Controlling the body temperature is how chordates maintain homeostasis. This allows animals to survive a habitat wherein the temperature varies from time to time.

Ectotherms (Ecto- means outside) regulate heat externally by losing or gaining to/from the environment and have a lower metabolic rate, while endotherms (endo- means inside) maintain heat internally in the body and have higher metabolic rate.

Maintenance of body temperature is vital as it is necessary for creating balance in homeostasis. A well-maintained body temperature can help the body to perform necessary processes and chemical reactions.

The three features are the source of heat, the organs to maintain and manipulate the heat, and structures to remove excess heat. These are very important functions organisms must have to survive.

See explanation.

**Endotherms** are animal species whose body temperature can be controlled and regulated internally. Examples are mammals and birds.

Because endotherms have various bodily processes and functions that generate a significant amount of heat needed by their body, they too have a relatively high metabolic rate even during their rest. In this regard, these organisms need a lot of energy-rich food like carbohydrates in order to keep up with the demand of their metabolism.

Lizard species are classified as **ectotherms**, meaning they rely on their environment for the maintenance of their body heat. They have a relatively low metabolic rate, thus their body does not generate enough heat for homeostasis.

The average climate of North Dakota during winter is very cold and thus, lizards won’t be able to survive in such an environment. Therefore, it would be very rare to none at all to find a giant lizard in North Dakota.