20) Microbes in our digestive tract that help us digest food demonstrate a(n) ________
association.
A) allelopathic
B) homeopathic
C) trophic
D) symbiotic
E) pathogenic
21) Which of the following are pioneer species?
A) lichens
B) sea urchins
C) beavers
D) aspen trees
E) zebra mussels
22) Techniques to eradicate zebra mussels ________.
A) are global and long-term
B) include introducing quagga mussels
C) are relatively simple
D) have not yet been attempted
E) include introducing predators and diseases
23) Efforts at urban restoration ________.
A) have failed in Vancouver
B) mostly have been attempted in developing nations
C) are relatively straightforward
D) intend to undo damage done to communities by urban development
E) are not viable conservation strategies for the future
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24) Kelp ________.
A) is eaten by sea otters
B) is eaten by orcas
C) suffers intense herbivory from zebra mussels
D) suffers intense herbivory from sea urchins
E) is inhabited by sea urchins
25) Environmentally and economically acceptable means of controlling introduced invasive
species include, among others, ________.
A) introduction of suitable predators and examination of imported goods
B) application of potent pesticides to kill the introduced species
C) banning of all importation of non-native species
D) removal of all the invasive individuals by collecting, baiting, trapping and, for plants, by
prescribed burning
E) killing off pollinators for invasive plants and removing food sources for invasive animals
26) Global climate change may produce major shifts in biomes for any given location because
________.
A) biodiversity and day length will change
B) mean temperature, precipitation, and salinity will change
C) many species may become extinct
D) food web dynamics will change
E) soil chemistry, pH of precipitation, and the frequency of invasive species will change
27) The Everglades Restoration Plan in Florida ________.
A) seeks to exterminate numerous invasive fish species and plants
B) will restore natural levels of water flow by undoing many dams and drainage projects
C) will result in serious depletion of drinking water supplies for humans in south Florida
D) will probably destroy much of the commercial fishing in the area
E) is a short-term restoration project with a two-year implementation plan
28) Which factor is important in determining terrestrial biomes, but not important in oceanic
biomes?
A) precipitation
B) temperature
C) salinity
D) light
E) nutrient availability
29) Different species of finches on the Galápagos Islands have differently shaped beaks,
allowing them to access different types of food. This in NOT an example of ________.
A) competitive exclusion
B) resource partitioning
C) character displacement
D) natural selection
E) reduction of competition
30) A pilot fish follows a shark and feeds on scraps of food left by the shark, and eats parasites
attached to the shark’s skin. The relationship between the two fish can be best described as a
combination of ________ and ________.
A) commensalism; amensalism
B) commensalism; predation
C) mutualism; amensalism
D) commensalism ; mutualism
E) mutualism; competitive exclusion
5.5 True/False Questions
1) Climbing up in elevation causes a much more rapid change in climate than moving the same
distance toward the poles.
2) The 30-year, $7.8-billion, Everglades Restoration Project intends to dam up portions of the
Everglades to aid in water control.
3) Temperature and oxygen concentrations are the two abiotic factors that exert the greatest
influence on biome determination.
4) Keystone species are most often found at lower trophic levels.
5) Commensalism is a relationship in which two species negatively affect each other.
6) Facilitation is an example of amensalism.
7) Biosphere is a large ecological unit influenced by temperature, elevation, precipitation, and
latitude.
5.6 Essay Questions
1) What ecological traits do successful invasive species possess? How do these traits interact to
make controlling them difficult?
2) Why do environmentalists favour the term food web as opposed to food chain?
3) List the three major trophic types in a food web. What organisms are found in each type?
Where are the autotrophs and heterotrophs found? Discuss the significance of each level for the
integral functioning of the food web.
4) Discuss ways to control invasive species.
5) Discuss the interrelationship between great whales, orcas, sea lions, sea urchins, and kelp in
the Pacific Ocean.
6) Discuss the differences between intraspecific and interspecific competition.
7) Zebra mussels have changed the aquatic communities of the Great Lakes. Explain who are the
winners and who are the losers of this change, and why.
8) Explain how an invasive species can cause economic harm. Provide an example.
9) Explain why the trophic pyramid has the shape of a pyramid. If, in a given community, the
producers obtain 1000 units of energy per year, how many units of energy would you expect to
get to the level of secondary consumers?
10) Explain secondary succession. Illustrate it by describing the sequence of events expected
after farmland is abandoned in eastern North America (the case illustrated by Figure 5.13 in the
textbook).
5.7 Scenario-Based Questions
Read the following scenario and answer the questions below.
Human activities release greenhouses gases, which cause measurable warming of Earth. This
warming can alter ecosystem dynamics, through direct and indirect effects. Direct effects may
include changes in growth and other metabolic rates of organisms with a rising temperature.
Indirect effects may be caused by changes in the ecosystem: shrinking of sea ice, increases in
precipitation in Arctic areas, retreat of glaciers, melting permafrost in the tundra, and increase in
the intensity of hurricanes in vulnerable areas. Within communities, climatic change can shift
interdependent species “out-of-sync,” potentially causing indirect loss of species.
1) If the climate warms significantly, glaciers may retreat . This may start the process of
________.
A) primary succession
B) secondary succession
C) coevolution
D) climax
E) facilitation
2) Which of the following might be the first to populate an area after a glacier retreated because
of global climate change?
A) lichens
B) shrubs
C) aspen trees
D) grasses
E) conifer trees
3) Intense hurricanes that may result from global warming can directly lead to ________ within
communities.
A) primary succession
B) secondary succession
C) coevolution
D) climax
E) facilitation
4) Global warming has been hypothesized to cause many plants to flower earlier in the year. If in
response to this bees search for food earlier, this would represent ________ within the
community.
A) facilitation
B) succession
C) coevolution
D) climax
E) extirpation
5) Global warming has been hypothesized to cause many plants to flower earlier in the year. If
caterpillars that feed on flower buds do not adjust to the earlier time in which flower buds burst
and subsequently starve, this could cause ________.
A) facilitation
B) succession
C) coevolution
D) community climax
E) extirpation
6) As result of warming, we have seen grizzly bears moving deeper into the Arctic and venturing
on ice in an attempt to hunt seals, the staple food of polar bears. If this continues, what will be
the most likely relationship between grizzlies and polar bears?
A) competition
B) amensalism
C) commensalism
D) parasitism
E) predation