Question 1

Which of the following statements is NOT true?

Accepted Answer

Endotherms do not gain all their heat from internal biochemical reactions; they can also gain heat from external sources.

Question 2

Peeper frogs freeze during the winter. As they begin to freeze, their livers break down glycogen and release glucose into the blood, which can then be taken up into cells. This provides a benefit to the frog in that

Accepted Answer

The glucose acts as a cryoprotectant both inside and outside cells by lowering the freezing point of the fluid, and it is also available for energy production through glycolysis once the frog thaws, making all the given options correct.

Question 3

Animals that practice freeze avoidance have antifreeze proteins which

Accepted Answer

Antifreeze proteins interact with ice crystals to prevent their growth, thereby inhibiting freezing and allowing animals to survive in cold environments.

Question 4

Heat shock proteins

Accepted Answer

Heat shock proteins are also known as stress proteins, molecular chaperones, and are attracted to hydrophobic amino acids normally located on the inside of folded proteins.

Question 5

Polar bears have black skin. This characteristic helps them deal with cold stress by

Accepted Answer

Polar bears have black skin, which helps in increasing the absorption of radiant energy from the sun. The black skin absorbs more heat from the sun, which is beneficial in the cold environments they inhabit.

Question 6

Vasoconstriction helps an animal retain heat by

Accepted Answer

Vasoconstriction helps retain heat by directing blood flow away from the surface of the body, reducing heat loss to the environment. This process minimizes the amount of heat transferred from the blood to the cooler external surroundings.

Question 7

The advantage of shivering over other forms of muscle activity (like running) as a means of thermogenesis is

Accepted Answer

Shivering is a form of thermogenesis that increases heat production through muscle activity without performing external work, meaning all the energy expended is released as heat. Unlike other forms of muscle activity such as running, shivering does not significantly increase heat loss through convection or conduction because it does not involve significant movement of the body through the environment or increased contact with cooler surfaces.

Question 8

Small desert mammals are often osmotically stressed in addition to being heat stressed; therefore they will want to

Accepted Answer

Small desert mammals avoid evaporative cooling to conserve water and reduce osmotic stress by burrowing and being active during cooler times.

Question 9

When a bird ruffles its feathers in response to heat stress it

Accepted Answer

When a bird ruffles its feathers in response to heat stress, it allows for both convective currents to carry heat away from the body surface and the exchange of air with 100% humidity for air with lower humidity, enabling evaporative cooling to occur. This is a mechanism birds use to regulate their body temperature under heat stress conditions.

Question 10

The thermal neutral zone (TNZ) is

Accepted Answer

The thermal neutral zone (TNZ) is defined as the range of environmental temperatures at which an animal does not need to expend extra energy to maintain its core body temperature. This includes not needing to expend large amounts of energy on thermoregulation (A) and relying on mechanisms involving insulation to maintain a stable internal temperature within this range (C). Therefore, both A and C are correct descriptions of aspects of the TNZ.

Question 11

In birds, the hypothalamus does not

Accepted Answer

The answer of In birds, the hypothalamus does not
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Question 12

The ambient temperature at which metabolism increases to cope with heat loss to the environment is called the

Accepted Answer

The lower critical temperature is the point below which an animal must increase its metabolic rate to generate additional heat to maintain its body temperature, as it starts losing more heat to the environment than it is producing.

Question 13

Fever

Accepted Answer

Fever is indeed a hypothalamic response to pyrogens released by white blood cells, making it a physiological mechanism rather than a pathological one, aimed at combating infections. This process is well understood, involving the body's immune response to infection or illness.

Question 14

Regional heterotherms are animals that are

Accepted Answer

Regional heterotherms are animals that maintain endothermic (warm-blooded) conditions in specific parts or tissues of their body, while the rest of the body may not be as warm.

Question 15

For reasons that are uncertain, hibernating animals periodically rewarm and recool during the hibernation period. It is thought that this is because

Accepted Answer

All of the reasons listed (A, B, C) are thought to be potential reasons why hibernating animals periodically rewarm and recool during hibernation. This includes the need to void wastes, eat a little to restore glycogen stores (especially in their brains), and rewarm to activate their immune systems in case of infection.

Question 16

Minimal metabolic rate is measured

Accepted Answer

Minimal metabolic rate is measured at the optimal temperature for the organism, as it represents the baseline energy expenditure necessary to maintain basic physiological functions at rest.

Question 17

For running mammals

Accepted Answer

The increase in metabolism for running mammals is roughly linear with velocity, meaning as a mammal runs faster, its metabolic rate increases in a linear relationship with its speed.

Question 18

Naked mole rats are unusual mammals that

Accepted Answer

Naked mole rats are unique among mammals because they are ectothermic, meaning they cannot regulate their body temperature internally and instead rely on external sources of heat. This trait is more commonly associated with reptiles and amphibians.

Question 19

According to the second law of thermodynamics, as life become more organized the
 environment becomes disorganized.

Accepted Answer

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time, and is constant if and only if all processes are reversible. In the context of life, as organisms become more organized (decreasing their own entropy), they must increase the entropy of their surroundings/environment, thus making it more disorganized. This is because to decrease their internal entropy, organisms must increase the entropy outside of their system to comply with the second law of thermodynamics.

Question 20

BMR and SMR are constant for a species.

Accepted Answer

BMR (Basal Metabolic Rate) and SMR (Standard Metabolic Rate) can vary within a species due to factors such as age, sex, body composition, and environmental conditions.

Quiz 15: Energy Balance and Thermal Physiology