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Ecology Teacher Packet
ECOLOGY BENCHMARK ASSESSMENT
Teacher Answer Packet
 Use these organisms to complete Numbers 1 – 3.
Bacteria
Grass
Grasshopper
Hawk
Snake
Toad
In the space below, complete the following:
1. Draw a food chain using the above organisms.
2. Label the trophic levels.
3. Label the food chain using the following terms:
Carnivore
Primary Consumer
Fourth-order Consumer
FOOD CHAIN
Bacteria
Decomposer
Secondary Consumer
Producer
TROPHIC LEVEL
6
Herbivore
Tertiary Consumer
TERMS
Decomposer
Hawk
5
Fourth-order Consumer, Carnivore
Snake
4
Tertiary Consumer, Carnivore
Toad
3
Secondary Consumer, Carnivore
Grasshopper
2
Primary Consumer, Herbivore
Grass
1
Producer
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Ecology Teacher Packet
 Use the food web below to answer Numbers 4 through 7.
4. Describe the niche of the
a. minnow primary consumer, herbivore
b. raccoon
secondary or tertiary consumer,
carnivore
c. duck secondary consumer, carnivore
d. algae
producer
5. Identify the organism(s) that undergo
a. photosynthesis
b. respiration
Algae and floating plants
All of them (plants, crustaceans, minnows, ducks, fish, raccoons)
6. Explain why arrows are drawn in the direction illustrated in the food web.
Arrows are drawn in the direction of energy flow. Energy flows up the food web as
the consumers gain energy by eating the organism on the trophic level below it.
7. Which organism in the food web contains the most energy? Explain.
The algae and floating plants contain the most energy because they are the producer.
Producers gain their energy directly from the sun. At each successive trophic level
after the producer, there is a 90% energy loss. Only 10% of the energy from one
trophic level is passed on to the next.
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Ecology Teacher Packet
 Use these organisms to complete Number 8.
Grass
Caterpillar
Shrew
Barn Owl
8. In the space below, draw an energy pyramid that includes the four organisms
pictured above. In your diagram, include the following:
a.
b.
c.
d.
e.
arrows to indicate energy flow
the sun
labeled trophic levels
explanation of the 10% rule
biomass at each trophic level, if the producer has a biomass of 26,000 kg
100%
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Barn Owl
Trophic Level 4
Tertiary Consumer 26 kg
Shrew
Trophic Level 3
Secondary Consumer
260 kg
Caterpillar
Trophic Level 2
Primary Consumer
2,600 kg
Grass
Trophic Level 1
Producer
26,000 kg
3
0.1%
1%
10%
Ecology Teacher Packet
9. Explain the significance of the shape of the energy pyramid. What does the
shape illustrate about the changes in energy and biomass in an ecosystem?
The amount of energy available to each level decreases because of the 10% rule. The transfer from
energy from one level to the next is never complete because energy is lost as heat and used by the
organism before it is passed on to the next level. Energy decreases at each successive trophic level,
since only 10% is passed on and 90% is lost. As a result, each trophic level is drawn smaller than the
previous one.
The amount of biomass is greatest at trophic level 1 and decrease as one moves toward the top. This
occurs because the amount of energy at each successive trophic level also decreases.
10.Complete the chart below on ecological relationships. Put a “+” if the species
benefits, a “-” if the species is harmed, and an “o” if the species is unaffected
by the relationship described.
Relationship
Species A
Species B
+
+
+
o
+
-
+
-
-
-
Mutualism
Commensalism
Parasitism
Predation
Competition
11.Choose the type of symbiosis from the word bank that best matches each
statement below.
Word Bank:
parasitism
mutualism
commensalism
a. ______parasitism__: The roots of a mistletoe plant absorb nutrients from living oak trees, causing
damage to the tissues of the trees.
b. ______mutualism__: Protozoa living in the intestine of a termite secrete enzymes that digest
cellulose, providing digestive end products of value to both organisms.
c. ______parasitism__: A tapeworm living in the digestive system of a cat.
d. ______commensalism__: An orchid uses a high tree branch as a place of attachment to receive
more sunlight; the tree is not affected by the orchid.
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Ecology Teacher Packet
e. ______mutualism__: A bee pollinating a flower and a flower providing nectar (food) to the bee.
f. ______parasitism__: A mosquito bites a human.
g. ______mutualism__: Nitrogen-fixing bacteria in the root nodule of a legume plant convert nitrogen
into a usable form. In return, the bacteria get a place to live.
h. ______mutualism__: A lichen is composed of an alga and fungus living together. Both benefit each
other.
i. ______parasitism__: A tick gets food from the blood it removes from a deer.
j. ______commensalism__: Cattle egrets forage in pastures and fields among cattle, feeding on the
insects stirred up by the movement of grazing animals. The egrets do not affect the cattle.
12.Choose the type of competition (interspecific or intraspecific) that best matches
each statement below.
a. ______interspecific__: Cows and horses living on the same farm both eat the same kind of grass.
b. ______interspecific__: Humans compete against a wide variety of species seeking to utilize our
food resources.
c. ______intraspecific__: Two oak trees growing close together compete for sunlight, nutrients, and
water.
d. ______interspecific__: In a classic study in the 1930s, Gauss cultured Paramecium. aurelia and P.
caudatum both alone and together in culture tubes. When grown separately, the populations grew to
a fairly predictable density. However, when grown together, P. caudatum always lost and
eventually went extinct.
e. ______intraspecific__: Chimpanzees go into fierce battles to achieve the supremacy in the tribe.
f. ______intraspecific__: Angelfish struggle for the best territory in an aquarium.
g. ______interspecific__: On Sable Island, scientists discovered that both gray and harbor seals feed
on the same prey – tiny fish called sand lances.
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Ecology Teacher Packet
13.Complete the chart below on biomes (continued on next page).
Name of
Biome
Climatogram Temperature Precipitation
Taiga /
Coniferous
Forest
Desert
Deciduous
Forest
Tundra
Tropical
Rainforest
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2 Unique Characteristics
(Answers will vary)
Winters are
long, cold and
dry with little
sunlight.
Temperatures
are below
freezing during
the winter.
Receives 40 to
200 cm of
precipitation a
year.
Cones of trees hold seeds.
Leaves are long, thin, and covered
in a waxy substance. Leaves are
shaped as needles to conserve
water and help shed snow in
winter.
Soil is poor and acidic due to
conifer needles.
Temperatures
can rise and fall
dramatically
with very hot
days followed
by very cold
nights.
Rarely gets
more than 25
cm (10 inches)
in any single
year.
Most desert animals are
nocturnal.
Desert soils tend to be rich in
minerals but poor in organic
matter.
Succulent plants have thick,
water-filled tissues.
Seasonal
Temperature
can be as high
as 30°C in the
summer, and
can fall to
-30° C in the
winter.
Air temperature
rarely reaches
above 10° C,
even in the
summer.
Receives 50 to
300 cm, which
falls regularly
throughout the
year.
Four well-defined seasons
Trees shed their leaves and are
dormant in winter.
More biodiversity than taiga
Forest has distinct layers
Abundant organic matter in soil
Soil makes excellent farmland
Usually
receives less
than 25 cm (10
inches) in any
single year,
mostly as ice
and snow.
Lowest biodiversity of all biomes,
making the ecosystem very fragile
and unstable if disturbed.
Permafrost – permanent frozen
layer beneath the top layer
Plants tend to be small and grow
close to the surface.
Temperatures
average 25°C
all year long.
Varies from
Most bioiversity of all biomes.
200 to 450 cm a Soil nutrients are limiting factor –
year.
soil is low in nutrients due to the
fast rate of decomposition.
Many arboreal species.
Forests have vertical layering.
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Ecology Teacher Packet
Name of
Biome
Climatogram Temperature Precipitation
2 Unique Characteristics
Temperatures
range from -5°
C to as high as
30° C.
Precipitation is the limiting factor
– gets more than a desert but not
enough to be a forest.
Fires are frequent.
Roots of plants extend deep into
the ground.
Agriculture and grazing animals
are common.
Grassland
Averages 50 to
75 cm a year.
14.Complete the chart below to describe population density determiners.
Illustration
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Identify the population
determiner illustrated
What would happen to a
population if this factor
increased?
Mortality
Population will decrease
Natality
Population will increase
Immigration
Population will increase
Emigration
Population will decrease
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Ecology Teacher Packet
15. 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? Exponential
What is the term for the leveling off in population growth that occurs at Arrow II? Carrying capacity
What type of growth pattern is presented overall in this graph? Logistic
Space, water, and food supply may cause the population to level off. What term describes the factors that
affect area II on the graph? Limiting Factors
16.For each of the factors, check whether it is density-dependent or densityindependent.
Limiting Factor
Density-dependent
√
Drought
Disease
√
Water
√
Food supply
√
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Density-independent
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Ecology Teacher Packet
17.What historical human population factor is being illustrated in this graph?
________________________________
Use of Soap
Improved
Sanitation
Modern Medicine
& Antibiotics
Advancements in health and medicine
18. Label the historical events that are noted by letters on the graph.
Old Stone Age
New Stone Age
Bronze Age
Iron Age
Middle Ages Modern
Times
B
A
A
B
A __Agricultural Revolution_____
B __Black Plague__________
C __Industrial Revolution_____
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C
Ecology Teacher Packet
19. Determine which cycle is being illustrated for each of the following. Label the
empty boxes with the correct term/process using the list of terms below.
Underneath each cycle briefly describe what occurs in each cycle using the terms
labeled in the cycle.
Atmospheric nitrogen
Carbon sink
Condensation
Combustion
Decomposition
Deforestation
Evaporation
Fossil fuels
Groundwater
Lightning
Nitrogen-fixing bacteria
Photosynthesis
Precipitation
Respiration
Transpiration
Waste products
Water Cycle
condensation
transpiration
precipitation
evaporation
groundwater
Heat from the sun makes water evaporate from the oceans, rivers, and lakes forming water vapor.
Water also evaporates from plants. This is known as transpiration. As the water vapor rises it cools
and starts to condense and become water again. This forms clouds. As the clouds get cooler the water
droplets become bigger and bigger. Eventually they fall as rain, snow, sleet, or hail. The water then
runs back into the oceans, rivers, and lakes or is soaked up by the land and eventually works its way
underground, becoming groundwater.
Carbon Cycle
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Ecology Teacher Packet
Carbon Cycle
photosynthesis
combustion
respiration
deforestation
Carbon sink
fossil fuels
decomposition
Plants use carbon dioxide and sunlight to make sugars and starches during photosynthesis. When
these nutrients are consumed by the plant or any other organism, carbon dioxide and energy are
released, during the process of respiration. The ocean holds a very large amount of carbon dioxide
because carbon dioxide dissolves easily in water. Substances such as coal, oil, and natural gas (fossil
fuels) are formed from the bodies of dead organisms. Because the bodies of these organisms never fully
decomposed, some of the carbon in them was never released. This carbon is released as carbon
dioxide when we burn fossil fuels, also known as combustion. Deforestation is a process which
reduces the amount of photosynthesis occurring, which in turn allows carbon dioxide levels in the
atmosphere to increase.
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Ecology Teacher Packet
Nitrogen Cycle
atmospheric nitrogen
lightning
Nitrogen-fixing
bacteria
waste products
Nitrogen gas is common in the atmosphere, but most living things cannot use nitrogen gas in
their cells. Organisms need nitrogen in a more chemically reactive form. Certain types of
bacteria can use nitrogen from the atmosphere. Such nitrogen-fixing bacteria produce ammonia.
Nitrogen-fixing bacteria live both in the soil and in the roots of legumes. But most ammonia is
consumed by other bacteria. These bacteria produce compounds called nitrites and nitrates.
Nitrate is the most common source of nitrogen for plants, and is now supplied to crop plants by
using manufactured chemical fertilizers as well as through bacterial action. Animals get the
nitrogen they need from proteins in the food they consume. Decomposers return nitrogen to the
soil in the form of ammonia. Lightning strikes fix the atmospheric nitrogen.
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