Intro to Ecology Classwork
Classwork #1
Name: __________________________
6th Grade PSI
Matching. Match each statement with the appropriate term from the right by writing the
letter on the line. Each choice will only be used once.
1. _____ Soil is a(n) _____ factor.
A. Abiotic
2. _____ Squirrels and hedgehogs cannot breed
because they belong to different ____.
3. _____ The flower box on your front porch
includes daisies, petunias and
gardenias. It also includes bees, ants,
soil, sunshine and water.
4. _____ The tropical rain forest is wet, warm and
B. Biome
C. Biosphere
D. Biotic
E. Community
F. Ecosystem
G. Population
H. Species
humid. It can be found in several
different places around Earth.
5. _____ Bacteria are _____ factors.
6. _____ A group of ants living together in an ant
hill by the tree in your front yard.
7. _____ In a tide pool by the beach, you find
populations of sea stars, horseshoe
crabs, barnacles and minnows.
8. _____ All biomes on Earth are grouped
together to form the _____.
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6th Grade PSI
Ecosystem Dynamics
Intro to Ecology Homework
Homework #1
Name: __________________________
6th Grade PSI
Intertidal Zone
The intertidal zone is a marine biome. It is located on the shore in the area between the
low tide mark and the high tide mark. In other words, the intertidal zone is the area of
the shore that is underwater during high tide but out of water during low tide.
Low tide mark – At
low tide, the water
reaches this point.
High tide mark – At
high tide, the water
reaches this point.
Intertidal Zone
The intertidal zone has a wide variety of conditions. It is sometimes inundated with
water while at other times it is completely exposed and dry. Because the water that is
left in this area evaporates quickly, salinity in the intertidal zone is very high. The
pounding of ocean waves creates a disturbing environment. There is also a large
temperature range. During high tide, the temperature is generally cooler because it is
covered by water. During low tide, the temperature can reach much higher
temperatures due to direct sunlight on land.
Organisms that live in the intertidal zone must be adapted to these conditions. They
must be able to live in both wet and dry environments. They must endure high salinity
and temperature fluctuations. Green algae and seaweeds grow well in the intertidal
zone. Animals that are adapted to live in this environment include snails, crabs, sea
stars, mussels and whelks.
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6th Grade PSI
Ecosystem Dynamics
1. Suppose that you go on a beach vacation with your family. How can you
determine where the intertidal zone is located?
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2. List three abiotic factors of the intertidal zone.
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3. List three biotic factors of the intertidal zone.
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4. Barnacles are invertebrates that survive well in the intertidal zone. Barnacles are
sessile (non-moving) organisms that are surrounding by a hard shell. They
permanently attach themselves to hard surfaces, such as rocks. Barnacles are
filter feeders. This means that they filter food particles out of water that passes
through their shells. When they are feeding, they open their outer shells to let
water in. When they are not feeding, they close these shells which protects them
from predators and prevents them from drying out. Based on this information and
what you have learned about the intertidal zone, describe two ways in which
barnacles are well adapted to this biome.
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6th Grade PSI
Ecosystem Dynamics
Ecological Interactions Classwork
Classwork #2
Name: __________________________
6th Grade PSI
1. In the chart below, determine whether each description is a habitat or a niche by
placing an X in the appropriate box:
Description
Habitat
Niche
The Tasmanian devil is only found in Tasmania, in
Australia.
Flying squirrels are nocturnal omnivores. They live 6
years in the wild and reproduce during February and
March.
Ticks are small arachnids that survive by sucking the
blood of mammals, birds, amphibians and reptiles.
Ticks undergo three stages of development: larval,
nymph and adult.
Tapeworms live in the digestive tracts of vertebrates.
Read each statement and decide what type of ecological interaction it describes.
2. ____________________Toadfish live on the bottom of the ocean. They bury
themselves in the sand/mud and wait to ambush their
prey, crustaceans and mollusks.
3. ____________________If there are several toadfish inhabiting the same area,
there may not be enough food to sustain all of them.
They will have to compete for prey.
4. ____________________Toadfish are not the only animals on the ocean bottom
that eat mollusks. Other animals that prey on mollusks
include sea stars and crabs. All of these species must
compete for the mollusks in one area.
5. ____________________Some species of crabs have evolved relationships with
algae. The crab provides a solid surface on which the
algae can grow. In return, the algae provides
camouflage to the crab, allowing it to blend into its
surroundings.
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6th Grade PSI
Ecosystem Dynamics
Ecological Interactions Homework
Homework #2
Name: __________________________
6th Grade PSI
Suppose that you are hiking through a deciduous forest and suddenly walk out into a
wildflower meadow. The meadow is filled with flowers of many different heights. You
notice tall purple stalks of flowers called Elephant head as well as Brome, a tall grass.
There are also smaller flowers, such as buttercup, goldenrod and daisies. Towards the
edges of the meadow, you see little mice scurrying in and out of the flowers and a rabbit
munching on grass. You notice many different butterflies, bees and hummingbirds flying
from flower to flower. Looking up, you also notice a hawk circling the meadow. As you
stand quietly observing the scene, you realize how lucky you are to be watching so
many different ecological interactions occurring at the same time.
Describe one example of the following ecological interactions found in the meadow.
1. Interspecific competition
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2. Intraspecific competition
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3. Predator/prey
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4. Mutualism
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6th Grade PSI
Ecosystem Dynamics
Population Dynamics Classwork
Classwork #3
Name: __________________________
6th Grade PSI
Decide if each scenario will result in a population increase or decrease.
1. ____________________Hawks prey on squirrels. If the hawk population
increases, what will happen to the squirrel population?
2. ____________________Two different species of barnacles, Chthamalus and
Balanus, are competing for space on a rock in the
intertidal zone. If Balanus outcompetes Chthamalus,
what will happen to the Chthamalus population?
3. ____________________Only 1% of sea turtle hatchlings will survive to
adulthood. What will happen to the adult population if
hatchling survival increases to 3%?
4. ____________________Former cropland is abandoned, quickly turning into a
wildflower meadow. What will happen to the local
population of pollinators?
5. ____________________Reforestation efforts have created a healthy forest
ecosystem next to your neighborhood. This has led to
immigration of many species. Is immigration an
increase or decrease in population size?
6. ____________________Overhunting has eliminated the fox population in your
town. What will happen to the population of the rabbit,
the fox’s prey?
7. ____________________A mini mall is built on previously forested land, where
many different owl species lived. What will happen to
the local owl population?
8. ____________________A virus sweeps through an apple orchard, killing 75% of
the trees.
9. ____________________Due to a forest fire, a population of deer emigrates to a
neighboring community. Is emigration an increase or
decrease in population size?
10. ____________________Seagulls often feed on anchovies. Overfishing removes
an entire population of anchovies from the coast of
California. How will this affect the seagull population?
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6th Grade PSI
Ecosystem Dynamics
Population Dynamics Homework
Homework #3
Name: __________________________
6th Grade PSI
For the past ten years, you have been working as a wildlife biologist at a maritime forest
state park. One of your jobs has been to monitor the deer population. When you first
started working at the park, the deer population was extremely low due to overhunting.
The population was in danger of disappearing completely. Due to conservation efforts,
the population is now stable. The data you have collected is shown in the table below.
Year
0
1
2
3
4
5
6
7
8
9
10
Deer Population
10
18
30
57
95
82
75
85
70
81
79
Create a graph of the deer population over time. Connect the points on your graph with
a smooth line. Then, answer the questions that follow.
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6th Grade PSI
Ecosystem Dynamics
1. The year you started working at the park coincided with the start of a ban on deer
hunting in the park. Describe how this affected the deer population.
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2. During the first few years of your population study, how did the deer population
compare to their available resources in the forest?
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3. How did the deer population compare to their available resources between years
5-10?
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4. Define a carrying capacity and describe it in terms of the deer population.
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5. What would you guess to be the carrying capacity of deer in this park?
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6th Grade PSI
Ecosystem Dynamics
Energy in Food Webs Classwork
Classwork #4
Name: __________________________
6th Grade PSI
Observe the food web below. Then, identify an organism that belongs to each category
listed below.
Hawk
Bear
Fungi
Squirrels
Deer
Bacteria
Berries/Nuts
Grasses
Producer:
____________________
Herbivore:
____________________
Carnivore:
____________________
Omnivore:
____________________
Decomposer: ____________________
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6th Grade PSI
Ecosystem Dynamics
Energy in Food Webs Homework
Homework #4
Name: __________________________
6th Grade PSI
Below is a food web for an Alaskan marine habitat. Answer the questions based on this
food web.
Source: USGS
1. Which group is the producer in this food web? How do you know?
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2. Which group are herbivores? How do you know?
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6th Grade PSI
Ecosystem Dynamics
3. If the rat goes extinct, how will this affect the kittiwake population? Explain.
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4. If the puffin population grows drastically, how will this affect the zooplankton
population?
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6th Grade PSI
Ecosystem Dynamics
Answer Key
Intro to Ecology Classwork
Classwork #1
1. A
2. H
3. F
4. B
5. D
6. G
7. E
8. C
Intro to Ecology Homework
Homework #1
1. You can observe the tides. Mark the beach at low tide and at high tide. The
space in between the marks is the intertidal zone.
2. Answers will vary.
3. Answers will vary.
4. Answers will vary. Examples: Because they permanently attach themselves to
surfaces, they are not affected by crashing waves. Because they can close their
shells when water is not present, they protect themselves from dry conditions.
Ecological Interactions Classwork
Classwork #2
1. Habitat, niche, niche, habitat
2. Predator/prey
3. Intraspecific competition
4. Interspecific competition
5. Mutualism
Ecological Interactions Homework
Homework #2
1. Answers will vary. Examples: Different short flowers may be competing for
sunlight. All flower species are competing for water, space, soil or pollinators.
Different pollinators are competing for pollen/nectar.
2. Answers will vary. Examples: Within each flower species, flowers are competing
for sunlight, water, space, soil or pollinators. Pollinators of the same species are
competing for pollen/nectar.
3. The hawk is the predator of the mouse.
4. Pollination is a mutually beneficial relationship. The pollinators get food while the
flower is given a method of moving pollen to another flower.
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6th Grade PSI
Ecosystem Dynamics
Population Dynamics Classwork
Classwork #3
1. Decrease
2. Decrease
3. Increase
4. Increase
5. Increase
6. Increase
7. Decrease
8. Decrease
9. Decrease
10. Decrease
Population Dynamics Homework
Homework #3
Population Size
Deer Population
100
90
80
70
60
50
40
30
20
10
0
0
1
2
3
4
5
6
7
8
9
10
11
Year
1. The deer was in a predator/prey relationship with hunters. When the predator
(hunter) was removed, the prey (deer) population increased dramatically.
2. At the beginning of the study, the deer population was very low. There were more
resources available than the deer could use. This allowed the population to grow
exponentially.
3. During years 5-10, the deer population reached its limit in terms of available
resources. The population could not grow, and in some years declined, because
of this. (It had reached its carrying capacity.)
4. The carrying capacity is the largest population size that can survive with the
available resources. Once the deer population grew to be a certain size, it could
not grow any larger because there was not enough resources to sustain the
population. During some years, intraspecific competition forced it to decrease.
5. 80 (or any guess close to this)
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6th Grade PSI
Ecosystem Dynamics
Energy in Food Webs Classwork
Classwork #4
Only one answer required per category.
Producer: Berries/nuts, grasses
Herbivore: Deer, squirrels
Carnivore: Hawk
Omnivore: Bear
Decomposer: Fungi, bacteria
Energy in Food Webs Homework
Homework #4
1. Phytoplankton are primary producers because they ingest water, nutrients, sun
and air.
2. Zooplankton are herbivores because they only eat the phytoplankton.
3. The rat preys on the kittiwake. If there are no more rats, then the kittiwake
population will increase.
4. Puffins prey on several animals who, in turn, prey on the zooplankton. If the
puffin population increases, the intermediate animal population will decrease.
Since the population of zooplankton predators have decreased, the population of
zooplankton will increase.
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6th Grade PSI
Ecosystem Dynamics