Deck 36: Communities of Organisms

Question 1

Which of the following is not a producer in an aquatic biome?

A) algae
B) mussels
C) phytoplankton
D) bacteria

Answer 1

B

Question 2

Which of the following organisms is not a producer?

A) plankton
B) cow
C) algae
D) oak tree

Answer 2

B

Question 3

Which of the following organisms is a producer?

A) fungus
B) human
C) cow
D) grass

Answer 3

D

Question 4

A farmer and his family raise 100 acres of corn, 12 chickens, and two cows. What is the keystone species?

A) corn
B) chickens
C) cows
D) people

Question 5

In a typical prairie food web, energy moves from grass to grasshopper to field mouse to fox. Which organism is the primary producer?

A) the grass
B) the grasshopper
C) the mouse
D) the fox

Question 6

Pancake batter consists of flour, eggs, butter, salt, baking powder, sugar, and milk. When we eat pancakes, we are acting as

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

Question 7

Organisms that eat producers are known as

A) cannibals.
B) secondary producers.
C) primary consumers.
D) predators

Question 8

Because island communities evolve in isolation, one of the most serious threats to their biodiversity is

A) native predators.
B) climate change.
C) succession.
D) introduced species.

Question 9

The sea star Pisaster ochraceus was removed from selected intertidal communities along the Washington coast. After 10 years how did those communities compare to control communities?

A) The communities were statistically indistinguishable from one another.
B) Without sea stars, mussels became abundant and crowded out other community members.
C) Other predatory sea stars replaced Pisaster.
D) The mussel populations declined, but most species were unaffected.

Question 10

The removal of a keystone species from a community usually results in

A) the death of all other community members.
B) the disappearance of that community.
C) substantial changes in the abundance of many species.
D) minor changes, if any.

Question 11

In a typical prairie food web energy moves from grass to grasshopper to field mouse to fox. Which organism is the tertiary consumer?

A) the grass
B) the grasshopper
C) the mouse
D) the fox

Question 12

In a typical prairie food web, energy moves from grass to grasshopper to field mouse to fox. Which organism is the primary consumer?

A) the grass
B) the grasshopper
C) the mouse
D) the fox

Question 13

Which of the following best characterizes humans' method of obtaining energy?

A) primary consumers only
B) secondary consumers only
C) primary, secondary, and occasionally tertiary consumers
D) secondary producers

Question 14

Into which category would a human be assigned when eating pepperoni pizza?

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

Question 15

Since humans arrived in Hawaii, the native biological community has

A) experienced an increase in biological diversity.
B) been negatively impacted by habitat destruction and introduced species.
C) been improved by selective hunting.
D) remained unchanged.

Question 16

In a typical prairie food web, energy moves from grass to grasshopper to field mouse to fox. Which organism is the secondary consumer?

A) the grass
B) the grasshopper
C) the mouse
D) the fox

Question 17

Into which category would a human be assigned when eating chicken?

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

Question 18

Why would a food web rather than a food chain be the preferred way to represent the movement of food through the community?

A) Food chains are oversimplified and suggest that a consumer eats only a single food item.
B) Food webs place producers at the bottom while food chains place them at the top.
C) Food webs are based on a foundation of producers.
D) Actually, ecologists prefer to use food chains to describe food movements.

Question 19

Can a human being be considered an ecological community?

A) Yes; for example, a community of microorganisms lives within the human digestive system.
B) Yes; human beings live with other humans, own pets, and grow domesticated crops.
C) No; a community is formed from many populations and it takes more than one individual to make up a population.
D) No; human populations are artificial rather than natural, and are considered to fall outside of ecology.

Question 20

Which of the following statements about communities is true?

A) They usually have few species of organisms.
B) There can be complex interactions between the organisms that make up a community.
C) They are more abundant in temperate areas.
D) They are made up of mammal species only.

Question 21

Which of the following can occur when the climate of an area changes?

A) Natural selection usually causes the community to adapt and survive the change with little visible effect.
B) That area becomes uninhabitable to all species and is abandoned.
C) That community may relocate to an area with a climate similar to that of the original location.
D) Continental drift restores communities to climates similar to those from which the communities came.

Question 22

Anthropogenic, or human-caused, changes to ecological communities typically

A) improve those habitats for other organisms.
B) cause long-term damage and reduce the complexity of existing communities.
C) do not influence the natural interactions between organisms.
D) generally increase the diversity of life on Earth.

Question 23

Which of the following experiments would help to identify a keystone species?

A) Introduce more of the suspected species into the area and observe the effects on other community members.
B) Remove the suspected species from the area and observe the effects on other community members.
C) Introduce an invasive species related to the suspected species into the area and observe the effects on the suspected species.
D) Introduce additional individuals of the suspected species' food source into the area and observe the effects on community members.

Question 24

Human-caused changes in ecological communities can be considered unique because

A) humans have control over the actions that might cause the changes.
B) human-caused changes are always more severe than natural changes.
C) human-caused changes almost always benefit the existing community.
D) human-caused changes almost always modify the regional climate.

Question 25

The process that establishes new communities and restores disturbed communities is termed

A) secondary growth.
B) eutrophication.
C) diversification.
D) succession.

Question 26

Food webs, like the one in the figure below, help biologists predict the impact to a community that changes in species abundance might produce.
After studying the food web above, select a reasonable outcome following the complete disappearance of leopard seals.

A) Killer whales may decline since they eat leopard seals
B) Chilean seas bass may increase since one of their primary predators is gone.
C) Baleen whales will increase as more krill becomes available
D) Sperm whales may decline as squid become less abundant.

Question 27

The climate of a given location can change over time for two reasons: global climate change and

A) continental drift.
B) agricultural activities.
C) change in the makeup of the local communities.
D) the effect of introduced species.

Question 28

Communities change with respect to several timescales; an example of long-term change would be

A) the annual variability in population size.
B) the presence or absence of a migrant species.
C) the species composition of the community.
D) the decline in prey abundance during a harsh winter.

Question 29

In which of the following situations would secondary rather than primary succession be most likely to occur?

A) on an island that has just risen out of the ocean
B) on bare ground exposed by the retreat of a glacier
C) on the surface of recently cooled lava
D) in a forest that had burned to bare ground

Question 30

If the original organisms that colonized Hawaii came from other places on Earth, why are the organisms that now live on Hawaii so different from organisms that live elsewhere on Earth?

A) Hawaii is a relatively young land mass, so evolution continues there although it has ceased in most other places on Earth.
B) The organisms that live on Hawaii do not have predators, which allows them to evolve into a greater variety of life forms.
C) Through time, adaptation and evolution caused speciation to produce new organisms unique to Hawaii.
D) none of the above

Question 31

Which of the following choices best explains, from an ecological perspective, why there are laws that require a wildlife survey before certain building or other land-use projects may proceed?

A) If a keystone species is found, it can be moved to another area where it will establish a new community of organisms.
B) If the only local habitat for a keystone species is disturbed, the entire community of populations will be affected.
C) If the species are surveyed before the land is used they will all be more likely to survive the building project.
D) If the species are surveyed before the land is used they will all be more easily distributed to other habitats.

Question 32

During _________ newly created habitat is inhabited.

A) primary succession
B) climax community formation
C) disturbance colonization
D) keystone recovery

Question 33

All of the following disturbances except _____ would be considered natural.

A) fire
B) flood
C) windstorm
D) mining

Question 34

All of the following except the _____ could be part of the same food chain.

A) clover
B) squirrel
C) rabbit
D) fox

Question 35

Once a climax community develops, is it likely to remain that way indefinitely?

A) No; over long-term timescales climate change will probably occur, causing the community to eventually change.
B) No; once a climax community develops, the lack of biotic variability eventually degrades the habitat.
C) Yes; once a climax community develops, it will always remain undisturbed
D) Yes; climax communities become so stable that they prevent disturbances from occurring.

Question 36

Which of the following could represent the linear flow of energy within a food web?

A) wolves, lions, and cheetahs
B) grass, bushes, and trees
C) lettuce, rabbits, and foxes
D) sheep, cows, and horses

Question 37

The figure below illustrates how, although pines first established themselves as the dominant tree in the Lake Michigan sand dune community, black oaks ultimately become the dominant species.
What best explains the gradual reduction of the pine?

A) Oaks trap sand, causing the dune to level out; pines can only survive in the low, protected areas between the dunes.
B) Pine needles and the shade from existing pines improve the soil composition and moisture, allowing oaks to become established and preventing new pines from surviving.
C) Pines replace the grasses but this destabilizes the dune and increases the amount of moving sand; the loss of pines is not related to the presence of the oaks.
D) Actually oak seeds were always present in the sand; they simply require more time to germinate.

Question 38

Why is the existence of food webs important even though food chains also exist?

A) Food webs address the activities of consumers, whereas food chains address the activities of producers.
B) Food chains describe all aspects of interactions within a community, whereas food webs tell us what organisms eat and which are eaten by other organisms.
C) Food webs are smaller groupings than food chains. Food chains allow us to look at the overall picture, whereas food webs provide specific directional information.
D) Food webs tie together many more organisms than a food chain does. If one organism in a food chain disappears, a food web may allow the organisms in the chain to survive based on their interactions with other organisms.

Question 39

As the figure below illustrates, communities vary tremendously in size from as large as an entire forest to the digestive system of a single deer.
How can biologists recognize where one community ends and a second begins?

A) Communities have no fixed boundaries; their sizes are simply defined according to what is convenient at a given point in time.
B) Each community is nested within a larger one, for example, the deer is part of the woodland, which is part of the forest.
C) Each community can be defined by the movement of food; all the organisms that get their energy from the same group of producers form the community.
D) Communities are human constructs rather than natural entities; as such their boundaries are arbitrarily established.

Question 40

Which of the following statements about human-caused disturbances to communities is true?

A) Human-caused disturbances are not important because they do not cause any long-term permanent changes.
B) When a community recovers from a human-caused disturbance, it returns to its predisturbance condition.
C) Some communities can recover from human-caused disturbances over a period of time.
D) All communities are able to recover from human-caused disturbances.

Question 41

A _______ is an association of populations of different species that live in the same area.

Question 42

A community may begin when new _______ is formed, such as when rock and soil are deposited by a retreating glacier.

Question 43

Secondary succession is more common following a disturbance than primary succession because _____ typically remain intact.

Question 44

During the past 35 million years the climate of North America has experienced significant change.

Question 45

The only source of energy for life on Earth is the sun.

Question 46

Succession has a major impact on the species makeup of a community at any given point in time.

Question 47

The process by which communities recover from _______ is known as secondary succession.

Question 48

The general process by which species in a community are replaced over time is called _______.

Question 49

By definition, primary consumers feed on secondary consumers.

Question 50

__________ consumers feed on primary consumers as part or all of their diet.

Question 51

The inhabitants of an aquarium can be considered a community.

Question 52

The consumer at the top of the food web is usually described as the primary consumer because it is the most important.

Question 53

_______ are organisms that make their food from an external energy source, such as the sun.

Question 54

A _______ is a single sequence of who eats whom in a community.

Question 55

A community whose species are not replaced by other species is classified as a _______ community.

Question 56

Although an icon of the western United States, the horse is not a native species; horses were introduced by Spanish explorers in the early 1500s. What does the integration of the horse to the semiarid grassland communities of the Southwest suggest?

A) The community reached its saturation point sometime before 1500.
B) Terrestrial communities have less definition than aquatic communities where the introduction of new species is almost always disastrous.
C) The establishment of the horse must have be associated with the disappearance of at least one horse-like species.
D) Neutral groups within the community had enough ecological flexibility that the horse was integrated without significant disruption.

Question 57

A _______ species has, relative to its own abundance, a large impact on the type and abundance of other species in its community.

Question 58

All natural communities consist of an equivalent number of species.

Question 59

The _________ of a community has two components: the number of different species that live in the community, and the relative abundances of those species

Question 60

_________ are those organisms obtaining energy by eating all or portions of other organisms or their remains.

Question 61

Communities never recover from disturbances caused by humans.

Question 62

Communities always recover quickly from disturbances caused by humans.

Question 63

Black oak trees are one of the earliest colonists after bare sand dunes are created.

Question 64

Burning of fossil fuels may affect climate but not communities.

Question 65

If initially present, a climax community will reform immediately after a habitat disturbance.