General Biology: BI101 Spring, 2007

General Biology: BI101 Spring, 2007

STUDY QUESTIONS: Ch 40

1. In the intertidal zone, diverse assemblages of many invertebrate species and algae exist attached to the rocks. If an oil spill occurred that directly affected only a species of starfish that is a keystone predator in this system, totally eliminating it, what do you predict would happen to the community?

a. No significant change in the structure of the community would be likely to occur.
b. The community is likely to become less diverse, increasingly dominated by a few species that are good competitors for space.
c. The community is likely to become more diverse, as strong and weak competitors can then coexist.

2. A habitat is best defined as:

a. the home or location where an organism lives.
b. the occupation of the organism in the ecosystem in which it resides.
c. all the organisms and their nonliving environment within a defined area.
d. all the interacting populations within an ecosystem.

3. In a farm pond location a landowner decided to introduce bluegill Lepomis macrochirus because she liked to fish and preferred to eat the bluegill species. The species of fish already living in the pond were sunfish Lepomis humilis. After introduction of the bluegill, which is very similar to sunfish in habitat and food preferences, the landowner discovered several years later that there were not as many sunfish in the pond; the sunfish numbers had diminished over time. This is an example of:

a. intraspecific competition. b. interspecific competition. c. competitive exclusion principle.
d. Both A and C are correct. e. Both B and C are correct.

1. The best definition for a keystone species is:

a. a species that first colonizes an area in the process of succession.
b. a species that is introduced into an area that it did not originally inhabit.
c. a species that plays a major role in determining community structure, a role that is out of proportion to its abundance in the community.
d. a species that is found nowhere else but in the confined area that defines its distribution.
e. a species that is locked into a obligatory symbiotic relationship with another species.

2. Humans have a ___________ relationship with the bats, which is causing the populations of fruit bats to diminish.

a. commensal b. competitive c. parasitic d. mutualistic e. predatory

3. When groups of species that interact with each other in a given area are considered together, this level of organization is called the:

a. biome. b. population. c. community. d. ecosystem. e. biosphere.

4. If the island population of fruit bats is competing with other nocturnal mammals, such as the sugar glider, for the same resources of fruit, pollen, nectar, and insects, what is the concept that best describes the splitting of this similar niche of food resource so that both species may coexist with these limited resources?

a. resource partitioning b. competitive exclusion principle c. adaptation
d. mimicry e. mutualism

1. When all vegetation is removed from a site by human activities or by natural forces such as volcanoes or glaciers, _______ species are the first to colonize the sites.

a. Archaea b. pioneer c. climax d. latent

2. Succession that begins on bare rock after glaciers have passed, or on newly formed volcanic islands, is:

a. primary. b. secondary. c. climatic. d. pioneer.

3. Why does a climax community tend to persist in an area?

a. because it is made up of large, hard-to-move organisms
b. because the species in it do not alter their environment significantly
c. because it is able to change the weather
d. because the species in it are able to kill off competitors

1. A sand dune in Georgia might take several ___________ years to reach a climax community, whereas a former cornfield that has been left unfarmed is likely to take a couple of ______ years to reach the same climax.

a. hundred; hundred b. thousand; hundred c. thousand; thousand
d. hundred; thousand

2. Which of the following is true of climax communities?

a. All areas will have the same climax community if enough time is allowed for succession.
b. The climax community that develops is determined by such factors as temperature, rainfall, elevation, and type of rock.
c. The climax community at a site changes rapidly.
d. Climax communities are made up of all the species that were found in each successional community.

.

3. The productivity of a community will usually _____ through succession.

a. decrease b. remain constant

4. Organisms in a succession community help to cause the changes that result in their own replacement because:

a. they become old and unfit for the environment.
b. they change the physical environment in ways that favor competitors.
c. they emigrate to other areas to make room for new species.

1. Describe what an ecological niche is and why it is important to organisms.

2. Describe the competitive exclusion principle.

5. Why do so many different types of butterflies have similar coloration as monarch butterflies?

6. What is mutualism?

Describe some examples of coevolution of predators and prey.

Why is it important to determine what types of organisms serve as keystone species in an ecosystem?

People have suppressed fires for decades. What are the implications of fire suppression for forest ecosystems and succession?

BI101SQ Ch40.doc 1 5/25/2007