Relationships of Organisms (Life Science) Assessment:
Relationships of Organisms
Name ______________________
Date _____________ Hour _____
A. TLW predict the effects of changes in one population of organisms
in a food web on another population of organisms.
Directions: Read the scenario and answer the questions that follow, justifying your answers.
Include a minimum of two consequences for each question.
On Isle Wilderness, farmers raised chickens and vegetable crops. There was a stable
population of wild rabbits and foxes on the island. Over a period of time, the farmers noticed
that their chickens were disappearing. After looking into the problem, the farmers blamed the
foxes for the loss of their chickens and decided to trap and move most of the foxes.
1. What will happen to the wild rabbit population?
2. What will happen to the vegetable crops?
3. What will happen to the population of the farmers’ chickens?
4. How could stable populations be reestablished on the island?
Relationships of Organisms (Life Science) Assessment:
C. TLW analyze the effect of changes in the environment
on the relationship between two organisms.
Directions: Read the following paragraph, study the graph, and then answer questions 1-5.
For many years Gull Lake has been an exciting outdoor laboratory for scientists who study
redwing blackbirds, the great blue heron, and the community of cattail plants. Gradually, a
dangerous alien species began to take control and threaten the cattail population. The enemy
was a plant called purple loosestrife! They crowded and out-competed the cattails. By 1996,
the shoreline of Gull Lake was covered with purple loosestrife. Human efforts to remove the
plants were unsuccessful. The redwing blackbirds lost their nesting spot in the cattails.
Muskrats lost their food - cattail roots. Beetles were introduced to eat the loosestrife.
5. Circle the letter for the statement below that best describes the relationship between the
redwing blackbirds and the purple loosestrife that is shown in the graph?
A- As the purple loosestrife population increases, the blackbird population increases.
B- As the purple loosestrife population increases, the blackbird population decreases.
C- As the purple loosestrife population decreases, the blackbird population decreases.
D- There is no relationship between redwing blackbirds and purple loosestrife.
Relationships of Organisms (Life Science) Assessment:
After the beetles were introduced to a selected area of purple loosestrife, scientists
noticed a decrease in the number of this alien species (the purple loosestrife). Predict
what will happen in this ecosystem. Using scientific reasoning, justify your answer with
at least two scenarios of possible consequences.
6. One thing that could happen is _______________________________________________
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7. Another thing that could happen is ____________________________________________
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8. Which statement BEST describes what will happen to the population of muskrats in this
area before the beetles are introduced?
A- The population will remain the same.
B- The population will decrease.
C- The population will increase.
9. Circle the letter for the term that BEST describes the relationship between the purple
loosestrife and the cattails?
A- Parasitic
B- Competition
C- Mutually beneficial
D- Predator - Prey
10. Explain your answer to question #9, ___________________________________________
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Relationships of Organisms (Life Science) Assessment:
D. TLW identify common patterns of relationships among populations in an ecosystem.
Directions: Study the food web and answer the following questions.
Food Web
Choose one food chain in the web. Name all the organisms. Identify the producers and
consumers in your selected chain.
11. ________________________________________________________________________
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12. Which answer below best describes what the arrows in the diagram represent?
A- The flow of energy in a food web
B- Evolution from less to more complex organisms
C- Symbiotic relationships among field organisms
D- The movement of organisms at night
13. The rabbit population might increase as a result of:
A An increase in the owl population.
B An increase in the coyote population.
C A decrease in the mouse population.
D An increase in the grass population.
Relationships of Organisms (Life Science) Assessment:
14. When the organisms in this web die, what type of organisms will feed on their remains?
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15. What happens to the dead organisms as the they are consumed by the organisms that
you named in question 4.
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16. Consider the following: The owl population has been infected with an unknown virus
causing their numbers to be drastically reduced. Describe all the effects the reduction
of owls has on the food web.
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Air, water, sunlight, sand, soil, and rocks are abiotic parts of the field environment
that support organisms in the food web. Select three of these non-living parts and
describe what each part does to supports an organism in the food web.
17. ________________________________________________________________________
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18. _________________________________________________________________________
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19. _________________________________________________________________________
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Relationships of Organisms (Life Science) Assessment:
G.
TLW identify and describe examples of populations, communities, and ecosystem.
Directions: Circle the appropriate letter to identify each group as a “population” P,
“community” C or “ecosystem” E.
20. P C
E squirrels in your back yard
21. P C
E
22. P C
E cattails in a marsh
23.
P C
E
Oak forests,
24. P C
E
leopard frogs in a pond
25.
P C
E
the Rouge River
26.
P C
E
the deer, owls, foxes mice, grasses, trees, birds and crickets in a forest
27.
P C E
the turtles, fishes, frogs, mosquitos, flies and grasses and reeds in a pond.
honey bees in an apple orchard
28. Choose one of the populations you identified above and describe an appropriate
rationale to explain how you know it is a population.
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29. Choose one of the communities you identified above and describe an appropriate
rationale to explain how you know it is a community.
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30. Choose one of the ecosystems you identified above and describe an appropriate rationale
to explain how you know it is an ecosystem.
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Relationships of Organisms (Life Science) Assessment:
Answer Key ~ Relationships of Organisms ~ Answer Key
1. What will happen to the wild rabbit population?
The rabbit population will increase because their natural predator the foxes are gone.
The larger rabbit population will eat all of their natural food sources up leaving little to eat.
The rabbit population will become weak because of poor diet and disease because of
overpopulation.
2. What will happen to the vegetable crops?
The vegetable crops will end up being eaten by the wild rabbits.
The farmers will lose money because the wild rabbits will have eaten all of their crops.
The farmers may have to spend money to fence their gardens to keep the rabbits out.
The farmers may have to spend more money to plant more crops.
3. What will happen the population of the farmer’s chickens?
The populations of the farmers’ chickens will remain stable.
The chickens will no longer “mysteriously” disappear.
4. How could stable populations be reestablished on the island?
Predators could be gradually reintroduced to the island.
Farmers could trap rabbits
The plant populations on the island could be restored.
5. B- As the purple loosestrife population increases, the blackbird population decreases.
6 & 7 Answers will vary, examples may include: The cattail population may begin to
reproduce. If the cattail population increases the redwing blackbirds may return to the area to
nest. Muskrats may return because their food source returns. The beetles that were introduced
may create another unexpected problem or cause an increase in the fish population if they turn
out to be good food for the fish.
8. B- The population will decrease.
9. B- Competition
10. Both the purple loosestrife and cattails are competing for the same habitat/area in the
wetlands. Both plants thrive in the same environment.
11. Answers will vary, example: grass (producer) - mouse (consumer) - owl (consumer)
(producers include: grass, alfalfa, consumers include: mouse, owl, grasshopper, rabbit, coyote)
12. A- The flow of energy in a food web.
13. D An increase in the grass population
14. decomposers
15. The dead organisms are broken down into chemical nutrients by the decomposers that can
them be used for energy by the decomposers and other living organisms.
16. Answers will vary, examples may include: The mouse population will increase, resulting in
a decrease in the grasshopper and grass populations. The alfalfa population will increase
because of the reduction in the grasshopper population. Coyotes population may increase
because of having more mice to eat. Rabbit populations may increase because fewer of them
will get eaten by the owls.
Relationships of Organisms (Life Science) Assessment:
17. to 19. Acceptable responses may include but are not limited to:
Plants and animals require air that has carbon dioxide and oxygen for respiration.
Air for the owl to fly through to hunt for food and escape predators.
The air blowing around spreads plant seeds and pollen.
Water is essential for all living things.
Organisms are comprised mostly of water.
Water is required for many of the chemical processes that allow living things to function.
Sunlight is the source of energy for all living things.
Sunlight is necessary for photosynthesis that makes food for plants which in turn provides
food for animals.
Sand and rocks provide habitat for plants and animals
Sand and rocks provide protection protection for plants and animals against weather and
predators.
Sand and soil provide nutrients for plants.
Sand and soil provide a place for plants to grow.
Soil serves as a habitat for many animals that borough.
Soil helps to hold water which is necessary for all living things.
20. P squirrels in your back yard
21. C
22. P cattails in a marsh
23.
E
Oak forests,
24. P leopard frogs in a pond
25.
E
the Rouge River
26.
C
the deer, owls, foxes mice, grasses, trees, birds and crickets in a forest
27.
P honey bees in an apple orchard
the turtles, fishes, frogs, mosquitos, flies and grasses and reeds in a pond.
28. Answers will vary, examples may include: The leapard frogs in a pond are a population
because they are all the same species living in a certain area.
29. Answers will vary, examples may include: The turtles, fishes, frogs, mosquitos, flies and
grasses and reeds in a pond are a community because they are a group of organisms that live
together in an area and what happens to one population affects the other populations.
30. Answers will vary, examples may include: The Rouge River is an ecosystem because it
includes not only the living organisms but also the water, light, and air that the organisms
depend on for life as well as the sand and soil that are necessary for the plants to live that the
fish and other animals need to live.