Question 1

Provide an example of primary succession.

Accepted Answer

Primary succession occurs in a newly cre...

Question 2

Does the diagram below represent a food web or a food chain? Identify which organism(s)in the diagram occupy the following roles: producers,primary consumers,secondary consumers,tertiary consumers,and quaternary consumers.

Accepted Answer

This diagram represents a food web.The p...

Question 3

Communities change with respect to several timescales.An example of long-term change would be the

Accepted Answer

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

Question 4

The total number of different species living within a community is referred to as

Accepted Answer

A)   an ecological community.
B)   species richness.
C)   relative species abundance.
D)   keystone species.E) None of the above
F) A) and B)

Question 5

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

Accepted Answer

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.E) B) and D)
F) B) and C)

Question 6

Which of the following statements represents a mutualistic relationship?

Accepted Answer

A)   One organism benefits while one organism is harmed by the relationship.
B)   Both organisms benefit from the relationship.
C)   One organism is neither harmed nor benefits from the relationship while the other organism is harmed.
D)   Both organisms are harmed by the relationship.E) B) and C)
F) B) and D)

Question 7

The sea star Pisaster ochraceus is a keystone species.Ten years after P.ochraceus is removed from selected intertidal communities along the Washington coast,how might those communities compare to control communities?

Accepted Answer

A)   The communities would be statistically indistinguishable from one another.
B)   Sea star prey, such as mussels, might increase in abundance and crowd out other community members.
C)   Other predators will simply replace P. ochraceus and take advantage of prey that P. ochraceus consumed.
D)   Prey species, such as mussels, would decline, but most species within the community would be unaffected.E) A) and B)
F) All of the above B

Question 8

Pathogens are considered a special type of parasite because they

Accepted Answer

A)   invariably kill their prey.
B)   affect specific portions of the host.
C)   cause disease in their hosts.
D)   live on or in the host organism.E) A) and B)
F) B) and C)

Question 9

The figure shown 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?

Accepted Answer

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)   Oak seeds were always present in the sand; they simply require more time to germinate.E) A) and C)
F) A) and D)

Question 10

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

Accepted Answer

A)   Natural selection usually causes the community to adapt and survive the change with little visible effect.
B)   The area becomes uninhabitable to all species and is abandoned.
C)   The 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.E) B) and C)
F) A) and B)

Question 11

Ecological communities

Accepted Answer

A)   have clearly fixed boundaries and are always defined on the same scale.
B)   can be nested within larger ecological communities.
C)   are defined as groups of four or more species within a given area.
D)   are groups of species that do not fluctuate over time.E) None of the above
F) C) and D)

Question 12

Using the data in the infographic below,illustrate how removal of a keystone species such as the wolves from Yellowstone can lead to secondary succession and eventually restoration of a climax community.

Accepted Answer

Secondary succession often occurs after ...

Question 13

Predators CANNOT

Accepted Answer

A)   restrict the distribution of their prey.
B)   cause the abundance of their prey to rise.
C)   quickly alter the behavior of their prey.
D)   drive their prey to extinction.E) A) and B)
F) A) and C)

Question 14

Which of the following would probably NOT occur if a single species was removed from an ecological community?

Accepted Answer

A)   The species richness would change.
B)   The relative species abundance would change.
C)   The diversity of the community would change.
D)   The community would cease to exist.E) A) and C)
F) None of the above

Question 15

Study the food web shown below.What would be a reasonable outcome following the complete disappearance of wolves?

Accepted Answer

A)   Coyotes may decline because they eat wolves.
B)   Coyotes may increase because one of their primary predators is gone.
C)   Grass, willow, and berries will increase as more elk become available.
D)   Voles may decline as coyotes become less abundant.E) B) and D)
F) All of the above

Question 16

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

Accepted Answer

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

Question 17

In comparing the two communities shown below,community

Accepted Answer

A)   A has a higher species richness.
B)   B has a higher species richness.
C)   A has more primary producers than community B.
D)   B has more primary producers than community A.E) A) and B)
F) All of the above B

Question 18

Identify a single food chain within the diagram below by indicating the organism at each level from producer to primary consumer,secondary consumer,and tertiary consumer.

Accepted Answer

One single food chain in this diagram wo...

Question 19

Every healthy human digestive system is home to countless microorganisms.In a normal digestive system,what type of relationship would this be considered?

Accepted Answer

A)   parasitic
B)   pathological
C)   competitive
D)   mutualisticE) All of the above
F) B) and C)

Question 20

Which of the following statements about communities is true?

Accepted Answer

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.E) A) and D)
F) B) and C)

Exam 20: Communities of Organisms

Provide an example of primary succession.

Correct AnswerverifiedPrimary succession occurs in a newly cre...View AnswerShow Answer

Does the diagram below represent a food web or a food chain? Identify which organism(s)in the diagram occupy the following roles: producers,primary consumers,secondary consumers,tertiary consumers,and quaternary consumers.

Correct AnswerverifiedThis diagram represents a food web.The p...View AnswerShow Answer

Communities change with respect to several timescales.An example of long-term change would be the

Correct AnswerverifiedC

The total number of different species living within a community is referred to as

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following statements represents a mutualistic relationship?

Correct AnswerverifiedShow Answer

The sea star Pisaster ochraceus is a keystone species.Ten years after P.ochraceus is removed from selected intertidal communities along the Washington coast,how might those communities compare to control communities?

Correct AnswerverifiedB

Pathogens are considered a special type of parasite because they

Correct AnswerverifiedShow Answer

The figure shown 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?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Ecological communities

Correct AnswerverifiedShow Answer

Using the data in the infographic below,illustrate how removal of a keystone species such as the wolves from Yellowstone can lead to secondary succession and eventually restoration of a climax community.

Correct AnswerverifiedSecondary succession often occurs after ...View AnswerShow Answer

Predators CANNOT

Correct AnswerverifiedShow Answer

Which of the following would probably NOT occur if a single species was removed from an ecological community?

Correct AnswerverifiedShow Answer

Study the food web shown below.What would be a reasonable outcome following the complete disappearance of wolves?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

In comparing the two communities shown below,community

Correct AnswerverifiedB

Identify a single food chain within the diagram below by indicating the organism at each level from producer to primary consumer,secondary consumer,and tertiary consumer.

Correct AnswerverifiedOne single food chain in this diagram wo...View AnswerShow Answer

Every healthy human digestive system is home to countless microorganisms.In a normal digestive system,what type of relationship would this be considered?

Correct AnswerverifiedShow Answer

Which of the following statements about communities is true?

Correct AnswerverifiedShow Answer

Correct Answer
verified
Primary succession occurs in a newly cre...
View Answer

Correct Answer
verified
This diagram represents a food web.The p...
View Answer

Correct Answer
verified
C

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
B

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Secondary succession often occurs after ...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
B

Correct Answer
verified
One single food chain in this diagram wo...
View Answer

Correct Answer
verified

Correct Answer
verified