Question 1

Based on the data that follow, which of the following statements is FALSE?

Accepted Answer

A)   The seagrass habitat has the lowest species richness.
B)   The African plains and Australian grasslands have identical species richness.
C)   The diversity (
D)   of African plains and Australian grasslands is the same.
D)   The Australian grasslands have lower species evenness than the African plains.
E)   The seagrass habitat has the highest species evenness. C

Question 2

What organisms in the figure appear NOT to be indirectly affected by insecticide?

Accepted Answer

A)   zooplankton
B)   tadpoles
C)   phytoplankton
D)   periphyton A

Question 3

Based on examples from the chapter, do most communities consist of species with independent or interdependent distributions? What particular types of environmental conditions favour one or the other type of distribution?

Accepted Answer

Experiments show that independent distributions are most common. However, communities in harsh environmental conditions appear to support interdependent species distributions.

Question 4

What is a major distinction between direct and indirect effects in a community?

Accepted Answer

A)   Indirect effects always include a resource such as water or light; direct effects do not.
B)   Direct effects result in competitive exclusion; indirect effects do not.
C)   Direct effects occur between species in different trophic levels; indirect effects include species from the same trophic level.
D)   Indirect effects always include more than two species; direct effects do not.

Question 5

What population trait allows a species to have high resilience to disturbance?

Accepted Answer

The answer of What population trait allows a species to...

Question 6

When Hairston, Smith, and Slobodkin suggested that Earth is green because carnivores depress the populations of herbivores that would otherwise consume most vegetation, they were focusing on __________ control of community structure.

Accepted Answer

A)   top-down
B)   bottom-up

Question 7

Use Figure 18.10a for MC questions 20 - 22.
 
-Which curve suggests that species richness is controlled by bottom-up factors?

Accepted Answer

A)   U-shaped
B)   negative
C)   none
D)   positive
E)   hump-shaped

Question 8

Use the following figure for questions 24 and 25.
 
-What is the relation between habitat diversity and species diversity?

Accepted Answer

A)   decrease with altitude
B)   hump shape
C)   positive
D)   negative if many invasive species are present

Question 9

Use the figure to answer questions 4 to 7.
 
-Which species is restricted to serpentine soils?

Accepted Answer

A)   black oak 
B)   hawkweed
C)   ragwort
D)   fireweed

Question 10

Hairston, Smith, and Slobodkin suggested that Earth is green because carnivores depress the populations of herbivores that would otherwise consume most vegetation. Is this the only possible explanation for the greenness of Earth?

Accepted Answer

The answer of Hairston, Smith, and Slobodkin suggested that Earth...

Question 11

Which relationships in the figure indicate top-down control? Which relationships indicate bottom-up control?

Accepted Answer

The answer of Which relationships in the figure indicate top-down...

Question 12

Use the following figure for questions 24 and 25.
 
-What is a reasonable explanation of the results in the figure?

Accepted Answer

A)   The plants are light limited.
B)   Plants that competed more successfully for fertilizer shaded out other plants.
C)   Plant growth is best supported by addition of fertilizer and light.
D)   Addition of fertilizer reduces plants' ability to use light efficiently for photosynthesis.

Question 13

Which statement best reflects the relationship between a disturbance and an alternative stable state?

Accepted Answer

A)   Many communities alter between stable states on a seasonal basis, which is not a true disturbance.
B)   A community will achieve an alternative stable state only after a major disturbance.
C)   An alternative stable state will not happen in aquatic communities, where there is no fire and water is not limiting.
D)   Communities can alternate among stable states in the absence of disturbance.

Question 14

How would sampling the same community in the plot with much less effort affect the shape of the plot?

Accepted Answer

The answer of How would sampling the same community in...

Question 15

Communities with ____________ species are ____________ stable.

Accepted Answer

A)   few; more
B)   few; consistently
C)   many; more
D)   many; consistently

Question 16

Use the figure to answer questions 4 to 7.
 
-Which species would you characterize as seemingly unresponsive to changes in soil conditions across the transect?

Accepted Answer

A)   black oak
B)   hawkweed
C)   ragwort
D)   fireweed

Question 17

Explain whether species would be limited more by resources or interspecific interactions in tropical rainforests (low latitude) or taiga (high latitude).

Accepted Answer

The answer of Explain whether species would be limited more...

Question 18

What is the suggested mechanism by which the presence of insecticide influences phytoplankton abundance?

Accepted Answer

A)   Periphyton abundance is reduced by insecticide.
B)   Tadpoles consume phytoplankton when periphyton is reduced in abundance.
C)   The reduction of zooplankton by insecticide reduces herbivory on phytoplankton, which increases abundance.
D)   Inert chemicals in the insecticide include nitrogen, which promotes phytoplankton growth.

Question 19

Which of the following statements would NOT be true about the species relationship in the figure?

Accepted Answer

A)   Zooplankton consume phytoplankton.
B)   Zooplankton consume periphyton.
C)   Tadpoles consume periphyton.
D)   Tadpole abundance is related to the abundance of its food resource.

Question 20

Use the following figure for questions 24 and 25.
 
-According to the experimental results shown in the figure, what factor best explains the reduction in plant species richness with addition of fertilizer?

Accepted Answer

A)   inhibition of photosynthesis
B)   intolerance to fertilizer
C)   competitive exclusion
D)   interaction of fertilizer and light

Exam 18: Community Structure

Based on the data that follow, which of the following statements is FALSE?

What organisms in the figure appear NOT to be indirectly affected by insecticide?

Based on examples from the chapter, do most communities consist of species with independent or interdependent distributions? What particular types of environmental conditions favour one or the other type of distribution?

What is a major distinction between direct and indirect effects in a community?

What population trait allows a species to have high resilience to disturbance?

When Hairston, Smith, and Slobodkin suggested that Earth is green because carnivores depress the populations of herbivores that would otherwise consume most vegetation, they were focusing on __________ control of community structure.

Use Figure 18.10a for MC questions 20 - 22. -Which curve suggests that species richness is controlled by bottom-up factors?

Use the following figure for questions 24 and 25. -What is the relation between habitat diversity and species diversity?

Use the figure to answer questions 4 to 7. -Which species is restricted to serpentine soils?

Hairston, Smith, and Slobodkin suggested that Earth is green because carnivores depress the populations of herbivores that would otherwise consume most vegetation. Is this the only possible explanation for the greenness of Earth?

Which relationships in the figure indicate top-down control? Which relationships indicate bottom-up control?

Use the following figure for questions 24 and 25. -What is a reasonable explanation of the results in the figure?

Which statement best reflects the relationship between a disturbance and an alternative stable state?

How would sampling the same community in the plot with much less effort affect the shape of the plot?

Communities with species are stable.

Use the figure to answer questions 4 to 7. -Which species would you characterize as seemingly unresponsive to changes in soil conditions across the transect?

Explain whether species would be limited more by resources or interspecific interactions in tropical rainforests (low latitude) or taiga (high latitude).

What is the suggested mechanism by which the presence of insecticide influences phytoplankton abundance?

Which of the following statements would NOT be true about the species relationship in the figure?

Use the following figure for questions 24 and 25. -According to the experimental results shown in the figure, what factor best explains the reduction in plant species richness with addition of fertilizer?