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CHAPTER INVESTIGATION
Sustainable Resource
Management
OVERVIEW AND PURPOSE Wood is a renewable
resource, but the demand for wood is continuing to grow
worldwide. Humans are harvesting trees more quickly than trees
have the ability to grow and replace themselves. The result is a
forest in decline. In this activity you will
• model what happens when trees are harvested to meet
the needs of a growing population
• calculate the rate at which the population of a renewable
resource declines
Question
MATERIALS
• coffee can with 120 craft
sticks
• bundle of 32 craft sticks
• stopwatch
Write
It Up
How can people meet the ongoing human demand for wood
without using all the trees? You will use the increasing human
demand for wood to determine how overuse of a resource
might affect a population. What would you like to discover
about resource management? Write a question that begins
with Which, How, Why, When, or What.
Procedure
Copy the data table on page 267 into your Science Notebook.
In your group of classmates, decide who will fill each of the
following roles: forest, timer, forest manager, harvester/record
keeper.
Forest: Get a coffee can of 120 craft
sticks. These sticks represent the available
tree supply.
Timer: Sound off each 15-second
interval and each minute.
266 Unit 2: Life Over Time
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Forest Manager: Get 32 sticks from the teacher.
You will add 1 new tree every 15 seconds by
putting a stick in the coffee can.
Harvester: At the end of the first minute, cut
down 1 tree by removing 1 stick from the coffee
can. At the end of the second minute, cut down
2 trees; at the end of the third, cut down 4 trees.
At the end of each additional minute cut down
twice as many trees as you did before. This
represents the doubling of the demand for
trees based on human population growth.
Observe and Analyze
Write
Conclude
It Up
1. INFER What effect does increasing human
population growth have on forests?
2. EVALUATE Was the forest always
shrinking?
3. EVALUATE How does this investigation
help you to answer or change your question
about resource management?
4. IDENTIFY LIMITS What aspects of
this investigation fail to model the natural
habitat?
Write
It Up
5. APPLY What other renewable resources
1. CALCULATE At the end of each minute,
add 4 trees, but subtract twice as many trees
as you subtracted the minute before.
2. RECORD AND CALCULATE Complete
the chart. How many trees are left in the forest after 8 minutes of harvesting?
need sustainable management?
INVESTIGATE Further
CHALLENGE Explain how you could use the
data gathered in this investigation to develop
methods of sustainable resource management.
ent
ource Managem
Sustainable Res
Harvest
Table 1. Rate of
Minutes
Number of
Trees at Start
of Minute
1
120
Number of
New Trees
4
Number of
Trees
Harvested
1
Number of
Trees at End
of Minute
123
2
3
4
5
6
7
8
Chapter 8: Population Dynamics 267
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Chapter Review
Populations are shaped by interactions
between organisms and the environment.
CONTENT REVIEW
CLASSZONE.COM
KEY CONCEPTS SUMMARY
1
Populations have many characteristics.
• Populations go through three stages:
growth
stability
decline
• Four characteristics define a population:
size
density
spacing
age structure
• Scientists can predict population changes.
2
Populations respond to pressures.
Populations change as they
respond to pressures from
limiting factors.
Two types of limiting factors
are density dependent and
density independent.
3
Human populations have unique responses
to change.
Humans can control many factors that limit most biological populations.
268 Unit 2: Life Over Time
VOCABULARY
population dynamics
p. 241
carrying capacity
p. 242
population size p. 244
population density
p. 245
VOCABULARY
immigration p. 251
emigration p. 251
limiting factor p. 252
opportunist p. 255
competitor p. 256
VOCABULARY
pollution p. 264
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Reviewing Vocabulary
Describe how the vocabulary terms in the following pairs are related to each other. Explain
the relationship in a one- or two-sentence
answer. Underline each vocabulary term in
your answers.
1. population dynamics and carrying capacity
2. immigration and emigration
3. limiting factor and population density
4. opportunists and competitors
Reviewing Key Concepts
Multiple Choice Choose the letter of the best
answer.
5. The study of changes in a population over time
and the factors that affect these changes is
called population
a. stability
c. spacing
b. dynamics
d. density
6. A population that has reached its maximum
size in a given area is said to have reached its
a. population range
b. gradual growth
c. carrying capacity
d. population projection
7. Assuming there is no immigration or emigration, a population size will remain constant if
a. the birth rate equals the death rate
b. the birth rate exceeds the death rate
c. the death rate exceeds the birth rate
d. the birth rate increases constantly
8. Distinct patterns in a population such as
clumped, uniform, or random populations are
examples of population
a. density
c. growth
b. spacing
d. dynamics
9. Which factors affect the size and growth of
a population?
a. number of births and deaths
b. emigration and immigration
c. competition between populations
d. all of the above
10. A limiting factor that depends on the size of
the population in a given area is a
a. density-dependent factor
b. density-independent factor
c. reproduction survival strategy
d. carrying capacity
11. Density-independent limiting factors include
a. predators
c. floods
b. parasites
d. competition
12. Which are abiotic factors in an environment?
a. disease and parasites
b. air, light, and water
c. pollution and overfishing
d. competition and predators
13. Which is an example of competition for
resources?
a. individuals in a population feeding on the
same food sources
b. movement of seagulls into a population of
other seagulls
c. an increase in the population of raccoons in
a particular environment at a steady rate
d. a population of fruit trees producing less
fruit because of drought
14. Two factors that have increased Earth’s
carrying capacity for humans are habitat
expansion, and
a. habitat disturbance
b. strategies of competitors
c. strategies of opportunists
d. technology
Chapter 8: Populations Dynamics 269
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Short Answer Write a short answer to each
question.
23. SYNTHESIZE What is an example of a densityindependent factor that has affected a human
population? Describe how this factor changed
the population.
15. What factors might affect the density of a
population?
16. What is the age structure of a population?
17. Describe three factors that account for the
rapid growth of the human population during
the past 500 years.
Thinking Critically
18. ANALYZE Under what conditions does gradual
growth in a population occur?
19. COMMUNICATE Describe four observations that
Darwin made about population growth.
20. PREDICT The graph below shows the exponential growth rate of a colony of unicellular
organisms. If the population continues to grow
at the same rate during the next 2 hours, what
will the population be after 10 hours? Explain
your answer.
60,000
Number of Individuals
50,000
25. EVALUATE Why do you suppose that the
growth rate of human populations differs dramatically in different countries?
26. SYNTHESIZE Human activity has resulted in the
decline of many populations of other species.
Choose one example of how humans have put
pressure on species around the world and
describe ways that humans can avoid causing
continued decreases in these populations.
27. INFER Look again at the picture on pages
238–239. Now that you have finished the
chapter, how would you change or add
details to your answer to the question on the
photograph?
28. SUMMARIZE Write one or more paragraphs
describing the factors that affect population
size, density, and age structure. Use the following terms in your descriptions.
40,000
30,000
20,000
10,000
0
24. INFER Wolves are the natural predators of
moose. Both populations are found on an
island in the middle of Lake Superior. During
one season, the population of moose
increased dramatically. What could have
caused the increase in the moose population?
immigration
density-dependent factors
emigration
density-independent factors
limiting factors
0
2
4
6
8
21. PREDICT In a certain population 35 percent of
the individuals are under the age of 20. What
predictions might you make about the size of
the population in 10 years?
22. PROVIDE EXAMPLES What limiting factors
might cause the carrying capacity of a
population to change? Provide at least three
examples. Describe how the population might
change.
270 Unit 2: Life Over Time
If you need to do an experiment for your unit project, gather the materials. Be sure to allow enough
time to observe results before the project is due.
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Standardized Test Practice
For practice on your
state test, go to . . .
TEST PRACTICE
CLASSZONE.COM
Analyzing Data
The graph below is an example of a population
growth curve.
6000
C
3. During which time interval do limiting factors in a
population begin to have an effect on the population growth?
a. interval A only
b. interval B only
c. interval C only
d. interval C and interval D
D
Number of Individuals
5000
4000
4. This graph represents a typical
a. gradual curve
b. rapid curve
c. slow curve
d. flat curve
B
3000
2000
1000
A
0
0
20
40
60
80
100
120
Time (in days)
Use the graph to answer the questions below.
1. What does the time interval marked D represent?
a. Population is decreasing.
b. Carrying capacity has been reached.
c. Birth rates exceed death rates.
d. Population is growing.
5. What conclusion can you draw from the
information in the graph?
a. Density-dependent factors have had no effect
on the population shown on the graph.
b. The graph indicates an absence of disease and
a supply of unlimited resources.
c. Resources have become more available, so the
population continues to increase exponentially.
d. As resources become less available, the population rate slows or stops.
2. Which time interval on the graph represents gradual growth?
a. interval A and interval B
b. interval C and interval D
c. interval C only
d. interval D only
Extended Response
6. What part of the graph above shows the growth
of the human population during the last
500 years? Explain. What are some factors that
might allow the human population to reach its
carrying capacity?
7. Choose a population of organisms in your area.
Describe the limiting factors that may affect the
growth of that population. Make sure you include
both density-dependent and density-independent
factors in your discussion.
Chapter 8: Population Dynamics 271
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272 Unit 2: Life Over Time