Question 1

Why is a pathogen generally more virulent in a new habitat?

Accepted Answer

A)  Intermediate host species are more motile and transport pathogens to new areas. 
B)  Pathogens evolve more efficient forms of reproduction in new environments. 
C)  Hosts in new environments have not had a chance to become resistant to the pathogen through natural selection. 
D)  New environments are almost always smaller in area so that transmission of pathogens is easily accomplished between hosts. 
A)  Intermediate host species are more motile and transport pathogens to new areas. 
B)  Pathogens evolve more efficient forms of reproduction in new environments. 
C)  Hosts in new environments have not had a chance to become resistant to the pathogen through natural selection. 
D)  New environments are almost always smaller in area so that transmission of pathogens is easily accomplished between hosts.

Question 2

Use the following diagram of a hypothetical food web to answer the question. The arrows represent the transfer of energy between the various trophic levels.
 
Which letter represents an organism that could only be a primary consumer?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 3

How might an ecologist test whether a species is occupying all of its fundamental niche or only a portion of it?

Accepted Answer

A)  Study the temperature range and humidity requirements of the species. 
B)  Observe if the species expands its range after the removal of a competitor. 
C)  Measure the change in reproductive success when the species is subjected to environmental stress. 
D)  Observe if the niche size changes after the introduction of a similar non-native species. 
A)  Study the temperature range and humidity requirements of the species. 
B)  Observe if the species expands its range after the removal of a competitor. 
C)  Measure the change in reproductive success when the species is subjected to environmental stress. 
D)  Observe if the niche size changes after the introduction of a similar non-native species.

Question 4

Which of the following is an example of a commensalism?

Accepted Answer

A)  fungi residing in plant roots, such as endomycorrhizae 
B)  bacteria fixing nitrogen on the roots of some plants 
C)  rancher ants that protect aphids in exchange for sugar-rich honeydew 
D)  cattle egrets eating insects stirred up by grazing bison 
A)  fungi residing in plant roots, such as endomycorrhizae 
B)  bacteria fixing nitrogen on the roots of some plants 
C)  rancher ants that protect aphids in exchange for sugar-rich honeydew 
D)  cattle egrets eating insects stirred up by grazing bison

Question 5

Resource partitioning would be most likely to occur between ________.

Accepted Answer

A)  sympatric populations of species with similar ecological niches 
B)  sympatric populations of a flowering plant and its specialized insect pollinator 
C)  allopatric populations of the same animal species 
D)  allopatric populations of species with similar ecological niches 
A)  sympatric populations of species with similar ecological niches 
B)  sympatric populations of a flowering plant and its specialized insect pollinator 
C)  allopatric populations of the same animal species 
D)  allopatric populations of species with similar ecological niches

Question 6

Based on the intermediate disturbance hypothesis, a community's species diversity is increased by ________.

Accepted Answer

A)  frequent immigrations of new species 
B)  stable conditions with no disturbance 
C)  moderate levels of disturbance 
D)  intensive disturbance by humans 
A)  frequent immigrations of new species 
B)  stable conditions with no disturbance 
C)  moderate levels of disturbance 
D)  intensive disturbance by humans

Question 7

Which of the following is a widely supported explanation for the tendency of tropical communities to have greater species diversity than temperate or polar communities?

Accepted Answer

A)  There are fewer parasites to negatively affect the health of tropical communities. 
B)  Tropical communities are low in altitude, whereas temperate and polar communities are high in altitude. 
C)  Tropical communities have higher sunlight and precipitation, and are generally older than temperate or polar communities. 
D)  More competitive dominant species have evolved in temperate and polar communities. 
A)  There are fewer parasites to negatively affect the health of tropical communities. 
B)  Tropical communities are low in altitude, whereas temperate and polar communities are high in altitude. 
C)  Tropical communities have higher sunlight and precipitation, and are generally older than temperate or polar communities. 
D)  More competitive dominant species have evolved in temperate and polar communities.

Question 8

According to the island equilibrium model, species richness would be greatest on an island that is

Accepted Answer

A)  large and remote. 
B)  small and remote. 
C)  large and close to a mainland. 
D)  small and close to a mainland. 
A)  large and remote. 
B)  small and remote. 
C)  large and close to a mainland. 
D)  small and close to a mainland.

Question 9

If two species are close competitors, and one species is experimentally removed from the community, the remaining species would be expected to ________.

Accepted Answer

A)  change its fundamental niche 
B)  decline in abundance 
C)  become the target of specialized parasites 
D)  expand its realized niche 
A)  change its fundamental niche 
B)  decline in abundance 
C)  become the target of specialized parasites 
D)  expand its realized niche

Question 10

Bouchard and Brooks studied the effect of insect flight on dispersal and speciation in rain forest insects. They sampled all of the insects in the study area and found that 60 insect species are flightless and 19 are able to fly. What can you conclude so far about this study?
(P) Bouchard and D. R. Brooks. 2004. Effect of vagility potential on dispersal and speciation in rainforest insects. Journal of Evolutionary Biology 17:994-1006.)

Accepted Answer

A)  Flightless insects have a greater dispersal potential from this study area. 
B)  Flightless insects are more numerous in the study area. 
C)  Flightless insects have a higher species richness in the study area. 
D)  Flightless insects are better suited for the tropics. 
A)  Flightless insects have a greater dispersal potential from this study area. 
B)  Flightless insects are more numerous in the study area. 
C)  Flightless insects have a higher species richness in the study area. 
D)  Flightless insects are better suited for the tropics.

Question 11

The feeding relationships among the species in a community determine the community's

Accepted Answer

A)  secondary succession. 
B)  ecological niche. 
C)  species richness. 
D)  trophic structure. 
A)  secondary succession. 
B)  ecological niche. 
C)  species richness. 
D)  trophic structure.

Question 12

Food chains are sometimes short because ________.

Accepted Answer

A)  only a single species of herbivore feeds on each plant species 
B)  local extinction of a species causes extinction of the other species in its food chain 
C)  most of the energy in a trophic level is lost as it passes to the next higher level 
D)  predator species tend to be less diverse and less abundant than prey species 
A)  only a single species of herbivore feeds on each plant species 
B)  local extinction of a species causes extinction of the other species in its food chain 
C)  most of the energy in a trophic level is lost as it passes to the next higher level 
D)  predator species tend to be less diverse and less abundant than prey species

Question 13

The symbols +, -, and 0 are used to show the results of interactions between individuals and groups of individuals. The symbol + denotes a positive interaction, - denotes a negative interaction, and 0 denotes interactions in which individuals are not affected. The first symbol refers to the first organism mentioned. What interactions exist between a lion pride and African wild dogs, if the dogs are found to typically avoid areas with lions?

Accepted Answer

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

Question 14

Which of the following is an example of Müllerian mimicry?

Accepted Answer

A)  two species of unpalatable butterfly that have the same color pattern 
B)  a day-flying hawkmoth that looks like a wasp 
C)  a chameleon that changes its color to look like a dead leaf 
D)  one species of a non-venomous snake which rattles its tail to mimic a venomous rattlesnake 
A)  two species of unpalatable butterfly that have the same color pattern 
B)  a day-flying hawkmoth that looks like a wasp 
C)  a chameleon that changes its color to look like a dead leaf 
D)  one species of a non-venomous snake which rattles its tail to mimic a venomous rattlesnake

Question 15

Imagine five forest communities, each with one hundred individuals distributed among four different tree species (W, X, Y, and Z). Which forest community would be most diverse?

Accepted Answer

A)  25W, 25X, 25Y, 25Z 
B)  40W, 30X, 20Y, 10Z 
C)  50W, 25X, 15Y, 10Z 
D)  70W, 10X, 10Y, 10Z 
A)  25W, 25X, 25Y, 25Z 
B)  40W, 30X, 20Y, 10Z 
C)  50W, 25X, 15Y, 10Z 
D)  70W, 10X, 10Y, 10Z

Question 16

Scientists interested in how populations interact within communities are attempting to determine the species diversity of an island under study. What kind of data would be most helpful to the scientists in determining diversity?

Accepted Answer

A)  the number of different species on the island and the size of the population of each species 
B)  the number of species on the island that are consumers, producers, and decomposers 
C)  the relative biomass of each species on the island separated by trophic level 
D)  the number of trophic levels on the island and the niche of each species 
A)  the number of different species on the island and the size of the population of each species 
B)  the number of species on the island that are consumers, producers, and decomposers 
C)  the relative biomass of each species on the island separated by trophic level 
D)  the number of trophic levels on the island and the niche of each species

Question 17

Use the figure to answer the following question.
  The figure proposes a combination of a top-down and bottom-up model (a hypothesis)to describe the variable effects of biological control herbivores on the fitness (growth and reproduction)of an invasive, non-native plant, spotted knapweed (Centaurea stoebe). These herbivores include multiple insects that were first studied in the plant's native home range in eastern Europe, where the plant is not dominant in grassland communities and does not pose a problem to land managers and conservationists. Many insects there were found to consume the plant's tissues, including stems, leaves, and seeds, and some were very host specific and were not found to attack plants other than C. stoebe. Several insects were subsequently transported and released in an attempt to reduce densities of this non-native and problematic weed in the United States. The y-axis shows C. stoebe plant fitness, and the x-axis represents the intensity of herbivory by the insects, from low to high. As the vertical shaded bar is moved along the x-axis, the ultimate effect of herbivory (now A, B, and C)on plant fitness can change based on its intensity and also may depend on the other factors. The horizontal dashed line represents no predicted change in fitness under the effects of varying intensity of herbivory, plant competition, and soil resources available to the plant (such as nitrogen or water), while the three solid lines represent other possible outcomes.
(D)G. Knochel and T.R. Seastedt. 2011. Reconciling contradictory findings of herbivore impacts on spotted knapweed (Centaurea stoebe)growth and reproduction. Ecological Applications 20(7):1903-1912.
What portion of the model would be characterized as bottom-up?

Accepted Answer

A)  plant fitness 
B)  resources available to the plant 
C)  intensity of herbivory on the plant 
D)  plant competition and fitness 
A)  plant fitness 
B)  resources available to the plant 
C)  intensity of herbivory on the plant 
D)  plant competition and fitness

Question 18

Food chains are sometimes short because

Accepted Answer

A)  only a single species of herbivore feeds on each plant species. 
B)  local extinction of a species causes extinction of the other species in its food chain. 
C)  most of the energy in a trophic level is lost as energy passes to the next higher level. 
D)  most producers are inedible. 
A)  only a single species of herbivore feeds on each plant species. 
B)  local extinction of a species causes extinction of the other species in its food chain. 
C)  most of the energy in a trophic level is lost as energy passes to the next higher level. 
D)  most producers are inedible.

Question 19

Use the figures to answer the following question.
 
According to the Shannon Diversity Index, which of the five blocks above, with each containing 36 squares, would show the greatest diversity? The different shades represent different species, and more squares of a shade represent higher abundance.

Accepted Answer

A)  1 
B)  2 
C)  4 
D)  5 
A)  1 
B)  2 
C)  4 
D)  5

Question 20

Use the figure to answer the following question.
  The figure proposes a combination of a top-down and bottom-up model (a hypothesis)to describe the variable effects of biological control herbivores on the fitness (growth and reproduction)of an invasive, non-native plant, spotted knapweed (Centaurea stoebe). These herbivores include multiple insects that were first studied in the plant's native home range in eastern Europe, where the plant is not dominant in grassland communities and does not pose a problem to land managers and conservationists. Many insects there were found to consume the plant's tissues, including stems, leaves, and seeds, and some were very host specific and were not found to attack plants other than C. stoebe. Several insects were subsequently transported and released in an attempt to reduce densities of this non-native and problematic weed in the United States. The y-axis shows C. stoebe plant fitness, and the x-axis represents the intensity of herbivory by the insects, from low to high. As the vertical shaded bar is moved along the x-axis, the ultimate effect of herbivory (now A, B, and C)on plant fitness can change based on its intensity and also may depend on the other factors. The horizontal dashed line represents no predicted change in fitness under the effects of varying intensity of herbivory, plant competition, and soil resources available to the plant (such as nitrogen or water), while the three solid lines represent other possible outcomes.
(D)G. Knochel and T.R. Seastedt. 2011. Reconciling contradictory findings of herbivore impacts on spotted knapweed (Centaurea stoebe)growth and reproduction. Ecological Applications 20(7):1903-1912.
What is the model's prediction for C. stoebe plant fitness when growing under high soil resource conditions?

Accepted Answer

A)  Plant fitness decreases as a result of low intensity herbivory. 
B)  Plant fitness increases under all levels of intensity of herbivory. 
C)  Plant fitness decreases only if the intensity of herbivory is very high. 
D)  Plant fitness does not change. 
A)  Plant fitness decreases as a result of low intensity herbivory. 
B)  Plant fitness increases under all levels of intensity of herbivory. 
C)  Plant fitness decreases only if the intensity of herbivory is very high. 
D)  Plant fitness does not change.

Exam 54: Community Ecology

Why is a pathogen generally more virulent in a new habitat?

Use the following diagram of a hypothetical food web to answer the question. The arrows represent the transfer of energy between the various trophic levels. Which letter represents an organism that could only be a primary consumer?

How might an ecologist test whether a species is occupying all of its fundamental niche or only a portion of it?

Which of the following is an example of a commensalism?

Resource partitioning would be most likely to occur between ________.

Based on the intermediate disturbance hypothesis, a community's species diversity is increased by ________.

Which of the following is a widely supported explanation for the tendency of tropical communities to have greater species diversity than temperate or polar communities?

According to the island equilibrium model, species richness would be greatest on an island that is

If two species are close competitors, and one species is experimentally removed from the community, the remaining species would be expected to ________.

The feeding relationships among the species in a community determine the community's

Food chains are sometimes short because ________.

Which of the following is an example of Müllerian mimicry?

Imagine five forest communities, each with one hundred individuals distributed among four different tree species (W, X, Y, and Z). Which forest community would be most diverse?

Scientists interested in how populations interact within communities are attempting to determine the species diversity of an island under study. What kind of data would be most helpful to the scientists in determining diversity?

Food chains are sometimes short because

Use the figures to answer the following question. According to the Shannon Diversity Index, which of the five blocks above, with each containing 36 squares, would show the greatest diversity? The different shades represent different species, and more squares of a shade represent higher abundance.

Evolution, the Themes of Biology, and Scientific Inquiry

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Viruses

DNA Tools and Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Vascular Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

Filters