondria which is a genetic maternal trait.

Pleisiosaur - a large turtle-shaped aquatic reptile group that lived during the Late Triassic to the end of the Cretaceous.