Deck 30: Water, Salts, and Excretion at Work: Mammals of Deserts and Dry Savannas

Question 1

Oryxes are

A) small herbivores.
B) small omnivores.
C) large omnivores.
D) large herbivores.

Answer 1

D

Question 2

Chapter 30 focuses on _______ and how they are able to live in such hot and dry environments.

A) mammals
B) small mammals
C) large mammals
D) large animals

Answer 2

C

Question 3

Deserts and semi-deserts cover about _______ of the land on Earth.

A) one-sixth
B) a quarter
C) a third
D) half

Answer 3

C

Question 4

Deserts receive less than _______ cm of precipitation per year.

A) 15
B) 20
C) 25
D) 30

Question 5

Deserts and savannas affect biological life by

A) presenting challenges for animals, but not plants.
B) presenting challenges for plants, but not animals.
C) presenting challenges for plants and animals.
D) creating an environment that does not support life.

Question 6

The dominant controlling factor of biological processes in dry savannas is

A) the air.
B) water.
C) the sun.
D) the sand.

Question 7

Which of the following does not occur in the Serengeti plains of East Africa?

A) Lack of rainfall for 4-6 months at a time
B) The drying of streams
C) Prolonged period during which soils are extremely wet
D) Dry, brown grass

Question 8

The principal reason deserts and savannas exist is

A) to balance out wetter areas of Earth.
B) because of the global pattern of air movements.
C) because of evaporation of water, which forms rain.
D) because of rain-shadowing caused by rivers.

Question 9

Near Los Angeles, the coastal mountains force the prevailing winds blowing _______ from the Pacific Ocean to _______, causing mountain rain.

A) west; fall
B) east; rise
C) south; rise
D) north; fall

Question 10

Scientists predict that the southern regions of Europe are likely to become _______ in the future.

A) less dry
B) drier
C) colder
D) more temperate

Question 11

Why does water in deserts and dry savannas often become salty?

A) Salt dissolves from the soil.
B) The rain carries a trace of salt.
C) Salt collects from dead organisms.
D) Salt dissolves from the soil and is collect from rain.

Question 12

In dry savannas and deserts, animals that weigh _______ have the most behavioral advantages.

A) 500 g
B) 100 kg
C) 200 kg
D) 300 kg

Question 13

In dry savannas and deserts, animals that weigh _______ have the fewest behavioral advantages.

A) 200 g
B) 400 g
C) 500 g
D) 2 kg

Question 14

In dry savannas and deserts, animals that weigh _______ face the heat most directly, thereby generating high heat stress.

A) 200 g
B) 250 g
C) 300 g
D) 40 kg

Question 15

In the desert heat, animals that are _______ with relatively _______ surface area for their size have the best chance at survival (assuming no shelter is available).

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

Question 16

Which animal has the most body-surface area per unit of weight?

A) Squirrel
B) Mouse
C) Dog
D) Horse

Question 17

Environmental heat enters an animal's body when

A) the air temperature is lower than the body temperature.
B) the air temperature is higher than the body temperature.
C) the air temperature is equal to the body temperature.
D) there is enough water available in the environment.

Question 18

A large desert mammal regulates its temperature to maintain a constant body temperature. When the air temperature is higher than the body temperature, the animal's evaporation rate will

A) create an unfavorable physiological condition.
B) be lower per unit of weight than for a smaller mammal.
C) decrease.
D) decrease first and then remain constant.

Question 19

Which animal has the lowest weight-specific metabolic rate?

A) Horse
B) Mouse
C) Kangaroo rat
D) Dog

Question 20

Which animal's core temperature will be affected most by an exogenous heat load?

A) Small, with relatively high surface area for their size
B) Small, with relatively low surface area for their size
C) Large, with relatively high surface area for their size
D) Large, with relatively low surface area for their size

Question 21

Which animal has the highest rate of endogenous heat production per unit of body weight?

A) Horse
B) Human
C) Kangaroo rat
D) Dog

Question 22

Which animal has the greatest capacity to void both exogenous and endogenous heat from its body through evaporation?

A) Mouse
B) Rat
C) Horse
D) Dog

Question 23

In small desert mammals, the water cost of being active in the daytime soars due to

A) the fact that they often hide in burrows to escape the heat rather than seek water.
B) the percentage of body weight lost per hour via evaporative thermoregulation.
C) their relatively small body-surface area per unit of weight.
D) their low metabolic rate.

Question 24

Which animal has the highest mass-specific evaporative water loss?

A) Monkey
B) Squirrel
C) Lion
D) Elephant

Question 25

Which animal has the highest weight-specific water costs to void endogenously produced heat?

A) Squirrel
B) Monkey
C) Lion
D) Elephant

Question 26

For most animals, dehydration becomes lethal under hot conditions when _______ or more of total body weight has been lost.

A) 5%
B) 7%
C) 8%
D) 12%

Question 27

If a dog, a human, a kangaroo rat, and a horse set out walking in a hot desert during the hottest part of the day, which animal would die first?

A) Dog
B) Human
C) Kangaroo rat
D) Horse

Question 28

Which animal would have the least chance of finding food sources in distant locations?

A) Grant's gazelle
B) Zebra
C) Common eland
D) Dwarf antelope

Question 29

The species that can travel furthest from standing water because they are drinking-water-independent is the

A) dwarf antelope.
B) wildebeest.
C) zebra.
D) kangaroo rat.

Question 30

An organism meets 30% of its water needs from metabolic water; the rest of its water needs are met

A) from preformed water.
B) by drinking.
C) by eating plants.
D) from preformed water and by drinking.

Question 31

To maximize water intake, an animal living in dry savannas should eat leaves

A) just before dawn.
B) at noon.
C) in the afternoon.
D) in the evening.

Question 32

The ambient humidity in deserts is highest

A) at pre-dawn.
B) in the morning.
C) in the afternoon.
D) at night.

Question 33

Which species is/are considered drinking-water-dependent herbivore(s)?

A) Wildebeest
B) Eland
C) Zebra
D) Wildebeest and zebra

Question 34

Which species does not migrate?

A) Grant's gazelle
B) Wildebeest
C) Thompson's gazelle
D) Zebra

Question 35

Which species is not drinking-water-independent?

A) Oryx
B) Eland
C) Wildebeest
D) Grant's gazelle

Question 36

Refer to the figure shown.
Which would be the most accurate y axis label for both figures?

A) Water loss (L/kg·day)
B) Water gain (L/kg·day)
C) Water flux (L/kg·day)
D) Metabolic water (L/kg·day)

Question 37

Refer to the figure shown.
Which panel shows evaporative water loss under near-desert temperatures?

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

Question 38

Refer to the figure shown.
In which panel does the wildebeest appear to be most dependent on preformed water?

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

Question 39

Refer to the figure shown.
What do the two lines in this figure represent?

A) Species of perennial grasses
B) Species of drinking-water- dependent herbivores
C) Species of drinking-water- independent herbivores
D) Species of desert insects

Question 40

Why do wildebeests migrate from the northwest to the southeast during the beginning of the rainy season?

A) The immediate lack of freshwater
B) Lack of food
C) The increase of predators
D) It is still unknown at this time

Question 41

Which statement about Arabian oryxes is false?

A) The more they acclimate, the lower their respiratory surface area.
B) The more they acclimate, the more water they conserve.
C) The more they acclimate, the less their total rate of evaporative water loss.
D) They turnover water at a rate one-quarter to that of other free-living mammals their size.

Question 42

If an Arabian oryx's urine osmolarity is 240 mOsm and the U/P ratio is 8, its plasma osmolarity would be _______ mOsm.

A) 30
B) 60
C) 240
D) 1920

Question 43

If an Arabian oryx's plasma osmolarity is 200 mOsm, its maximum urine osmolarity would be _______ mOsm.

A) 200
B) 800
C) 1600
D) 3200

Question 44

The osmotic U/P ratio for a dik-dik is about

A) 5.
B) 8.
C) 10.
D) 12.

Question 45

Among the animals listed, the species with the lowest peak urine osmotic pressure is the

A) African buffalo.
B) Somali donkey.
C) Arabian oryx.
D) dromedary camel.

Question 46

On a summer day, oryxes exhibit the highest average body temperature at

A) midnight.
B) 6:00 AM.
C) noon.
D) 6:00 PM.

Question 47

It has been shown that oryxes can survive without drinking water for

A) days.
B) weeks.
C) months.
D) years.

Question 48

Oryxes living in deserts or savannas raise their body temperature to

A) release heat.
B) absorb heat.
C) store heat.
D) evaporate excess heat.

Question 49

In an oryx living in a dry savanna, the amount of water saved per day as a result of a cycling body temperature as opposed to a constant one is

A) 0.1 L.
B) 0.2 L.
C) 0.3 L.
D) 1.0 L.

Question 50

The highest recorded rectal temperature in a vertebrate is

A) 38.5°C.
B) 43°C.
C) 46.5°C.
D) 49°C.

Question 51

Based on studies of recently dead animals, oryxes exposed to severe drought in their natural habitat seem to die mostly of

A) predation.
B) dehydration.
C) hyponatremia.
D) severe nutritional deficiency.

Question 52

The strategy that conserves the most water in large herbivores is

A) cessation of urination.
B) cycling body core temperature.
C) shedding fur.
D) lowering brain energy consumption.

Question 53

Refer to the figure shown.
The y axis is most likely measuring

A) urine concentration.
B) body temperature.
C) insulation thickness.
D) metabolic rate.

Question 54

Refer to the figure shown.
The most accurate description of the results in the figures is

A) gazelles cycle their metabolic rate more in summer than in winter.
B) oryxes have less consistent body water content in winter than in summer.
C) gazelles have more variable urine concentrations in winter than in summer.
D) oryxes have more variable body temperatures in summer than in winter.

Question 55

According to most biologists, what is the proper definition of a desert?

Question 56

Deserts and savannas have extreme conditions. Explain why these conditions exist.

Question 57

Describe the advantages and disadvantages that large mammals have living in hot deserts and dry savannas over small mammals in the same environment.

Question 58

Describe the advantages and disadvantages that small mammals living in hot deserts and dry savannas have over large mammals in the same environment.

Question 59

Endothermic animals that live in hot climates regulate their body heat. Where is the heat coming from and how do they regulate it? Does the size of the animal play a role in thermoregulation?

Question 60

D. B. Dill was a pioneer in the study of exercise and heat. Describe his experiments and explain the results.

Question 61

In an experiment to study water budgets, the drinking-water-dependent common wildebeest and the drinking-water-independent beisa oryx were studied under two sets of conditions. Explain the results of this experiment.

Question 62

All species of large herbivores obtain a considerable amount of preformed water, but some require more than others. Explain how different groups of these mammals maintain their water budget.

Question 63

What are the mechanisms by which oryxes achieve exceptional water conservation and low water turnover rates?

Question 64

List the strategies dromedary camels employ to conserve water.