Definition

1. Adjective:
   • Describing animals (excluding birds and mammals) whose body temperature varies with the temperature of their surrounding environment. This means the animal's internal temperature is not internally regulated but instead changes to match the conditions outside its body.

Usage and Examples

• Adjective:
  • Reptiles, such as snakes and lizards, are classic examples of ectothermic animals.
  • Because they are ectothermic, the fish's activity level decreases significantly in colder water.
  • An ectothermic organism relies on external heat sources, like sunlight, to warm its body.

Advanced Usage

• Scientific Context: The term is used primarily in biology, zoology, and ecology to classify organisms and discuss their physiological adaptations.
  • The study compared the metabolic rates of ectothermic and endothermic species under varying climatic conditions.
• "Ectothermy" (noun): The condition of being ectothermic.
  • Ectothermy is a common survival strategy in many aquatic invertebrates.

Variants and Related Words

• Ectotherm (noun): An animal that is ectothermic.
  • The turtle is an ectotherm that basks on logs to regulate its temperature.
• Poikilothermic (adjective): A near-synonym often used interchangeably with "ectothermic," emphasizing variable body temperature.
• Cold-blooded (adjective): A common, non-scientific term for ectothermic. (Note: "Cold-blooded" is less precise as it does not necessarily mean the animal's blood is cold, but that its temperature depends on the environment.)

Synonyms

• Poikilothermic: Having a body temperature that varies with the environment.
• Cold-blooded: (Informal) Not maintaining a constant, high body temperature internally.

Antonyms

• Endothermic: (Adjective) Describing animals (birds and mammals) that generate internal heat to maintain a constant body temperature.
• Warm-blooded: (Informal) Maintaining a relatively constant and high body temperature independently of the environment.
• Homeothermic: Maintaining a constant body temperature.

Adjective

1. of animals except birds and mammals; having body temperature that varies with the environment