AP BIOLOGY

Detailed explanation-1: -Ectotherms depend mainly on external heat sources, and their body temperature changes with the temperature of the environment. Animals exchange heat with their environment through radiation, conduction-sometimes aided by convection-and evaporation.

Detailed explanation-2: -Ectotherms rely largely on external heat sources such as sunlight to achieve their optimal body temperature for various bodily activities. Accordingly, they depend on ambient conditions to reach operational body temperatures.

Detailed explanation-3: -Despite most ectotherms exhibit behavioural plasticity that allows them to adjust their body temperature to environmental conditions, rising temperatures can put ectotherms outside their physiological optima and closer, or even above, their thermal tolerance limits (Kingsolver et al., 2013; Sunday et al., 2014).

Detailed explanation-4: -In contrast, ectotherms rely on behavior to regulate their body temperature. They must move their bodies into the shade or sun to cool down or warm up. This requires less energy than constant metabolic regulation. This is why many reptiles and other ectotherms can eat one large meal and not eat again for some time.

Detailed explanation-5: -Endotherms regulate their own internal body temperature, regardless of fluctuating external temperatures, while ectotherms rely on the external environment to regulate their internal body temperature.