ectotherms

Ectotherms are organisms whose body temperature is predominantly determined by external heat sources. They rely on environmental heat and behavioral strategies to regulate body temperature, rather than producing large amounts of metabolic heat internally. Ectotherms are widespread across many taxa and include most invertebrates (such as insects, mollusks, and crustaceans) as well as fish, amphibians, and reptiles.

Because their metabolic rate is temperature dependent, ectotherms generally show slower activity in cool environments and higher activity in warm conditions. They regulate heat mainly by behavior: basking in the sun to warm up, seeking shade or burrows to cool down, changing activity times, or moving to microhabitats with favorable temperatures.

Reproduction and development are often temperature sensitive. In many reptiles and some amphibians, incubation temperature influences growth rate and, in some species, the sex of offspring. Ectotherms may lay eggs or give birth to live young, depending on the species.

Ecology and distribution: Ectotherms inhabit a broad range of environments, from deserts and forests to freshwater and marine systems. Their geographic ranges and seasonal activity patterns are closely tied to ambient temperatures and water availability, making them particularly vulnerable to temperature extremes and climate change.

Evolution and conservation: Ectothermy represents an energy-efficient strategy in resource-limited or variable environments, trading constant body heat for flexible metabolism and lower energy requirements. Many ectotherm populations face habitat loss, pollution, and shifting climates, highlighting the importance of temperature and habitat protection for their survival.