You are studying a large tropical reptile that has a high and relatively stable body temperature. How would you determine whether this animal is an endotherm or an ectotherm?
A) You know from its high and stable body temperature that it must be an endotherm.
B) You know that it is an ectotherm because it is not a bird or mammal.
C) You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate follow the ambient temperature. You conclude that it is an ectotherm.
D) You note that its environment has a high and stable temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm.
E) You measure the metabolic rate of the reptile, and because it is higher than that of a related species that lives in temperate forests, you conclude that this reptile is an endotherm and its relative is an ectotherm.

Question

Quizplus · Accepted Answer

By subjecting the reptile to various temperatures and observing that its body temperature and metabolic rate follow ambient temperature, we can conclude that it is an ectotherm. Endotherms generate their own heat, whereas ectotherms rely on external sources of heat to regulate their body temperature. A high and relatively stable body temperature is not conclusive evidence for endothermy, as some ectotherms, such as reptiles, can maintain their body temperature within a narrow range by basking in the sun or seeking shade. Option A is incorrect because a high and stable body temperature alone does not indicate endothermy. Option B is incorrect because not all birds and mammals are endothermic, and not all ectotherms are reptiles. Option D is incorrect because environmental temperature does not necessarily determine an animal's thermoregulation strategy. Option E is incorrect because comparing metabolic rates between species is not a reliable method for determining endothermy or ectothermy.

You Are Studying a Large Tropical Reptile That Has a High