Deck 20: Communities and Ecosystems

Question 1

In order to assess the species diversity of a community, you would need to know the number of different species present as well as ________.

A)the number of trophic levels in the community
B)the intensity of interspecific competition in the community
C)the fraction of these species that are plants
D)the relative abundance of the different species

Answer 1

D

Question 2

A traveler was crossing the border from Canada to the United States and with a bag of Washington State apples. The customs officer at the border would not let the traveler take the apples into the United States, despite the apples originating from the United States. Why did the customs officer refuse to allow the traveler to cross the border with the apples?

A)Washington State apples are considered an endangered fruit.
B)There may have been a species that was not native to the United States hitching a ride on the apples.
C)Forcing the traveler to buy more apples from a store in the United States is better for the US economy.

Answer 2

B

Question 3

Populations of two coexisting species are both tertiary consumers in a community. What relationship may exist between these two organisms?

A)predation
B)mutualism
C)competition
D)succession

Answer 3

C

Question 4

Bears eat berries, humans, and large fish; large fish eat smaller fish and insects; humans eat bears, large fish, and berries. The scenario described here is an example of ________.

A)an ecosystem
B)parasitism
C)a food web
D)a food chain

Question 5

Two lakes have the same number of species. Most of the fish in Lake 1 are of a single species, with a few individuals each for the remaining species. Lake 2, on the other hand, has about equal numbers of each species. Which lake has higher species diversity?

A)Lake 1
B)Lake 2
C)They are equally diverse.
D)The number and relative abundance of species are not related to diversity.

Question 6

Most decomposers are ________.

A)plants and fungi
B)bacteria and plants
C)fungi and prokaryotes
D)animals

Question 7

In the food chain grass → antelope → human → lion, the human is a ________.

A)tertiary consumer
B)secondary consumer
C)primary consumer
D)producer

Question 8

In an aquatic food chain, small fishes that eat zooplankton are ________.

A)primary consumers
B)producers
C)tertiary consumers
D)secondary consumers

Question 9

Approximately what percentage of the visible light that reaches Earth's producers is converted to chemical energy?

A)10%
B)0)1%
C)1%
D)0)01%

Question 10

As a result of a severe disturbance, a community will ________.

A)not be repopulated
B)be replaced by organisms in random order
C)not change
D)undergo succession

Question 11

What is one way in which the movement of energy and chemicals differ in an ecosystem?

A)Energy flow is unidirectional; chemical elements can be recycled.
B)Energy can enter but cannot leave an ecosystem; chemical elements can leave but cannot enter an ecosystem.
C)Energy flows from lower to higher trophic levels; chemicals cycle from higher to lower trophic levels.
D)Both energy and chemical elements always remain within a single ecosystem.

Question 12

Herbivory is an example of a ________ interaction.

A)+/+
B)-/-
C)0/+
D)+/-

Question 13

The single greatest threat to biodiversity comes from ________.

A)habitat destruction and fragmentation
B)invasive species
C)overexploitation
D)pollution

Question 14

An example of a mutualism, or +/+ relationship, is ________.

A)between corals and unicellular algae
B)cryptic coloration in frogs
C)between snails and the plants that they eat
D)between birds that use some of the same resources

Question 15

The present rate of species loss ________.

A)suggests that about 25% of all plant and animal species may be extinct by the end of the century
B)is about the same as it has been during the last 100,000 years
C)is as much as 100 times higher than at any time in the last 100,000 years
D)is slower than in recent years because of conservation efforts

Question 16

Organisms that consume producers are ________.

A)tertiary consumers
B)decomposers
C)primary consumers
D)secondary consumers

Question 17

In the food chain grass → antelope → human → lion, the antelope is ________.

A)both an herbivore and a secondary consumer
B)both a producer and a primary consumer
C)both an herbivore and a primary consumer
D)a secondary consumer only

Question 18

In Yellowstone National Park, wolves were hunted to extinction in the 1920s. A current restoration project has reintroduced wolves to Yellowstone National Park. Predict the response of the Yellowstone ecological community if wolves are a keystone species.

A)Species richness should decrease.
B)The relative abundances of each species should become more unequal.
C)Species diversity should decrease.
D)Species richness should increase, and the relative abundances of each species should be about equal.

Question 19

Which of these organisms convert organic matter to inorganic matter by breaking down dead organisms?

A)producers
B)carnivores
C)decomposers
D)primary consumers

Question 20

Biomass is the total amount of ________ an ecosystem.

A)organic matter contained in the consumers of
B)organic matter contained in the producers of
C)chemical elements recycled by the detritivores of
D)organic material in

Question 21

The ecosystem that has low primary production but contributes a large proportion of Earth's total net primary production is ________.

A)tropical rain forest
B)coral reef
C)open ocean
D)desert

Question 22

The major abiotic reservoir for phosphorus is ________.

A)the oceans
B)the atmosphere
C)rock
D)dead organic matter

Question 23

Sustainable development ________.

A)will require making difficult decisions regarding the environment and lifestyle, but is not necessary for the survival of the human species nor will it require global, multinational cooperation
B)is necessary for the survival of the human species, but will not require making difficult decisions regarding the environment and lifestyle nor global, multinational cooperation
C)will require global, multinational cooperation, but not involve making difficult decisions regarding the environment and lifestyle, nor is it necessary for the survival of the human species
D)will require making difficult decisions regarding the environment and lifestyle, is necessary for the survival of the human species, and will require global, multinational cooperation

Question 24

Landscape ecology ________.

A)is the application of ecological principles to the study of land-use patterns
B)focuses primarily on how to restore human-altered ecological systems
C)deals primarily with ecosystems in urban settings
D)deals with the study of the ranges of different species

Question 25

Why are most food chains limited to three to five trophic levels?

A)The higher the trophic level, the larger the organism; the larger the organism, the less likely it will be prey.
B)The nutritional quality of existing biomass decreases with increasing trophic level.
C)Most ecosystems have insufficient space to support the increased number of organisms that more trophic levels would require.
D)There is insufficient energy to support more trophic levels.

Question 26

Species found in only one place on Earth are called ________ species.

A)hot spot
B)invasive
C)keystone
D)endemic

Question 27

The organisms that can convert atmospheric nitrogen gas to a form that can be utilized by plants are ________.

A)bacteria
B)protists
C)animals
D)fungi

Question 28

________ convert nitrogen from nitrates to N₂.

A)Nitrifying bacteria
B)Nitrogen-fixing bacteria living in the soil
C)Denitrifying bacteria
D)Nitrogen-fixing bacteria living in the root nodules of legumes

Question 29

The rate at which an ecosystem's producers convert solar energy to chemical energy stored in biomass is called ________.

A)energy flow
B)chemical cycle
C)primary productivity
D)trophic structure

Question 30

What is the range of actual efficiencies of energy transfer from one trophic level to the next?

A)5-20%
B)20-30%
C)10-25%
D)90-100%

Question 31

The primary goal of conservation biology is to ________.

A)catalog species
B)maximize the land set aside for wildlife
C)integrate human culture back into nature
D)counter the loss of biodiversity

Question 32

Besides the atmosphere, abiotic reservoirs of carbon dioxide include ________.

A)fossil fuels and dissolved carbon compounds in the oceans
B)rocks and dissolved carbon compounds in the oceans
C)fossil fuels, but not dissolved carbon compounds in the oceans or rocks
D)rocks, but not fossil fuels or dissolved carbon compounds in the oceans

Question 33

A regional assemblage of interacting ecosystems is a ________.

A)community
B)landscape
C)movement corridor
D)hot spot

Question 34

With regard to nutrient pollution in aquatic ecosystems, when is the worst time to apply fertilizer to your lawn?

A)when it is raining, or is about to rain
B)when it is cold, or is about to get cold
C)at the same time you apply pesticides
D)at night

Question 35

Modern conservation science increasingly aims at ________.

A)protecting federally listed endangered species
B)countering pollution
C)sustaining entire ecosystems
D)maintaining genetic diversity within species

Question 36

Movement corridors ________.

A)always created by humans
B)found only along stream sides
C)never harmful because they allow for dispersal
D)both harmful and beneficial, depending on the organisms that are dispersed

Question 37

The atmosphere is approximately 80% ________ gas.

A)CO₂
B)H₂O
C)NH₃
D)N₂

Question 38

Plants can most readily utilize the ________ form of nitrogen.

A)nitrous oxide
B)N₂
C)amino
D)nitrate

Question 39

A movement corridor ________.

A)is a path used by migratory animals when they move to their winter habitats
B)is the path most commonly used by an animal within its home range
C)connects otherwise isolated patches of quality habitat for a species
D)is a natural component of the environment

Question 40

Small areas that have a large number of endangered and threatened species are referred to as ________.

A)biologically magnified
B)endemic environments
C)biodiverse environments
D)biodiversity hot spots

Question 41

The figure shows the results of an experiment where sea stars were removed from communities. What is the sea star's role in the community?

A)The sea star is a keystone species, because its presence maintains diversity.
B)The sea star is an invasive species, because its absence reduces diversity.
C)The sea star competitively excludes other species from the community.

Question 42

If a small forest fragment (less than 2.5 hectares in size)was found to have 0.01 infected nymph ticks per square meter, what characteristic would you expect this fragment to have?

A)a corridor to a larger forest fragment
B)edges that are good habitat for tick hosts
C)vegetation that required bioremediation
D)endemic species that increase tick population size

Question 43

Examine the figure. If both barnacle species (Chthalamus and Balanus)had identical niches, but Balanus is a superior competitor, how would the figure need to be changed? Assume the captions would be edited appropriately.

A)Chthalamus would not be present in in (a)and Balanus would be distributed to the high tide line.
B)Chthalamus would not be distributed below the low tide line in (b).
C)Balanus would be between the low and high tide lines, and Chthalamus below the low tide line in (a).

Question 44

Humans, mosquitoes, and Plasmodium together would be considered a(n)________.

A)population
B)community
C)ecosystem

Question 45

Refer to the accompanying figure. Together, all of the living components of the coral reef represent a(n)________.

A)population
B)species
C)community
D)ecosystem

Question 46

Why is it important to reverse the decline of endangered species such as the Tasmanian devil?

A)They provide ecosystem services that benefit humans and the ecological community.
B)They may evolve to compete with humans for resources.
C)They do not have economic value, but do have cultural value.

Question 47

Why might one savanna ecosystem have 4 trophic levels, while a second one has 5?

A)The second ecosystem has less biomass of primary producers compared to the first.
B)The second ecosystem is a large savanna, while the first ecosystem is small.
C)The second ecosystem exhibits a greater loss of energy between trophic levels.
D)The second ecosystem has a higher rate of denitrification.

Question 48

Examine the figure. What is the interaction between Chthalamus and Balanus?

A)interspecific competition
B)commensalism
C)mutualism
D)herbivory

Question 49

The figure below shows the growth curves of two populations of Paramecium, P. aurelia and P. caudatum. From the data, we can conclude that ________.

A)the ecological niches of the two species are very different
B)P) aurelia is a predator of P. caudatum
C)P) aurelia and P. caudatum have a mutualistic relationship
D)P) aurelia is the superior competitor in this habitat

Question 50

Examine the figure. Zooplankton feed on phytoplankton that are contaminated by PCBs in the water. Which comparison correctly describes the concentration of PCBs in different trophic levels?

A)Primary consumers have higher PCB concentration than secondary consumers.
B)Quaternary consumers have the highest PCB concentration.
C)Tertiary consumers have the highest PCB concentration.
D)Cod has a higher PCB concentration than the secondary consumers.

Question 51

This graph shows the results of a study on black-legged tick nymphs that are infected with the Lyme disease bacterium. The density of infected nymphs was calculated for forest fragments of different sizes (area in hectares). Answer the following questions using this graph.
Humans can be infected with the Lyme disease bacterium. According to the graph, a hiker has the highest risk of encountering an infected black-legged tick nymph in forests that are ________ in area.

A)1 hectare
B)3 hectares
C)5 hectares
D)10 hectares

Question 52

Why does the invasive brown treesnake have a negative effect on the biodiversity of Guam?

A)It disrupts mutualistic interactions that are necessary for the reproduction of primary producers.
B)It eats poultry and causes frequent power outages by shorting out high-voltage wires.
C)It competes with native snakes for nesting sites and prey.
D)It is venomous and kills forest scientists who study Guam's biodiversity.

Question 53

The figure shows the results of an experiment where sea stars were removed from communities. What is the effect of sea stars on barnacle A?

A)When sea stars are present, the relative abundance of barnacle A is lower compared to when sea stars are absent.
B)When sea stars are present, the relative abundance of barnacle A is higher compared to when sea stars are absent.
C)When sea stars are present, the species richness of barnacle A is lower compared to when sea stars are absent.
D)When sea stars are present, the species richness of barnacle A is higher compared to when sea stars are absent.

Question 54

In the ecosystem shown, a toxin that accumulates in body tissues would have the largest effect on ________.

A)corals that obtain their food from photosynthesizing dinoflagellates
B)herbivorous shrimp
C)fish that eat shrimp and other invertebrates
D)The toxin would affect all of these equally.

Question 55

If there were an additional trophic level in this figure that consisted of organisms that prey on snakes, about how much energy would be available to organisms at that trophic level?

A)100 kcal
B)90%
C)1 kcal
D)10 kcal

Question 56

Species that require large areas to survive are disappearing as their habitat is destroyed. Researchers have found that increased forest fragmentation is associated with a higher risk of Lyme disease, which is carried by white-footed mice and transmitted from mice to humans by black-legged ticks. The researchers hypothesized that communities with higher biodiversity contain hosts for the Lyme disease bacteria that do not spread the bacteria to humans. Propose an alternative hypothesis that uses energy flows in ecosystems to explain their findings.

A)Smaller forest fragments support fewer trophic levels, and thus are less likely to have predators like coyotes to reduce mouse population size.
B)A greater percentage of energy is lost during each transfer of energy in larger forest fragments than in smaller ones, and decreases the amount of food sources for mouse hosts.
C)Larger forest fragments have faster energy flow, which makes it more difficult for small organisms like bacteria to survive.

Question 57

What is the estimated annual value of ecosystem services?

A)$1 billion
B)$30 trillion
C)$30 billion
D)$1 trillion

Question 58

One problem with eradicating invasive species is that sometimes the disturbed area is unable to be colonized by native species. For example, in forests where the invasive plant garlic mustard has been removed, native plants and animals do not recolonize because they are extinct in that patch of forest. How should restoration ecologists increase species diversity and recover ecosystem function?

A)Introduce tertiary consumers.
B)Develop movement corridors for primary producers.
C)Develop movement corridors for species with similar niches.
D)Eliminate keystone species.

Question 59

Use the following information to answer the following questions.
Malaria is an infectious disease caused by a unicellular eukaryotic organism belonging to the genus Plasmodium. These eukaryotic organisms are transmitted from one person to another by the female Anopheles mosquito when it feeds on human blood. Within humans, the Plasmodium species destroy red blood cells and, without effective treatment, serious infections can lead to death. Currently, more than 400 million people are afflicted with malaria and between 1 and 3 million people die from it each year. Historically, a chemical compound called quinine has been used in developing effective drugs against malaria. In its natural environment, quinine is produced by certain trees native to South America. This chemical is synthesized in the outer layer of tree trunks and acts as an herbivore deterrent.
Based on the relationship between Plasmodium spp. and humans, Plasmodium would be considered ________.

A)parasites
B)hosts
C)producers
D)carnivores

Question 60

Examine the figure. Which statement correctly compares the biomass of different trophic levels to the concentrations of PCB contained in each level.

A)Only some of the biomass from one level moves to the consumer, whereas PCBs become more concentrated with each trophic transfer.
B)Higher trophic levels have more total biomass and higher concentrations of PCBs than lower trophic levels.
C)Biomass increases with each trophic transfer, while PCBs become less concentrated.

Question 61

Use the following information to answer the following questions.
In East Java, Indonesia, a mud volcano has been erupting since 2006. One controversial hypothesis is that the mud volcano in East Java is erupting because a gas mining company was drilling a deep hole nearby. When a mud volcano erupts, hot water deep below the earth's surface mixes with various minerals, and this mud spews out over the surface of the earth. The hot mud flow destroys organismal habitats, including the homes and livelihoods of people.
When the mud volcano stops erupting, colonization of the disturbed area would be ________.

A)primary succession if there is no biomass inside the area
B)primary succession if primary production relies on plants that survived the disturbance
C)secondary succession if there are no biotic components of the carbon cycle
D)secondary succession if there is no organic matter in the area

Question 62

Despite being used for many years, quinine-based drugs have not led to the eradication of malaria and currently there are parasites that are resistant to the compound. What process was likely important in the development of this resistance to quinine?

A)natural selection
B)mutualism
C)interspecific competition
D)biological magnification

Question 63

Use the following information to answer the following questions.
In East Java, Indonesia, a mud volcano has been erupting since 2006. One controversial hypothesis is that the mud volcano in East Java is erupting because a gas mining company was drilling a deep hole nearby. When a mud volcano erupts, hot water deep below the earth's surface mixes with various minerals, and this mud spews out over the surface of the earth. The hot mud flow destroys organismal habitats, including the homes and livelihoods of people.
When the mud volcano stops erupting, the disturbed area will be colonized by a variety of species. This process of colonization is called ________.

A)biological magnification
B)species diversity
C)ecological succession
D)disturbance