CHAPTER 41 Flashcards

There are more species in tropical areas than in places more distant from the equator. This is
probably a result of
A) fewer predators.
B) more intense annual solar radiation.
C) more frequent ecological disturbances.
D) fewer agents of disease.
E) fewer predators, more intense annual solar radiation, more frequent ecological disturbances,
and fewer agents of disease.

Why do tropical communities tend to have greater species diversity than temperate or polar
communities?
A) They are less likely to be affected by human disturbance.
B) There are fewer parasites to negatively affect the health of tropical communities.
C) Tropical communities are low in altitude, whereas temperate and polar communities are high
in altitude.
D) Tropical communities are generally older than temperate and polar communities.
E) More competitive dominant species have evolved in temperate and polar communities.

Which of the following is a correct statement about the McArthur/Wilson Island Equilibrium
Model?
A) The more species that inhabit an island, the lower the extinction rate.
B) As the number of species on an island increases, the emigration rate decreases.
C) Competitive exclusion is less likely on an island that has large numbers of species.
D) Small islands receive few new immigrant species.
E) Islands closer to the mainland have higher extinction rates.

Which of the following best describes the consequences of white-band disease in Caribbean
coral reefs?
A) Staghorn coral has been decimated by the pathogen, and Elkhorn coral has taken its place.
B) Key habitat for lobsters, snappers, and other reef fishes has improved.
C) Algal species take the place of the dead coral, and the fish community is dominated by
herbivores.
D) Algal species take over and the overall reef diversity increases due to increases in primary
productivity.
E) Other coral species take the place of the affected Staghorn and Elkhorn species.

Zoonotic disease
A) is caused by suborganismal pathogens such as viruses, viroids, and prions only.
B) is caused by pathogens that are transferred from other animals to humans by direct contact or
by means of a vector.
C) can only be spread from animals to humans through direct contact.
D) can only be transferred from animals to humans by means of an intermediate host.
E) is too specific to study at the community level, and studies of zoonotic pathogens are
relegated to organismal biology.

Which of the following studies would shed light on the mechanism of spread of H5N1 from
Asia?
A) Perform cloacal or saliva smears of migrating waterfowl to monitor whether any infected
birds show up in Alaska.
B) Test fecal samples for H5N1 in Asian waterfowl that live near domestic poultry farms in
Asia.
C) Test for the presence of H5N1 in poultry used for human consumption worldwide.
D) Locate and destroy birds infected with H5N1 in Asian open-air poultry markets.
E) Keep domestic and wild fowl from interacting with each other to minimize the probability
that wild fowl could get infected and migrate out of Asia.

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

In terms of community ecology, why are pathogens often more virulent now than before?
A) More new pathogens have recently evolved.
B) Host organisms have become more susceptible because of weakened immune systems.
C) Human activities are transporting pathogens into new habitats (or communities) at an
unprecedented rate.
D) Medicines for treating pathogenic disease are in short supply.
E) Sequencing of genes in pathogenic organisms is particularly difficult.

The oak tree pathogen Phytophthora ramorum has migrated 800 km in 15 years. West Nile
virus spread from New York State to 46 other states in 5 years. The difference in the rate of
spread is probably related to
A) the lethality of each pathogen.
B) the mobility of their hosts.
C) the fact that viruses are very small.
D) innate resistance.
E) dormancy viability.

Which of the following statements is a valid conclusion of this experiment?
A) Balanus can survive only in the lower intertidal zone because it is unable to resist desiccation.
B) Balanus is inferior to Chthamalus in competing for space on rocks lower in the intertidal
zone.
C) The two species of barnacles do not compete with each other because they feed at different
times of day.
D) The removal of Balanus shows that the realized niche of Chthamalus is smaller than its
fundamental niche.
E) These two species of barnacle do not show competitive exclusion.
F) If Chthamalus were removed, Balanus's fundamental niche would become larger.

Connell conducted this experiment to learn more about
A) character displacement in the color of barnacles.
B) habitat preference in two different species of barnacles.
C) desiccation resistance and barnacle species.
D) how sea-level changes affect barnacle distribution.
E) competitive exclusion and distribution of barnacle species.

According to the Shannon Diversity Index, which block would show the greatest diversity?
A) 1
B) 2
C) 3
D) 4
E) 5

Which letter represents an organism that could be a producer?
A) A
B) B
C) C
D) D
E) E

Which letter represents an organism that could be a primary producer?
A) A
B) B
C) C
D) D
E) E

Which island would likely have the greatest species diversity?
A) A
B) B
C) C
D) D
E) E

Which island would likely exhibit the most impoverished species diversity?
A) A
B) B
C) C
D) D
E) E

Which island would likely have the lowest extinction rate?
A) A
B) B
C) C
D) D
E) E

What interactions exist between the cattle egret and grazing cattle?
A) o/-
B) +/o
C) +/-
D) o/o
E) -/-

What interactions exist between a lion pride and a hyena pack?
A) +/+
B) +/o
C) +/-
D) o/o
E) -/-

What interactions exist between a bee and a flower?
A) +/+
B) +/o
C) +/-
D) o/o
E) -/-

What interactions exist between a tick on a dog and the dog?
A) +/+
B) +/o
C) +/-
D) o/o
E) -/-

What interactions exist between cellulose-digesting organisms in the gut of a termite and the
termite?
A) +/+
B) +/o
C) +/-
D) o/o
E) -/-

What interactions exist between mycorrhizae and evergreen tree roots?
A) +/+
B) +/o
C) +/-
D) o/o
E) -/-

The feeding relationships among the species in a community determine the community's
A) secondary succession.
B) ecological niche.
C) species richness.
D) species-area curve.
E) trophic structure.

Based on the intermediate disturbance hypothesis, a community's species diversity is
increased by
A) frequent massive disturbance.
B) stable conditions with no disturbance.
C) moderate levels of disturbance.
D) human intervention to eliminate disturbance.
E) intensive disturbance by humans.

Which of the following could qualify as a top-down control on a grassland community?
A) limitation of plant biomass by rainfall amount
B) influence of temperature on competition among plants
C) influence of soil nutrients on the abundance of grasses versus wildflowers
D) effect of grazing intensity by bison on plant species diversity
E) effect of humidity on plant growth rates