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Chapter 03 - Ecosystems - What Are They and How Do They Work
d.
is plentiful and rarely limits primary productivity
e.
cycling has not been affected by humans
53. Human activities have affected the sulfur cycle primarily by ____.
a.
producing carbon dioxide, which reacts with sulfur in the atmosphere
b.
capturing sulfur emissions from volcanoes
c.
converting sulfur into hydrogen sulfide gas
d.
replenishing sulfur resources
e.
releasing large amounts of sulfur dioxide (SO2) gas into the atmosphere
54. Geographic Information System (GIS) software allows scientists to ____.
a.
simulate real-world conditions in laboratory experiments
b.
connect to the internet from remote locations in the field
c.
connect to and control experiments in the field
d.
capture, store, analyze, and display geographic data
e.
simulate the behavior of ecosystems
55. One challenge of laboratory research is that ____.
a.
too many variables are uncontrolled
b.
real organisms cannot be used
c.
observations may not reflect what actually takes place in nature
d.
field locations can be expensive and difficult to access
e.
measurements are difficult to make in that environment
56. Phosphate can be lost from the phosphorus cycle for long periods of time when ____.
a.
phosphorus-containing fertilizer is applied to agricultural soil
Chapter 03 - Ecosystems - What Are They and How Do They Work
b.
bacteria convert it into a gas
c.
exposed rocks containing phosphate are eroded by running water
d.
it is taken up by plants
e.
it is washed into the ocean and deposited as marine sediment
57. Of the following water cycle processes, the one working against gravity is
a.
percolation
b.
infiltration
c.
runoff
d.
transpiration
e.
precipitation
58. Carbon is cycled through the biosphere through ____.
a.
fuel combustion and decomposition
b.
photosynthesis and aerobic respiration
c.
soil bacteria and precipitation
d.
volcanic activity and organic decay
e.
the rock cycle
59. The most common gas in the atmosphere is ____.
a.
nitrogen
b.
carbon dioxide
c.
oxygen
d.
hydrogen
e.
methane
Chapter 03 - Ecosystems - What Are They and How Do They Work
60. Nitrogen fixation is accomplished by ____.
a.
legumes
b.
bacteria
c.
algae
d.
protozoa
e.
round worms
61. Molecules of water are attracted to each other by ____.
a.
neutron bonds
b.
tension bonds
c.
covalent bonds
d.
hydrogen bonds
e.
oxygen bonds
62. Net primary productivity (NPP) is the rate at which producers use photosynthesis to produce and store chemical
energy minus ____.
a.
the rate at which they use some of this stored chemical energy through aerobic respiration
b.
the amount of chemical energy they already have stored
c.
the rate at which the producers are consumed
d.
the average rate of photosynthesis in cloudy conditions
e.
the average rate of photosynthesis among similar organisms
63. Photosynthesis is performed by ____.
a.
heterotrophs
b.
autotrophs
c.
decomposers
d.
detritivores
e.
herbivores
64. Oxygen accounts for about ____ of the air in the atmosphere.
a.
5%
b.
21%
c.
53%
d.
66%
e.
82%
65. The oceans contain about ____ of the earth’s water.
a.
38%
b.
55%
c.
71%
d.
85%
e.
97%
66. Phytoplankton in the open ocean are examples of ____.
a.
producers
b.
consumers
c.
heterotrophs
d.
detritivores
e.
decomposers
67. Water evaporates from the surfaces of plants through a process called ____.
a.
transpiration
b.
respiration
c.
runoff
d.
infiltration
e.
percolation
Chapter 03 - Ecosystems - What Are They and How Do They Work
Narrative (questions 43-45):
In the Sonoran desert of the southwestern United States, scientists observed that population clusters of a small cactus were
pronounced around nests of desert woodrats. Given this spatial relationship, they began to think the woodrat was related
to the seeding of these cactus plants.
After years of counting and observing woodrat nests and nearby cactus plants, scientists collected woodrat droppings for
laboratory analysis to determine whether they contained cactus seeds. They also collected the droppings and transported
them to other areas to see if this would bring about new population clusters of the cactus.
Scientists then programmed the data they had collected into a computer. A computer program enabled them to predict that
increases in the woodrat population would result in corresponding increases in the cactus population, and likewise, a
decrease in the number of woodrats would signal an impending decrease in cactus.
68. Which phase of the study could be described as modeling?
a.
when the scientists gathered woodrat droppings for lab analysis
b.
when the scientists determined from computer programs how woodrat nest numbers would impact cactus
populations
c.
when the scientists first observed the proximity of woodrat nests and cactus plants
d.
when the scientists transported woodrat droppings to other areas
e.
when the scientists first wondered whether or not woodrats were connected to the seeding of the cactus plants
69. The transport of woodrat dropping to other areas could be described as ____.
a.
remote sensing
b.
laboratory research
c.
a controlled experiment
d.
behavioral science
e.
chemical analysis
70. Which statement best describes the scientists’ initial observations?
a.
Woodrat nests had no apparent effect on cactus populations.
b.
Cactus plants were less common in proximity to woodrat nests.
c.
Cactus plants were more common in proximity to woodrat nests.
Chapter 03 - Ecosystems - What Are They and How Do They Work
d.
Woodrats were spreading cactus seeds.
e.
The effect of woodrats on cactus plants was different from season to season.
71. A(n) ____________________ consists of populations of different species living in a particular place and potentially
interacting with each other.
72. Precipitation that infiltrates through soil into underground layers of rock, sand, and gravel is stored as
____________________.
73. Another word for an autotroph is a(n) ____________________.
74. A primary consumer can also be described as a(n) ____________________, a word that means “plant eater”.
75. Bacteria are more important in the ____________________ than in the carbon or phosphorous cycles.
76. The ____________________ occupies those parts of the atmosphere, hydrosphere, and geosphere where life is found.
Chapter 03 - Ecosystems - What Are They and How Do They Work
77. Carnivores such as tigers, hawks and killer whales that feed on the flesh of other carnivores are known as
_______________ consumers.
78. A sequence of organisms, each of which serves as a source of nutrients or energy for the next, is called a(n)
____________________.
79. ____________________ makes up 78% of the volume of the atmosphere.
80. Since the late 1960s, ecologists have developed mathematical ____________________ that simulate ecosystems.
81. Although ____________________ cover only about 2% of the earth’s land surface, studies indicate that they contain
up to half of the world’s known terrestrial plant and animal species.
82. The ____________________ consists of the earth’s intensely hot core, a thick mantle composed mostly of rock, and a
thin outer crust.
83. As solar energy interacts with carbon dioxide, water vapor, and several other gases in the troposphere, it warms the
troposphere— a process known as the ____________________.
84. ____________________ allows the earth to hold onto its atmosphere and helps to enable the movement and cycling of
chemicals through air, water, soil, and organisms.
85. ____________________ is the rate at which an ecosystem’s producers (usually plants) convert solar energy into
chemical energy stored in compounds found in their tissues, not accounting for the use of chemical energy through
aerobic respiration.
86. Most precipitation falling on terrestrial ecosystems becomes ____________________, which ultimately flows into
streams, lakes, wetlands, and oceans.
87. The troposphere and stratosphere are layers of the ____________________.
88. Primary consumers and producers are two examples of ____________________ levels, a way to classify living
organisms based on their source of nutrients.
89. Bacteria in soil convert ammonia and ammonium ions to ___________________.
Chapter 03 - Ecosystems - What Are They and How Do They Work
90. Unlike the phosphorus cycle, a large portion of the planet’s nitrogen can be found in the ____________________.
Subjective Short Answer
Figure 3.5
91. In the accompanying figure of an ecosystem, which components can be categorized as abiotic?
Chapter 03 - Ecosystems - What Are They and How Do They Work
Figure 3.10
92. What trophic level is occupied by the emperor penguin in the above food web? Briefly state the reason for your
choice.
93. What trophic level does the blue whale occupy in this food web?
94. Why is a vegetarian diet more efficient than a meat-based diet?
95. Clearly explain the difference between ultraviolet (UV) and infrared radiation and how this relates to the greenhouse
effect.
96. Why is it that most top predators (e.g., lions, tigers, bears, and wolves) have extremely large territories and are
relatively rare?
97. Clearly explain the distinction between Gross Primary Productivity (GPP) and Net Primary Productivity (NPP).
98. Explain the role that life (excluding the impacts of human activities) plays in the carbon cycle.
99. Explain why decomposers are a necessary and important part of ecosystems.
100. Compare the roles of bacteria in the nitrogen and phosphorus cycles.
