Chapter 40

Most land-dwelling invertebrates and all of the amphibians _____. A) are ectothermic organisms with variable body temperatures B) alter their metabolic rates to maintain a constant body temperature of 37°C C) are endotherms but become thermoconformers when they are in water D) become more active when environmental temperatures drop below 15°C

A) are ectothermic organisms with variable body temperatures

You discover a new species of bacteria that grows in aquatic environments with high salt levels. While studying these bacteria, you note that their internal environment is similar to the salt concentrations in their surroundings. You also discover that the internal salt concentrations of the bacteria change as the salt concentration in their environment changes. The new species can tolerate small changes in this way, but dies from large changes because it has no mechanism for altering its own internal salt levels. What type of homeostatic mechanism is this species using to regulate its internal salt levels? A) conformation B) regulation C) integration D) assimilation

A) conformation

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. A) elephant; mouse B) elephant; human C) human; penguin D) mouse; snake

A) elephant; mouse

A woman standing and watching the stars on a cool, calm night will lose most of her body heat by _____. A) radiation B) convection C) conduction D) evaporation

A) radiation

An example of an ectothermic organism that has few or no behavioral options when it comes to its ability to adjust its body temperature is a _____. A) sea star living deep in the ocean B) bass living in a farm pond C) hummingbird flying through a prairie D) honeybee in a hive on a rural farm

A) sea star living deep in the ocean

) Examine the figure above. Near a goose's abdomen, the countercurrent arrangement of the arterial and venous blood vessels causes the _____. A) temperature difference between the contents of the two sets of vessels to be minimized B) venous blood to be as cold near the abdomen as it is near the feet C) blood in the feet to be as warm as the blood in the abdomen D) loss of the maximum possible amount of heat to the environment

A) temperature difference between the contents of the two sets of vessels to be minimized

The temperature-regulating center of vertebrate animals is located in the _____. A) thyroid gland B) hypothalamus C) subcutaneous layer of the skin D) liver

B) hypothalamus

An example of a properly functioning homeostatic control system is seen when _____. A) the core body temperature of a runner rises gradually from 37°C to 45°C B) the kidneys excrete salt into the urine when dietary salt levels rise C) a blood cell shrinks when placed in a solution of salt and water D) the blood pressure increases in response to an increase in blood volume

B) the kidneys excrete salt into the urine when dietary salt levels rise

Positive feedback differs from negative feedback in that _____. A) positive feedback benefits the organism, whereas negative feedback is detrimental B) the positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite of it C) the effector's response increases some parameter (such as body temperature), whereas in negative feedback it can only decrease the parameter D) positive feedback systems have only effectors, whereas negative feedback systems have only receptors

B) the positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite of it

Hummingbirds are small birds that require a regular food supply. When hummingbirds are faced with a situation that decreases their food supply, such as a storm, which of the following adaptations would be most useful for the bird to survive such an unpredictable and short-term absence of food resources? A) shivering B) torpor C) hibernation D) burrowing into soil

B) torpor

Organisms maintain dynamic homeostasis (internal balance) through behavioral and physiological mechanisms. Which of the following statements is an accurate explanation of a negative feedback mechanism used by animals to regulate body temperature? A) Squirrels are able to cool themselves during warmer months by producing more brown fat, which contains abundant mitochondria and a rich blood supply. B) Desert jackrabbits have unusually large ears that serve as solar heat collectors to enable them to maintain their body temperatures. C) A ground squirrel's hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production. D) A goldfish slows its movements when the water temperature is lower.

C) A ground squirrel's hypothalamus detects changes in environmental temperatures and responds by activating or suppressing metabolic heat production.

Which principle of heat exchange is the most important explanation for why birds look larger in colder weather because they fluff their feathers? A) Fluffing feathers results in less cooling by radiation because feathers emit less infrared radiation than other tissues do. B) Fluffing decreases the amount of heat lost by conduction when the bird makes contact with cold objects in its environment. C) Fluffing creates a pocket of air near the bird that acts as insulation. D) Fluffing decreases the surface-area-to-volume ratio, thus decreasing the amount of heat lost to the environment.

C) Fluffing creates a pocket of air near the bird that acts as insulation.

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 change with 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

C) 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.

Chum salmon (Oncorhynchus keta) are born in freshwater environments and then migrate to the sea. Near the end of their lives, they return to the freshwater stream where they were born to spawn. In freshwater, water constantly diffuses into the body and ions are lost from the body. In salt water, body water diffuses out of the body and excess ions are gained from the water. A salmon's gills have special cells to pump salt in or out of the body to maintain homeostasis. In response to the salmon's moves between freshwater and salt water, some cells in the gills are produced and others are destroyed. These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following? A) evolution B) trade-off C) acclimatization D) adaptation

C) acclimatization

The body's automatic tendency to maintain a constant and optimal internal environment is termed _____. A) balanced equilibrium B) physiological chance C) homeostasis D) static equilibrium

C) homeostasis

In a cool environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm _____. A) maintains a higher basal metabolic rate B) expends more energy per kilogram of body mass than does the endotherm C) invests little energy in temperature regulation D) has greater insulation on its body surface

C) invests little energy in temperature regulation

The metabolic breakdown of specialized brown fat depots in certain animals is substantially increased during _____. A) acclimatization B) torpor C) nonshivering thermogenesis D) shivering thermogenesis

C) nonshivering thermogenesis

To prepare flight muscles for use on a cool morning, hawkmoths _____. A) relax the muscles completely until after they launch themselves into the air B) decrease their standard metabolic rate C) rapidly contract and relax these muscles to generate metabolic warmth D) reduce the metabolic rate of the muscles to rest them before flight

C) rapidly contract and relax these muscles to generate metabolic warmth

The thin horizontal arrows in the figure above show that the _____. A) warmer arterial blood can bypass the legs as needed, when the legs are too cold to function well B) warmer venous blood transfers heat to the cooler arterial blood C) warmer arterial blood transfers heat to the cooler venous blood D) arterial blood is always cooler in the abdomen, compared to the temperature of the venous blood in the feet of the goose

C) warmer arterial blood transfers heat to the cooler venous blood

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) blubber or fat layer

C) wind blowing across the body surface

A researcher is setting up an experiment to measure basal metabolic rate in prairie voles (Microtus ochrogaster-a small rodent). Which of the following would be the best set of conditions for the voles immediately before and during the measurement? A) House the animals in a cage with plenty of food and water to avoid stress; conduct measurements in a warmer room than the room where housed. B) House the animals in a cage with plenty of food and water to avoid stress; conduct measurements in a room the same temperature as the room where housed. C) House the animals in a cage with no food for a few hours before measurement; conduct measurements in a colder room than the room where housed, and exercise the voles. D) House the animals in a cage with no food for a few hours before measurement; conduct measurements in a room the same temperature as the room where housed.

D) House the animals in a cage with no food for a few hours before measurement; conduct measurements in a room the same temperature as the room where housed.

Which of the following is an example of negative feedback? A) During birthing contractions, oxytocin (a hormone) is released and acts to stimulate further contractions. B) When a baby is nursing, suckling leads to the production of more milk and a subsequent increase in the secretion of prolactin (a hormone that stimulates lactation). C) After a blood vessel is damaged, signals are released by the damaged tissues that activate platelets in the blood. These activated platelets release chemicals that activate more platelets. D) When the level of glucose in the blood increases, the pancreas produces and releases the hormone insulin. Insulin acts to decrease blood glucose. As blood glucose decreases, the rate of production and release of insulin decreases as blood glucose decreases.

D) When the level of glucose in the blood increases, the pancreas produces and releases the hormone insulin. Insulin acts to decrease blood glucose. As blood glucose decreases, the rate of production and release of insulin decreases as blood glucose decreases.

Which of the following animals most likely uses the largest percentage of its energy budget for homeostatic regulation? A) a marine jelly (an invertebrate) living deep in the ocean B) a snake in a tropical forest C) a shark swimming in the open ocean D) a bird living year round in a desert

D) a bird living year round in a desert

Standard metabolic rate (SMR) and basal metabolic rate (BMR) are _____. A) used differently: SMR is measured during exercise, whereas BMR is measured at rest B) used to compare metabolic rates during feeding and other active conditions C) both measured across a wide range of temperatures for a given species D) both measured in animals in a resting and fasting state

D) both measured in animals in a resting and fasting state

There are advantages and disadvantages to adaptations. Animals that are endothermic are likely to be at the greatest disadvantage in _____. A) very cold environments B) very hot environments C) environments with a constant food source D) environments with variable and limited food sources

D) environments with variable and limited food sources

Sweating allows a person to lose heat through the process of _____. A) conduction B) convection C) radiation D) evaporation

D) evaporation

The panting responses that are observed in overheated birds and mammals dissipate excess heat by _____. A) countercurrent exchange B) acclimation C) vasoconstriction D) evaporation

D) evaporation

An animal's inputs of energy and materials would exceed its outputs if _____. A) the animal is an endotherm, which must always take in more energy because of its high metabolic rate B) it is actively foraging for food C) it is hibernating D) it is growing and increasing its mass

D) it is growing and increasing its mass

Snake behavior in Wisconsin changes throughout the year. For example, a snake is _____. A) less active in winter because the food supply is decreased B) less active in winter because it does not need to avoid predators C) more active in summer because that is the period for mating D) more active in summer because it can gain body heat by conduction

D) more active in summer because it can gain body heat by conduction

A moth preparing for flight on a cold morning may warm its flight muscles via _____. A) acclimatization B) torpor C) evaporative cooling D) shivering thermogenesis

D) shivering thermogenesis

Independent of whether an organism is an endotherm or ectoderm, the LEAST reliable indicator of an animal's metabolic rate is the amount of _____. A) food eaten in one day B) heat generated in one day C) oxygen used in mitochondria in one day D) water consumed in one day

D) water consumed in one day