Textbook: Population Change | AP Human Geography - Grade 9 PDF Download

 Page 1


75 CHAPTER 4: POPULATION CHANGE
Population Change
Topics 2.4–2.9
Topic 2.4 Population Dynamics
Learning Objective: Explain factors that account for contemporary and  historical 
trends in population growth and decline. (IMP-2.A)
Topic 2.5 The Demographic Transition Model
Learning Objective: Explain theories of population growth and decline. 
 (I M P - 2 . B)
Topic 2.6 Malthusian Theory
Learning Objective: Explain theories of population growth and decline. 
 (I M P - 2 . B)
Topic 2.7 Population Policies
Learning Objective: Explain the intent and effects of various population and im -
migrant policies on population size and composition. (SPS-2.A)
Topic 2.8 Women and Demographic Change
Learning Objective: Explain how the changing role of females has  demographic 
consequences in different parts of the world. (SPS-2.B)
Topic 2.9 Aging Populations
Learning Objective: Explain the causes and consequences of an aging 
 p opul a t ion . (S PS - 2 . C )
A ?nite world can support only a ?nite population; therefore, 
population growth must eventually equal zero.
—Garrett Hardin, “The Tragedy of the Commons,” 1968
Source: Getty Images
Educating women 
and children plays 
an important role in 
population dynamics. 
(See Topic 2.8 for the 
changing role of women.)
CHAPTER 4
Page 2


75 CHAPTER 4: POPULATION CHANGE
Population Change
Topics 2.4–2.9
Topic 2.4 Population Dynamics
Learning Objective: Explain factors that account for contemporary and  historical 
trends in population growth and decline. (IMP-2.A)
Topic 2.5 The Demographic Transition Model
Learning Objective: Explain theories of population growth and decline. 
 (I M P - 2 . B)
Topic 2.6 Malthusian Theory
Learning Objective: Explain theories of population growth and decline. 
 (I M P - 2 . B)
Topic 2.7 Population Policies
Learning Objective: Explain the intent and effects of various population and im -
migrant policies on population size and composition. (SPS-2.A)
Topic 2.8 Women and Demographic Change
Learning Objective: Explain how the changing role of females has  demographic 
consequences in different parts of the world. (SPS-2.B)
Topic 2.9 Aging Populations
Learning Objective: Explain the causes and consequences of an aging 
 p opul a t ion . (S PS - 2 . C )
A ?nite world can support only a ?nite population; therefore, 
population growth must eventually equal zero.
—Garrett Hardin, “The Tragedy of the Commons,” 1968
Source: Getty Images
Educating women 
and children plays 
an important role in 
population dynamics. 
(See Topic 2.8 for the 
changing role of women.)
CHAPTER 4
76 HUMAN GEOGRAPHY: AP
®
 EDITION
2.4
Population Dynamics
Essential Question: What are the factors that account for contemporary 
and historical trends in population growth and decline?
Before the 19
th
 century, the total human population grew very slowly. By 
making small improvements in farming techniques, clearing forested areas to 
expand land for crops, and finding new regions of the ocean dense in fish, 
people became more efficient at extracting energy from the environment. 
Around 1800, the population reached 1 billion. In the 200-plus years since 
then, world population has exploded—it is around 7.4 billion today. The United 
Nations predicts it will reach nearly 11 billion by 2100. What problems—and 
what opportunities—will this growth present? 
WORLD POPULATION GROWTH SINCE 1760
1760 1780 1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100
11
10
9
8
7
6
5
4
3
2
1
0
2.5%
2.0%
1.5%
1.0%
0.5%
0.0%
Annual growth rate of the world population
(See scale on the right.)
World population in billions
(See scale on the left.)
0.9 Billion
1.65 Billion
3 Billion
4.4 Billion
7.4 Billion
9.2 Billion
10.2 Billion
10.8 Billion
11.2 Billion
WORLD POPULATION GROWTH SINCE 1760
Source: Population projections come from “World Population Prospects: The 2015 Revision, ” UN Department of 
 Economic and Social Affairs, 2015.
Compare the relationship between the population growth rate and the total population. What does the line 
representing the total population do when the growth rate line spikes? What is the relationship between the 
two dotted (predicted) lines after 2060?
Page 3


75 CHAPTER 4: POPULATION CHANGE
Population Change
Topics 2.4–2.9
Topic 2.4 Population Dynamics
Learning Objective: Explain factors that account for contemporary and  historical 
trends in population growth and decline. (IMP-2.A)
Topic 2.5 The Demographic Transition Model
Learning Objective: Explain theories of population growth and decline. 
 (I M P - 2 . B)
Topic 2.6 Malthusian Theory
Learning Objective: Explain theories of population growth and decline. 
 (I M P - 2 . B)
Topic 2.7 Population Policies
Learning Objective: Explain the intent and effects of various population and im -
migrant policies on population size and composition. (SPS-2.A)
Topic 2.8 Women and Demographic Change
Learning Objective: Explain how the changing role of females has  demographic 
consequences in different parts of the world. (SPS-2.B)
Topic 2.9 Aging Populations
Learning Objective: Explain the causes and consequences of an aging 
 p opul a t ion . (S PS - 2 . C )
A ?nite world can support only a ?nite population; therefore, 
population growth must eventually equal zero.
—Garrett Hardin, “The Tragedy of the Commons,” 1968
Source: Getty Images
Educating women 
and children plays 
an important role in 
population dynamics. 
(See Topic 2.8 for the 
changing role of women.)
CHAPTER 4
76 HUMAN GEOGRAPHY: AP
®
 EDITION
2.4
Population Dynamics
Essential Question: What are the factors that account for contemporary 
and historical trends in population growth and decline?
Before the 19
th
 century, the total human population grew very slowly. By 
making small improvements in farming techniques, clearing forested areas to 
expand land for crops, and finding new regions of the ocean dense in fish, 
people became more efficient at extracting energy from the environment. 
Around 1800, the population reached 1 billion. In the 200-plus years since 
then, world population has exploded—it is around 7.4 billion today. The United 
Nations predicts it will reach nearly 11 billion by 2100. What problems—and 
what opportunities—will this growth present? 
WORLD POPULATION GROWTH SINCE 1760
1760 1780 1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100
11
10
9
8
7
6
5
4
3
2
1
0
2.5%
2.0%
1.5%
1.0%
0.5%
0.0%
Annual growth rate of the world population
(See scale on the right.)
World population in billions
(See scale on the left.)
0.9 Billion
1.65 Billion
3 Billion
4.4 Billion
7.4 Billion
9.2 Billion
10.2 Billion
10.8 Billion
11.2 Billion
WORLD POPULATION GROWTH SINCE 1760
Source: Population projections come from “World Population Prospects: The 2015 Revision, ” UN Department of 
 Economic and Social Affairs, 2015.
Compare the relationship between the population growth rate and the total population. What does the line 
representing the total population do when the growth rate line spikes? What is the relationship between the 
two dotted (predicted) lines after 2060?
77 2.4: POPULATION DYNAMICS
Population Change
Populations always change—sometimes they shrink, but more often than not, 
they grow. For example, the population of the United States has grown steadily 
since the first census was taken in 1790.
UNITED STATES POPULATION GROWTH 
Year Population  
(in millions)
1790 3.9
1900 76.2
2020 332.6
Prior to 1910, U.S. population grew 20 percent to 40 percent per decade, even during the 1860s, which 
included the American Civil War. Since 1980, it has increased 7 percent to 14 percent per decade. 
Measuring and predicting population change over time is key to 
understanding the world. Geographers use a simple equation, the demographic 
balancing equation, to describe the future population of a region of any scale: 
Future population = Current population + (number of births – number of deaths) + 
(number of immigrants – number of emigrants)
Figuring the demographic balancing equation takes several variables into 
account. The number of births and deaths are only part of a country’s total 
population change. Migration also plays a part. To calculate a country’s total 
population change, the number of immigrants—people who moved into 
the country—and the number of emigrants—people who moved out of the 
country—must be added to the equation.
The challenge for geographers is to understand and predict births, deaths, 
immigration, and emigration accurately. This chapter and the next will examine 
the concepts associated with population change and explore the ways that 
geographers use them to understand human populations. 
Measuring the Number of Births
Geographers commonly use two different statistics to describe the rate at which 
children are born:
• The crude birth rate (CBR) is the number of live births per year for each 
1,000 people.
• In contrast, the total fertility rate (TFR) focuses on women in their 
childbearing years of ages 15 to 49. TFR is the average number of children 
who would be born per woman of that group in a country, assuming 
every woman lived through her childbearing years.
Of the two statistics, the TFR more accurately reflects cultural norms—
such as how people weigh the costs and benefits of having a child and how 
people perceive the role of women in society. The CBR is simpler to calculate 
and clearly relects the total population change within a country.
Page 4


75 CHAPTER 4: POPULATION CHANGE
Population Change
Topics 2.4–2.9
Topic 2.4 Population Dynamics
Learning Objective: Explain factors that account for contemporary and  historical 
trends in population growth and decline. (IMP-2.A)
Topic 2.5 The Demographic Transition Model
Learning Objective: Explain theories of population growth and decline. 
 (I M P - 2 . B)
Topic 2.6 Malthusian Theory
Learning Objective: Explain theories of population growth and decline. 
 (I M P - 2 . B)
Topic 2.7 Population Policies
Learning Objective: Explain the intent and effects of various population and im -
migrant policies on population size and composition. (SPS-2.A)
Topic 2.8 Women and Demographic Change
Learning Objective: Explain how the changing role of females has  demographic 
consequences in different parts of the world. (SPS-2.B)
Topic 2.9 Aging Populations
Learning Objective: Explain the causes and consequences of an aging 
 p opul a t ion . (S PS - 2 . C )
A ?nite world can support only a ?nite population; therefore, 
population growth must eventually equal zero.
—Garrett Hardin, “The Tragedy of the Commons,” 1968
Source: Getty Images
Educating women 
and children plays 
an important role in 
population dynamics. 
(See Topic 2.8 for the 
changing role of women.)
CHAPTER 4
76 HUMAN GEOGRAPHY: AP
®
 EDITION
2.4
Population Dynamics
Essential Question: What are the factors that account for contemporary 
and historical trends in population growth and decline?
Before the 19
th
 century, the total human population grew very slowly. By 
making small improvements in farming techniques, clearing forested areas to 
expand land for crops, and finding new regions of the ocean dense in fish, 
people became more efficient at extracting energy from the environment. 
Around 1800, the population reached 1 billion. In the 200-plus years since 
then, world population has exploded—it is around 7.4 billion today. The United 
Nations predicts it will reach nearly 11 billion by 2100. What problems—and 
what opportunities—will this growth present? 
WORLD POPULATION GROWTH SINCE 1760
1760 1780 1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100
11
10
9
8
7
6
5
4
3
2
1
0
2.5%
2.0%
1.5%
1.0%
0.5%
0.0%
Annual growth rate of the world population
(See scale on the right.)
World population in billions
(See scale on the left.)
0.9 Billion
1.65 Billion
3 Billion
4.4 Billion
7.4 Billion
9.2 Billion
10.2 Billion
10.8 Billion
11.2 Billion
WORLD POPULATION GROWTH SINCE 1760
Source: Population projections come from “World Population Prospects: The 2015 Revision, ” UN Department of 
 Economic and Social Affairs, 2015.
Compare the relationship between the population growth rate and the total population. What does the line 
representing the total population do when the growth rate line spikes? What is the relationship between the 
two dotted (predicted) lines after 2060?
77 2.4: POPULATION DYNAMICS
Population Change
Populations always change—sometimes they shrink, but more often than not, 
they grow. For example, the population of the United States has grown steadily 
since the first census was taken in 1790.
UNITED STATES POPULATION GROWTH 
Year Population  
(in millions)
1790 3.9
1900 76.2
2020 332.6
Prior to 1910, U.S. population grew 20 percent to 40 percent per decade, even during the 1860s, which 
included the American Civil War. Since 1980, it has increased 7 percent to 14 percent per decade. 
Measuring and predicting population change over time is key to 
understanding the world. Geographers use a simple equation, the demographic 
balancing equation, to describe the future population of a region of any scale: 
Future population = Current population + (number of births – number of deaths) + 
(number of immigrants – number of emigrants)
Figuring the demographic balancing equation takes several variables into 
account. The number of births and deaths are only part of a country’s total 
population change. Migration also plays a part. To calculate a country’s total 
population change, the number of immigrants—people who moved into 
the country—and the number of emigrants—people who moved out of the 
country—must be added to the equation.
The challenge for geographers is to understand and predict births, deaths, 
immigration, and emigration accurately. This chapter and the next will examine 
the concepts associated with population change and explore the ways that 
geographers use them to understand human populations. 
Measuring the Number of Births
Geographers commonly use two different statistics to describe the rate at which 
children are born:
• The crude birth rate (CBR) is the number of live births per year for each 
1,000 people.
• In contrast, the total fertility rate (TFR) focuses on women in their 
childbearing years of ages 15 to 49. TFR is the average number of children 
who would be born per woman of that group in a country, assuming 
every woman lived through her childbearing years.
Of the two statistics, the TFR more accurately reflects cultural norms—
such as how people weigh the costs and benefits of having a child and how 
people perceive the role of women in society. The CBR is simpler to calculate 
and clearly relects the total population change within a country.
78 HUMAN GEOGRAPHY: AP
®
 EDITION
TOTAL FERTILITY RATES
6–8
2–4
4–6
0–2
Number of Births
per Woman in
Child-Bearing Years
TOTAL FERTILITY RATES
The total fertility rates (TFR) vary widely among different regions of the world. TFR varies among 
countries and it generally declines as countries become wealthier.
In most of the world, the TFR was higher in the past than it is today. In 
parts of Europe before 1800, the TFR averaged 6.2 children. In those days, most 
people lived on farms and having more children meant more people to work 
the land. However, because so many children died as infants, the average life 
span was only about 40 years. Despite the high TFR, population growth was 
slow.
Life Expectancy
Even though the total fertility rate worldwide has been decreasing, the world’s 
population continues to grow. This growth reflects a decrease in the death rate 
and an increase in how long people live.
Global Population Increase
The most important factor in the increase in global population is the rise in life 
expectancy, the average number of years people live. It is commonly expressed 
from the time of a person’s birth, but it can be calculated at any point in his 
or her lifetime. A century ago, the global life expectancy was about 34 years 
at birth; today it is nearly 70 years. In most of Europe, life expectancy at birth 
is more than 80 years. However, in less-developed areas, such as many sub-
Saharan African countries, life expectancy at birth is less than 50 years. 
One of the most important factors that affects increasing life expectancy is 
the drop in the infant mortality rate, the number of children who die before 
their first birthday. For example, in Massachusetts, the infant mortality rate per 
1,000 live births dropped from 130 in 1850, to about 4 today.
Page 5


75 CHAPTER 4: POPULATION CHANGE
Population Change
Topics 2.4–2.9
Topic 2.4 Population Dynamics
Learning Objective: Explain factors that account for contemporary and  historical 
trends in population growth and decline. (IMP-2.A)
Topic 2.5 The Demographic Transition Model
Learning Objective: Explain theories of population growth and decline. 
 (I M P - 2 . B)
Topic 2.6 Malthusian Theory
Learning Objective: Explain theories of population growth and decline. 
 (I M P - 2 . B)
Topic 2.7 Population Policies
Learning Objective: Explain the intent and effects of various population and im -
migrant policies on population size and composition. (SPS-2.A)
Topic 2.8 Women and Demographic Change
Learning Objective: Explain how the changing role of females has  demographic 
consequences in different parts of the world. (SPS-2.B)
Topic 2.9 Aging Populations
Learning Objective: Explain the causes and consequences of an aging 
 p opul a t ion . (S PS - 2 . C )
A ?nite world can support only a ?nite population; therefore, 
population growth must eventually equal zero.
—Garrett Hardin, “The Tragedy of the Commons,” 1968
Source: Getty Images
Educating women 
and children plays 
an important role in 
population dynamics. 
(See Topic 2.8 for the 
changing role of women.)
CHAPTER 4
76 HUMAN GEOGRAPHY: AP
®
 EDITION
2.4
Population Dynamics
Essential Question: What are the factors that account for contemporary 
and historical trends in population growth and decline?
Before the 19
th
 century, the total human population grew very slowly. By 
making small improvements in farming techniques, clearing forested areas to 
expand land for crops, and finding new regions of the ocean dense in fish, 
people became more efficient at extracting energy from the environment. 
Around 1800, the population reached 1 billion. In the 200-plus years since 
then, world population has exploded—it is around 7.4 billion today. The United 
Nations predicts it will reach nearly 11 billion by 2100. What problems—and 
what opportunities—will this growth present? 
WORLD POPULATION GROWTH SINCE 1760
1760 1780 1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100
11
10
9
8
7
6
5
4
3
2
1
0
2.5%
2.0%
1.5%
1.0%
0.5%
0.0%
Annual growth rate of the world population
(See scale on the right.)
World population in billions
(See scale on the left.)
0.9 Billion
1.65 Billion
3 Billion
4.4 Billion
7.4 Billion
9.2 Billion
10.2 Billion
10.8 Billion
11.2 Billion
WORLD POPULATION GROWTH SINCE 1760
Source: Population projections come from “World Population Prospects: The 2015 Revision, ” UN Department of 
 Economic and Social Affairs, 2015.
Compare the relationship between the population growth rate and the total population. What does the line 
representing the total population do when the growth rate line spikes? What is the relationship between the 
two dotted (predicted) lines after 2060?
77 2.4: POPULATION DYNAMICS
Population Change
Populations always change—sometimes they shrink, but more often than not, 
they grow. For example, the population of the United States has grown steadily 
since the first census was taken in 1790.
UNITED STATES POPULATION GROWTH 
Year Population  
(in millions)
1790 3.9
1900 76.2
2020 332.6
Prior to 1910, U.S. population grew 20 percent to 40 percent per decade, even during the 1860s, which 
included the American Civil War. Since 1980, it has increased 7 percent to 14 percent per decade. 
Measuring and predicting population change over time is key to 
understanding the world. Geographers use a simple equation, the demographic 
balancing equation, to describe the future population of a region of any scale: 
Future population = Current population + (number of births – number of deaths) + 
(number of immigrants – number of emigrants)
Figuring the demographic balancing equation takes several variables into 
account. The number of births and deaths are only part of a country’s total 
population change. Migration also plays a part. To calculate a country’s total 
population change, the number of immigrants—people who moved into 
the country—and the number of emigrants—people who moved out of the 
country—must be added to the equation.
The challenge for geographers is to understand and predict births, deaths, 
immigration, and emigration accurately. This chapter and the next will examine 
the concepts associated with population change and explore the ways that 
geographers use them to understand human populations. 
Measuring the Number of Births
Geographers commonly use two different statistics to describe the rate at which 
children are born:
• The crude birth rate (CBR) is the number of live births per year for each 
1,000 people.
• In contrast, the total fertility rate (TFR) focuses on women in their 
childbearing years of ages 15 to 49. TFR is the average number of children 
who would be born per woman of that group in a country, assuming 
every woman lived through her childbearing years.
Of the two statistics, the TFR more accurately reflects cultural norms—
such as how people weigh the costs and benefits of having a child and how 
people perceive the role of women in society. The CBR is simpler to calculate 
and clearly relects the total population change within a country.
78 HUMAN GEOGRAPHY: AP
®
 EDITION
TOTAL FERTILITY RATES
6–8
2–4
4–6
0–2
Number of Births
per Woman in
Child-Bearing Years
TOTAL FERTILITY RATES
The total fertility rates (TFR) vary widely among different regions of the world. TFR varies among 
countries and it generally declines as countries become wealthier.
In most of the world, the TFR was higher in the past than it is today. In 
parts of Europe before 1800, the TFR averaged 6.2 children. In those days, most 
people lived on farms and having more children meant more people to work 
the land. However, because so many children died as infants, the average life 
span was only about 40 years. Despite the high TFR, population growth was 
slow.
Life Expectancy
Even though the total fertility rate worldwide has been decreasing, the world’s 
population continues to grow. This growth reflects a decrease in the death rate 
and an increase in how long people live.
Global Population Increase
The most important factor in the increase in global population is the rise in life 
expectancy, the average number of years people live. It is commonly expressed 
from the time of a person’s birth, but it can be calculated at any point in his 
or her lifetime. A century ago, the global life expectancy was about 34 years 
at birth; today it is nearly 70 years. In most of Europe, life expectancy at birth 
is more than 80 years. However, in less-developed areas, such as many sub-
Saharan African countries, life expectancy at birth is less than 50 years. 
One of the most important factors that affects increasing life expectancy is 
the drop in the infant mortality rate, the number of children who die before 
their first birthday. For example, in Massachusetts, the infant mortality rate per 
1,000 live births dropped from 130 in 1850, to about 4 today.
79 2.4: POPULATION DYNAMICS
LIFE EXPECTANCY BY COUNTRY, 2015
Over 74
69–74
64–69
Under 64
No data
Life Expectancy 
in Years
LIFE EXPECTANCY BY COUNTRY, 2015
What regions of the world have the highest and lowest life expectancies? What is the scale of analysis used 
on the map? Note: Some regions on the map have no data because of political instability. 
The decrease in infant mortality rate and increase in life expectancy can 
be explained by economic, political, and technological changes. Economic 
development has increased wealth and increased the amount and quality of 
food available to millions of people. Political stability has allowed for improved 
sanitation infrastructure, and advances in technology have greatly improved 
healthcare. 
Better Food Production and Nutrition
Over the past 250 years, several advances in agriculture have helped increase 
life expectancy:
• mechanizing food production, such as replacing horses with tractors
• improving seeds, fertilizers, and farming techniques through research by 
state universities and private companies
• transporting products more efficiently in trucks, trains, and ships, often 
on roads, rail lines, or canals built with government support
In the United States in 1800, most of the population farmed. T oday farmers 
make up less than 3 percent of the population, yet they produce enough food to 
feed everyone in the country and export vast quantities. Advances in agriculture 
such as the following had effects that rippled through society:
• Greater farming efficiency freed people to work in nonfarm industries, 
easing the transition to industrialization.
• Food security improved around the world. Hunger and famines still 
occurred because people were too poor to purchase food or because of 
political issues or distribution problems, not because of food shortage.
• As farms depended less on manual labor, farm families became smaller.