Name: ___________________________
Pd. ____
Ecology Homework Packet
Part of Section 3.1 Ecology (p. 66-67) and Section 3.2 Ecology and Energy (p. 69-72)
1. (Read p. 66 & 67) What is the difference between abiotic and biotic factors?
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2. What is an autotroph?
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3. What is the relationship between an autotroph and primary producer?
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4. Define chemosynthesis.
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5. What are the two primary sources of energy that power living systems?
a.
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b.
6. What is a heterotroph?
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7. What is the relationship between a heterotroph and consumer?
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8. How are detrivores different from decomposers?
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a. Give an example of a decomposer? ___________________________
b. Give an example of a detrivore? ___________________________
9. Classify each of the following as an herbivore, a carnivore, an omnivore, or a detrivore:
a. Earthworm ___________________________
b. Bear ___________________________
c. Cow ___________________________
d. Snail ___________________________
e. Owl ___________________________
f. Human ___________________________
10. People who explore caves where there is running water but no sunlight often find them
populated with unique types of fishes and insects. Write a hypothesis that can explain the
ultimate source of energy for these organisms.
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1
Name: ___________________________
Pd. ____
Section 3.3 Energy Flow in Ecosystems (p. 73-78) and part of 3.4 Cycles (p. 85-86)
1. What is the relationship between food chains and food webs?
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2. What role do decomposers have in a food web?
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3. Explain what you think might happen to the Everglades ecosystem shown in Figure 3-9 if there
were a sudden decrease in the number of crayfish.
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4. Define trophic level.
5.
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On average, how much energy is passed from one trophic level to the next? ______ %
6. Draw an energy pyramid for a five-step food chain. If 100% of the energy is available at the first
trophic level, what percentage of that energy is available at the highest trophic level?
7. Why is the transfer of energy in a food chain usually only about 10% efficient?
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8. Define limiting nutrient.
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9. How does nutrient availability relate to the productivity of an ecosystem?
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Name: ___________________________
Pd. ____
Section 4.2 Niches and Community Interactions
1. What is a niche?
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2. What is the relationship between a niche and its habitat?
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3. Define tolerance as it relates to ecology.
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4. What is the relationship between competition and limited ecological resources?
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5. What is the Competitive Exclusion Principle?
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6. Define predation.
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7. Define herbivory.
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8. What is a keystone species?
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9. What are the three major types of symbiosis?
a.
b.
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c.
10. Bacteria living in a cow’s stomach help the cow break down the cellulose in grass, gaining
nutrients in the process. Is this an example of commensalism or mutualism?
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a. Explain your answer.
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11. Explain the difference between a predator and parasite.
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3
Name: ___________________________
Pd. ____
Section 4.3 Succession (p.106-109)
1. What is primary succession?
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2. Define pioneer species.
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3. What effect do pioneer species have on an environment undergoing primary succession?
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4. What is secondary succession?
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5. How does primary succession differ from secondary succession?
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6. Why does succession occur? (i.e. why do communities change over time?).
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7. Look at figures 4-12 and 4-13, describe the general order of succession. (i.e. what is the order of
the plants?).
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8. What is a climax community?
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9. What kinds of conditions might prevent a community from returning to its pre-disturbance
state?
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10. Explain why secondary succession usually proceeds faster than primary succession.
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4
Name: ___________________________
Pd. ____
Section 5.1 How Populations Grow (p. 130-135)
1. List the four characteristics that are used to describe population.
a.
b.
c.
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d.
2. What is meant by the term geographic range?
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3. On your travels through eastern Canada and the U.S., you notice gray squirrels everywhere.
What can you infer about the squirrels’ geographic range?
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4. Define population density.
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5. What are the three patterns of population distribution?
a.
b.
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c.
6. Define age structure.
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7. List the four factors that affect population size:
a.
b.
c.
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d.
8. What is the difference between emigration and immigration?
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9. More dandelion seedlings develop in a lawn than dandelion plants are removed. What is likely
to happen to the lawn’s dandelion population?
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10. When do populations grow exponentially?
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11. Why does exponential growth show a characteristic J-shaped curve?
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12. Define logistic growth.
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13. What factors might cause the carrying capacity of a population to change?
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5
Name: ___________________________
Pd. ____
Section 5.2 Limits to Growth (p.137-141)
1. In the context of a population, what is a meant by limiting factor?
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2.
How do limiting factors affect the growth of populations?
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3. List 5 density-dependent limiting factors.
a.
b.
c.
d.
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e.
4. What is the relationship between competition and population size?
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5. Describe how a predator-prey relationship can control both the predator population and the
prey population.
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6. What would happen to a population of predators if there was a sudden increase in food for the
prey? Explain your answer.
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7. What is a density-independent limiting factor?
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8. List 3 examples of density-independent limiting factors?
a.
b.
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c.
9. Would a density-independent limiting factor have more of an effect on populations size in a
large ecosystem or in a small ecosystem?
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