Name ______________________________ Class __________________ Date __________________
Exploration Lab
MODELING
Modeling Population Changes
Population projections are important to leaders and scientists, in order to plan for
the future needs of the population. Consider the following scenarios:
Schools: The local Department of Education must determine the need for a new
school in the next five to 10 years. What type of information will they need to
make this decision?
Infrastructure: City planners are responsible for making sure the city has
enough roadways, water, sewers, and utilities. How will they know whether too
many people will strain these resources in the next five to 10 years?
Healthcare: A local hospital manages the healthcare facilities for several towns.
Where will a new center be needed the most in the next five to 10 years?
Environment: Environmentalists work to make sure that the habitat for wildlife
in an area is not destroyed. If more people move there, the forest will be cut down
to build new homes. How will they know if this will be a problem in the next five
to 10 years?
In this exercise, you will be asked to simulate and make projections about the
population growth of the United States. With these projections, you will be able to
evaluate the results of different possible scenarios and interpret these changes.
OBJECTIVES
Evaluate the utility of population projections.
Organize information about modeling population change.
Analyze information about population projections and population growth change.
Describe different scenarios of population projections.
MATERIALS
• colored pencils (4 colors)
• graph paper
Procedure
PART I—SHORT-TERM PROJECTION
1. Review the components of population change described in your textbook.
a. What is the natural way a population grows?
_______________________________________________________________
b. What is the natural way a population declines?
_______________________________________________________________
c. What else causes a population to change size?
_______________________________________________________________
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
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The Human Population
Name ______________________________ Class __________________ Date __________________
Modeling Population Changes continued
d. Write an equation for population change using the components listed above.
_______________________________________________________________
2. To predict the future size of a population, you need to know the current
population size along with some assumptions about the components of change.
a. How can you find out the current population size?
_______________________________________________________________
b. What factors are used to predict future population change?
_______________________________________________________________
_______________________________________________________________
3. In this simulation, the approximate number of births, deaths, and migrants to
the United States has been provided for the period from 2000 to 2005. Using a
calculator, complete the table to predict the population size in the United
States for 2005.
UNITED STATES POPULATION CHANGE FROM 2000–2005
2000 Total Population
Population Change from 2000– 2005 Total Population
(thousands)
2005 (thousands)
(thousands)
Age
Population +Births –Deaths +Migrants
Age
Population
19,000
3
130
0-4
0-4
18,800
2
260
5-9
5-9
19,700
1
340
10-14
10-14
19,900
1
570
15-19
15-19
19,800
2
660
20-24
20-24
18,500
2
690
25-29
25-29
17,800
2
680
30-34
30-34
19,500
3
460
35-39
35-39
22,200
4
330
40-44
40-44
22,600
6
230
45-49
45-49
19,900
8
160
50-54
50-54
7,200
10
120
55-59
55-59
13,300
20
110
60-64
60-64
10,600
30
90
65-69
65-69
9,400
40
50
70-74
70-74
8,700
60
20
75-79
75-79
7,400
70
15
80-84
80-84
4,900
80
5
85-89
85+
4,300
150
1
90+
Total(th
Total(th
ousand
ousands
s)
)
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Environmental Science
29
The Human Population
Name ______________________________ Class __________________ Date __________________
Modeling Population Changes continued
PART II—LONG-TERM PROJECTION
4. Because the assumptions about fertility, mortality, and migration are based in
part on human behavior, predictions made by demographers are not always
accurate. The level of uncertainty increases as the time period of the projection
increases. For this reason, demographers use different scenarios that reflect
variations in assumptions made about fertility, mortality, and migration.
Examine the different scenarios of change for United States population growth
shown in the figure below.
POSSIBLE COMPONENTS OF CHANGE OF U.S. POPULATION 2000–2100
5. Which graph in the figure above would result in the greatest increase in
population by the year 2100? the least increase?
_______________________________________________________________
_______________________________________________________________
Analysis
1. Organizing Data What was the total change projected in the U.S. population
from 2000 to 2005?
_______________________________________________________________
_______________________________________________________________
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Environmental Science
30
The Human Population
Name ______________________________ Class __________________ Date __________________
Modeling Population Changes continued
2. Organizing Data Which age group in 2000 had the greatest percentage increase
by 2005?
3. Constructing Graphs Using the four possible scenarios of change shown in the
figure, create a graph on a separate sheet of paper that shows the four resulting
projections of population change in the United States from 2000 to 2100. Use
a different color pencil for each scenario. Use the total population for 2000
that you calculated in the table as a starting population.
CONCLUSIONS
4. Analyzing Graphs What is the difference in the projected population of the
United States in 2100 between the highest projection and the lowest
projection? in 2060?
_______________________________________________________________
_______________________________________________________________
5. Drawing Conclusions Explain why the difference in population projections
increases over longer projection periods.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
Extension
1. Research and Communications Use information from the U.S. Census
Bureau’s International Data Base, available on the Internet or at your local
library, to examine population projections for other countries or regions.
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Environmental Science
31
The Human Population
TEACHER RESOURCE PAGE
Exploration Lab
MODELING
Modeling Population Changes
Teacher Notes
TIME REQUIRED One 45-minute class period
SKILLS ACQUIRED
Classifying
Collecting data
Constructing models
Identifying/recognizing patterns
Interpreting
Predicting
RATING
Teacher Prep–2
Student Set-Up–2
Concept Level–1
Clean Up–1
THE SCIENTIFIC METHOD
Make Observations Procedure, step 5
Analyze the Results Analysis, questions 1–3
Draw Conclusions Procedure, steps 1–4; Conclusions, questions 4 and 5
MATERIALS
The materials on the student page are enough for a group of no more than five
students.
TIPS AND TRICKS
Countries can be assigned randomly to students. Review the components of
population change.
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Environmental Science
64
The Human Population
TEACHER RESOURCE PAGE
Name ______________________________ Class ___________________ Date __________________
Exploration Lab
MODELING
Modeling Population Changes
Population projections are important to leaders and scientists, in order to plan for
the future needs of the population. Consider the following scenarios:
Schools: The local Department of Education must determine the need for a new
school in the next five to 10 years. What type of information will they need to
make this decision?
Infrastructure: City planners are responsible for making sure the city has
enough roadways, water, sewers, and utilities. How will they know whether too
many people will strain these resources in the next five to 10 years?
Healthcare: A local hospital manages the healthcare facilities for several towns.
Where will a new center be needed the most in the next five to 10 years?
Environment: Environmentalists work to make sure that the habitat for wildlife
in an area is not destroyed. If more people move there, the forest will be cut down
to build new homes. How will they know if this will be a problem in the next five
to 10 years?
In this exercise, you will be asked to simulate and make projections about the
population growth of the United States. With these projections, you will be able to
evaluate the results of different possible scenarios and interpret these changes.
OBJECTIVES
Evaluate the utility of population projections.
Organize information about modeling population change.
Analyze information about population projections and population growth change.
Describe different scenarios of population projections.
MATERIALS
• colored pencils (4 colors)
• graph paper
Procedure
PART I—SHORT-TERM PROJECTION
1. Review the components of population change described in your textbook.
a. What is the natural way a population grows?
through births________________________________________________________
b. What is the natural way a population declines?
through deaths_______________________________________________________
c. What else causes a population to change size?
migration____________________________________________________________
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Environmental Science
65
The Human Population
TEACHER RESOURCE PAGE
Name ______________________________ Class ___________________ Date __________________
Modeling Population Changes continued
d. Write an equation for population change using the components listed above.
(births deaths) (immigrants emigrants) growth (or decline)_________________
2. To predict the future size of a population, you need to know the current
population size along with some assumptions about the components of change.
a. How can you find out the current population size?
from census and survey data____________________________________________
b. What factors are used to predict future population change?
total fertility rate, life expectancy or survivorship curves, and migration_______
patterns_____________________________________________________________
3. In this simulation, the approximate number of births, deaths, and migrants to
the United States has been provided for the period from 2000 to 2005. Using a
calculator, complete the table to predict the population size in the United
States for 2005.
UNITED STATES POPULATION CHANGE FROM 2000–2005
2000 Total Population
Population Change from 2000– 2005 Total Population
(thousands)
2005 (thousands)
(thousands)
Age
Population
+Births –Deaths +Migrants
Age
Population
19,000
3
130
0-4
19,127
0-4
18,800
2
260
5-9
19,058
5-9
19,700
1
340
10-14
20,039
10-14
19,900
1
570
15-19
20,469
15-19
19,800
2
660
20-24
20,458
20-24
18,500
2
690
25-29
19,188
25-29
17,800
2
680
30-34
18,478
30-34
19,500
3
460
35-39
19,957
35-39
22,200
4
330
40-44
22,526
40-44
22,600
6
230
45-49
22,824
45-49
19,900
8
160
50-54
20,052
50-54
7,200
10
120
55-59
17,310
55-59
13,300
20
110
60-64
13,390
60-64
10,600
30
90
65-69
10,660
65-69
9,400
40
50
70-74
9,410
70-74
8,700
60
20
75-79
8,660
75-79
7,400
70
15
80-84
7,345
80-84
4,900
80
5
85-89
4,825
85+
4,300
150
1
90+
4,151
Total(th
264,500
19,000
494
4,921
Total(th
297,927
ousand
ousands
s)
)
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Environmental Science
66
The Human Population
TEACHER RESOURCE PAGE
Name ______________________________ Class ___________________ Date __________________
Modeling Population Changes continued
PART II—LONG-TERM PROJECTION
4. Because the assumptions about fertility, mortality, and migration are based in
part on human behavior, predictions made by demographers are not always
accurate. The level of uncertainty increases as the time period of the projection
increases. For this reason, demographers use different scenarios that reflect
variations in assumptions made about fertility, mortality, and migration.
Examine the different scenarios of change for United States population growth
shown in the figure below.
POSSIBLE COMPONENTS OF CHANGE OF U.S. POPULATION 2000–2100
5. Which graph in the figure above would result in the greatest increase in
population by the year 2100? the least increase?
Conditions shown in Graph C would result in the greatest population increase._
Conditions in Graph B would produce the least increase (slight decrease).______
Analysis
1. Organizing Data What was the total change projected in the U.S. population
from 2000 to 2005?
Using the data from the table, the population in 2005 was projected to increase _
8.5% over the population in 2000.________________________________________
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Environmental Science
67
The Human Population
TEACHER RESOURCE PAGE
Name ______________________________ Class ___________________ Date __________________
Modeling Population Changes continued
2. Organizing Data Which age group in 2000 had the greatest percentage increase
by 2005?
The 25–29 year olds in 2000 increased 3.8% by 2005, when they became 30–34__
year olds.____________________________________________________________
3. Constructing Graphs Using the four possible scenarios of change shown in the
figure, create a graph on a separate sheet of paper that shows the four resulting
projections of population change in the United States from 2000 to 2100. Use
a different color pencil for each scenario. Use the total population for 2000
that you calculated in the table as a starting population.
Conclusions
4. Analyzing Graphs What is the difference in the projected population of the
United States in 2100 between the highest projection and the lowest
projection? in 2060?
The projections using graphs C and B differed by about 900 million people in___
2100; and by about 300 million people in 2060._____________________________
5. Drawing Conclusions Explain why the difference in population projections
increases over longer projection periods.
As more time passes, the uncertainty of predictions about the components of___
population change increases, causing greater differences in the resulting_______
projections.__________________________________________________________
____________________________________________________________________
Extension
1. Research and Communications Use information from the U.S. Census
Bureau’s International Data Base, available on the Internet or at your local
library, to examine population projections for other countries or regions.
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Environmental Science
68
The Human Population