Question 1

Which feature is an important adaptation of animals to cold climates?

Accepted Answer

A reduced surface area-to-volume ratio helps to reduce heat loss by decreasing the amount of body surface area in comparison to the volume of the body, thus reducing the amount of heat that can be lost to the colder environment.

Answer: B
 Thinner layers of body fat allow animals to conserve heat more efficiently as heat loss decreases with a reduced layer of fat.

Answer: E
 Increased flow of blood to the skin allows animals to lose heat more quickly by increasing the rate of heat transfer from the body to the surrounding environment.

Question 2

In a mammal, metabolic rate is highest when the ambient temperature is _______ the thermoneutral zone and the animal is _______.

Accepted Answer

The metabolic rate in mammals is highest when the ambient temperature is below the thermoneutral zone and the animal is active. This is because the animal needs to generate additional heat to maintain its body temperature, leading to an increase in metabolic rate.

Question 3

Countercurrent heat exchange in "hot" fish

Accepted Answer

Countercurrent heat exchange in "hot" fish involves the transfer of heat from warm blood coming from the muscles to cold blood flowing into the muscles, allowing the fish to maintain a higher internal temperature than the surrounding water.

Question 4

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature begins at its upper critical temperature and increases by 3°C-5°C.

Accepted Answer

When the environmental temperature exceeds a mammal's upper critical temperature, the body must work harder to dissipate excess heat, leading to an increased metabolic rate to fuel mechanisms like panting or sweating.

Question 5

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature increases far above 50°C.

Accepted Answer

When the environmental temperature increases far above 50°C, a mammal's body cannot regulate its temperature effectively and will likely suffer from heatstroke, leading to organ failure and death. Therefore, the metabolic rate also decreases, and death is the eventual outcome.

Question 6

Which anatomical feature possessed by endotherms reduces heat loss?

Accepted Answer

Short appendages help reduce heat loss in endotherms by minimizing the surface area exposed to the environment, thus conserving body heat.

Question 7

Evaporative cooling is used only as a last resort by animals in hot and dry environments because

Accepted Answer

Evaporative cooling, which involves sweating or panting, can help animals dissipate heat, but it also causes water loss. In hot and dry environments, water is scarce, so animals may avoid using evaporative cooling unless it is necessary to avoid overheating.

Question 8

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature begins at its lower critical temperature and decreases by 3°C-5°C.

Accepted Answer

When the environmental temperature drops below the lower critical temperature, mammals typically increase their metabolic rate to generate more heat and maintain their body temperature.

Question 9

Which is the most important and most common characteristic of endotherms adapted to cold climates compared with those adapted to warm climates?

Accepted Answer

The most important and most common characteristic of endotherms adapted to cold climates is greater insulation. This can include thick fur, feathers or blubber, and helps retain heat in the body. Higher basal metabolic rates (A) are seen in endotherms in general, but not specifically in those adapted to cold climates. Q₁₀ values (B) refer to the thermoneutral zone and do not specifically relate to adaptations for warm or cold climates. Brown fat (C) is a type of adipose tissue that generates heat and is more commonly found in newborns and some hibernating animals, but is not necessarily a defining characteristic of endotherms adapted to cold climates. Hibernation (E) is a strategy employed by some animals to survive the winter, but is not a characteristic of all endotherms adapted to cold climates.

Question 10

Which is an adaptation used by endotherms, but not by ectotherms, to produce an increase in body temperature?

Accepted Answer

Endotherms, such as mammals, can metabolize brown fat to produce heat, a process known as non-shivering thermogenesis. This is a specific adaptation to increase body temperature that ectotherms, which rely on external heat sources, do not possess.

Question 11

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature fluctuates between its upper and lower critical temperatures.

Accepted Answer

The upper and lower critical temperatures are the temperatures at which a mammal begins to expend energy to maintain its internal body temperature. As the environmental temperature fluctuates within this range, there is no need for the mammal to adjust its metabolic rate to maintain its body temperature, so there is no change in metabolic rate.

Question 12

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature begins at its lower critical temperature and increases by 3°C-5°C.

Accepted Answer

The answer of The list below shows possible metabolic responses...

Question 13

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature begins at 0°C and increases by 3°C-5°C.

Accepted Answer

When the environmental temperature increases, mammals typically decrease their metabolic rate to reduce heat production, as their bodies do not need to work as hard to maintain a stable internal temperature. This is part of thermoregulation.

Question 14

The elephant is better adapted to the temperatures of tropical habitats than those of polar climates because of its

Accepted Answer

The answer of The elephant is better adapted to the...

Question 15

Compared with "cold" fish, "hot" fish, such as bluefin tuna, keep a higher temperature difference between their body and the surrounding water in part because they

Accepted Answer

Hot fish, such as bluefin tuna, have a countercurrent heat exchange system of veins and arteries that allows them to retain heat in their muscles, keeping their body temperature higher than the surrounding water. This helps them to maintain their high metabolic rate and fast swimming speed.

Question 16

Endotherms invest energy to maintain their body temperatures across the range of environmental temperatures they encounter, except in the range of environmental temperatures

Accepted Answer

Endotherms have a range of environmental temperatures within which they can maintain their body temperature without expending any additional energy, called the thermoneutral zone. They do not need to invest energy to maintain their body temperature within this range. Therefore, the correct answer is B - within their thermoneutral zone.

Question 17

The mechanism of heat production in brown fat depends on

Accepted Answer

Brown fat produces heat through a process called uncoupling, which occurs when proton movement is not coupled to ATP production. This uncoupling is caused by the presence of a unique protein, called uncoupling protein 1 (UCP1), which is found in the inner membrane of brown adipose tissue mitochondria. UCP1 allows protons to leak from the intermembrane space into the mitochondrial matrix, dissipating the proton gradient and releasing energy as heat instead of using it for ATP production.

Question 18

Which animal is behaving as an endotherm to warm its body?

Accepted Answer

Moths quivering their wings before flight is an example of generating heat through muscle activity, a characteristic of endothermy. Other options describe ectothermic behavior, where animals rely on external heat sources.

Question 19

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature begins at its upper critical temperature and decreases by 3°C-5°.

Accepted Answer

The answer of The list below shows possible metabolic responses...

Question 20

Which is the best description of the limits of the thermoneutral zone in an endotherm?

Accepted Answer

The thermoneutral zone is the range of environmental temperatures over which an animal does not need to expend energy for thermoregulation. In an endotherm, this zone is typically above the lower critical temperature and below the upper critical temperature. Within this zone, the animal's metabolic rate is primarily determined by its basal metabolic rate, which is the minimum amount of energy required to maintain basic physiological functions in a resting state. Therefore, choice B is the most accurate description of the limits of the thermoneutral zone.

Quiz 39: Physiology, Homeostasis, and Temperature Regulation

Which feature is an important adaptation of animals to cold climates?

In a mammal, metabolic rate is highest when the ambient temperature is _ the thermoneutral zone and the animal is _.

Countercurrent heat exchange in "hot" fish

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature begins at its upper critical temperature and increases by 3°C-5°C.

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature increases far above 50°C.

Which anatomical feature possessed by endotherms reduces heat loss?

Evaporative cooling is used only as a last resort by animals in hot and dry environments because

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature begins at its lower critical temperature and decreases by 3°C-5°C.

Which is the most important and most common characteristic of endotherms adapted to cold climates compared with those adapted to warm climates?

Which is an adaptation used by endotherms, but not by ectotherms, to produce an increase in body temperature?

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature fluctuates between its upper and lower critical temperatures.

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature begins at its lower critical temperature and increases by 3°C-5°C.

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature begins at 0°C and increases by 3°C-5°C.

The elephant is better adapted to the temperatures of tropical habitats than those of polar climates because of its

Compared with "cold" fish, "hot" fish, such as bluefin tuna, keep a higher temperature difference between their body and the surrounding water in part because they

Endotherms invest energy to maintain their body temperatures across the range of environmental temperatures they encounter, except in the range of environmental temperatures

The mechanism of heat production in brown fat depends on

Which animal is behaving as an endotherm to warm its body?

The list below shows possible metabolic responses of a mammal to environmental temperature change.Choose the most likely response of a mammal when the environmental temperature begins at its upper critical temperature and decreases by 3°C-5°.

Which is the best description of the limits of the thermoneutral zone in an endotherm?