TRUE/FALSE – Ch 3 What are Ecosystems and How do they Work?
1. Although tropical rain forests are only about 2% of the earth's land surface, they contain at least 50% of
the world's land plant and animal species.
3-0 Core Case Study
2. Only about 14% of the tropical rain forests have been destroyed or disturbed at this point.
3-0 Core Case Study
3. Destruction of the tropical rain forest will likely change regional weather patterns in ways that will
prevent their return.
3-0 Core Case Study
4. Greenhouse gases, including methane, CO2, and water vapor, make up about 30% of the earth's
troposphere.
3-1 What Keeps Us and Other Organisms Alive?
5. While the troposphere is 11 miles thick above sea level at the tropics, it is only four miles thick above the
North and South poles.
3-1 What Keeps Us and Other Organisms Alive?
6. If the earth were an apple, all life would be contained in the thickness of the skin.
3-1 What Keeps Us and Other Organisms Alive?
7. Part of the solar energy striking the earth generates winds.
3-1 What Keeps Us and Other Organisms Alive?
8. All life is based on the power of the sun.
3-1 What Keeps Us and Other Organisms Alive?
9. The "greenhouse effect" is a strictly artificial (human-made) phenomenon.
3-1 What Keeps Us and Other Organisms Alive?
10. A "trophic level" refers to the ability of an organism to survive outside the optimum range in a range of
tolerance.
3-2 What Are the Major Components of an Ecosystem?
11. An ecosystem is defined as a community of different populations of species interacting with one another
and their nonliving environment.
3-2 What Are the Major Components of an Ecosystem?
12. Most producers capture sunlight to produce energy-rich carbohydrates through photosynthesis.
3-2 What Are the Major Components of an Ecosystem?
13. Autotroph is another word for a consumer in a trophic system.
3-2 What Are the Major Components of an Ecosystem?
14. Deep sea habitats are an exception to the first principle of sustainability, in that they use a non-solar
source of energy.
3-2 What Are the Major Components of an Ecosystem?
15. All microbes are pathogenic (disease causing) or otherwise dangerous.
Science Focus: Many of the World's Most Important Organisms are Invisible to Us
16. Transfer of energy through food chains or webs is very efficient, making a lot of energy available to
organisms.
3-3 What Happens to Energy in an Ecosystem?
17. The larger the number of trophic levels in a food chain or web, the greater the accumulated loss of energy.
3-3 What Happens to Energy in an Ecosystem?
18. The reason we observe a "pyramid" of energy flow instead of an energy flow "cube" is because the low
ecological efficiency of biological systems limits the numbers of organism in the higher trophic levels.
3-3 What Happens to Energy in an Ecosystem?
19. A larger number of humans could be supported on the earth if more of them consumed grains,
vegetables, and fruits rather than eating meat.
Connections: Energy Flow and Feeding People
20. Gross primary productivity (GPP) is the biomass produced by photosynthesis minus the rate at which
biomass is used for aerobic respiration.
3-3 What Happens to Energy in an Ecosystem?
21. Nutrient cycles connect past, present, and future forms of life.
3-4 What Happens to Matter in an Ecosystem?
22. The hydrologic cycle is a way nature renews water quality.
3-4 What Happens to Matter in an Ecosystem?
23. In hundreds of years we have released large quantities of fossil fuels that took millions of years to form.
3-4 What Happens to Matter in an Ecosystem?
24. Nitrogen gas, the major component of the atmosphere, cannot directly be used by plants and animals.
3-4 What Happens to Matter in an Ecosystem?
25. Because the soil contains a sufficient amount of phosphates, phosphorus is not usually a limiting plant
nutrient.
3-4 What Happens to Matter in an Ecosystem?
26. Agricultural runoffs containing phosphates cause huge blooms of algae in streams and lakes.
3-4 What Happens to Matter in an Ecosystem?
27. Over land, most water that reaches the atmosphere comes from transpiration.
3-4 What Happens to Matter in an Ecosystem?
28. Because carbon makes up such a small amount of the earth’s atmosphere, even a small change, caused by
nature or by humans, affects the earth’s climate.
3-4 What Happens to Matter in an Ecosystem?
29. Since 1950 human activities have more than doubled the annual release of nitrogen into the environment.
3-4 What Happens to Matter in an Ecosystem?
30. Ecologists do not make use of most new technologies, preferring to continue the "muddy-boots biology"
style of research.
3-5 How Do Scientists Study Ecosystems?
COMPLETION
1. Destruction of tropical rain forests will help accelerate ____________________.
ANS: global warming
PTS: 1
DIF: Moderate
TOP: 3-0 Core Case Study
2. Tropical rain forests may be prevented from returning to cleared areas if an irreversible ______________
is reached.
ANS: ecological tipping point
PTS: 1
DIF: Moderate
TOP: 3-0 Core Case Study
3. The study of connections in nature is ____________________.
ANS: ecology
PTS: 1
DIF: Easy
TOP: 3-1 What Keeps Us and Other Organisms Alive?
4. A group of individuals of the same species living in the same place at the same time is a(n)
____________________.
ANS: population
PTS: 1
DIF: Easy
TOP: Active Figure 3-5
5. Ecologists assign every type of organism in an ecosystem to a feeding level or ____________________.
ANS: trophic level
PTS: 1
DIF: Easy
TOP: 3-2 What Are the Major Components of an Ecosystem?
6. Organisms that convert simple inorganic compounds into nutrients, without sunlight, are called
____________________ organisms.
ANS: chemosynthetic
PTS: 1
DIF: Moderate
TOP: 3-2 What Are the Major Components of an Ecosystem?
7. Organisms that cannot produce their own food and, therefore, must eat other organisms, are called
____________________.
ANS:
heterotrophs
consumers
PTS: 1
DIF: Easy
TOP: 3-2 What Are the Major Components of an Ecosystem?
8. Decomposers are mainly bacteria and ____________________.
ANS: fungi
PTS: 1
DIF: Easy
TOP: 3-2 What Are the Major Components of an Ecosystem?
9. A sequence of organisms, each of which serves as a source of food or energy for the next, is called a(n)
____________________.
ANS: food chain
PTS: 1
DIF: Easy
TOP: 3-3 What Happens to Energy in an Ecosystem?
10. ____________________ from the sun is captured, converted into chemical energy, and stored as biomass
in the tissues of the producer.
ANS: Energy
PTS: 1
DIF: Moderate
TOP: 3-3 What Happens to Energy in an Ecosystem?
11. The rate at which an ecosystem's producers convert solar energy into chemical energy as biomass is
called ____________________.
ANS:
gross primary productivity
GPP
PTS: 1
DIF: Easy
TOP: 3-3 What Happens to Energy in an Ecosystem?
12. _______________ are by far the most productive aquatic ecosystem when measured as average net
primary productivity per square meter per year.
ANS: Estuaries
PTS: 1
DIF: Moderate
TOP: 3-3 What Happens to Energy in an Ecosystem?
13. Some precipitation sinks through soil and permeable rock formations and into ____________________
where it is stored as ____________________.
ANS: aquifers; groundwater
PTS: 1
DIF: Difficult
TOP: 3-4 What Happens to Matter in an Ecosystem?
14. The major reservoir for nitrogen is the ____________________.
ANS: atmosphere
PTS: 1
DIF: Easy
TOP: 3-4 What Happens to Matter in an Ecosystem?
15. Carbon cycles through the biosphere and depends on the process of ____________________ and
____________________.
ANS:
photosynthesis; respiration
respiration; photosynthesis
PTS: 1
DIF: Moderate
TOP: 3-4 What Happens to Matter in an Ecosystem?
16. Nitrogen fixation is accomplished by specialized ____________________ in the soil and
____________________ in aquatic environments.
ANS:
bacteria; blue green algae
bacteria; cyanobacteria
PTS: 1
DIF: Moderate
TOP: 3-4 What Happens to Matter in an Ecosystem?
17. The rotten-egg smell coming from volcanoes and anaerobic decomposition in bogs and swamps comes
from the gas ____________________.
ANS:
hydrogen sulfide
H2S
PTS: 1
DIF: Easy
TOP: 3-4 What Happens to Matter in an Ecosystem?
18. ____________________ can help scientists understand large and very complex systems by allowing them
to change variables and project possible changes.
ANS:
Computer modeling
Computer simulations
PTS: 1
DIF: Difficult
TOP: 3-5 How Do Scientists Study Ecosystems?
19. Human activities are altering both the __________ of energy flow and the __________ of nutrients within
the carbon cycle.
ANS:
rate
cycling
PTS: 1
DIF: Moderate
TOP: 3-5 How Do Scientists Study Ecosystems?