38. Animal Form and Function

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?

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.)