Download Env Sc chapter 5 revision

Env Sc chapter 5 revision
Multiple Choice (Any 45)
1 Mark each
Identify the choice that best completes the statement or answers the question.
____
1. Which of the following statements is not correct?
a. Plants and other producers get their energy directly from the sun.
b. Animals get their energy from the sun indirectly.
c. Rare bacteria that live deep in the ocean get their energy from hydrogen sulfide in hot
water.
d. Consumers get their energy directly from the sun.
____
2. Which kind of organism obtains energy only from producers?
a. decomposers
c. omnivores
b. herbivores
d. All of the above
____
3. If an insect eats a plant and a bird eats the insect, about how much energy from the plant is stored in the
insect for the bird to use?
a. 90 percent
c. 10 percent
b. 50 percent
d. 1 percent
____
4. Which of the following does not contain carbon from the bodies of plants and animals that died millions
of years ago?
a. coal
c. natural gas
b. oil
d. phosphate salts
____
5. Which gas makes up 78 percent of our atmosphere but can be used by plants only when transformed by
bacteria first?
a. nitrogen
c. hydrogen
b. oxygen
d. carbon dioxide
____
6. Which of the following plants is likely to be a pioneer species?
a. lichen
c. shrub
b. grass
d. oak tree
____
7. What kind of natural disaster helps some forest communities by allowing some trees to release their seeds,
by clearing away deadwood, and by encouraging new growth?
a. fire
c. windstorm
b. flood
d. drought
____
8. Where would an ecologist be least likely to go to study primary succession?
a. a new island formed by a volcanic eruption
b. a gravel-filled valley that had been covered by a glacier until recently
c. a locked, abandoned asphalt parking lot in New York City
d. the Amazon Rain Forest
____
9. Which statement describes how humans are affecting the balance of carbon in the atmosphere?
a. Fewer agricultural crops are planted, reducing the amount of carbon dioxide released into
the atmosphere.
b. Burning fossil fuels in great quantities has increased the amount of carbon dioxide in the
atmosphere.
c. Overgrazing of grasslands has reduced the amount of carbon dioxide in the atmosphere.
d. Severe drought in large areas of the world has decreased the amount of carbon dioxide that
is released into the atmosphere.
____ 10. Which of the following is not a true statement about cellular respiration?
a. It is essentially photosynthesis in reverse.
b. Oxygen is one of the primary reactants.
c. It produces energy for organisms to use.
d. Sugar molecules are its primary products.
____ 11. Which of the following are photosynthetic organisms?
a. fungal decomposers
c. freshwater algae
b. deeply buried soil bacteria
d. intestinal bacteria
____ 12. Consumers are organisms that
a. eat only other animal species.
b. get solar or other energy indirectly.
c. are also known as self-feeders.
d. occupy an ecosystem’s lowest energy level.
____ 13. The energy consumed by organisms
a. can be stored in fat and sugar molecules.
b. remains constant at all trophic levels.
c. undergoes magnification in food chains.
d. is not partially lost during digestion.
____ 14. Plants play a crucial role in the carbon cycle because they
a. do not release carbon dioxide during cellular respiration.
b. allow carbon to enter an ecosystem through photosynthesis.
c. have special bacteria that live in their root systems.
d. are chemically converted into fossil fuels when burned.
____ 15. The bacteria that live within the roots of a soybean plant are a critical part of the nitrogen cycle because
they
a. provide the plant with sugars needed for growth.
b. transform nitrates into nitrogen gas for release.
c. change atmospheric nitrogen into a usable form.
d. release nitrogen by decomposing dead plant parts.
____ 16. Succession is possible because
a. climates change over time.
b. it is a rapid and chaotic process that is very difficult to control.
c. existing plants reproduce quickly.
d. new species make the environment less suitable for previous ones.
____ 17. Which of the following is an example of secondary succession?
a. breaking down of bare rock by fungi and mosses
b. pioneer plants begin to grow after glacial melting
c. growth of plants after a forest is destroyed by fire
d. appearance of weeds in cracks in a concrete surface
____ 18. Which of the following is not a likely component of soil formed during primary succession?
a. cast-off parts of shrubs and trees
c. dust particles from the air
b. decayed lichens and bacteria
d. broken bits of stone and rock
____ 19. Which organism is likely to be in the bottom trophic level of a food chain?
a. leopard seal
c. krill
b. algae
d. killer whale
____ 20. What term is used to refer to the many feeding relationships that are possible in an ecosystem?
a. food web
c. energy pyramid
b. food chain
d. energy transfer
____ 21. Which of the following is responsible for making nitrogen in the atmosphere usable by living organisms?
a. absorption of nitrogen into water systems
b. conversion of nitrogen into carbohydrates by photosynthesis
c. nitrogen-fixing bacteria
d. decomposing bacteria
____ 22. Which item is a carbon sink and not part of the carbon cycle?
a. carbon in the atmosphere in the form of carbon dioxide
b. consumers breaking down carbohydrates into carbon dioxide during respiration
c. carbon found within limestone rocks
d. carbon dioxide being converted into carbohydrates during photosynthesis
____ 23. What type of vegetation would you expect to find on an abandoned farm that has remained undisturbed
for 150 years?
a. short grasses
c. young pine trees
b. shrubs
d. tall, mature oak trees
____ 24. What type of succession occurs after a natural process such as a volcanic eruption or flood?
a. primary succession
c. old-field succession
b. secondary succession
d. climax community
____ 25. Which of the following is one of the largest carbon reservoirs on Earth?
a. limestone
c. Amazon rain forest
b. fossil fuels
d. Atlantic Ocean
Completion ( Any Twelve)
Complete each statement.
1 Mark Each /12
1. A process in which energy from the sun is used to make sugar molecules is called
_________________________.
2. In deep-ocean ecosystems, the _________________________ that escapes from the cracks in the ocean
floor is used by bacteria to make their own food.
3. Organisms that get their food by breaking down dead organisms are called ____________________.
4. A process within the cell of an organism that uses glucose and oxygen to produce carbon dioxide, water,
and energy is called ______________________________.
5. Nitrogen-fixing bacteria live within the nodules on the roots of plants called ____________________.
6. Some natural disasters, such as ____________________, help some forest communities by allowing some
trees to release their seeds, by clearing away deadwood, and by encouraging new growth.
7. On new islands formed by volcanic activity, you will most likely find ____________________
succession.
8. The first organisms to colonize any newly available area are known as _________________________.
9. During primary succession, ____________________ often begin the process by breaking down the rocks
into soil.
10. When energy is passed from one trophic level to the next, only about ____________________ of the
energy is passed to the next level.
11. In the deep-ocean ecosystem, ____________________ would occupy the bottom trophic level of an
energy pyramid.
12. Excessive use of ____________________ on lawns and gardens can affect the nitrogen and phosphorus
cycles in nearby lakes and streams.
13. During succession, a final and stable community is referred to as a(n) _________________________.
14. Succession that occurs on abandoned farmland is called ____________________ succession.
15. A gradual process of change and replacement of the types of species in a community is called
____________________ succession.
16. Horses and cattle are ____________________ because they eat only producers.
17. Organisms called ______________________________ can transform unusable nitrogen in the
atmosphere into chemical compounds containing nitrogen that can be used by other organisms.
18. A common type of succession that occurs on a surface where an ecosystem has previously existed is
known as ______________________________.
19. A lion is an example of a group of consumers called ____________________.
20. Bacteria and fungi are examples of a group of consumers called ____________________.
21. The energy transfer in a(n) ____________________ is more complex than energy transfer in a food chain,
because the interaction between many organisms is considered.
22. The ultimate source of energy for all organisms except those living deep in the ocean near a thermal vent
is the ____________________.
23. In the carbon cycle, the source of carbon for producers is the ____________________.
24. Underground carbon sources composed of plants and animals that died millions of years ago are known as
____________________.
25. The burning of ____________________ over many years has resulted in an increase in the amount of
carbon dioxide in the atmosphere.
Short Answer
5 Marks
/5
1. All living things must be able to make proteins, and protein molecules always contain nitrogen. Explain
how the nitrogen used for making proteins in a lion's body traveled from the atmosphere to the lion. How
will it be returned to the atmosphere after the lion dies?
2. Use your knowledge of energy flow within ecosystems to offer a simple explanation for the following
statement: “All flesh is grass.”
3. The phosphorus, carbon, and nitrogen cycles are termed biogeochemical cycles—bio meaning “living”;
geo for the earth (soil); and chemical referring to matter changing form. Explain why this term is
appropriate.
4. Describe one way in which consumers depend on producers.
5. Explain why an energy pyramid is used to represent the amount of energy at each trophic level.
6. Explain how carbon is cycled from the atmosphere through producers and consumers, and back into the
atmosphere.
7. Briefly explain how fossil fuels are formed and where they are located.
8. A local lake is experiencing algal bloom and many of the fish are dying. Explain why this may be
occurring.
9. A student noticed that lichens were growing on the surface of a rocky cliff. Describe how lichens
contribute to primary succession.
10. Describe an energy pyramid that could be present in a small garden.
11. Describe how DDT moves through an aquatic food chain. Explain how this almost resulted in the
extinction of the bald eagle.
12. Only about 10 percent of the energy is passed from one trophic level to the next. Explain where the other
90 percent of the available energy goes.
13. Some states are allowing grass carp, a fish that is a native of China and the Soviet Union, to be used to
clean lakes that have overabundant vegetation. Grass carp can eat large quantities of vegetation. Many of
these grass carp are sterile and unable to reproduce. This limits the population of offspring and provides
some control over the amount of vegetation that is removed from an ecosystem. Other fish that are being
used are able to reproduce and are showing up in rivers and tributaries where they haven’t been
intentionally introduced. What effect could an uncontrolled grass carp population have on the energy
pyramids of a lake environment?
14. In the 1930s, a large section of the Plains States in the U.S. became known as the Dust Bowl because of
the dust blizzards created by erosion of exposed topsoil. During this time, land was overcultivated and
poorly managed. Poor land management and severe drought resulted in dust blizzards and crop failures.
Many farmers had to abandon their farms to search for other occupations. What type of succession would
you expect to find in the abandoned farmlands? Explain your answer.
15. Your grandparents, who love to garden, are thinking about buying a house in the country. Next weekend,
they are going to look at two houses. One has a large garden that hasn’t been cultivated since the owners
moved back to the city three years ago. The other is part of a small farm that was abandoned 25 years ago.
Use what you know about succession to make a list of some of the likely advantages of each place.
Problem Solving
5 Marks
/5
fig.(a)
1. Determine the percentage of energy available for new plant tissue in the farm-field ecosystem represented
by the pie graphs in fig.(a).
2. Compare the energy losses due to respiration for the three organisms in the pie graphs in fig.(a).
3. In fig.(a), the mice eat only 1.6 percent of the available plant material. Other consumers may eat only a
portion of the remaining vegetation. What eventually happens to the energy stored in the plant material
that is not eaten?
Essay ( Any Two)
5 Marks Each /10
1. Draw a food web that shows the following relationships. (You may draw pictures or just write the names.)
In a mountain meadow, grasshoppers and aphids eat the flowers and grasses. Ladybugs eat the aphids, and
blue jays eat the grasshoppers and ladybugs. Blue jays also eat grass seeds and pine nuts and even an
occasional small frog from the pond. The frogs ate algae in the pond when they were tadpoles, but now
they catch grasshoppers and other insects. The field mice eat grass seeds and pine nuts. Rabbits eat young
grass shoots, and the deer graze on small green willow twigs. Owls and hawks eat the frogs, mice, and
rabbits, and once in a while a cougar visits the meadow and preys on a fawn or sick deer. Use arrows to
show who eats what. Then answer the following question: Do you think there would be more rabbits or
owls living in this area? Explain your answer.
2. Succession from bare rock to mature plant community on an island in northern Lake Superior included the
following stages: exposed rock, lichens and mosses, small herbs and shrubs, black spruce, and white
spruce?
a. Was the succession primary or secondary? Explain.
b. What is the most likely explanation for the exposed rock?
c. Identify the pioneer organisms.
d. How are lichens able to live on bare rock?
e. Small herbs and shrubs require soil to support their roots. How was this soil formed?
f. Why did the taller white spruce trees flourish and eventually replace the black spruce?
g. The white spruce are a part of which community?
Env Sc chapter 2 revision
Answer Section
MULTIPLE CHOICE
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22. ANS:
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C
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D
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2. ANS: hydrogen sulfide
REF: 1
OBJ: 1
PTS: 1
DIF: 2
3. ANS: decomposers
REF: 1
OBJ: 2
PTS: 1
DIF: 2
4. ANS: cellular respiration
REF: 1
OBJ: 3
PTS: 1
5. ANS: legumes
DIF: 2
REF: 1
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PTS: 1
6. ANS: fire
DIF: 2
REF: 2
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PTS: 1
7. ANS: primary
DIF: 2
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DIF: 2
8. ANS: pioneer species
REF: 3
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9. ANS: lichens
DIF: 2
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PTS: 1
10. ANS: 10 percent
DIF: 2
REF: 3
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PTS: 1
11. ANS: bacteria
DIF: 2
REF: 1
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PTS: 1
12. ANS: fertilizers
DIF: 2
REF: 1
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PTS: 1
DIF: 2
13. ANS: climax community
REF: 2
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COMPLETION
1. ANS: photosynthesis
PTS: 1
14. ANS: old-field
DIF: 2
REF: 3
OBJ: 1
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15. ANS: ecological
DIF: 2
REF: 3
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16. ANS: herbivores
DIF: 2
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DIF: 2
17. ANS: nitrogen-fixing bacteria
REF: 1
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18. ANS: secondary succession
REF: 2
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19. ANS: carnivores
DIF: 2
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20. ANS: decomposers
REF: 1
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21. ANS: food web
DIF: 2
REF: 1
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22. ANS: sun
DIF: 2
REF: 1
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PTS: 1
23. ANS: atmosphere
DIF: 2
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24. ANS: fossil fuels
DIF: 2
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25. ANS: fossil fuels
DIF: 2
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SHORT ANSWER
1. ANS:
Nitrogen-fixing bacteria capture nitrogen from the air and convert it to a form that can be used by plants.
Herbivores acquire nitrogen by eating the plants, and the lion acquires nitrogen by eating the herbivores.
After the lion dies, decomposers break down the lion's carcass and convert the nitrogen in it to ammonia.
Other bacteria will convert the ammonia to nitrogen gas and release it into the atmosphere.
PTS: 1
DIF: 3
REF: 2
OBJ: 4
2. ANS:
All animals are dependent on the organic compounds synthesized by producers.
PTS: 1
DIF: 3
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3. ANS:
These life-sustaining materials are continuously recycled through the air, water, soil, plants, and animals,
changing form in the process. These chemical compounds may be a part of an organism at one point
(organic carbon molecules) and part of its nonliving environment at another (atmospheric carbon dioxide).
PTS: 1
DIF: 3
REF: 2
OBJ: 1
4. ANS:
Accept any reasonable answer. Sample answer: Owls eat mice and mice eat grain. Both owls and mice
depend upon the plants that produce grain for their energy source. Grain is the producer in this scenario.
PTS: 1
DIF: 3
REF: 1
OBJ: 2
5. ANS:
A pyramid is the perfect shape to represent energy levels. Because the base is the largest part of the
pyramid, it is used to show where the most energy is located. As you go up the energy pyramid it
gradually narrows, showing that trophic energy is lost at each succeeding trophic level.
PTS: 1
DIF: 3
REF: 1
OBJ: 5
6. ANS:
Carbon is in the atmosphere in the form of carbon dioxide. Plants remove the carbon dioxide from the air
and convert it into carbohydrates through photosynthesis. Consumers eat plants or other organisms that
eat plants and use the carbon in their bodies as their energy source. Organisms release carbon dioxide
back into the atmosphere during cellular respiration and the process begins again.
PTS: 1
DIF: 3
REF: 2
OBJ: 1
7. ANS:
The bodies of carbon-containing organisms are converted into fats, oils, and other molecules that store
energy. Over time these fats are converted into coal, oil, and natural gas underground.
PTS: 1
DIF: 3
REF: 2
OBJ: 2
8. ANS:
Excess fertilizer washes away and collects in lakes and streams. The nitrogen and phosphorus stimulate
algal growth. The resulting algal bloom in the lakes and streams ties up the oxygen that would otherwise
be used by aquatic organisms, suffocating them.
PTS: 1
DIF: 3
REF: 2
OBJ: 6
9. ANS:
Lichens are producers that are composed of two different species, a fungus and an alga. The alga
photosynthesizes, while the fungus absorbs nutrients from rocks and holds water. The lichen slowly
breaks down the rock into soil. Over time, the dead lichen adds organic material to the newly created soil,
thus enabling other plants to grow.
PTS: 1
DIF: 3
REF: 3
OBJ: 4
10. ANS:
Accept all reasonable answers. Sample answer: Leaf lettuce gets its energy from the sun through
photosynthesis. The lettuce would be on the bottom level of the pyramid as the producer. The primary
consumer that could be on the next level of the energy pyramid is a leaf-eating caterpillar. A meadowlark
could be the secondary consumer and occupy the next level of the energy pyramid. An owl could eat the
meadowlark and occupy the top level of the energy pyramid as the tertiary consumer.
PTS: 1
DIF: 3
REF: 1
OBJ: 5
11. ANS:
Fish ate the algae and bacteria that contained the DDT. The fat in the tissues of the fish absorbed the
DDT. Birds ate these contaminated fish, gradually accumulating increasing amounts of DDT in their
bodies. The levels of DDT in the bodies of these birds began to affect the quality of their eggs. Many of
these eggs didn’t hatch, resulting in fewer birds. The bald eagle was one of the species of birds that was
affected by DDT contamination.
PTS: 1
DIF: 3
REF: 1
OBJ: 2
12. ANS:
Ninety percent of the energy is lost through heat, cellular respiration, carrying out the functions of living
such as producing new cells, maintaining body temperature, and movement.
PTS: 1
DIF: 3
REF: 1
OBJ: 5
13. ANS:
Accept any reasonable answer. Sample answer: Grass carp could deplete the vegetation in an aquatic
environment. This would remove a large portion if not all of the producers from the aquatic environment.
Death through starvation would occur all the way up the energy pyramid.
PTS: 1
DIF: 3
REF: 1
OBJ: 5
14. ANS:
Secondary succession would quickly cover the abandoned farmland with grasses and weeds. Old-field
succession would begin on the abandoned farmland.
PTS: 1
DIF: 3
REF: 3
OBJ: 3
15. ANS:
Answers may vary but should reflect the student's understanding of the process of succession. Answers
might include the following points: Advantages at the recently vacated home—mostly small, weedy
plants would have grown in the garden, which would be relatively easy to dig up or till; there would not
have been time for large trees, which would be difficult to remove, to grow in the garden area. Advantage
to the older site—fewer weeds and weed seeds to eliminate, and if trees in the garden area are cut down,
they could be used as firewood.
PTS: 1
DIF: 3
REF: 3
OBJ: 1
PROBLEM
1. ANS:
100% – 15% = 85% of available energy is used in plant production.
PTS: 1
DIF: 3
REF: 1
OBJ: 5
2. ANS:
The plants lose a small percentage of their intake energy to respiration (15 percent). Both consumers
expend the majority of their assimilated energies in respiration, although a substantial difference exists
between the respiratory loss of the mouse (68 percent) and that of the weasel (93.3 percent).
PTS: 1
3. ANS:
DIF: 3
REF: 1
OBJ: 4
The remaining vegetation is eventually decomposed, and a portion of its stored energy is returned to the
ecosystem via the decomposing organisms (mainly bacteria and fungi).
PTS: 1
DIF: 3
REF: 1
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ESSAY
1. ANS:
Students' diagrams should be similar to the one shown on page 122 of the text. Students should use arrows
to show that most of the organisms in this ecosystem eat more than one kind of food. There would be
more rabbits than owls in this ecosystem because owls eat at a higher trophic level than rabbits. Only a
fraction of the energy that the rabbits obtained from plants is available to the owls. Ecosystems generally
support fewer carnivores than herbivores.
PTS: 1
2. ANS:
DIF: 3
REF: 1
OBJ: 4
a. The succession was primary because no previous ecosystem existed. Soil had to be formed by natural
processes.
b. retreating glaciers
c. lichens and mosses
d. A lichen is composed of a fungus and an alga living together in a mutualistic relationship. The fungus
dissolves and absorbs nutrients from the rock, while the alga produces food by photosynthesis.
e. Lichens and later mosses, aided by weathering, acted to break down the rock. Soil was formed over
many years by the accumulation of broken rock, dust particles, and decaying organisms (e.g., lichens,
bacteria, and mosses).
f. Shade and other conditions created by the black spruce allowed for the successful germination and
growth of the more shade-tolerant white spruce. The taller white spruce created a canopy overhead
that caused the shade-intolerant black spruce to be gradually eliminated (the latter could no longer
reproduce).
g. climax community
PTS: 1
DIF: 3
REF: 3
OBJ: 1