Biology / Unit 12 Bio 2729 short lesson, about 20 seconds
Endotherms and Ectotherms
Captions available
The idea
An endotherm generates and conserves its own body heat to stay relatively constant regardless of environment; an ectotherm's temperature instead tracks the environment.
In practice
A polar bear's fur and fat maintain a warm core in freezing water; a lizard's temperature rises and falls with the sun.
Where people slip
"Cold-blooded" is loose shorthand — a desert ectotherm can run warm despite tracking its environment.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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