Ecosystems and Communities
Chapter Test A
(removed questions on Freshwater and Marine Ecosystems)
Multiple Choice
Write the letter that best answers the question or completes the statement on the line provided.
_____ 1. How does an area’s weather differ from the area’s climate?
a. Weather involves temperature and preciapitation and climate involves only temperature.
b. An area’s weather depends on where it is located on Earth and the area’s climate does
c. An area’s weather does not change very much and an area’s climate changes many times.
d. Weather is the area’s day-to-day conditions and climate is the area’s average conditions.
_____ 2. The tendency for warm air to rise and cool air to sink results in
a. global wind patterns.
c. the seasons.
b. ocean upwelling.
d. regional precipitation.
_____ 3. An organism’s niche is
a. the range of physical and biological conditions in which an organism lives and the way it
obtains what it needs to survive and reproduce.
b. all the physical and biological factors in the organism’s environment.
c. the range of temperatures that the organism needs to survive.
d. a full description of the place an organism lives.
_____ 4. No two species can occupy the same niche in the same habitat at the same time
a. because of the interactions that shape the ecosystem.
b. unless the species require different abiotic factors.
c. because of the competitive exclusion principle.
d. unless the species require different biotic factors.
_____ 5. What would likely happen if the
population of the bird species shown
in the ecosystem in Figure 4–1 were to
suddenly decrease?
a. The fish population would decrease.
b. The fish population would increase.
c. The fish population would remain
the same.
d. Fish would leave the ecosystem.
Figure 4–1
_____ 6. A wolf pack hunts, kills, and feeds on a moose. In this interaction, the wolves are
a. hosts.
c. mutualists.
b. prey.
d. predators.
_____ 7. A symbiotic relationship in which one organism is harmed and another benefits is
a. mutualism.
c. commensalism.
b. parasitism.
d. predation.
_____ 8. What is one difference between primary and secondary succession?
a. Primary succession is rapid and secondary succession is slow.
b. Secondary succession begins on soil and primary succession begins on newly exposed
c. Primary succession modifies the environment and secondary succession does not.
d. Secondary succession begins with lichens and primary succession begins with trees.
_____ 9. A tropical rain forest may not return to its original climax community after which of the
following disturbances?
a. burning of a forest fire
c. volcanic eruption
b. clearing and farming
d. flooding after a hurricane
_____ 10. Which two biomes have the least precipitation?
a. tropical rain forest and temperate grassland
b. tropical savanna and tropical dry forest
c. tundra and desert
d. boreal forest and temperate woodland and shrubland
_____ 11. Which landforms are not classified into a major biome?
a. prairies
b. mountain ranges
c. coastlines
d. islands
Complete each statement on the line provided.
16. Over time, some plants growing in an area are crowded out by other plants. The new plants
use up water and nutrients needed by the previous plants. The disappearance of the first plants
is due to
17. Predator is to prey as herbivore is to
18. Some orchids grow high on trees so that they can get enough light for photosynthesis. The trees are
unaffected by the presence of the orchids. The relationship between the orchids and the trees is an
example of
19. Regrowth of grasses, ferns, wildflowers, and saplings after a forest fire is an example of
Short Answer
In complete sentences, write the answers to the questions on the lines provided.
21. How are microclimates related to climates?
22. The concentration of greenhouse gases in the atmosphere
can and does change. Would conditions on Earth be worse
if the concentration of these gases increased or if it
decreased? Use Figure 4–2 to explain your answer.
23. How do predators affect the populations of their prey?
Figure 4–2
24. Deserts vary greatly depending on elevation and latitude. What characteristic do all deserts share?
Write the answer to each question on the lines provided.
31. Explain how ocean currents originate and affect Earth’s climates.
32. Describe the stages of primary succession in land environments, including the roles played by
grasses, lichens, trees, mosses, and shrubs.
Figure 4–4
Deer and Wolf Populations
on an Arizona Plateau, 1910–1935
33. Figure 4–4 shows a decrease in the deer population after 1925. Give one possible reason for this
population decline. Explain your reasoning.
34. The general characteristics of temperate grasslands found in the United States, Central Asia, and
Argentina are similar. Identify some characteristics of temperate grasslands, and explain why
these regions share characteristics in spite of the distance between the locations. Mention climate,
climate zones, biomes, and biotic and abiotic factors in your answer.
Chapter 4—Test A
Multiple Choice 1. d 2. a 3. a 4. c 5. b 6. d 7. b 8. b 9. b 10. c 11. b 12. c 13. c 14. a 15. b
Completion 16. competitive exclusion 17. plant 18. commensalism 19. secondary
Short Answer
21. An area’s climate is made up of the average conditions for that area over long periods. A climate area can be
divided into several microclimates because environmental conditions can vary over small distances.
22. Accept any response that is properly supported by an explanation. Sample answer: Conditions on Earth
would be worse if the concentration of greenhouse gases increased because
the amount of heat trapped by the gases would increase. This increase in global temperature would change
climates on Earth. Alternate answer: Conditions on Earth would be worse if the concentration of greenhouse
gases decreased because the amount of heat escaping into space would increase. This increased loss of heat
would decrease global temperature and would change the climates on Earth.
23. Predators keep the population of their prey from getting too large by eating the prey animals.
24. A desert biome is defined as having less than 25 cm of annual rainfall.
Using Science Skills
31. Cold water near the poles sinks and then flows parallel to the ocean bottom, eventually rising again in
warmer regions through a process called upwelling. Meanwhile, surface water is moved by winds. In both cases,
the water flow creates ocean currents. Like air currents, ocean currents transport heat within the biosphere.
Surface ocean currents warm or cool the air above them, thus affecting the weather and climate of nearby
32. Primary succession occurs on newly exposed surfaces, such as a fresh lava flow that has destroyed the
previous ecosystem. The first organisms to appear are lichens that colonize the newly formed volcanic rock.
Over time, lichens break down the rock, fix atmospheric nitrogen, and add organic material as they decompose,
creating soil. Various types of plants, including mosses and grasses, can then take root in the thin layer of soil.
As the soil gets thicker and richer from decomposing organisms, seeds of shrubs and trees may take root. A
characteristic ecological community may eventually dominate the area.
33. Competition between deer probably caused the population decline. The deer population grew so much that
there were not enough resources to support all the deer. The deer had to compete for resources and many died.
34. Temperate grasslands in the United States, Central Asia, and Argentina belong to the same biome. They
share the abiotic characteristics of hot, dry summers, cold winters, moderate precipitation, fertile soils, drought,
and susceptibility to wildfires. They share the biotic characteristics of lush perennial grasses adapted to cold and
fire. All of these grasslands are found in temperate biomes, even though they are far from one another, because
the angle at which the sun strikes Earth in these areas is similar. Since they are in the same biome, these areas
have similar climates. Plants and animals in all these locations display similar characteristics, since they have
adaptations enabling them to survive in similar climates.
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