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1

Which statement regarding the June solstice is true?

a) The Northern Hemisphere is tilted toward the sun.

b) Locations in the Southern Hemisphere experience long days and short nights.

c) Locations in the Northern Hemisphere experience 12 hours of daylight and 12 hours of darkness.

d) The Southern Hemisphere is tilted toward the sun.

a

2

At what time of year is the intensity of solar radiation striking each of Earth’s hemispheres weakest?

a) The intensity of solar radiation is weakest in the Southern Hemisphere in March and in the Northern Hemisphere in June.

b) The intensity of solar radiation is weakest in the Northern Hemisphere in June and in the Southern Hemisphere in September.

c) The intensity of solar radiation is weakest in the Southern Hemisphere in June and in the Northern Hemisphere in December.

d) The intensity of solar radiation is weakest in the Northern Hemisphere in March and in the Southern Hemisphere in September.

c

3

Which statement accurately describes Earth on February 21, a date that falls between the December solstice and the March equinox?

a) Locations in the Southern Hemisphere experience more than 12 hours of daylight.

b) In the Northern Hemisphere, there are more daylight hours than hours of darkness, but the difference is not as extreme as on the December solstice.

c) The Southern Hemisphere experiences its longest day and shortest night of the year.

d) Locations in the Northern Hemisphere experience less than 12 hours of darkness.

a

4

Of the following, which is the most inclusive level of organization in nature?

a) cell

b) biosphere

c) community

d) population

e) ecosystem

b

5

Which of the following causes Earth's seasons?

A) global wind patterns

b) vertical air circulation

c) Earth's tilt on its axis

d) ocean currents

e) changes in the Earth's distance from the sun

c

6

Which of the following investigations is an example of the study of an abiotic factor?

a) identifying food sources for an egret population

b) investigating how an elk population competes for food

c) the relationship between finch beak size and food availability on two different Galapagos Islands

d) investigating how the amount of annual precipitation affects the distribution of a tree species

e) observing interactions among various organisms in a rainforest canopy

d

7

Which of the following causes seasons on Earth?

a) the variation in proximity of the Earth to the sun at different times of the year

b) the variation or wobble of Earth's tilt during the year

c) the distance between the Earth and the sun in winter versus in the summer

d) the constant tilt of the Earth, combined with its orbit around the sun

d

8

Which of the following might be an investigation of microclimate?

a) how sunlight intensity affects plant community composition in the zone where a forest transitions into a meadow

b) the effect of ambient temperature on the onset of caribou migration

c) competitive interactions among various species of songbirds during spring migration

d) the seasonal population fluctuation of nurse sharks in coral reef communities

a

9

In creating global climate patterns, which of the following factors is the primary cause of all of the other factors that are listed?

a) precipitation differences between tropical and polar regions

b) variation in the heating of Earth's surface

c) global wind patterns

d) global ocean currents

b

10

For mountain ranges that are subjected to prevailing winds, why is the climate drier on the leeward (downwind) side?

a) Pushed by the prevailing winds on the windward side, air is forced to rise, cool, condense, and drop its precipitation, leaving drier air to descend the leeward side.

b) The sun illuminates the leeward side of mountain ranges at a more direct angle, converting to heat energy, which evaporates most of the water present.

c) Air masses pushed by the prevailing winds are stopped by mountain ranges and the moisture is used up in the stagnant air masses on the leeward side.

d) Deserts create dry conditions on the leeward side of mountain ranges.

a

11

Subtropical plants are commonplace in Land's End, England, whose latitude is the equivalent of Labrador in coastal Canada, where the local flora is instead subarctic. Which statement best explains why this apparent anomaly exists between North America and Europe?

a) Labrador receives sunlight of lower duration and intensity than does Land's End.

b) Labrador does not get enough rainfall to support the subtropical flora found in Land's End.

c) Warm ocean currents interact with England, whereas cold ocean currents interact with Labrador.

d) Rainfall fluctuates greatly in England; rainfall is consistently high in Labrador.

c

12

In mountainous areas of western North America, north-facing slopes would be expected to _____.

a) support biological communities similar to those found at higher elevations on similar south-facing slopes

b) receive more sunlight than similar southern exposures

c) be warmer and drier than comparable southern exposed slopes

d) support biological communities similar to those found at lower elevations on similar south-facing slopes

a

13

Imagine some cosmic catastrophe jolts Earth so that its axis is perpendicular to the orbital plane between Earth and the sun. The most obvious effect of this change would be ________.

a) the elimination of tides

b) the elimination of seasonal variation

c) an increase in the length of a year

d) a decrease in temperature at the equator

b

14

The main reason polar regions are cooler than the equator is that ________.

a) solar radiation strikes the poles at a lower angle and travels through more atmosphere

b) the poles are farther from the sun than is the equator

c) the poles are permanently tilted away from the sun

d) the polar atmosphere is thinner and contains fewer greenhouse gases

a

15

Generalized global air circulation and precipitation patterns are caused by ________.

a) solar radiation that warms dry air masses at the poles, causing them to sink toward the tropics, gain moisture, and then release it as precipitation.

b) polar, cool, moist, high-pressure air masses from the poles that move along the surface, releasing precipitation along the way to the equator, where they are heated and dried

c) solar radiation that warms moist air masses near the equator, which then cool and release precipitation as they rise, and then, at high altitude, move north or south of the tropics and sink back to the surface as dry air masses

d) air masses that are dried and heated over continental areas, which then rise, cool aloft, and descend over oceanic areas, followed by a return flow of moist air from ocean to land, delivering high amounts of precipitation to coastal areas

c

16

Generally speaking, deserts are located in places where air masses are usually ________.

a) descending

b) tropical

c) at the start of trade winds

d) ascending

a

17

If the direction of Earth's rotation reversed, the most predictable effect would be ________.

a) an elimination of deserts and increase in tropics

b) the elimination of ocean currents

c) winds blowing from west to east along the equator

d) a loss of seasonal variation at high latitudes

c

18

What are the two major factors determining the distribution of terrestrial biomes?

a) temperature and light

b) temperature and rainfall

c) light and rainfall

d) plants and animals

e) temperature and plants

b

19

Which of these biomes is characterized by little rainfall?

a) temperate broad leaf forest

b) coniferous forest

c) desert

d) temperate grassland

e) tropical rain forest

c

20

Which of these is the largest terrestrial biome on Earth?

a) tundra

b) coniferous forest

c) temperate broadleaf forest

d) temperate grassland

e) desert

b

21

Which biome is characterized by an extensive canopy that allows little light to penetrate to the ground and by the presence of epiphytes?

a) temperate grassland

b) coniferous forest

c) tropical rain forest

d) desert

e) tundra

c

22

Which biome is characterized by the presence of permafrost?

a) taiga

b) tropical forest

c) tundra

d) coniferous forest

e) desert

c

23

Which action influences the abiotic components of an organism's environment?

a) Water pollution.

b) Introduction of exotics.

c) Interactions with offspring.

d) Extinction of predators.

a

24

Which aspects of a region's climate have the most impact on plants and animals?

a) Temperature and moisture.

b) Moisture and wind.

c) Soil composition and temperature.

d) Sunlight and wind.

a

25

True or false? Weather is defined as the prevailing long-term atmospheric conditions in a particular region.

a) True

b) False

b

26

Which of the following statements about Hadley cells is true?

a) Warm air begins to cool as it starts to sink at about 30° North and South latitude.

b) As warm air rises, air at the top of the atmosphere is pushed poleward and cools.

c) Warm air expands and rises from the surface of the atmosphere around the poles.

d) The moisture in cool air condenses into clouds and precipitates because cool air holds more moisture than warm air.

b

27

Which location on Earth receives the most solar radiation per unit area?

a) 30° North and South latitude.

b) South Pole.

c) Equator

d) North Pole.

c

28

What are rain shadows?

a) Wet regions on the windward side of mountain ranges.

b) Wet regions on the leeward side of mountain ranges.

c) Dry regions on the leeward side of mountain ranges.

d) Dry regions on the windward side of mountain ranges.

c

29

Which desert is caused by a Hadley cell?

a) Sahara Desert in Africa.

b) Atacama Desert in Chile.

c) Desert next to the Rockies.

d) Patagonian Desert in Argentina.

a

30

In most cases, the two major climatic factors affecting the distribution of organisms in terrestrial ecosystems are _____.

a) water and temperature

b) wind and water

c) predators and parasites

d) temperature and sunlight

e) competitors and predators

a

31

What is a biome?

a) a major type of ecosystem

b) a specific set of abiotic factors

c) a set of similar communities

d) a major type of biosphere

e) an area with a uniform distribution of organisms and abiotic environmental conditions

a

32

Which of the biomes—tundra, coniferous forest, temperate broadleaf forest, temperate grassland, savanna, chaparral, desert, tropical rainforest—require periodic fires to maintain their existence?

a) tropical forest, savanna, chaparral, temperate grassland, and coniferous forest

b) savanna, desert, chaparral, temperate grassland, and temperate broadleaf forest

c) savanna, chaparral, temperate grassland, tundra, and coniferous forest

d) savanna, chaparral, temperate grassland, and coniferous forest

e) savanna and chaparral

d

33

When climbing a mountain, we can observe transitions in biological communities that are analogous to the changes _____.

a) in a community through different seasons

b) in biomes at different latitudes

c) in an ecosystem as it evolves over time

d) across the United States from east to west

...

34

Which of the following biomes spans the largest annual mean temperature range, but the narrowest mean precipitation range?

a) taiga

b) desert

c) temperate forest

d) tropical forest

b

35

If global warming continues at its present rate, which biomes will likely take the place of the coniferous forest (taiga)?

a) tropical forest and savanna

b) temperate broadleaf forest and grassland

c) desert and chaparral

d) chaparral and temperate broadleaf forest

b

36

If you conclude that vegetation at every point on Earth exactly resembles the predicted biome distribution in a climograph, then ________.

a) you are ignoring the fact that local differences in soil, elevation, or topography can result in considerably different plant communities that are embedded within named biomes

b) the biome spanning the smallest combined ranges in precipitation and temperature is the tundra

c) you are ignoring human land use changes or impacts, which have highly altered many regions within biomes

d) the biome most sensitive (in danger) from global warming is the desert

a

37

Which of the following statements best describes the interaction between fire and ecosystems?

a) Many kinds of plants and plant communities have adapted to frequent fires.

b) The likelihood of a wildfire occurring in a given ecosystem is highly predictable over the short term.

c) The suppression of forest fires by humans has prevented certain communities, such as grasslands, from reaching their climax stage.

d) Chaparral communities have evolved to the extent that they rarely burn.Submit

a

38

Which of the following is an important feature of most terrestrial biomes?

a) vegetation demonstrating vertical layering

b) clear boundaries between adjacent biomes

c) a distribution predicted almost entirely by rock and soil patterns

d) annual average rainfall in excess of 250 centimeters

a

39

Two plant species live in the same biome but on different continents. Although the two species are not at all closely related, they may appear quite similar as a result of _____.

a) gene flow

b) introgression

c) convergent evolution

d) allopatric speciation

c

40

Some arctic tundra ecosystems receive as little precipitation as deserts but have much more dense vegetation.What climatic factor might explain this difference?

a) Tundra is much cooler than deserts, so less water evaporates during the growing season and the tundra stays more moist.

b) Tundra is much warmer than deserts, so less water evaporates during the growing season and the tundra stays more moist.

c) In addition to rain, tundra also receives water in the form of snow.

d) Tundra plants are better adapted to dry conditions than desert plants.

a

41

Why are experiments that involve transplanting species seldom conducted today?

a) The transplanted species are often disruptive to their new communities.

b) The success of the transplant cannot be measured in one researcher's lifetime.

c) The potential range of a transplanted species can never be greater than its actual range.

d) Species transplants still are a popular experimental tool.

e) There are no criteria to determine if they are successful.

a

42

Which of the following types of organisms is likely to have the widest geographic distribution?

a) bacteria

b) lizards

c) songbirds

d) bears

a

43

Which would be a consequence of the removal of predators from a population such as the Trinidadian guppy population?

a) Guppies would produce fewer but larger offspring.

b) Guppy color patterns would change.

c) Primary producers such as algae would overgrow.

d) Guppy color patterns would change; guppies would produce fewer but larger offspring; the nitrogen excretion rate would increase and the rate of growth of primary producers such as algae would increase.

e) The nitrogen excretion rate would increase.

d

44

Which of the following examples demonstrate an ecological effect leading to an evolutionary effect?

a) A few individuals with denser fur survive the coldest years of an ice age, and the offspring of the reproducing survivors of the ice age will likely have more dense fur.

b) The insects that spend the most time exposed to sunlight have the most mutations from UV light, and thus evolve the fastest

c) When seeds are not plentiful, trees produce more seeds.

d) Fish that swim the fastest in running water catch the most prey and more easily escape predation.

a

45

Which of the following areas of study focuses on the exchange of energy, organisms, and materials between ecosystems?

a) landscape ecology

b) organismal ecology

c) population ecology

d) ecosystem ecology

e) community ecology

a

46

Which of the following disease-causing organisms is most similar to that which causes Zika?

a) protozoan that causes malaria

b) bacterium that causes Lyme disease

c) nematode that causes onchocerciasis

d) virus that causes HIV

d

47

he discovery of which of the following mosquitoes in Ohio would raise the most concern that Zika will soon be found there?

a) Aedes agypti

b) Anopheles

c) Asian tiger

d) Culex pipiens

a

48

Which of the following is true?

a) It is unknown as to whether a single mosquito species can transmit more than one disease.

b) Mosquitoes do not transmit diseases.

c) A single mosquito species can transmit more than one disease.

d) A single mosquito species can transmit only one disease.

c

49

Which of the following would likely be most beneficial in the effort to decrease mosquito populations in Latin America?

a) Keeping trees neatly trimmed.

b) Growing numerous native flower species around homes.

c) Properly disposing of human waste.

d) Covering outdoor water containers.

d

50

If trends continue as predicted, which of the following is most likely?

a) Mosquito life cycles will speed up.

b) Mosquito life cycles will speed up in the northern hemisphere but slow down in the southern hemisphere.

c) Mosquito life cycles will slow down.

d) Mosquito life cycles will stay the same length as they are now.

a

51

In ecological terms, disturbance is an event such as a storm, fire, or human activity that changes a community, removing organisms and altering resource availability. Which of the following statements about the effects of disturbance is correct?

a) A healthy community is in an equilibrium state of balance, with few disturbances.

b) Disturbances can create patches of different habitats in a community.

c) The effects of disturbance on a community are almost always negative.

b

52

In Australia, researchers tested the hypothesis that sea urchin abundance limits kelp distribution. Select the evidence that offers the best support for this hypothesis.

a) Sea urchins graze on kelp.

b) There is an inverse relationship between the abundance of sea urchins and the abundance of kelp.

c) When sea urchins were removed from experimental plots, kelp cover increased.

c

53

Which of the following is an example of a population?

a) all the plants that live near each other in a forest

b) the earthworms that live in a grassland plus the earthworms that live in a forest

c) a spider and the fly it is about to eat

d) all the coyotes on Earth

e) all of the redwood trees that live in a forest

e

54

To determine the density of a rabbit population, you would need to know the number of rabbits and _____.

a) their pattern of dispersion

b) the size of the area in which they live

c) the factors that limit population growth for that rabbit population

d) the birth rate

e) the growth rate of the population

b

55

In wild populations, individuals most often show a _____ pattern of dispersion.

a) random

b) equilibrium

c) density-dependent

d) clumped

e) uniform

d

56

Suppose researchers marked 800 turtles and later were able to trap a total of 300 individuals in that population, of which 150 were marked. What is the estimate for total population size?

a) 1,600

b) 200

c) 2,100

d) 1,050

a

57

Which of the following assumptions must be made regarding the mark-recapture estimate of population size?

I) Marked and unmarked individuals have the same probability of being trapped.
II) The marked individuals have thoroughly mixed with the population after being marked.
III) No individuals have entered or left the population by immigration or emigration, and no individuals have been added by birth or eliminated by death during the course of the estimate.

a) I only

b) II only

c) I and II only

d) I, II, and III

d

58

Which of the following is the most important assumption for the mark-recapture method to estimate the size of wildlife populations?

a) There is a 50:50 ratio of males to females in the population before and after trapping and recapture.

b) More individuals emigrate from, as opposed to immigrate into, a population.

c) Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase.

d) Over 50% of the marked individuals were trapped during the recapture phase.

c

59

An ecologist recorded 12 white-tailed deer, Odocoileus virginianus, per square kilometer (km2) in one woodlot and 20 km2in another woodlot. What was the ecologist comparing?

a) density

b) range

c) dispersion

d) carrying capacity

a

60

Uniform spacing patterns in plants such as the creosote bush are most often associated with _____.

a) competitive interaction between individuals of the same population

b) patterns of high humidity

c) the random distribution of seeds

d) the concentration of nutrients within the population's range

a

61

Which of the following groups would be most likely to exhibit uniform dispersion?

a) cattails, which grow primarily at edges of lakes and streams

b) red squirrels, who actively defend territories

c) lake trout, which seek out cold, deep water high in dissolved oxygen

d) dwarf mistletoes, which parasitize particular species of forest tree

b

62

Which of the following is the best natural example of a uniform pattern of dispersion?

a) mushrooms growing on the floor of an old growth forest

b) moss spores floating in the wind to new locations of a forest

c) territorial songbirds in a mature forest during mating season

d) bees collecting pollen in a wildflower meadow

a

63

In the models that describe population growth, r stands for _____.

a) total number of individuals in the population

b) per capita population growth rate

c) population density

d) a time interval

e) carrying capacity

b

64

In July 2008, the United States had a population of approximately 302,000,000 people. How many Americans were there in July 2009, if the estimated 2008 growth rate was 0.88%?

a) 2,657,600

b) 567,760,000

c) 304,657,600

d) 304,000,000

c

65

In 2008, the population of New Zealand was approximately 4,275,000 people. If the birth rate was 14 births for every 1,000 people, approximately how many births occurred in New Zealand in 2008?

a) 59,850

b) 6,000

c) 140,000

d) 42,275

a

66

Starting from a single individual, what is the size of a population of bacteria at the end of a 2-hour time period if they reproduce by binary fission every 20 minutes?

a) 16

b) 128

c) 64

d) 32

c

67

During exponential growth, a population always ________.

a) loses some individuals to emigration

b) adds more new individuals when the population is small than when it is large

c) quickly reaches its carrying capacity

d) grows at its maximum per capita rate

d

68

The number of individuals that a particular habitat can support with no degradation of that habitat is called _____.

a) community

b) carrying capacity

c) survivorship

d) biotic potential

e) niche

b

69

As N approaches K for a certain population, which of the following outcomes is predicted by the logistic equation?

a) The carrying capacity of the environment will increase.

b) The population growth rate will not change.

c) The population size will increase exponentially.

d) The population growth rate will approach zero.

d

70

Which of the following causes populations to shift most quickly from an exponential to a logistic population growth?

a) competition for resources

b) decreased death rate

c) removal of predators

d) favorable climatic conditions

a

71

According to the logistic growth equation, dNdt=rN(K−N)K, ________.

a) the per capita growth rate (r) increases as N approaches K

b) the population grows exponentially when K is small

c) population growth is zero when N equals K

d) the number of individuals added per unit time is greatest when N is close to zero

c

72

Resource competition, territoriality, disease, and toxic wastes are some of the factors that provide _____ and help regulate population.

a) positive feedback

b) population dynamics

c) metapopulations

d) negative feedback

e) zero population growth

d

73

A broad-based pyramid-shaped age structure is characteristic of a population that is _____.

a) at carrying capacity

b) stable

c) growing rapidly

d) limited by density-dependent factors

e) shrinking

c

74

Which of the following is regarded as a density-independent factor in the growth of natural populations?

a) emigration

b) interspecific competition

c) intraspecific competition

d) predation

e) flooding

e

75

Which of the following is the most accurate statement on Earth's carrying capacity for humans?

a) K is smaller now than it was a thousand years ago.

b) The human population is still a long way from K.

c) Our technology has allowed the human population to keep increasing K.

d) When it comes to humans, the concept of K is irrelevant.

e) The human population has already exceeded K.

c

76

Why does the U.S. population continue to grow even though the United States has essentially established a zero population growth (ZPG)?

a) emigration

b) immigration

c) the 2007-2009 economic recession

d) baby boomer reproduction

b

77

Which of the following statements regarding the future of populations in developing, less industrialized countries are correct?

I) The reproductive rates are predicted to remain below replacement level.
II) Survivorship will increase.
III) Overall population size will increase dramatically.
IV) The fertility rate is predicted to remain high, especially in some regions.

a) only II, III, and IV

b) only II and IV

c) only I, II, and III

d) only I and III

a

78

A human eats a deer. Which of these terms applies to the relationship between the human and the deer?

a) parasitism

b) mutualism

c) commensalism

d) predation

e) competition

d

79

Humans and sharks both eat fish. Which of these terms applies to the relationship between the human and the shark?

a) predation

b) commensalism

c) mutualism

d) parasitism

e) competition

e

80

Humans who have pets tend to be healthier than humans who do not have pets. Which of these terms applies to the relationship between a human and a pet?

a) competition

b) mutualism

c) predation

d) parasitism

e) commensalism

b

81

Which of these terms applies to the relationship between a dog and a blood-sucking tick?

a) mutualism

b) commensalism

c) predation

d) parasitism

e) competition

d

82

An egret eats insects stirred up by grazing animals. Which of these terms applies to the relationship between the egret and the grazing animal?

a) parasitism

b) predation

c) competition

d) mutualism

e) commensalism

e

83

According to the principle of competitive exclusion, two species cannot continue to occupy the same _____.

a) range

b) environmental habitat

c) territory

d) ecological niche

e) biome

d

84

Of the choices below, which best describes the effect predation has on the predator/prey organisms involved in the relationship?

A) harmed ... harmed

b) benefit ... benefit

c) no effect ... benefit

d) benefit ... harmed

e) benefit ... no effect

d

85

The term used to describe a harmless organism resembling a harmful one is _____.

a) Batesian mimicry

b) aposematic coloration

c) cryptic coloration

d) Müllerian mimicry

e) warning coloration

a

86

Cellulose-digesting microorganisms live in the guts of termites and ruminant mammals. The microorganisms have a home and food, and their hosts gain more nutrition from their meals. This relationship is an example of _____.

a) parasitism

b) predation

c) mutualism

d) commensalism

e) herbivory

c

87

Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects and small vertebrates, birds follow and pick off any insects or small vertebrates that fly or jump out of the way of the ants. This situation is an example of what kind of species interaction between the birds and the ants?

a) mutualism

b) commensalism

c) consumption

d) parasitism

b

88

The symbols +, -, and 0 are used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes interactions in which individuals are not affected. The first symbol refers to the first organism mentioned. What interactions exist between a lion pride and African wild dogs, if the dogs are found to typically avoid areas with lions?

a) -/-

b) +/-

c) 0/0

d) +/+

b

89

The symbols +, -, and 0 are used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes interactions in which individuals are not affected. The first symbol refers to the first organism mentioned. Which fact is correct when describing species interactions?

a) +/0 will always remain such.

b) A +/- interaction could shift to +/0 or +/+ over time, depending on other factors such as competition, population density, or environmental changes.

c) Species interactions occur in isolation and cannot affect the structure of ecological communities.

d) A -/- interaction benefits both of the species in the relationship.

b

90

If two species are close competitors, and one species is experimentally removed from the community, the remaining species would be expected to _____.

a) become the target of specialized parasites

b) change its fundamental niche

c) decline in abundance

d) expand its realized niche

d

91

Which of the following is an example of a commensalism?

a) rancher ants that protect aphids in exchange for sugar-rich honeydew

b) bacteria fixing nitrogen on the roots of some plants

c) cattle egrets eating insects stirred up by grazing bison

d) fungi residing in plant roots, such as endomycorrhizae

c

92

An organism's "trophic level" refers to _____.

a) its food source

b) whether it is early or late in ecological succession

c) where it lives

d) the rate at which it uses energy

e) the intensity of its competition with other species

a

93

Keystone species are those species _____.

a) whose absence would cause major disruption in a community

b) that live primarily on or under rocks and stones

c) with the largest number of individuals in a community

d) that have the most biomass in the community

e) that provide important foods and medicines

a

94

Elephants are not the most abundant species in African grasslands, yet they influence community structure. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands are converted to forests or to shrublands. The newly growing forests support fewer species than the previous grasslands. Which of the following statements describes why elephants are the keystone species in this scenario?

a) Elephants help other populations survive by keeping out many of the large African predators.

b) Elephants are the biggest herbivore in this community.

c) Grazing animals depend upon the elephants to convert forests to grassland.

d) Elephants exhibit a disproportionate influence on the structure of the community relative to their abundance.

d

95

Which of the following statements is a likely explanation for why invasive species take over communities into which they have been introduced?

a) Invasive species have a higher reproductive potential than native species.

b) Invasive species come from geographically isolated regions, so when they are introduced to regions where there is more competition, they thrive.

c) Invasive species are not held in check by the predators and agents of disease that have always been in place for native species.

d) Invasive species are less efficient than native species in competing for the limited resources of the environment.

c

96

Keystone predators can maintain species diversity in a community if they _____.

a) allow immigration of other predators

b) prey only on the least abundant species in the community

c) prey on the community's dominant species

d) competitively exclude other predators

c

97

Food chains are sometimes short because _____.

a) predator species tend to be less diverse and less abundant than prey species

b) only a single species of herbivore feeds on each plant species

c) most of the energy in a trophic level is lost as it passes to the next higher level

d) local extinction of a species causes extinction of the other species in its food chain

c

98

Which of the following best illustrates ecological succession?

a) Overgrazing causes a nutrient loss from soil.

b) Grass grows on a sand dune, is replaced by shrubs, and then by trees.

c) Introduced pheasants increase, and native quail populations disappear.

d) Decomposition in soil releases nitrogen that plants can use.

e) A mouse eats seeds, and an owl eats the mouse.

b

99

Why is a pathogen generally more virulent in a new habitat?

a) Intermediate host species are more motile and transport pathogens to new areas.

B) Pathogens evolve more efficient forms of reproduction in new environments.

c) New environments are almost always smaller in area so that transmission of pathogens is easily accomplished between hosts.

d) Hosts in new environments have not had a chance to become resistant to the pathogen through natural selection.

d

100

Caribbean coral reef communities have been strongly influenced by an unknown pathogen that causes white-band disease. How can the effect of white-band disease best be described?

a) commensalism

b) mutualism

c) a cascade event that shifts the entire makeup of the community

d) Batesian mimicry

e) the removal of a keystone species

c

101

The energy for nearly every organism in nearly every ecosystem ultimately comes from _____.

a) minerals in the soil

b) the sun

c) heat from Earth

d) respiration

e) decomposition

b

102

On a global scale, energy _____ ecosystems whereas chemical elements _____ ecosystems.

a) is biologically magnified in ... are recycled in

b) is dissipated in ... flow through

c) flows through ... are recycled in

d) is continuously supplied to ... are continuously removed from

e) is recycled in ... flow through

c

103

Consider this segment of a food web: Snails and grasshoppers eat pepper plants; spiders eat grasshoppers; shrews eat snails and spiders; owls eat shrews. The shrew occupies the trophic level(s) of _____.

a) primary consumer only

b) secondary consumer only

c) tertiary consumer only

d) primary and secondary consumers

e) secondary and tertiary consumers

e

104

Which of the following terms encompasses all of the others?

a) primary consumers

b) carnivores

c) herbivores

d) heterotrophs

d

105

If the sun were to suddenly stop providing energy to Earth, most ecosystems would eventually vanish. Which of the following ecosystems would likely survive the longest after this hypothetical disaster?

a) tundra

b) deep benthic ocean

c) pelagic ocean

d) a desert spring

b

106

To recycle nutrients, an ecosystem must have, at a minimum, _____.

a) producers

b) producers, primary consumers, and decomposers

c) producers and decomposers

d) producers, primary consumers, secondary consumers, and decomposers

c

107

Which of the following organisms is correctly paired with its trophic level?

a) fungus: primary consumer

b) phytoplankton: primary producer

c) grasshopper: secondary consumer

d) cyanobacterium: primary consumer

b

108

Which of the following has the greatest effect on the rate of chemical cycling within an
ecosystem?

a) the trophic efficiency of the ecosystem

b) the ecosystem's rate of primary production

c) the rate of decomposition in the ecosystem

d) the secondary production efficiency of the ecosystem's consumers

c

109

The producers in aquatic ecosystems include organisms in which of the following groups?

a) cyanobacteria

b) algae

c) plants

d) photoautotrophs

e) All of the above are correct.

e

110

The relationship between biomass and primary productivity is that _____.

a) biomass is the rate of primary productivity

b) biomass is the inverse of primary productivity

c) biomass is the natural log of primary productivity

d) primary productivity is the inverse of biomass

e) primary productivity is the rate at which biomass is produced

e

111

_____ are secondary consumers.

a) Producers

b) Herbivores

c) Plants

d) Cows

e) Carnivores

e

112

Approximately _____% of the energy at one trophic level is passed on to the next highest trophic level.

a) 0–5

b) 5–10

c) 10–15

d) 15–20

e) 90–100

b

113

10,000 kcal of producer could support approximately _____ kcal of tertiary consumer.

a) 1,000

b) 100

c) 10

d) 1

e) 0

c

114

Why is a diagram of energy flow from trophic level to trophic level shaped like a pyramid?

a) Organisms at each level store most of the energy and pass little on.

b) There are more producers than primary consumers, and so on.

c) Organisms eventually die.

d) Most energy at each level is lost, leaving little for the next.

e) Secondary consumers are larger than primary consumers, and so on.

d

115

Which one of the following correctly ranks these organisms in order from lowest to highest percent in production efficiency?

a) fish, insects, mammals

b) mammals, fish, insects

c) mammals, insects, fish

d) insects, fish, mammals

b

116

Owls eat rats, mice, shrews, and small birds. Assume that, over a period of time, an owl consumes 5,000 J of animal material. The owl loses 2,300 J in feces and owl pellets and uses 2,500 J for cellular respiration. What is the production efficiency of this owl?

a) 8%

b) 7.4%

c) 2%

d) 40%

b

117

How does inefficient transfer of energy among trophic levels result in the typically high endangerment status of many top-level predators?

a) Top-level predators are more likely to be stricken with parasites.

b) Predators are more disease-prone than animals at lower trophic levels.

c) Top-level predators are destined to have small populations that are sparsely distributed.

d) Predators have relatively large population sizes.

c

118

Why does a vegetarian leave a smaller ecological footprint than an omnivore?

a) Eating meat is an inefficient way of acquiring photosynthetic productivity.

b) Vegetarians need to ingest less chemical energy than omnivores.

c) There is an excess of plant biomass in all terrestrial ecosystems.

d) Fewer animals are slaughtered for human consumption.

a

119

For most terrestrial ecosystems, pyramids composed of species abundances, biomass, and energy are similar in that they have a broad base and a narrow top. The primary reason for this pattern is that _____.

a) secondary consumers and top carnivores require less energy than producer

b) stop carnivores and secondary consumers have a more general diet than primary producers

c) at each step, energy is lost from the system

d) biomagnification of toxic materials limits the secondary consumers and top carnivores

c

120

Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems?

a) Nutrient cycling rates tend to be limited by decomposition.

b) Energy transfer between trophic levels is usually less than 20 percent efficient.

c) Many primary and higher-order consumers are opportunistic feeders.

d) Decomposers compete with higher-order consumers for nutrients and energy.

b

121

h trophic level is most vulnerable to extinction?

a) tertiary consumer level

b) secondary consumer level

c) primary consumer level

d) producer level

a

122

Which statement best describes what ultimately happens to the chemical energy that is consumed but not used to produce new biomass in the process of energy transfer between trophic levels in an ecosystem?

a) Heat produced by cellular respiration is used by heterotrophs for thermoregulation.

b) It is used by organisms to maintain their life processes through the reactions of cellular respiration.

c) It is eliminated as feces or is dissipated into space as heat as a result of cellular respiration consistent with the second law of thermodynamics.

d) It is undigested and winds up in the feces and is not passed on to higher trophic levels.

c

123

Consider the food chain of grass → grasshopper → mouse → snake → hawk. About how much of the chemical energy fixed by photosynthesis of the grass (100 percent) is available to the hawk?

a) 0.01%

b) 1%

c) 0.1%

d) 10%

a

124

If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps involving humans, starting from phytoplankton to zooplankton to fish to seals to polar bears, then which of the following could be accurate?

a )The total biomass of the fish is lower than that of the seals.

b) Polar bears can provide more food for humans than seals can.

c) Fish can potentially provide more food for humans than seal meat.

d) Seal populations are larger than fish populations.

c

125

What name is given to the process by which detritivores return carbon to the atmosphere?

a) burning

b) predation

C) photosynthesis

d) predation and photosynthesis

e) decomposition

e

126

Which of these removes carbon from the atmosphere?

a) logging trees

b) rabbits

c) burning fossil fuels, such as oil

d) bobcats

e) algae

d

127

Detritus is composed of _____.

a) detritivores

b) dead organic matter

c) inorganic minerals

d) excreted wastes

e) dead organic matter and excreted wastes

e

128

Which of these provides your body with energy?

a) minerals

b) fats

c) oxygen

d) vitamins

e) light

b

129

Plants use _____ as a source of energy.

a) minerals

b) fats

c) oxygen

d) vitamins

e) light

e

130

What element is found in all organic compounds?

a) carbon

b) oxygen

c) helium

d) iron

e) nitrogen

a

131

Plants obtain carbon from _____.

a) water

b) carbon dioxide

c) sugar

d) oxygen

e) glucose

b

132

Where do plants get the energy to make organic molecules?

a) minerals

b) glucose

c) vitamins

d) light

e) water

d

133

Which of these is NOT an organic molecule?

a) carbohydrates

b) minerals

c) proteins

d) glucose

e) lipids

b

134

Where do plants get the carbon they use to make organic molecules?

a) glucose

b) oxygen

c) water

d) starch

e) carbon dioxide

e

135

An ecosystem is unlikely to be limited by the supply of _____ because it is obtained from the air.

a) water

b) carbon

c) phosphorus

d) calcium

e) nitrogen

b

136

Matter may be gained by, or lost from, ecosystems. How does this occur?

a) Heterotrophs convert heat to energy.

B) Chemoautotrophic organisms can convert matter to energy.

c) Photosynthetic organisms convert solar energy to sugars.

d) Matter can move from one ecosystem to another.

d

137

In contrast to bioremediation, which is a strategy for _____, biological augmentation _____ a degraded ecosystem.

a) adding new species to control problem species...adds fertilizer to nutrient-poor soils in

b) using organisms to add essential materials ... removes harmful substances from

c) removing harmful substances...uses organisms to add essential materials to

d) eradicating a crippling disease in a keystone species...involves planting fruit- and grain-bearing crops to provide more forage in

e) replacing extirpated species... removes man-created pollutants and toxins from

c

138

The first step in ecosystem restoration is to _____.

a) restore native species that have been extirpated due to disturbance

b) remove toxic pollutants

c) restore the physical structure

d) remove competitive invasive species

c

139

The goal of restoration ecology is to ________.

a) return degraded ecosystems to a more natural state

b) manage competition among species in human-altered ecosystems

c) replace a ruined ecosystem with a more suitable ecosystem for that area

d) prevent further degradation by protecting an area with park status

a

140

The discipline that applies ecological principles to returning degraded ecosystems to a more natural state is known as _____.

a) resource conservation

b) conservation ecology

c) landscape ecology

d) restoration ecology

d

141

Which of the following would be considered an example of bioremediation?

a) adding fertilizer to soil poor in nutrients to increase plant growth

b) dredging a river bottom to remove contaminated sediments

c) adding nitrogen-fixing microorganisms to a degraded ecosystem to increase nitrogen availability

d) using a bulldozer to regrade a strip mine

c

142

Which of the following processes remove carbon dioxide (CO2) from the atmosphere?

a) photosynthesis

b) cellular respiration by plants

c) decomposition

d) the burning of fossil fuels

a

143

The formation of a wide, deep canyon causes a very large, genetically diverse plant population to split into two populations. The resulting populations are genetically similar to each other, and both are large (though smaller than the original population). Little gene flow occurs between these populations, and environmental conditions differ on the two sides of the canyon. Under these conditions, genetic differences between these populations are most likely to

a) decrease over time as natural selection favors different alleles in each population.

b) increase over time as natural selection favors different alleles in each population.

c) increase over time due to increased gene flow between the populations.

d) decrease over time due to decreased gene flow between the populations.

b

144

Suppose that 60% of Earth’s species became extinct during a mass extinction. If you could survey Earth’s biological communities 10,000 years after the end of this mass extinction, which of the following would you most expect to find?

a) Food webs would show fewer connections and fewer trophic levels than before the extinction.

b) Net primary production (NPP) would be higher than before the extinction.

c) Species that were well adapted to conditions before the extinction would have survived.

d) The number of species would have recovered to pre-extinction levels.

a

145

From 1930 to 1939 fire ants spread inland about 60 miles from their point of introduction in Mobile, Alabama. What was the cause of their spread over this distance?

a) a natural spread

b) airplanes

c) being transported along with soil

d) being transported along with plants

e) dispersion via ship ballast

a

146

From 1940 to 1970 fire ants spread through many southern states, sometimes at a rate of 100 miles in a year. What was the cause of their spread over this distance?

a) a natural spread

b) dispersion via ship ballast

c) airplanes

d) being transported along with plants

e) being transported along with plants and soil

e

147

In 1958 federal law restricted the movement of soil and plants from areas where fire ants were established. Why was this law unsuccessful in stopping the spread of fire ant colonies?

a) People were unaware of the federal law and, when they moved, transported plants bearing fire ant colonies.

b) A single mated queen can be transported without being noticed.

c) Many states originally thought to be free of fire ant colonies already had them.

d) People were unaware of the federal law and, when they moved, transported plants bearing fire ant colonies; moreover, a single mated queen can be transported without being noticed.

e) People were unaware of the federal law and, when they moved, transported plants bearing fire ant colonies; a single mated queen can be transported without being noticed; and many states thought to be free of fire ant colonies already had them.

e

148

Techniques used, or are being considered for use, in controlling the spread of fire ants include _____.

a) setting baits that kill the queen when they are carried back to the nest

b) applying chemical powders that kill the colony

c) introducing a protist to infect the fire ant queen and her eggs

d) introducing a fly that lays eggs in fire ants so that the eggs will hatch into larvae that eat their way into the ants' heads, which will then fall off

e) setting baits that kill the queen when they are carried back to the nest, applying chemical powders that kill the colony, introducing a protist to infect the fire ant queen and her eggs, and introducing a fly that lays eggs in fire ants so that the eggs will hatch into larvae that eat their way into the ants' heads, which will then fall off

e

149

Which of the following is part of conservation biology?

a) evolutionary biology

b) physiology

c) ecology

d) molecular biology and genetics

e) All of the choices are correct.

e

150

Which of the following organisms was/were introduced by humans into the United States or its territories?

a) brown tree snake

b) kudzu

c) European starling

d) zebra mussels

e) All of the choices are correct.

e

151

The single greatest current threat to biodiversity is _____.

a) reduced genetic variability

b) introduced species

c) global warming

d) habitat destruction

e) overexploitation

d

152

If all individuals in the last remaining population of a particular frog species were all highly related, which type of diversity would be of greatest concern when planning to prevent the species from going extinct?

a) genetic diversity

b) ecosystem diversity

c) local diversity

d) global diversity

a

153

What is the biological significance of genetic diversity between populations?

a) Genetic diversity reduces the probability of extinction.

b) Genes for traits conferring an advantage to local conditions are unlikely.

c) Diseases and parasites are not spread between separated populations.

d) The population that is most fit would survive by competitive exclusion.

a

154

Tropical forests are being converted to farm or pasture land at an alarming rate, and one major focus is on the biodiversity and the impact to these ecosystems. What is a direct benefit to humans that helps explain why these forests need to be preserved?

a) The plant diversity provides shade, which lowers global warming.

b) Natural and undisturbed areas are important wildlife habitats.

c) The diversity could contain novel drugs for consumers.

d) This diversity provides areas for coffee growing.

c

155

Ecosystem services include processes that increase the quality of the abiotic environment. Which of the following processes would fall under this category?

a) Keystone predators have a marked effect on species diversity.

b) The presence of dams improves flood control.

c) Green plants and phytoplankton produce the oxygen we breathe.

d) Bees, flies, and wasps pollinate many plants.

c

156

Erwin and Scott used an insecticidal fog to knock down insects from the top section of a L. seemannii tree. The researchers identified over 900 species of beetles among the individuals that fell. Erwin also projected that this entire tree from top to bottom is host to about 600 arthropod species that are unique to this tree species and not found on any other tree species. There are approximately 50,000 species of tropical trees. Although it could not be entirely accurate, what would be the best way to estimate the total number of arthropod species?

a) Add 900 to 600, and then multiply by 50,000.

b) Estimate the species density and then multiply by 50,000.

c) Multiply 50,000 by 900.

d) Multiply 600 by 50,000.

d

157

The human impact that scientists determined has caused the most extinctions on record is ________, and beyond further losses from this impact, the other impact with the largest potential to cause future extinctions is ________.

a) habitat loss; overharvesting

b) climate change; habitat loss

c) habitat loss; climate change

d) introduced species; habitat loss

c

158

Which of the following observations provides the best evidence of a biodiversity crisis?

a) climate change

b) high rate of extinction

c) the incursion of a non-native species

d) increasing pollution levels

b

159

Which of the following terms includes all of the others?

a) ecosystem diversity

b) biodiversity

c) species diversity

d) genetic diversity

b

160

Loss of biodiversity matters not only with regard to mammals or other vertebrates, but also microbes. Why are microbes worthy of discovery and protection from extinction?

a) Microbes may be the most sensitive to the next large extinction event.

b) Microbes may produce unique proteins useful in genetic research.

c) Microbes play a role in digestion.

d) Microbes are much greater in species number than any other taxa on Earth.

b

161

Overharvesting encourages extinction and is most likely to affect ________.

a) edge-adapted species

b) animals that occupy a broad ecological niche

c)most organisms that live in the oceans' coral reefs

d) large animals with low intrinsic reproductive rates

d

162

Of the following ecosystem types, which have been impacted the most by humans?

a) tundra and arctic

b) desert and high alpine

c) wetland and riparian

d) taiga and second-growth forests

c

163

Burning fossil fuels releases oxides of sulfur and nitrogen. These air pollutants can be responsible for ________.

a) precipitation with a pH as high as 8.0

b) the death of fish in lakes

c) eutrophication of lakes

d) global temperature decrease

b

164

Which of the following criteria have to be met for a species to qualify as invasive?

a) endemic to the area, spreads slowly, and displaces native species

b) endemic to the area, spreads rapidly, and displaces foreign species

c) introduced to a new area, spreads rapidly, and displaces other invasive species

d) introduced to a new area, spreads rapidly, and displaces native species

d

165

Which of these would NOT contribute to a global increase in temperature?

a) deforestation

b) increasing the use of gasoline-burning vehicles

c) increasing the industrial release of carbon dioxide

d) planting trees

e) increasing the amount of animal life on Earth

d

166

Switching from fossil fuels to _____ energy would significantly decrease the release of carbon dioxide into the atmosphere.

a) solar

b) nuclear

c) geothermal

d) solar and geothermal

e) solar, nuclear, and geothermal

e

167

Which of these are the two major sources of nitrate pollution in rivers?

a) the burning of fossil fuels by factories and cars

b) animal wastes and the burning of fossil fuels by cars

c) animal wastes and fertilizers

d) fertilizer runoff and the burning of fossil fuels by cars

e) animal wastes and the burning of fossil fuels by factories

c

168

Aquatic nitrate pollution can result in _____.

a) algal bloom

b) oxygen depletion

c) fish kills

d) hypoxia

e) an algal bloom that, when the algae die and are decomposed by bacteria, leads to hypoxia and the death of fish

e

169

Which of the following statements best describes why ecologists are currently concerned with global warming and the thawing of permafrost in many areas of the tundra biome?

a) Populations of humans inhabiting the Arctic will have to move to more southern latitudes, resulting in increased competition for resources in already densely populated areas.

b) The thawing process will likely decrease the abundance and diversity of soil-dwelling organisms in the tundra.

c) Migratory species of birds will likely be less successful finding food in thawed tundra, and their abundance will drop dramatically.

d) Oil and coal deposits will thaw and rise to the surface (due to their lower density) of the tundra, destroying millions of acres of arctic habitat.

e) The bacterial decomposition of thawed organic materials over the widespread areas of the tundra will produce large quantities of CO2, which will add to greenhouse gases and exacerbate global warming.

e

170

The effort to develop, manage, and conserve Earth's resources to meet the needs of people today without limiting the ability of future generations to meet their needs is called _____.

a) landscape management

b) bioremediation

c) biophilia

d) restoration ecology

e) sustainable development

e

171

The main goal of sustainable development is to _____.

a) use natural resources such that they do not decline over time

b) use only natural resources in the construction of new buildings

c) involve more countries in conservation efforts

d) reevaluating and re-implementing management plans over time

a