38. Animal Form and Function

Which of the following is a description of a behavior that helps warm the body?

During a fever, the __________ readjusts the set point of the body to a __________ temperature.

Sweating __________.

In the late fall, bats hibernate in clusters with many bats pressed together and holding on to one another. Which of the following statements does not represent an advantage of this behavior?

On a cold day, blood vessels in the skin __________.

By definition, an ectotherm __________.

The term endotherm refers specifically to __________.

Which statement is true regarding thermoregulation?

The wolf, his coat glowing in the early spring sunshine, sat atop a cold boulder after unsuccessfully pursuing a plump jackrabbit. He continued to pant while __________.

It is a cold day in the lecture hall. When you rest your arm on the cool laminated desktop at your seat, heat is transferred __________.

Which of the following statements is true?

What do host cells provide for viruses? a. ATP b. nucleotides and amino acids c. ribosomes d. all of the above

Which of the following would increase the rate of heat exchange between an animal and its environment? a. feathers or fur b. vasoconstriction c. wind blowing across the body surface d.countercurrent heat exchanger

Which of the following is not an adaptation for reducing the rate of heat loss to the environment? a. feathers or fur b. increasing blood flow to surface blood vessels c. huddling behavior of penguins d. countercurrent heat exchange

Which of the following is an advantage that ectotherms have over endotherms of the same size? a. They require much less food. b. They are less vulnerable to predation during cold weather. c. They can remain active in cold weather or on cold nights. d. They have higher metabolic rates and grow more quickly.

The outer surface of a virion consists of either a membranous envelope or a protein capsid. How does the outer surface correlate with a virus's mode of exiting a host cell?

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? a. You know from its high and stable body temperature that it must be an endotherm. b. 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. c. 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. d. 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.

The metabolic rate of a frog in summer (at 35°C) is about eight times higher than in winter (at 5°C). Compare and contrast the frog's ability to move, exchange gases, and digest food at the two temperatures. During which season will the frog require more food energy, and why?

Explain why most endotherms are homeothermic and most ectotherms are poikilothermic.

Consider three spheres with radii of 1 cm, 5 cm, and 10 cm. Calculate the surface area and the volume of each sphere, and plot the results on a graph with radius on the x-axis and surface area and volume on the y-axis. (Surface area of a sphere = 4πr2; volume of a sphere = (4/3)πr3.) Explain how the graph shows the relationship between size and surface area to volume ratio.

If you were in charge of the government's budget devoted to stemming the AIDS epidemic, would you devote most of the resources to drug development or preventive medicine? Defend your answer.

Explain why it would be impossible for a gorilla the size of King Kong to have fur. (Your answer should explain how the surface area to volume ratio of a normal-sized gorilla would compare to Kong's; relate this to the role of surface area and volume in heat generation and heat transfer, and consider the function of fur.)

The dinosaur Apatosaurus (Brontosaurus) is one of the largest terrestrial animals that ever lived—over 20 m in length and weighing over 20 metric tons. Is it more likely that Apatosaurus was homeothermic or poikilothermic? Explain.

The mosquito-borne Zika virus (ZIKV) is one of the most feared viruses for pregnant women. Recent statistics justify this fear: Infants born to mothers infected with ZIKV during pregnancy face a risk of up to 42 percent of developing birth defects, including microcephaly (an abnormally small head and decreased brain volume). What do we know about how ZIKV causes damage to the developing brain? ZIKV is a Baltimore class IV virus. Based on this classification, what do you know about the structure of its genome?

After a long, hot run together, your friend tells you that you should dunk your head into a cooler of water to lower your body temperature more rapidly, rather than sitting and waiting to cool down. What do you think? Form a hypothesis about how the ice-cold water might affect the rate at which your body temperature returns to normal. How could you test your hypothesis?

You are in a room of empty chairs. As the chairs fill with people, you become hotter and hotter. A ceiling fan is turned on, and you feel cooler. You gained heat by _________ and lost heat to the environment by _________ . a. conduction … convection b. radiation … convection c. radiation … conduction d. convection … radiation

Can ectotherms have stable body temperatures? Explain.

Some diuretics are on a list of substances that the International Olympic Committee has banned for use by athletes. What do diuretics do? Propose an explanation for how diuretic use could be an unfair advantage for a competitor in a sport like wrestling, in which weight classes are part of the competition.

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?

Dolphins have an insulating layer of blubber that protects them from cold water, but their flippers are not insulated. Propose a hypothesis to explain why dolphin flippers do not freeze. Describe an experiment you could do to test your hypothesis. (You may assume you have equipment for measuring temperatures in dolphin flippers.) What results would you expect if your hypothesis is correct?

In 1847, the German biologist Christian Bergmann noted that mammals and birds living at higher latitudes (farther from the equator) are on average larger and bulkier than related species living at lower latitudes. Suggest an evolutionary hypothesis to explain this observation.