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Chapter 5 Study Guide
Study Tip
Have students work in pairs to review
the Key Concepts and the Vocabulary
for each section. Students might first
quiz each other on the Key Concepts,
with one student reading the text
statement but omitting the key
terms, and the other student supplying the terms. For the first Key
Concept in Section 5–1, for example,
the first student would say, “The
main characteristics of a population
are . . .,” and the second student
would identify the characteristics. A
similar approach can be used to
review Vocabulary.
Thinking Visually
1. Density-dependent factors
2. Density-independent factors
3. Competition
4. Unusual weather or seasonal cycles
Page 134
Chapter 5 Study Guide
5–1 How Populations Grow
Key Concepts
5–2 Limits to Growth
Key Concepts
• Three important characteristics of a population
are its geographic distribution, density, and
growth rate.
• Three factors affect population size: the number
of births, the number of deaths, and the number
of individuals that enter or leave the population.
• Under ideal conditions and unlimited resources, a
population will continue to grow in a pattern
called exponential growth. As resources are used
up and population growth slows or stops, the
population exhibits logistic growth.
• Density-dependent limiting factors include
competition, predation, parasitism, and disease.
• Unusual weather, natural disasters, seasonal
cycles, and certain human activities—such as
damming rivers and clear-cutting forests—are all
examples of density-independent limiting factors.
Vocabulary
population density, p. 119
immigration, p. 120
emigration, p. 120
exponential growth, p. 121
logistic growth, p. 122
carrying capacity, p. 122
5–3 Human Population Growth
Key Concepts
• Like the populations of many other living organisms, the size of the human population tends to
increase with time.
• The characteristics of populations, and the social
and economic factors that affect them, explain
why some countries have high population
growth rates while populations of other countries
grow slowly or not at all.
Chapter 5 Assessment
Vocabulary
demography, p. 130
demographic transition, p. 130
age-structure diagram, p. 131
Reviewing Content
1. c
2. c
3. b
4. b
5. b
6. a
7. b
8. a
9. d
10. a
Thinking Visually
Using information from this chapter, complete the following concept map:
Understanding Concepts
134
Chapter 5
Populations
SECTION RESOURCES
Technology:
• Teaching Resources, Chapter Vocabulary
Review, Graphic Organizer, Chapter 5 Tests:
Save
Levels A and B
e
• Computer Test Bank, Chapter 5 Test
• iText, Chapter 5 Assessment
Tim
Print:
r
11. The movement of individuals into
an area occupied by an existing population is called immigration.
Emigration occurs when individuals
move out of a population.
12. The graphs should show the
characteristic J-shape of exponential
population growth as illustrated in
Figure 5–3 on page 121.
13. Logistic growth occurs when a
population’s growth rate slows or
stops following a period of exponential growth. Population growth may
slow down when the birthrate
decreases or the death rate increases,
or when both events occur at the
same rate. Population growth may
also slow down when the rate of
immigration decreases, the rate of
emigration increases, or both.
14. Carrying capacity represents the
largest number of individuals that a
given environment can support.
Examples will vary.
Vocabulary
limiting factor, p. 124
density-dependent limiting factor, p. 125
predator-prey relationship, p. 126
density-independent limiting factor, p. 127
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Page 135
Chapter 5 Assessment
Interactive textbook with
assessment at PHSchool.com
Reviewing Content
Choose the letter that best answers the question or
completes the statement.
8. A limiting factor that depends on population size
is called a
a. density-dependent limiting factor.
b. density-independent limiting factor.
c. predator-prey relationship.
d. parasitic relationship.
1. The number of individuals of a single species per
unit area is known as
a. carrying capacity. c. population density.
b. logistic growth.
d. population growth rate.
9. The scientific study of human populations is called
a. immigration.
b. emigration.
c. demographic transition.
d. demography.
2. The movement of individuals into an area is called
a. demography.
c. immigration.
b. carrying capacity. d. emigration.
3. The range or area occupied by a population is its
a. growth rate.
b. geographic distribution.
c. age structure.
d. population density.
10. The demographic transition is complete when
a. population growth stops.
b. the birthrate is greater than the death rate.
c. the death rate begins to fall.
d. the death rate is greater than the birthrate.
4. The graph below represents
Number of Individuals
Understanding Concepts
11. Distinguish between immigration and emigration.
12. Sketch the exponential growth curve of a hypothetical population.
13. Describe the conditions under which logistic
growth occurs.
14. What is carrying capacity? Give an example.
15. How might the introduction of a limiting nutrient
in a pond affect the carrying capacity of that pond?
Time
a.
b.
c.
d.
16. Describe the long-term effects of competition on
populations of two different species competing
for the same resources.
carrying capacity.
exponential growth.
logistic growth.
limiting factors.
17. Describe how a predator-prey relationship can be
a mechanism of population control.
5. The maximum number of organisms of a particular species that can be supported by an environment is called
a. logistic growth.
b. carrying capacity.
c. exponential growth.
d. population density.
18. How do parasites serve as a density-dependent
limiting factor?
19. Explain how density-independent limiting factors
can affect populations.
20. How can you account for the fact that the human
population has grown more rapidly during the
past 500 years than throughout its previous
history?
6. If a population grows larger than the carrying
capacity of its environment, the
a. death rate may rise.
b. birthrate may rise.
c. death rate may fall.
d. immigration rate may increase.
21. What is the significance of the demographic
transition in studies of the human population?
7. Density-independent limiting factors include
a. predation.
c. competition.
b. hurricanes.
d. parasitism.
23. Explain how a limited resource can affect the
survival of a species. Give a specific example.
HOMEWORK GUIDE
Section 5–1
1–6, 11–14, 28
Section 5–2
7, 8, 15–19, 23–25, 29–31
Sav26,
e 27, 32
9, 10, 20–22,
e
Section 5–3
Tim
Questions:
r
Section:
22. How does the age structure of a population affect
its growth rate?
Your students can go online to access
an interactive version of the Student
Edition and a self-test.
(Continued from page 134)
15. The addition of a limiting nutrient to a pond would most likely
cause an increase in the carrying
capacity of those species directly
dependent on that nutrient.
16. When two species compete for
the same resources, both species are
under pressure to change in ways
that decrease their competition. Over
time, the species may evolve to occupy separate niches.
17. The rise in the population of the
prey would normally be followed by
a rise in the predator population. As
the population of predators rises, the
population of prey declines. Since
there is less prey available, the population of predators also declines. This
cycle repeats itself and functions as a
means of population control.
18. Parasites take nourishment from
their hosts, often weakening them
and causing disease or death.
19. Density-independent factors have
similar effects on all individuals in a
population regardless of the population’s density. Examples include the
effects of a prolonged drought, a
killing frost, or a flood.
20. Human population began growing more rapidly 500 years ago due
to favorable growth conditions.
Agriculture and industry made life
easier. The world’s food supply
became more reliable. Improved sanitation, medicine, and healthcare
dramatically reduced the death rate.
Simultaneously, the birthrate
remained high.
21. Demographic transition is a prediction of population changes based
on an analysis of changes in birthrate
and death rate.
22. Populations with nearly equal
numbers of people in each age group
will have a slow but steady growth
rate for the near future. Populations
with many more young children than
teenagers, and many more teenagers
than adults, will grow at a fast rate.
23. A limited resource can affect the
survival of a species if that species
depends on the resource as part of its
habitat. Most students will describe
destruction of panda habitat.
Populations
135
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Chapter 5 Assessment
Page 136
Chapter 5 Assessment
Critical Thinking
Critical Thinking
24. Since the communicable virus is
more likely to spread when people
are crowded together, it is densitydependent.
25. In most cases, it will have a
greater effect on the population of a
small ecosystem. A small population
will be more susceptible to serious
damage from a density-independent
limiting factor such as a flood or
storm.
26. Because there are relatively small
numbers of individuals in younger
age groups, the population of
Sweden is likely to stay about the
same or even decline over the next
50 years.
27. The growth curve of a small town
made up mostly of senior citizens
would show a decline in population.
A growth curve of a small town made
up of newly married couples would
show an increase in population.
28. The carrying capacity of a population is affected by limiting factors
such as competition, predation, parasitism, disease, climate, drought, and
human disturbances. Likewise, the
carrying capacity of a city’s roads
depends on such limiting factors as
the number and width of roads, the
number of intersections, and the
number of vehicles traveling on the
road.
29. If there is a sudden increase in
food for the prey, the population of
predators would probably increase as
well. An increase in food for prey
would allow for a greater number of
prey. More predators would then be
supported.
30. In parasitic and predator-prey
relationships, one member of the
relationship benefits, while the other
is harmed or killed.
31. The population of fish would
most likely decrease due to a
decrease in the size of the ecosystem.
The decreased size would provide a
smaller amount of resources.
32. A demographer would ask questions such as: “Have changes in
society, such as access to healthcare
and medicines, lowered the death
rate?” and “Does the birthrate
remain high, or are there signs that
the birthrate is falling?”
24. Applying Concepts Why might a contagious
virus that causes a fatal disease be considered a
density-dependent limiting factor?
30. Comparing and Contrasting How is the
relationship between parasites and their hosts
similar to a predator-prey relationship?
25. Inferring Would a density-independent limiting
factor have more of an effect on population size in
a large ecosystem or in a small ecosystem? Explain.
31. Applying Concepts If the water level of a river
drops, how might that affect a fish population
living in that river?
26. Predicting Study the age-structure diagram for
Sweden below. Then, predict how Sweden’s rate
of population growth is likely to change over the
next 50 years.
32. Asking Questions What questions would a
demographer need to answer in order to determine whether a country is approaching the
demographic transition?
136
Chapter 5
Age (years)
Age-Structure Diagram for Sweden
85+
80–84
75–79
70–74
65–69
60–64
55–59
50–54
45–49
40–44
35–39
30–34
25–29
20–24
15–19
10–14
5–9
0–4
Males
Females
8 7 6 5 4 3 2 10 1 2 3 4 5 6 78
Percentage of Population
27. Comparing and Contrasting Describe the
most likely population growth curve you would
expect to see in a small town made up mainly of
senior citizens. Compare this growth curve to that
of a small town made up of newly married
couples in their twenties.
28. Using Analogies How is the carrying capacity
of a city’s roads similar to the carrying capacity of
an ecosystem?
29. Predicting What will happen to a population of
predators if there is a sudden increase in food for
the prey? Explain.
The fertilizer washing into the pond would
increase the level of a limiting factor in the pond
ecosystem—nitrogen. This would increase the carrying capacity of the pond and probably lead to
rapid growth of the algae population.
Science, Technology, and Society Nitrogen is a
limiting factor in aquatic ecosystems. Suppose that
runoff from a field washes nitrogen-rich fertilizer into a
pond containing a population of algae. Predict how
the fertilizer will affect the carrying capacity of the
pond for algae. Refer to the information on limiting
nutrients in Section 3–3.
Write a paragraph on populations. Include the
characteristics of a population, factors that affect its
size, and the changes in the size of the human
population from about 500 years ago to the present.
Give a projection on how large the world population
might be in the year 2050 and on how the growth
rate in 2050 might compare to that in 2000. (Hint:
Outline your ideas before you begin to write.)
Performance-Based Assessment
Multimedia Presentation Create a visual presentation that describes how limiting factors regulate
population growth. Be sure to distinguish between
density-dependent limiting factors and densityindependent limiting factors.
For: An interactive self-test
Visit: PHSchool.com
Web Code: cba-2050
Students’ paragraphs will vary. All should include
mention of population density; carrying capacity;
types of growth; and limiting factors, both densitydependent and density-independent. Students
should also describe changes in the human population, drawing upon the text and figures in Section
5–3 for support for their descriptions. Using data in
Figure 5–14, students should note that the projected population in 2050 is 9,078,850,714 and that
the growth rate in 2050 is projected to be 0.43 percent annually, compared with an average annual
growth rate of 1.23 percent in 2000.