1. 33.2 Controlling Body Temperature

2. Ectotherm Animal that relies on interactions with the environment to help it control body temperature.

3. Endotherm Animal that generates its own body heat and controls its body temperature from within.

4. Key Concept The control of body temperature is important for maintaining homeostasis in vertebrates, particularly in habitats where temperature varies widely with time of day and with season.

5. Key Concept Most reptiles, fishes, and amphibians are ectotherms animals whose body temperatures are controlled primarily by picking up heat from, or losing heat to, their environment.