Deck 10: Thermal Relations

Question 1

An ectotherm is also called a

A) thermoregulator.
B) thermoconformer.
C) homeotherm.
D) poikilotherm.

Answer 1

D

Question 2

A homeotherm is a

A) nonthermoregulating poikilotherm.
B) thermoregulating ectotherm.
C) nonthermoregulating endotherm.
D) thermoregulating endotherm.

Answer 2

D

Question 3

Most animals are _______. Most endotherms are _______.

A) endotherms; thermoregulators
B) ectotherms; thermoconformers
C) endotherms; nonthermoregulators
D) ectotherms; thermoregulators

Answer 3

D

Question 4

The environmental temperature is 15°C. The internal temperature of a sphinx moth after 30 minutes of rest is _______ and the internal temperature of a sphinx moth after 30 minutes of flight is _______.

A) 10°C; 15°C
B) 15°C; 15°C
C) 15°C; 38°C
D) 10°C; 38°C

Question 5

The optimum temperature of flight muscle of a sphinx moth is _______ and this _______ with decreasing environmental temperature.

A) 15°C; decreases
B) 15°C; remains constant
C) 40°C; decreases
D) 40°C; remains constant

Question 6

Suppose that due to global climate change, the average minimum air temperature during January increased by 4°C. What would be the likely effect on the northern range limit for birds such as the eastern phoebe?

A) The limit would move farther north to the new ‒4°C isotherm.
B) The limit would move farther north to the new 0°C isotherm.
C) The limit would move farther north to the new 4°C isotherm.
D) The limit would move farther south.

Question 7

A 20-kg metal block and a 100-kg metal block are both brought to room temperature, which is 25°C. Choose the correct statement.

A) Both blocks would melt the same amount of ice because their temperatures are the same.
B) The 100-kg block will melt more ice because its heat content is higher.
C) The 20-kg block will melt more ice because its heat content is higher.
D) Both blocks would melt the same amount of ice because their heat contents are the same.

Question 8

The environmental temperature is 25°C. A small lizard at 20°C will _______ the environment whereas a large dog at 37°C contains _______ heat than the lizard and will _______ the environment.

A) lose heat to; more; lose heat to
B) gain heat from; less; lose heat to
C) gain heat from; more; lose heat to
D) gain heat from; more; gain heat from

Question 9

Which of the following is not one of the mechanisms by which animals exchange heat with their environment?

A) Convection
B) Evaporation
C) Metabolic heat production
D) Thermal radiation

Question 10

Which statement about an animal's body temperature is true?

A) The body temperature of a poikilotherm is always constant.
B) The body temperature of an endotherm is always constant.
C) Body temperature will remain constant when heat gained is equal to heat lost.
D) Body temperature is always constant because metabolic heat production is equal to heat exchanged by thermal radiation.

Question 11

When the body temperature of ghost crabs is raised from 15°C to 24°C, resting metabolic rate and V̇_O2max both increase, but the increase in V̇_O2max is much greater than the increase in resting metabolic rate. Given this information, what would be the likely result if ghost crabs in nature experienced conditions that raised their typical body temperature from 15°C to 24°C?

A) Aerobic scope and capacity for aerobic exercise would increase.
B) Aerobic scope and capacity for aerobic exercise would decrease.
C) Aerobic scope would decrease and capacity for aerobic exercise would increase.
D) Aerobic scope would increase and capacity for aerobic exercise would decrease.

Question 12

For animals, an advantage of fur is that

A) if the air it traps is motionless, heat is transferred by convection.
B) if the air it traps is motionless, heat is transferred by conduction.
C) it has a high convection coefficient.
D) it has a high thermal conductivity.

Question 13

Besides temperature, the factor that is important for conduction, convection, and thermal radiation is

A) thermal conductivity.
B) wind speed.
C) emissivity.
D) surface area.

Question 14

Dry heat transfer refers to heat exchange

A) by convection only.
B) by conduction and convection only.
C) by conduction, convection, and thermal radiation.
D) in any environment with low humidity.

Question 15

With respect to heat flow between animals and their environments, high conductance corresponds to _______ insulation and to _______ resistance to heat loss

A) high; high
B) high; low
C) low; high
D) low; low

Question 16

For a typical bird or mammal, the slope of the line below the thermoneutral zone equals _______ and is steeper for an animal with _______ insulation and higher thermal conductance.

A) C; higher
B) C; lower
C) -C; lower
D) -C; higher

Question 17

All else being equal, the convective coefficient (per unit area) is likely to be highest when wind speed is _______ and animal size (diameter) is _______.

A) high; low
B) high; high
C) low; low
D) low; high

Question 18

You are in Las Vegas in summer and you see a dog tied to a fence with no access to shade. As the dog is obviously having problems with the heat, what would be the fastest means of cooling the dog's internal temperature?

A) Put the dog in an 87°F pool of water.
B) Put a few ice cubes in the dog's water bowl.
C) Put the dog in the shade and near a fan.
D) Shave the dog's fur off.

Question 19

Animals, plants, and other objects in the natural environment generally emit radiation at wavelengths of _______ or longer.

A) 3-4 nm
B) 3-4 $\mu$ m
C) 3-4 mm
D) 3-4 m

Question 20

Per unit of surface area, animals emit _______ radiation than the sun; at wavelengths shorter than 3 $\mu$ m, they emit _______ radiation than the sun.

A) more; more
B) more; less
C) less; more
D) less; less

Question 21

When thermal radiation strikes an object, it is

A) absorbed.
B) reflected or absorbed.
C) absorbed or transmitted (pass through).
D) reflected, absorbed, or transmitted (pass through).

Question 22

On an overcast night, as opposed to a night with a clear sky, the thermal environment experienced by a desert rodent will be

A) warmer because less radiant heat is lost to an overcast sky.
B) warmer because the rodent has lower emissivity when the sky is overcast.
C) cooler because the rodent has higher emissivity when the sky is overcast.
D) cooler because the atmosphere's convective coefficient is increased by an overcast sky.

Question 23

Evaporation is an effective mechanism for cooling because the latent heat of

A) vaporization for water is large.
B) vaporization for water is small.
C) fusion for water is large.
D) fusion for water is small.

Question 24

Suppose that an animal is sweating profusely. The dripping of sweat off the animal's surface

A) cools the animal due to the latent heat of condensation.
B) heats the animal due to the latent heat of fusion.
C) cools the animal due to the latent heat of vaporization.
D) does not contribute to heating or cooling of the animal.

Question 25

Animals most commonly use _______ in terms of their thermal relationship with the environment.

A) poikilothermy.
B) endothermy.
C) thigmothermy.
D) homeothermy.

Question 26

Behavioral thermoregulation depends on _______ of the thermal environment and preferential selection of _______ sites within the environment.

A) heterogeneity; particular
B) heterogeneity; sunny
C) homogeneity; sunny
D) homogeneity; particular

Question 27

The three time frames over which animals respond physiologically to environmental change are

A) acclimation, acclimatization, and adaptation.
B) acute, chronic, and evolutionary.
C) eons, eras, and periods.
D) behavioral, physiological, and cognitive.

Question 28

Based on how the metabolic rates of ectotherms and endotherms respond to temperature, at which temperature would you expect the differences in metabolic rates between ectotherms and endotherms to be largest? (Hint: Think about the response curve of each type of animal to environmental temperature.)

A) 5°C
B) 15°C
C) 25°C
D) 35°C

Question 29

Suppose an animal has a metabolic rate of 3 ml O₂/h at 10°C? The Q₁₀ is 2. What is its metabolic rate at 20°C?

A) 2 ml O₂/h
B) 3 ml O₂/h
C) 6 ml O₂/h
D) 9 ml O₂/h

Question 30

Suppose an animal has a metabolic rate of 10 ml O₂/h at 20°C. The Q₁₀ is 2.5. What is its metabolic rate at 10°C?

A) 2.5 ml O₂/h
B) 4 ml O₂/h
C) 10 ml O₂/h
D) 25 ml O₂/h

Question 31

Most commonly, the slope of the line depicting the chronic response of metabolic rate to temperature is _______ the slope of the lines depicting the acute response of metabolic rate to temperature.

A) parallel to but higher than
B) parallel to but lower than
C) steeper than
D) shallower than

Question 32

Compensation is acclimation via

A) behavioral changes.
B) metabolic rate changes.
C) postural changes.
D) changes in vasculature diameter.

Question 33

Refer to the figure shown. Fish were housed under three different temperature conditions. Their response to acute and chronic temperature changes is plotted on the figure.
What is the property most likely to be plotted on the y axis?

A) Rate of oxygen consumption
B) Mass-specific metabolic rate
C) Metabolic rate on a log scale
D) Ventilation rate

Question 34

Refer to the figure shown. Fish were housed under three different temperature conditions. Their response to acute and chronic temperature changes is plotted on the figure.
Which line best represents the acute response line of animals acclimated to the coldest temperature?

A) I
B) II
C) III
D) IV

Question 35

Refer to the figure shown. Fish were housed under three different temperature conditions. Their response to acute and chronic temperature changes is plotted on the figure.
Which line best represents the chronic response of animals being cooled from 30°C to 10°C?

A) I
B) II
C) III
D) IV

Question 36

Refer to the figure shown. Fish were housed under three different temperature conditions. Their response to acute and chronic temperature changes is plotted on the figure.
What will happen to line IV as temperature continues to increase beyond the scale of the visible x axis?

A) The line will continue along the same slope indefinitely.
B) The line will slope downward at 30°C until it reaches 0.
C) The line will continue along the same slope, but ultimately turn downward.
D) The line will increase along slope it reached at 30°C until the animal dies.

Question 37

Performance curves

A) should always be calculated acutely.
B) should always be calculated chronically.
C) are equivalent to measurements of evolutionary fitness.
D) can be used to calculate critical temperatures.

Question 38

In aquatic poikilotherms, the most likely reason for impairment of function in the pejus range is

A) destruction of DNA.
B) irreversible denaturation of proteins.
C) oxygen limitation.
D) disruption of osmotic balance.

Question 39

The maximum sprinting speeds of lizards

A) are always highest near a body temperature of 40°C.
B) are often well-correlated with the average body temperature of the species in nature.
C) often peak at lower temperatures.
D) are uncorrelated with body temperature.

Question 40

Enzyme-substrate affinity

A) generally decreases with temperature.
B) generally increases with temperature.
C) does not vary with temperature.
D) increases with temperature in eurythermal species but decreases with temperature in stenothermal species.

Question 41

At any given temperature, LDH-substrate affinity _______ across species of poikilotherms; at the temperatures at which these species typically live in nature, LDH-substrate affinity _______ across species.

A) varies; varies
B) is similar; varies
C) varies; is similar
D) is similar; is similar

Question 42

Antarctic fur seals live in cold water, thermoregulate, and maintain elevated core body temperatures. Manatees, another marine mammal, live in warm water, thermoregulate, and maintain elevated core body temperatures. Based on general principles, one would predict that for Antarctic fur seals, the effect of temperature on enzyme-substrate activity would be similar to that of _______-water fish, and for manatees it would be similar to that of _______-water fish.

A) stenothermal cold; stenothermal warm
B) eurythermal cold; eurythermal warm
C) stenothermal cold; eurythermal warm
D) stenothermal warm; stenothermal warm

Question 43

When carp or goldfish that are acclimated to warm temperatures are subsequently acclimated to colder temperatures, their swimming performance is impaired initially but then improves over time. Which of the following is thought to be the most likely explanation?

A) Shifts in myosin isoforms and shifts in isozyme forms for glycolysis and the Krebs cycle
B) Shifts in myosin isoforms, but no shifts in isozyme forms for glycolysis or the Krebs cycle
C) Shifts in isozyme forms for glycolysis and the Krebs cycle, but no shifts in myosin isoforms
D) Shifts in the amounts of enzymes for glycolysis and the Krebs cycle, but no shifts in myosin isoforms

Question 44

Refer to the figure shown. Multiple species of poikilotherms that naturally experience different body temperatures are shown in the figure. The response of each species at multiple temperatures is plotted on the figure.
What is the most appropriate label for the y axis?

A) Oxygen consumption
B) Metabolic rate
C) Enzyme-substrate affinity
D) Rate of performance

Question 45

Refer to the figure shown. Multiple species of poikilotherms that naturally experience different body temperatures are shown in the figure. The response of each species at multiple temperatures is plotted on the figure.
Which line indicates the species that naturally experiences the narrowest body temperature range?

A) I
B) II
C) III
D) IV

Question 46

Refer to the figure shown. Multiple species of poikilotherms that naturally experience different body temperatures are shown in the figure. The response of each species at multiple temperatures is plotted on the figure.
Which line indicates the species that needs to be coldest for enzyme function to be in the range favored by evolution?

A) I
B) II
C) III
D) IV

Question 47

Some animals can survive freezing and others cannot. Which of the following is associated with the ability of animals to survive freezing?

A) Freezing of the intracellular and extracellular fluids
B) Freezing of the intracellular fluids only
C) Freezing of the extracellular fluids only
D) Their colligative properties

Question 48

Over evolutionary time, membrane fluidity can be maintained at lower temperatures by

A) adding cholesterol to the membranes.
B) adding more saturation to the phospholipids.
C) unsaturating the phospholipids.
D) making the membranes thinner.

Question 49

Antifreezes are synthesized primarily by

A) marine and freshwater fish.
B) amphibians and marine fish.
C) insects and marine fish.
D) insects and amphibians.

Question 50

During the onset of a fever, the body's temperature set point _______ and results in the body adjusting to this new set point by _______.

A) decreases; sweating
B) decreases; shivering
C) increases; sweating
D) increases; shivering

Question 51

Compared to the average field metabolic rates for a nonavian reptile, the average field metabolic rate of a similar size bird or mammal is

A) twice as high.
B) 4-10 times higher.
C) 12-20 times higher.
D) 100-300 times higher.

Question 52

What happens to a homeotherm's resting metabolic rate when the temperature is outside its thermoneutral zone?

A) Resting metabolic rate goes up.
B) Resting metabolic rate goes down.
C) Answer depends on whether it is too hot or too cold.
D) Resting metabolic rate does not change.

Question 53

Birds adjust their insulation via

A) ptilomotor and vascular responses.
B) ptilomotor, vascular, and postural responses.
C) ptilomotor, vascular, postural, and thermogenic responses.
D) ptilomotor, vascular, postural responses, and nonshivering thermogenesis.

Question 54

Uncoupling protein 1 is critical for

A) freeze tolerance.
B) brown adipose tissue.
C) mitochondria in birds.
D) supercooling.

Question 55

In winter, some birds stand on frozen ponds and lakes. How do they prevent their feet from freezing while simultaneously preventing excessive heat loss?

A) By alternately standing on one foot and then the other
B) By metabolizing brown adipose tissue in their lower legs and feet
C) By selective shivering
D) By allowing their feet to cool below core temperature but remain above freezing

Question 56

A rete mirabile is

A) a specialized tissue for heat production.
B) a part of the body whose temperature differs from the core body temperature.
C) the splitting of arteries and veins into many intermingling finer vessels.
D) the controller "thermostat" for body temperature.

Question 57

In a very hot environment, the benefit of hyperthermia is that it

A) saves water and reduces heat gain.
B) saves water but does not reduce heat gain.
C) reduces heat gain, although it does not save water.
D) maintains the lipid structure in the skin that prevents dehydration.

Question 58

Which method of evaporative water loss can induce respiratory alkalosis?

A) Gular fluttering
B) Panting
C) Saliva spreading
D) Sweating

Question 59

Which group includes only forms of hypothermia?

A) Estivation, hibernation, and torpor
B) Thermogenesis, hibernation, and torpor
C) Shivering, thermogenesis, and metabolic heat production
D) Gular fluttering, panting, and sweating

Question 60

Suppose that a mammal that was a temporal heterotherm needed to survive in a winter environment with severely limited food resources. At which of the following mean ambient temperatures would the animal most likely survive the winter?

A) 5°C
B) 10°C
C) 15°C
D) 25°C

Question 61

_______ describes the process of rewarming of the tissues of a mammal after controlled hypothermia.

A) Metabolic acclimatization
B) Endothermy
C) Q₁₀ effect
D) Arousal

Question 62

Refer to the figure shown. One species of homeotherm under two different environmental conditions was exposed to temperature changes.
What is the most appropriate label for the y axis?

A) Maximum metabolic rate
B) Resting metabolic rate
C) Body temperature
D) Membrane-lipid fluidity

Question 63

Refer to the figure shown. One species of homeotherm under two different environmental conditions was exposed to temperature changes.
Data from which species is most likely represented in this figure?

A) Mouse
B) Naked human
C) Fox
D) Rabbit

Question 64

Refer to the figure shown. One species of homeotherm under two different environmental conditions was exposed to temperature changes.
Which term best describes what was studied in this experiment?

A) Acclimatization
B) Metabolic rate
C) Heterothermy
D) Thermal tolerance

Question 65

Refer to the figure shown. One species of homeotherm under two different environmental conditions was exposed to temperature changes.
In the following list, what is the lowest lower-critical temperature represented in this figure?

A) -50°C
B) -14°C
C) 0°C
D) 10°C

Question 66

The dromedary camel can survive without drinking water for days because of

A) the water stored in its humps.
B) its very large bladder, which stores water.
C) daily heat loading and unloading.
D) its very low metabolic rate.

Question 67

Compared to a summer acclimatized fox, what is a winter fox's resting metabolic rate when both are placed at -50°C?

A) Resting metabolic rate in the winter fox is higher than the summer fox.
B) Resting metabolic rate in the winter fox is lower than the summer fox.
C) Resting metabolic rate in both foxes will be similar.
D) There is not enough information to predict the relationship of their resting metabolic rates.

Question 68

In 10°C ocean water, you would expect the tip of a killer whale's flipper to be about

A) 37°C.
B) 8°C.
C) 12°C.
D) 45°C.

Question 69

The reason that most fish species cannot be warm-bodied is

A) the lack of ability to store fat.
B) they are too small.
C) the high conduction of water.
D) water temperature is too variable.

Question 70

Which structure has a physiological function that shares major similarities with the function of brown adipose tissues?

A) Stomach of lamnid sharks
B) Parts of the extraocular eye muscles of billfishes
C) Red swimming muscles in tunas
D) White swimming muscles in tunas

Question 71

During particularly cold winters

A) bee hives will survive as long as they do not freeze.
B) a larger bee hive will have an advantage because it will take longer to freeze.
C) a larger bee hive will be able to produce more heat and have a better chance at maintaining a warm temperature.
D) smaller bee hives have an advantage because they are able to heat more quickly.

Question 72

Endothermy in insects

A) typically is restricted to the abdomen.
B) typically is restricted to the thorax.
C) occurs only in the largest insects.
D) occurs only during flight.

Question 73

Which statement about insect flight is true?

A) In order to fly, all insects require high abdominal and high thoracic temperatures.
B) In order to fly, all insects require high thoracic but not high abdominal temperatures.
C) In order to fly, all insects require elevated flight muscle temperatures.
D) Some insects can fly despite low abdominal and low thoracic temperatures.

Question 74

How might a vapor barrier liner in a sleeping bag decrease a person's heat loss when camping outside in the cold?

Question 75

How would the emissivities (e) of a desert rodent and a desert lizard compare at wavelengths of 3‒4 mm or longer?

Question 76

Why is it that the body temperatures of terrestrial poikilotherms can substantially exceed air temperature but body temperatures of aquatic poikilotherms are generally very close to water temperature?

Question 77

On hot days some dragonflies tip their abdomen and point it directly at the sun. From the perspective of heat exchange, what effect might this have and why?

Question 78

Suppose you use inanimate lizard models to comprehensively and randomly sample the thermal environment of a lizard's habitat. You then compare that distribution of inanimate model temperatures with the distribution of actual body temperatures from lizards in that habitat. If the distributions differ, what does the discrepancy indicate?

Question 79

You collect lizards from three populations, immediately measure each lizard's metabolic rate at 20°C and find that the rates differ among the lizards. Other than genetic differences among the populations, what factor could these differences be attributed to?

Question 80

Human blood has an osmolarity of about 300 mOsm and shark blood has an osmolarity of about 1000 mOsm. If you collected blood samples from both humans and sharks and attempted to freeze them, which would freeze at a lower temperature?