Strong competition can lead to _________ _________, local elimination of a competing species.

competitive exclusion

__________ _________, or camouflage, makes prey difficult to spot.

cryptic coloration

Animals with effective chemical defense often exhibit bright warning coloration, called __________ _________.

aposematic coloration

__________ mimicry: a harmless species mimics a harmful one.

Batesian

________ mimicry: two unpalatable species mimic each other.

Müllerian

In _________, one organism, the parasite, derives nourishment from another organism, its host, which is harmed in the process.

parasitism

________ is an interspecific interaction that benefits both species.

mutualism

__________: the relation between two different kinds of organisms when one receives benefits from the other without damaging it.

Commensalism

________ __________ is the total number of different species in the community.

Species richness

________ _________ of a community is the variety of organisms that make up the community.

Species diversity

_________ _________ is the proportion each species represents of the total individuals in the community.

Relative abundance

__________ _________ is the feeding relationships between organisms in a community. It is a key factor in community dynamics.

Trophic structure

_________ _________ are those that are most abundant or have the highest biomass.

Dominant species

_________ ________ are not necessarily abundant in a community.

keystone species

Some ________ _______ act as facilitators that have positive effects on survival and reproduction of some other species in the community.

foundation species

The __________ model of community organization proposes a unidirectional influence from lower to higher trophic levels. In this case, presence or absence of mineral nutrients determines community structure, including abundance of primary producers.

bottom-up

The ______ model proposes that control comes from the trophic level above.

top-down

Which of the following statements is consistent with the principle of competitive exclusion?
A) Bird species generally do not compete for nesting sites.
B) The random distribution of one competing species will have a positive impact on the population growth of the other competing species.
C) Two species with the same fundamental niche will exclude other competing species.
D) Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species.
E) Natural selection tends to increase competition between related species.

Answer: D

According to the competitive exclusion principle, two species cannot continue to occupy the same
A) habitat.
B) niche.
C) territory.
D) range.
E) biome.

Answer: B

Which of the following is an example of cryptic coloration?
A) bands on a coral snake
B) brown or gray color of tree bark
C) markings of a viceroy butterfly's wings
D) colors of an insect-pollinated flower's petals
E) a "walking stick" insect that resembles a twig

Answer: E

Which of the following is an example of Müllerian mimicry?
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) two species of rattlesnakes that both rattle their tails
E) two species of moths with wing spots that look like owl's eyes

Answer: A

Which of the following is an example of Batesian mimicry?
A) an insect that resembles a twig
B) a butterfly that resembles a leaf
C) a nonvenomous snake that looks like a venomous snake
D) a fawn with fur coloring that camouflages it in the forest environment
E) a snapping turtle that uses its tongue to mimic a worm, thus attracting fish

Answer: C

Which of the following is an example of aposematic coloration?
A) stripes of a skunk
B) eye color in humans
C) green color of a plant
D) colors of an insect-pollinated flower
E) a katydid whose wings look like a dead leaf

Answer: A

Dwarf mistletoes are flowering plants that grow on certain forest trees. They obtain nutrients and water from the vascular tissues of the trees. The trees derive no known benefits from the dwarf mistletoes. Which of the following best describes the interactions between dwarf mistletoes and trees?
A) mutualism
B) parasitism
C) commensalism
D) facilitation
E) competition

Answer: B

Evidence shows that some grasses benefit from being grazed. Which of the following terms would best describe this plant-herbivore interaction?
A) mutualism
B) commensalism
C) parasitism
D) competition
E) predation

Answer: A

Which of the following would be most significant in understanding the structure of an ecological community?
A) determining how many species are present overall
B) determining which particular species are present
C) determining the kinds of interactions that occur among organisms of different species
D) determining the relative abundance of species
E) determining how many species are present overall, which particular species are present, the kinds of interactions that occur among organisms of different species, and the relative abundance of species

Answer: E

Which of the following studies would a community ecologist undertake to learn about competitive interactions?
A) selectivity of nest sites among cavity-nesting songbirds
B) the grass species preferred by grazing pronghorn antelope and bison
C) nitrate and phosphate uptake by various hardwood forest tree species
D) stomach analysis of brown trout and brook trout in streams where they coexist
E) selectivity of nest sites among cavity-nesting songbirds, the grass species preferred by grazing pronghorn antelope and bison, nitrate and phosphate uptake by various hardwood forest tree species, and stomach analysis of brown trout and brook trout in streams where they coexist

Answer: E

White-breasted nuthatches and Downy woodpeckers both eat insects that hide in the furrows of bark in hardwood trees. The Downy woodpecker searches for insects by hunting from the bottom of the tree trunk to the top, whereas the white-breasted nuthatch searches from the top of the trunk down. These hunting behaviors best illustrate which of the following ecological concepts?
A) competitive exclusion
B) resource partitioning
C) character displacement
D) keystone species
E) bottom-up and top-down hypotheses

Answer: B

Monarch butterflies are protected from birds and other predators because of cardiac glycosides they incorporate into their tissues from eating milkweed when they were in their caterpillar stage. The wings of a different species of butterfly, the Viceroy, look nearly identical to the Monarch so predators that have learned not to eat the bad-tasting Monarch avoid Viceroys as well. This example best describes
A) aposmatic coloration.
B) cryptic coloration.
C) Batesian mimicry.
D) Müllerian mimicry.
E) mutualism.

Answer: C

Prairie dogs once covered the expanses of the Great Plains. Their grazing made the grass more nutritious for the huge herds of bison, and they were preyed upon by a variety of snakes, raptors, and mammals. In fact, the black-footed ferret (now endangered) specialized in prairie dog predation. Today, increases in housing and agricultural developments have eradicated many prairie dog towns. Which of the following statements about prairie dogs is true?
A) Their realized niche has expanded.
B) They have a competitive relationship with bison.
C) They are probably a poor candidate for keystone species.
D) Their fundamental niche has been compromised.
E) Their fundamental niche has expanded.

Answer: E

Which statement best describes the evolutionary significance of mutualism?
A) Mutualism offers more biodiversity to a community.
B) Individuals partaking in a mutualistic relationship are more resistant to parasites.
C) Interaction increases the survival and reproductive rates of mutualistic species.
D) Mutualistic interaction lessens competition in communities where it is present.
E) Mutualistic relationships allow organisms to synthesize and use energy more efficiently.

Answer: C

How might an ecologist test whether a species is occupying its realized or its fundamental niche?
A) Study the temperature range and humidity requirements of the species.
B) Observe if the niche size changes after the addition of nutritional resources to the habitat.
C) Observe if the niche size changes after the introduction of a similar non-native species.
D) Measure the change in reproductive success when the species is subjected to environmental stress.
E) Remove a competitor species to see if the species expands its range.

Answer: E

Which of the following terms is used by ecologists to describe the community interaction where one organism makes the environment more suitable for another organism?
A) parasitism
B) mutualism
C) inhibition
D) facilitation
E) commensalism

Answer: D

How did Eugene Odum describe an ecological niche?
A) the "address" of an organism
B) an entity that is synonymous with an organism's specific trophic level
C) an organism's "profession" in the community
D) the organism's role in recycling nutrients in its habitat
E) the interactions of the organism with other members of the community

Answer: C

Approximately how many kg of carnivore biomass can be supported by a field plot containing 1,000 kg of plant material?
A) 10,000
B) 1,000
C) 100
D) 10
E) 1

Answer: D

In a tide pool, 15 species of invertebrates were reduced to eight after one species was removed. The species removed was likely a(n)
A) pathogen.
B) keystone species.
C) herbivore.
D) resource partitioner.
E) mutualistic organism.

Answer: B

Elephants are not the most dominant species in African grasslands, yet they influence community structure. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands convert to forests or to shrublands. The newly growing forests support fewer species than the previous grasslands. Which of the following describes why elephants are the keystone species in this scenario?
A) Essentially all of the other species depend on the presence of the elephants to maintain the community.
B) Grazing animals depend upon the elephants to convert forests to grassland.
C) Elephants prevent drought in African grasslands.
D) Elephants are the biggest herbivore in this community.
E) Elephants help other populations survive by keeping out many of the large African predators.

Answer: A

Why are food chains relatively short?
A) Top-level feeders tend to be more numerous than lower-trophic-level species.
B) Top-level feeders tend to be small but are capable of conserving more energy.
C) Longer chains are less stable and energy transfer between levels is inefficient.
D) There are only so many organisms that are adapted to feed on other types of organisms.
E) Food chain length is ultimately determined by the photosynthetic efficiency of producers.

Answer: C

Which term do ecologists use to describe the ability of a community either to resist change or to recover to its original state after change?
A) stability
B) succession
C) partitioning
D) productivity
E) competitive exclusion

Answer: A

In a particular case of secondary succession, three species of wild grass all invaded a field. By the second season, a single species dominated the field. A possible factor in this secondary succession was
A) equilibrium.
B) facilitation.
C) immigration.
D) inhibition.
E) parasitism.

Answer: D

Why do moderate levels of disturbance result in an increase in community diversity?
A) Habitats are opened up for less competitive species.
B) Competitively dominant species infrequently exclude less competitive species after a moderate disturbance.
C) The environmental conditions become optimal.
D) The resulting uniform habitat supports stability, which in turn supports diversity.
E) Less-competitive species evolve strategies to compete with dominant species.

Answer: A

Species richness increases
A) as we increase in altitude in equatorial mountains.
B) as we travel southward from the North Pole.
C) on islands as distance from the mainland increases.
D) as depth increases in aquatic communities.
E) as community size decreases.

Answer: B

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.

Answer: B

A community's actual evapotranspiration is a reflection of
A) solar radiation, temperature, and water availability.
B) the number of plants and how much moisture they lose.
C) the depth of the water table.
D) wind speed and the frequency of wind gusts.
E) plant biomass and plant water content.

Answer: A

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.

Answer: D

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.

Answer: D

During the course of the formation of a parasite/host relationship, a critical first step in this evolution would be
A) changing the behavior of the host or intermediate host.
B) developing asexual reproduction.
C) deriving nourishment without killing the host.
D) starting as an ectoparasite and then later becoming an endoparasite.
E) utilizing heterotropic nutrition during infection and autotrophic nutrition during dormancy.

Answer: C

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

Answer: E

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

Answer: B

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

Answer: C

Which of the following would be considered a keystone species in McDonaldland?
A) Big Mac
B) Large French Fries
C) Premium Caesar Salad with Crispy Chicken
D) Filet-O-Fish
E) Chicken McNuggets

Answer: A

Which two "species" are likely to compete for the same ecological niche?
A) Big Mac and Quarter Pounder
B) French Fries and Hash Browns
C) Premium Caesar Salad with Crispy Chicken and Premium Crispy Chicken Classic Sandwich
D) Filet-O-Fish and Double Cheeseburger
E) No two species can ever occupy the same ecological niche.

Answer: E

According to the McDonaldland scenario, which of the following would best define an ecological community?
A) all of the sandwiches sold at McDonaldland
B) the entire menu at McDonaldland
C) all of the fast-food restaurants in the United States
D) the condiments served at McDonaldland
E) the breakfast menu at McDonaldland

Answer: B

In a two-week marketing analysis, McDonald's was interested in finding out the popularity of the Big Mac. Using the realized/fundamental niche concept of community ecology, what should the marketing researchers do?
A) Study the sales of McDonald's restaurants that are in close proximity to other fast-food restaurants.
B) Serve only Big Macs at McDonald's and analyze the sales.
C) Remove the Quarter Pounder from the menu and see if Big Mac sales increase.
D) Serve Big Macs without the special sauce to see if sales go down.
E) Serve Big Macs during breakfast hours.

Answer: C

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.

Answer: E

The principle of competitive exclusion states that
A) two species cannot coexist in the same habitat.
B) competition between two species always causes extinction or emigration of one species.
C) competition in a population promotes survival of the best-adapted individuals.
D) two species that have exactly the same niche cannot coexist in a community.
E) two species will stop reproducing until one species leaves the habitat.

Answer: D

Keystone predators can maintain species diversity in a community if they
A) competitively exclude other predators.
B) prey on the community's dominant species.
C) allow immigration of other predators.
D) reduce the number of disruptions in the community.
E) prey only on the least abundant species in the community.

Answer: B

The most plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that
A) tropical communities are younger.
B) tropical regions generally have more available water and higher levels of solar radiation.
C) higher temperatures cause more rapid speciation.
D) diversity increases as evapotranspiration decreases.
E) tropical regions have very high rates of immigration and very low rates of extinction.

Answer: B