Question 1

The variable (pi) used in the Shannon's Diversity Index (or Shannon-Wiener Index) is

Accepted Answer

A)  the number of trophic levels in the food web under study. 
B)  the number of connections between species in the food web under study. 
C)  the relative abundance value for each of the species in the community under study. 
D)  the relative evenness value for each of the species in the community under study. 
A)  the number of trophic levels in the food web under study. 
B)  the number of connections between species in the food web under study. 
C)  the relative abundance value for each of the species in the community under study. 
D)  the relative evenness value for each of the species in the community under study.

Question 2

Which is an example of a trait-mediated indirect effect?

Accepted Answer

A)  A predator causes a consumer to change its foraging pattern, affecting the amount of food consumed. 
B)  Predators consume most of their main prey, then switch to omnivory. 
C)  Herbivores migrate in and out of communities depending on perceived predation risk. 
D)  Herbivores consume vegetation, which reduces hiding places for predators stalking their prey. 
A)  A predator causes a consumer to change its foraging pattern, affecting the amount of food consumed. 
B)  Predators consume most of their main prey, then switch to omnivory. 
C)  Herbivores migrate in and out of communities depending on perceived predation risk. 
D)  Herbivores consume vegetation, which reduces hiding places for predators stalking their prey.

Question 3

You have been keeping a list of the bird species that frequent your property. At the end of the year you have tallied eight seedeaters, one nectar sipper, three woodpeckers, six insectivores, two frugivores, four predators, and one carrion feeder. You have organized your tally according to

Accepted Answer

A)  habitat. 
B)  community. 
C)  population. 
D)  guild. 
A)  habitat. 
B)  community. 
C)  population. 
D)  guild.

Question 4

What can we learn about the roles of species in a community from food web structure alone?

Accepted Answer

The food web structure can provide valua

Question 5

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

Accepted Answer

In tropical rainforests, species are lik

Question 6

Which of the following is NOT an example of a trait-mediated indirect effect?

Accepted Answer

A)  The presence of raptors causes squirrels to forage at night instead of during the day. 
B)  Greater numbers of aspen trees grow in areas where predation risk from wolves prevents elk from browsing. 
C)  Grasses increase because the presence of spiders has reduced grasshopper foraging. 
D)  Zooplankton abundance in a pond increases because piscivorous largemouth bass cause small fish (zooplanktivores) to take refuge in pond margins away from zooplankton. 
A)  The presence of raptors causes squirrels to forage at night instead of during the day. 
B)  Greater numbers of aspen trees grow in areas where predation risk from wolves prevents elk from browsing. 
C)  Grasses increase because the presence of spiders has reduced grasshopper foraging. 
D)  Zooplankton abundance in a pond increases because piscivorous largemouth bass cause small fish (zooplanktivores) to take refuge in pond margins away from zooplankton.

Question 7

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

Accepted Answer

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

Question 8

In hiking up a mountain you are likely to pass through various community types as you proceed from the low-elevation lands to the summit. This change in community is called

Accepted Answer

A)  succession. 
B)  zonation. 
C)  trophic cascade. 
D)  bottom-up control. 
A)  succession. 
B)  zonation. 
C)  trophic cascade. 
D)  bottom-up control.

Question 9

Explain the difference between a trophic level and a guild with an example to illustrate the difference.

Accepted Answer

A trophic level refers to the position t

Question 10

The graph suggests that

Accepted Answer

A)  plant survival rate is not affected by elevation. 
B)  plant survival rate is not affected by the presence or absence of a neighboring species. 
C)  plant survival is dependent on the presence of a neighboring species. 
D)  plant survival is independent of the presence of a neighboring species. 
A)  plant survival rate is not affected by elevation. 
B)  plant survival rate is not affected by the presence or absence of a neighboring species. 
C)  plant survival is dependent on the presence of a neighboring species. 
D)  plant survival is independent of the presence of a neighboring species.

Question 11

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

Question 12

How can predation increase prey species richness and evenness in a community?

Accepted Answer

Predation can play a significant role in

Question 13

Which would likely have very high resilience to disturbance?

Accepted Answer

A)  soil microbes 
B)  redwood forest 
C)  desert vegetation 
D)  grassland 
A)  soil microbes 
B)  redwood forest 
C)  desert vegetation 
D)  grassland

Question 14

Explain how the second law of thermodynamics limits the number of trophic levels in a food web.

Accepted Answer

The second law of thermodynamics states

Question 15

How can rainfall indirectly result in an alternative stable state in a community dominated by either grassland or forest?

Accepted Answer

Rainfall can indirectly result in an alt

Question 16

What is the difference between a food chain and food web?

Accepted Answer

A food chain and a food web are both eco

Question 17

Which is an example of an ecosystem engineer?

Accepted Answer

A)  beavers, which build dams on streams 
B)  termites, which build very large hives and eat the wood in buildings 
C)  bees, which pollinate many types of flowers and crops 
D)  zebra mussels, which clog water intake structures 
A)  beavers, which build dams on streams 
B)  termites, which build very large hives and eat the wood in buildings 
C)  bees, which pollinate many types of flowers and crops 
D)  zebra mussels, which clog water intake structures

Question 18

Based on the data that follow, which of the following statements is FALSE? 
$\begin{array}{c}
\begin{array}{lll}
\text{Seagrass Habitat}\
\text{Species}\\
\text{green turtle}\
\text{dugong}\\\\
\end{array}
\begin{array}{lll}
\text{}\
\text{N}\\
3,000\
2,990\\\\
\end{array}
\begin{array}{lll}
\text{African Plains}\
\text{Species}\\
\text{wildebeest}\
\text{zebra}\
\text{hartebeest}\
\text{rhino}\
\text{gazelle}\
\end{array}
\begin{array}{l}
\
N \\
1,000 \
200 \
250 \
18 \
2,000\
\end{array}
\begin{array}{l}
\text{Australian Grassland}\
\text{Species}\\
\text{red kangaroo}\
\text{wallaby}\
\text{walleroo}\
\text{wombat}\
\text{gray kangaroo}\
\end{array}
\begin{array}{l}
\
\text{N}\\
\text{1,000}\
\text{20}\
\text{2}\
\text{2}\
\text{6}\
\end{array}
\end{array}$

Accepted Answer

A)  The seagrass habitat has the lowest species richness. 
B)  The African plains and Australian grasslands have identical species richness. 
C)  The rank abundance curves for the African plains and Australian grasslands data would have the same shape. 
D)  The Australian grasslands have lower species evenness than the African plains. 
E)  The seagrass habitat has the highest species evenness. 
A)  The seagrass habitat has the lowest species richness. 
B)  The African plains and Australian grasslands have identical species richness. 
C)  The rank abundance curves for the African plains and Australian grasslands data would have the same shape. 
D)  The Australian grasslands have lower species evenness than the African plains. 
E)  The seagrass habitat has the highest species evenness.

Question 19

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

Accepted Answer

A population trait that allows a species

Question 20

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

Accepted Answer

If you were to sample the same community

Exam 18: Community Structure

The variable (pi) used in the Shannon's Diversity Index (or Shannon-Wiener Index) is

Which is an example of a trait-mediated indirect effect?

You have been keeping a list of the bird species that frequent your property. At the end of the year you have tallied eight seedeaters, one nectar sipper, three woodpeckers, six insectivores, two frugivores, four predators, and one carrion feeder. You have organized your tally according to

What can we learn about the roles of species in a community from food web structure alone?

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

Which of the following is NOT an example of a trait-mediated indirect effect?

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

In hiking up a mountain you are likely to pass through various community types as you proceed from the low-elevation lands to the summit. This change in community is called

Explain the difference between a trophic level and a guild with an example to illustrate the difference.

The graph suggests that

What is the relation between habitat diversity and species diversity?

How can predation increase prey species richness and evenness in a community?

Which would likely have very high resilience to disturbance?

Explain how the second law of thermodynamics limits the number of trophic levels in a food web.

How can rainfall indirectly result in an alternative stable state in a community dominated by either grassland or forest?

What is the difference between a food chain and food web?

Which is an example of an ecosystem engineer?

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

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

Introduction: Ecology, Evolution, and the Scientific Method

Adaptations to Aquatic Environments

Adaptations to Terrestrial Environments

Adaptations to Variable Environments

Climates and Soils

Terrestrial and Aquatic Biomes

Evolution and Adaptation

Life Histories

Reproductive Strategies

Social Behaviors

Population Distributions

Population Growth and Regulation

Population Dynamics Over Space and Time

Predation and Herbivory

Parasitism and Infectious Diseases

Competition

Mutualism

Community Succession

Movement of Energy in Ecosystems

Movement of Elements in Ecosystems

Landscape Ecology and Global Biodiversity

Global Conservation of Biodiversity

Filters

Exam 18: Community Structure　