* Ectothermic animals rely on external sources of heat to regulate their body temperature. This means their body temperature fluctuates depending on the surrounding environment. They often bask in the sun to warm up or seek shade to cool down. Examples include reptiles, amphibians, fish, and insects.
* Endothermic animals generate their own body heat internally. They have a relatively stable internal temperature regardless of the external environment. This is achieved through metabolic processes and insulation like fur or feathers. Examples include mammals and birds.
Here's a table summarizing the key differences:
| Feature | Ectothermic Animals | Endothermic Animals |
|---------------|---------------------|---------------------|
| Body temperature | Variable, depends on environment | Relatively stable |
| Heat source | External (sun, environment) | Internal (metabolism) |
| Metabolic rate | Lower | Higher |
| Energy requirement | Lower | Higher |
| Examples | Reptiles, amphibians, fish, insects | Mammals, birds |
It's important to note:
* The terms "cold-blooded" and "warm-blooded" are outdated and misleading. Ectotherms are not necessarily "cold" and endotherms are not always "warm."
* There are some exceptions to these general classifications. For example, some fish and insects can maintain a relatively stable internal temperature.
* "Cold-blooded" and "warm-blooded" are still commonly used in casual conversation, but it's better to use the more accurate terms "ectothermic" and "endothermic."