Download Practice Exam: Ecology

PRACTICE EXAM #3 – NUTRIENTY CYCLES & ECOLOGY
48. All plants are
a. autotrophs
b. unicellular
c. heterotrophs
d. prokaryotes
49. Energy flows through an ecosystem from the sun to
a. producers and then consumers
b. consumers and then producers
c. primary consumers
d. secondary consumers
50. In which organisms is the GREATEST amount of biomass contained?
a. hawks
b. insect-eating birds
c. mushrooms and other fungi
d. grasses and shrubs
51. The movements of energy and nutrients through living systems are different because
a. energy flows in one direction and nutrients recycle
b. energy is limited in the biosphere and nutrients are always available
c. nutrients flow in one direction and energy recycles
d. energy forms chemical compounds and nutrients are lost as heat
52. Organisms that obtain nutrients by breaking down dead and decaying plants and animals are called
a. decomposers
b. omnivores
c. autotrophs
d. producers
53. In a particular ecosystem, alligators eat fish. Only about 10 percent of the energy available to the fish is
available to the alligators. What happens to the remaining energy?
a. It is lost from the ecosystem as heat.
b. It is destroyed in chemical reactions.
c. It is converted into the fish’s biomass.
d. It is absorbed during cellular respiration.
54. What is the trophic level of the robin in this food chain?
Oak tree → Caterpillar → Robin → Fox
a. primary consumers
b. secondary consumers
c. decomposers
d. autotrophs
55. The end result of ecological succession is usually
a. a climax community
b. an unstable community
c. an aquatic biome
d. a land biome
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Practice Exam - Ecology
56. What is one difference between primary and secondary succession?
a. Primary succession is slow, and secondary succession is rapid.
b. Secondary succession begins on soil, and primary succession begins on newly exposed surfaces.
c. Primary succession modifies the environment, and secondary succession does not.
d. Secondary succession begins with lichens, and primary succession begins with trees.
57. The process of succession
a. demonstrates that ecosystems are always changing
b. leads to a stable ecosystem in which no further changes occur
c. always begins on bare land or rock
d. always results from a sudden disturbance, such as a volcanic eruption
58. A lichen is a symbiosis between a fungus and a green alga. The alga provides food. The fungus provides
protection and minerals. This type of relationship is known as
a. coexistence
b. mutualism
c. commensalism
d. parasitism
59. The various growth phases through which most population go are represented on
a. a linear growth curve
b. an exponential growth curve
c. a normal growth curve
d. a boom and bust curve
60. The chart below shows the growth of a population of wolves over the course of four decades.
Year
1915
1925
1935
1945
1955
Growth Of A Wolf Population
Number of Breeding Male Wolves
(Thousands)
2,000
6,000
9,000
10,000
10,000
Which statement best explains how abiotic factors could have caused the population
changes shown in the chart?
a. The available water supply limited the growth of the wolf population.
b. The population shrank over time as a result of increased predation from other animals.
c. Competition for food with other animals slowed the growth of the wolf population.
d. Human disturbances to the wolves’ habitat caused the population to increase rapidly.
61. What happens when the carrying capacity of a population is reached?
a. The size of the population begins decreasing rapidly.
b. The size of the population remains fairly stable.
c. The rate of growth in the population increases.
d. The population must begin looking for new sources of food.
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Practice Exam - Ecology
62. The predator-prey relationship, such as between wolves and moose on Isle Royale in Lake Superior,
a. contributes to exponential growth of the predator species
b. represents competition between species
c. is highly effective at controlling populations of both species
d. is usually a cause of extinction of one of the species
63. The first, and perhaps the best known, case of biological magnification involved the pesticide
a. PCB
b. Dieldrin
c. NO2
d. DDT
64. A factory regularly releases chemical runoff into a river. Over time, scientists notice that river otters
show a high concentration of the chemical. The increase is probably due to
a. the extinction of local producers
b. a change in the otters’ prey
c. biological magnification of the chemical
d. biodegradable substances in the runoff
65. Which of the following is a renewable resource?
a. water
b. coal
c. natural gas
d. oil
66. How does the burning of fossil fuels by humans affect the carbon cycle?
a. It prevents carbon from being stored underground.
b. It converts carbon dioxide to oxygen through photosynthesis.
c. It releases carbon dioxide into the atmosphere
d. It releases carbon dioxide into oceans through erosion.
67. Fossil fuels are an important source of energy for human activities. Which statement about fossil fuels is
true?
a. They form rapidly.
b. They release oxygen when burned.
c. They are formed from the remains of dead organisms.
d. They exist in unlimited supplies in most parts of the world.
68. In just over a hundred years, the average temperature of Earth’s atmosphere has risen about 0.6° Celsius.
The effects of this global warming may include
a. coastal flooding and more droughts during the North American growing season
b. coastal flooding and more rainfall during the North American growing season
c. receding oceans and mass extinctions of marine life
d. receding oceans and marine life adapting to live on land
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Practice Exam - Ecology
69. When fertilizers wash off farmland into streams and ponds, the nitrogen content of the water increases.
This can lead to rapid growth of algae in a process call eutrophication. How can this process affect other
organisms in the water?
a. The algae us up oxygen, reducing the resources available to other organisms.
b. The water becomes better able to support bacteria and other prokaryotic organisms.
c. The algae provide food from fish and other organisms, leading to decreased algae populations.
d. The extra nitrogen provides additional food for the other organisms, increasing their population.
70. In the nitrogen cycle, what organisms return molecular nitrogen to the atmosphere?
a. green plants called legumes
b. nitrogen-fixing bacteria on the roots of legumes
c. denitrifying bacteria
d. nitrifying bacteria
71. Nitrogen fixation is carried out primarily by
a. humans
b. plants
c. bacteria
d. consumers
72. Fossil fuels are formed by
a. the emission of carbon dioxide gas
b. cutting and burning forests
c. volcanic activity
d. the conversion of dead organisms under pressure
73. All of the following are processes involved in the carbon cycle EXCEPT:
a. evaporation
b. photosynthesis
c. respiration
d. combustion
74. Bacteria play many roles in ecosystems. One important role is nitrogen fixation. What is another
essential role of bacteria in the environment?
a. condensation
b. respiration
c. decomposition
d. transpiration
75. Elements and compounds cycle through ecosystems so they are available for all kinds of organisms.
They are considered as nutrients when they control the growth of organisms. When nutrients are limited,
organisms cannot grow well and may die. Which would be the major limiting nutrient for plants?
a. Carbon
b. Oxygen
c. Nitrogen
d. Water
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Practice Exam - Ecology
76. Suppose 50,000 kilocalories of the Sun’s energy falls on a lawn. How much of this energy is available to
rabbits that nibble on the lawn?
a. 50,000 kilocalories
b. 5,000 kilocalories
c. 500 kilocalories
d. 50 kilocalories
77. Swamps differ from marshes in that swamps
a. are dominated by trees and shrubs
b. have acid soil
c. are dominated by grasses and rushes
d. are rich in waterfowl
78. The cold water counterpart to a coral reef is a(n)
a. kelp forest
b. aphotic zone
c. swamp
d. rock jetty
79. The distinct zones of the ocean depend upon
a. distance from the shore and temperature
b. temperature and types of organisms
c. distance from shore and depth
d. types of organisms and distance from shore
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Practice Exam - Ecology