ANIMALS

You are studying a large tropical reptile that has a high and relatively stable body temperature. How do you determine whether this animal is an endotherm or an ectotherm?

• You know from its high and stable body temperature that is must be an endotherm.

• You subject this reptile to various temperatures in the lab

  and find that its body temperature and metabolic rate

  change with the ambient temperature. You conclude that it

  is an ectotherm.

• 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.

• 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.

Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The _____ would have the highest total annual energy expenditure and the ___ would have the highest energy expenditure per unit mass.

• elephant; mouse

• elephant; human

• mouse; snake

• penguin; mouse

Which of the following would increase the rate of heat exchange between an animal and its environment?

• Feathers or fur

• Vasoconstriction

• Wind blowing across the body surface

• Countercurrent heat exchanger

An animal's inputs of energy and materials would exceed its outputs ____

• if the animal is an endotherm, which must always take in more energy because of its high metabolic rate.

• if it is actively foraging for food.

• if it is growing and increasing its mass.

• never; due to homeostasis, these energy and material budgets always balance.

Cite a biological process wherein

form, function, and behavior contribute to your body's homeostasis?