Ecology Review Packet
ECOLOGY UNIT ASSESSMENT
Student Review Packet
1.
Match the living parts of an ecosystem with the examples below. Write the
correct letter on the line to the right of each example.
A = producer
B = primary consumer
C = secondary consumer
D = decomposer
A tree _______
A hawk eating a lizard _______
A squirrel eating a nut _______
A grasshopper eating grass
_______
Bacteria changing dead plants to
nitrates _______
A human eating lettuce _______
A frog eating a grasshopper
_______
Bracket fungi decaying a stump
_______
2.
Complete the following sentences by writing the correct word or words from the
word bank in the space provided.
Word Bank: autotrophs
food chain
biome
heterotroph
biotic
ecology
ecosystem
nitrates
A(n) _____ is an area characterized by certain living things and a certain
climate.
A(n) _____ is a pathway of food through an ecosystem.
__________________
_____ is the study of how the living and nonliving things in an ecosystem
affect each other.
The living parts of an ecosystem are the _____ parts.
___________________
Plants get needed nitrogen mostly from substances called _____.
__________________
_____ are living things that make food.
__________________
A(n) _____ is a combination of the living and nonliving things in an area.
__________________
Living things that get their food by eating other living things are _____.
__________________
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__________________
__________________
Ecology Review Packet
3.
Each of the following statements describes a stage in land succession. Number the
statements in the order they would occur in land succession.
_______ A forest is present.
_______ Bushes and small trees are present.
_______ Bare soil is present.
_______ First primary consumers appear.
_______Weeds begin to appear.
4.
Each of the following statements describes an example of succession. Identify if
each is an example of primary succession or secondary succession.
_____________ Lichens appear on rocks, where life has never before existed.
_____________ Growth in an agricultural field no longer farmed.
_____________ Land exposed by a retreating glacier.
_____________ Growth in Yellowstone National Park after a large forest fire.
___________ A lake begins to fill with sediment.
5.
Choose the type of symbiosis from the word bank that best matches each
statement below.
Word Bank:
parasitism
mutualism
commensalism
Protists inside termites digest the wood the termites eat.
___________________________
A mosquito “bites” you.
___________________________
Protists live inside a mosquito but do not harm the mosquito.
___________________________
Bacteria in a lump on the clover root change nitrogen into a form used by clover and get a place to live.
___________________________
A fungus uses some of a tree’s nutrients.
___________________________
An alga and a fungus live together. Both benefit each other.
___________________________
A tick gets food from the blood it removes from a dog.
___________________________
Orchids grow on trees to capture more sunlight. The tree is not harmed.
___________________________
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Ecology Review Packet
6.
Circle the word that best completes each statement.
If the number of births goes up and other things remain the same, the population (increases, decreases).
If the predator population increases, (more, less) prey are eaten.
A population cannot increase in size forever because of (limiting factors, people).
A (refuge, habitat) is where an animal lives.
The role an organism plays in the ecosystem is its (niche, habitat).
Blue crabs in the Chesapeake Bay are an example of a (community, population).
7.
Examine the population graph below and answer the following questions.
Number of Reindeer vs. Time in Years
Explain the population trend shown in the graph._______________________________________________
______________________________________________________________________________________
For how many years did the reindeer population increase? _______________________________________
What was the highest number of reindeer in the population? _____________________________________
What kind of growth pattern is evident between years 1930 and 1938? _____________________________
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Ecology Review Packet
8.
Examine the population graph below and answer the following questions.
Number of Willow Trees vs. Time in Years
II
I
What kind of growth pattern is evident at Arrow I? ____________________________________________
What is the term for the leveling off in population growth that occurs at Arrow II? ___________________
Space, water, and food supply may cause the population to level off. What term describes the factors that
affect area II on the graph? ________________________________________
9.
Use the word bank below to fill in the blanks for the following environmental
issues statements.
Word Bank: Acid Precipitation
Global Warming
Deforestation
Greenhouse Gases
Endangered Species
Ozone Depletion
Pfiesteria
As a result of _________________________, more ultraviolet radiation will reach the earth’s surface.
Continued development and habitat destruction is increasing the number of _________________________.
Carbon dioxide and methane are examples of __________________________.
__________________________ is a microscopic algae often thought to be the cause of lesions (sores) on
fish throughout coastal regions.
An increase in the release of carbon dioxide and methane into the atmosphere may result in an increase in
the Earth’s average surface temperature, called __________________________.
Rain, hail, sleet, or snow that has a pH lower than normal may be considered an example of
__________________________.
As a result of __________________________, there will be an increase in the amount of surface runoff
and erosion from the land.
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Ecology Review Packet
10.
CARBON CYCLE
B
C
A
E
D

Match the following components of the carbon cycle to the appropriate letter in
the diagram.
carbon dioxide in the atmosphere ___________
decomposition ___________
combustion (burning of fossil fuels) ___________
photosynthesis ___________
cellular respiration ___________

Place a plus sign (+) next to the component of the carbon cycle if it adds carbon
dioxide to the atmosphere and minus sign (-) next to the component if it removes
carbon dioxide from the atmosphere.
decomposition ___________
combustion ___________
photosynthesis ___________
cellular respiration ___________
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Ecology Review Packet
11. NITROGEN CYCLE
C
A
B
D
E
F

Match the following components of the nitrogen cycle to the appropriate letter in
the diagram.
nitrogen gas in the atmosphere ___________
absorption of nitrates by plants ___________
nitrogen fixation by lightning and soil bacteria ___________
denitrification ___________
ammonification (nitrogen fixed as ammonium) ___________
bacteria convert ammonia to nitrates ___________

Nitrogen-fixing bacteria is associated with the root nodules of legume plants, such
as bean plants. What would happen to the nitrogen cycle if a large majority of the
legume plants in an ecosystem began to die off?
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Ecology Review Packet
12. WATER CYCLE
A
B
D
E
C
G
F

Match the following components of the water cycle to the appropriate letter in the
diagram.
precipitation ___________
condensation ___________
evaporation ___________
transpiration ___________
surface water ___________
runoff from the surface ___________
seepage and infiltration to groundwater ___________

If the tropical rainforest is burned to make room for agricultural land, how will
this impact the water cycle? Identify at least two ways the water cycle will be
affected.

What is the primary role of the sun in the water cycle?
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Ecology Review Packet
13.
Complete the table below using information from the map and your textbook.
Biome
Location Temperature
Average
on map
Range
precipitation per year
Some common plants
and animals
TROPICAL
FOREST
DESERT
TEMPERATE
DECIDUOUS
FOREST
GRASSLAND
TAIGA
TUNDRA
BIOME MAP OF NORTH AMERICA
D
A
B
C
F
E
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Ecology Review Packet
14. You have just purchased an iguana as your new pet. First, complete the table
below by describing 4 abiotic and 4 biotic factors that will affect your pet iguana.
Then explain the effect each of these factors has on the iguana.
Type of Pet
I
G
U
A
N
A
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Abiotic factors
Effect of the
factor
Biotic factors
1.
1.
2.
2.
3.
3.
4.
4.
9
Effect of the
factor
Ecology Review Packet
15. Complete the energy pyramid using the organisms in the food web below. Then,
use the energy pyramid to answer the questions that follow.
hawk
fungus
rat snake
small
lizard
oriole
bird
grasshopper
plant
How does the energy amount change among the different trophic levels?
_____________________________________________________________________________
In what form(s) is energy lost from the pyramid?
_____________________________________________________________________________
How does the biomass amount change among the different trophic levels?
_____________________________________________________________________________
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Ecology Review Packet
SELECTED-RESPONSE REVIEW QUESTIONS
Directions:
Use the following information to answer Numbers 16 and 17.
ULTRAVIOLET RADIATION IS KILLING AMPHIBIANS
It is widely known that ultraviolet radiation (UV) causes damage to cells by altering the
physical structure of DNA and proteins. Over the last six years, biologists have reported that many
of the world’s 4,500 known species of amphibians are declining in number. Some species have
nearly disappeared. Hard-hit areas include desert, rain forest, lowland, and mountain environments
in the western United States, Australia, and Central and South America.
Researchers have shown that UV radiation passing through Earth’s thinning ozone layer is
responsible for a worldwide decline in frogs, toads, and salamanders. The impact of UV radiation
on some frog and toad eggs was reported by a team of researchers from Oregon State University.
The basic conclusion is that UV radiation kills frog eggs in nature. The researchers performed field
experiments, which showed that when UV radiation is filtered out, the frog eggs hatch more quickly
and successfully, and the death rate is lowered.
The researchers need more information to help determine the cause of the decline in the
numbers of amphibians. Follow-up studies are being planned to get additional information to test
their theory that UV radiation kills the eggs of amphibians.
16.
Which of these additional studies would best support the claim that increases in UV radiation
are responsible for a decline in the population of amphibians?
A The birth rates of amphibians should be compared with those of animals that are not as sensitive
to UV radiation.
B The death rates of amphibians should be compared with those of animals that are not as sensitive
to UV radiation.
C Field measurements of UV radiation should be made in regions of the world where the amphibian
populations are declining.
D Field measurements of UV radiation should be made in regions of the world where amphibian
populations are declining and in regions where they are stable.
17.
The field researchers claim that by filtering out UV radiation, frog eggs hatch more quickly and
have a higher survival rate. Which of these should be done to improve their study?
F
G
H
J
show that ozone levels are higher in hard-hit areas of the world
determine if increases in hatching rates lead to a decrease in survival rates
show that DNA damage in frog eggs is increased by filtering out UV radiation
control for other variables in the local environment that might affect amphibian reproduction
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Ecology Review Packet
Use the reading passage and the diagram below to answer Numbers 18 and 19.
WHY ARE SEA OTTER
POPULATIONS DECLINING?
The number of sea otters living along Alaska's
Aleutian Islands has fallen to 10% of what it was a decade
ago. The investigation into what is happening to this
population is revealing a great deal of information about
the complex nature of food webs. It is also showing how
fragile the links in a food web can be.
The immediate cause of the sea otters' decline seems
to be predation by killer whales, which are turning to sea
otters as a food source. James Estes, a University of
California marine ecologist, first witnessed a killer whale
eating a sea otter in 1991. Since then, a dozen such attacks
have been reported. Estes suspected that these attacks were
ultimately caused by disruption of the marine food web.
Many fish populations have declined dramatically, and species that marine mammals feed upon have
been hit especially hard. The cause of this decline is not entirely understood, but it is thought to be due to a
combination of overfishing, warming ocean temperatures, and other factors. Killer whales normally eat sea
lions and harbor seals, but with local fish populations so low, these seal populations have rapidly declined.
This has caused killer whales to resort to a new food source, the smaller and less nutritious sea otter.
This decline in the sea otter population has disrupted much of the coastal ecosystem along the Aleutian
Islands. Sea otters prey upon sea urchins, which, in turn, feed upon kelp, a type of large seaweed that is
abundant in many coastal ecosystems. Kelp beds provide protection for many species of fish and other
small animals, and are an important basis of the coastal food web. In Estes' view, these changes are "an
ecological chain reaction," with events that occur far out at sea causing massive changes to the coastal
ecosystem
18.
Which of these statements best summarizes James Estes' hypothesis about the decline of sea
otter populations?
A
B
C
D
19.
The killer whales are eating more seals and sea lions.
Kelp beds are an important basis of the coastal food web.
The sea otter population has fallen to 10% of what it was a decade ago.
Killer whale attacks on sea otters are caused by a disruption of marine food webs.
Which of these follow-up studies would best evaluate James Estes' hypothesis about the decline
of sea otter populations?
F contrast the nutritional content of seal meat and sea otter meat
G count the total population of sea urchins living off the Aleutian Islands
H survey the number of attacks on sea otters by killer whales in the Aleutian Islands over the next
ten years
J survey the number of attacks on sea otters by killer whales in an area where both sea otters and
seals are abundant
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Ecology Review Packet
Use the diagram of the ocean food web below to answer Numbers 20 and 21.
OCEAN FOOD WEB
20.
Which of these organisms is not an omnivore?
A
B
C
D
21.
herring
shrimp
blue whale
killer whale
Improvements in fishing techniques have led to an increase in the amount of herring harvested
in recent decades. What would be a direct effect of increased harvests of herring?
F
G
H
J
The blue whale population would decrease.
The herring gull population would increase.
The killer whale population would increase.
The shrimp population would increase.
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Ecology Review Packet
The energy pyramid below shows the flow of energy through the organisms in a Maryland river.
Use the diagram to answer Numbers 22 through 25.
ENERGY PYRAMID SHOWING
FLOW OF ENERGY
22.
Which of these organisms are the producers in the river ecosystem?
A
B
C
D
23.
If the trout population were over fished, which population of organisms would most likely
increase as a direct result?
F
G
H
J
24.
algae
minnows
trout
zooplankton
Which level of the pyramid represents the largest percentage of available energy?
A
B
C
D
25.
algae
minnows
trout
zooplankton
algae
minnows
trout
zooplankton
According to the pyramid, what is the niche of the trout?
F
G
H
J
autotroph
carnivore
herbivore
primary consumer
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Ecology Review Packet
26.
Approximately 45 million acres of tropical rain forest are destroyed each year. Which of these
probably does not result from the burning and clearing of tropical rain forests?
A
B
C
D
an increase in global warming
a decrease in the sources for new medicines
an increase in oxygen in the atmosphere
a decrease in the number of different species
Use the Creek Food Web and the information below to answer Numbers 27 through 28.
CREEK FOOD WEB
A small, cold creek flows through a dense forest. The
trees that line the banks of the creek provide shade for
most of the day. Algae grow well only in the few areas of
the creek that receive direct sunlight for several hours
each day. Most of the food energy enters the creek
ecosystem in the form of dead leaves that fall from the
trees.
27. Which of these describes the role of the brown
stonefly in the creek food web?
F
G
H
J
28.
parasite
omnivore
scavenger
carnivore
A fire swept through the forest, burning all the leaves but leaving the trees standing. This
greatly increased the amount of direct sunlight reaching the creek, but did not produce more
than the usual amount of erosion. As a result of the fire, which of these most likely increased in
the creek?
A
B
C
D
organic matter
brown stoneflies
caddisflies
algae
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