### Chapter 2: Population

```Chapter 2: Population
Key Issue 2: Why Do Populations
Rise & Fall in Particular Places?
AP Human Geography is not just another class…
It is a matter of
LIFE and DEATH!
Key Issue Overview
• Introduction
• Natural Increase
–
–
–
–
Crude Birth Rate (CBR)
Crude Death Rate (CDR)
Natural Increase Rate (NIR)
Doubling Time
• Fertility
– Total Fertility Rate (TFR)
• Mortality
– Infant Mortality Rate (IMR)
– Life Expectancy
Measuring Population Change
Demographic Balancing Equation
Population change = (Births -Deaths)
+(Immigrants -Emigrants)
Or using the common notation, it can be
expressed: Pt -P0 = (B -D) + (I-E)
Where: P0 is the initial population and Pt is the
population after time t
Measuring Population Change
Natural Increase
• In this chapter, we will just be looking at births
and deaths.
• This is called the ‘Natural Increase’.
• We will bring migration into the equation in
Chapter 3.
WORLD POPULATION GROWTH
WORLD POPULATION GROWTH
•
•
Natural Increase Rate (NIR)
– Percentage by which a population grows in a year
– Only uses birth and death rates
– Immigration and emigration are excluded
Doubling time
– Number of years needed to double a population
Crude Birth Rate (CBR)
Total number of live births per year / 1,000 people in a society
•
Crude Death Rate (CDR)
– Total number of deaths per year / 1,000 people in a society
• Natural Increase Rate
• Percentage by which a population grows in a year
• NIR = (CBR – CDR) / 10
Components of Population Growth
– Natural Increase
• About 82 million people are added to the population of
the world annually.
• Rate of natural increase affects the doubling time–
number of years needed to double the population,
assuming a constant rate of natural increase.
– Twenty-First Century Rate (1.2 percent): 54 years
» Global population in 2100 would reach 24 billion.
– 1963 (2.2): 35 years
» Global population in 2010 would have been 10 billion
instead of nearly 7 billion.
• More than 95 percent of the natural increase is clustered in
developing countries.
Natural Increase Rate Example
United States (2010):
Population ≈ 308,745,538
Births ≈ 3,999,386
Deaths ≈ 2,437,163
-
CBR ≈
CDR ≈
CBR = #Births / (Total Population / 1000)
CBR = 3,999,386 / (308,745,538 / 1000)
CBR = 3,999,386 / 308,746
CBR = 13.0
Natural Increase Rate Example
United States (2010):
Population ≈ 308,745,538
Births ≈ 3,999,386
Deaths ≈ 2,437,163
-
CBR ≈ 13
CDR ≈
CDR = #Deaths / (Total Population / 1000)
CDR = 2,437,163 / (308,745,538 / 1000)
CDR = 2,437,163 / 308,746
CDR = 8
Natural Increase Rate Example
United States (2010):
Population ≈ 308,745,538
Births ≈ 3,999,386
Deaths ≈ 2,437,163
NIR = (CBR – CDR) / 10
NIR = (13 – 8) /10
NIR = 5/10
NIR = .5%
CBR ≈ 13
CDR ≈ 8
Doubling Times
The doubling time is the number of years before a
population will be twice as large as it is today.
Population
650000000
600000000
550000000
500000000
Population
450000000
400000000
350000000
1
8
15
22
29
36
43
50
57
64
71
78
85
92
99
106
113
120
127
134
300000000
Doubling Times
The doubling time
is the number of
years before a
population will be
twice as large as it
is today.
World = 50
U.S = 138
MDCs = 143
LDCs = 40
Africa = 27 years
Latin America = 38 years
Asia = 46 years
North America = 117 years
Europe = decreasing!
•
Total Fertility Rate (TFR)
– Average number of children a woman will have throughout her
childbearing years (ages 15-49)
• Behavior predictor
Total Fertility Rate
Palestinian
Territories
Total
Fertility Rate
• the average number of children a women
will have in her childbearing years (15-49
yrs. old).
1975-1980
7.39
1980-1985
7.00
1985-1990
6.43
1990-1995
6.46
1995-2000
5.99
• This rate varies from just over 1 (Japan,
Italy) to around 7 (Niger, Mali).
2000-2005
5.57
• The U.S. rate is 2.
1975-1980
1.72
1980-1985
1.80
• The global average is 2.5
1985-1990
1.81
1990-1995
1.78
• 2.1 is generally regarded as the
replacement rate (the rate at which a
population neither grows nor shrinks) in
the developed world.
1995-2000
1.70
2000-2005
1.66
• TFR exceeds 5 in sub-Saharan Africa,
while 2 or less in nearly all European
countries
U.K.
Africa
Total
Fertility Rate
Total
Fertility Rate
1975-1980
6.60
1980-1985
6.45
1985-1990
6.11
1990-1995
5.67
1995-2000
5.26
2000-2005
4.97
•
Infant Mortality Rate (IMR)
– Annual number of deaths of infants under 1 year of age, compared with total live
births
• IMR is 5 in developed countries and 80 in sub-Saharan Africa
•
Life expectancy
– Number of years a newborn infant can expect to live, assuming current mortality
levels
• Health care access and wealth indicator
Compare the following demographic
factors:
LDC (Least Developed Country)
•
•
•
•
•
•
Crude Birth Rate = high
Crude Death Rate = low
Infant Mortality Rate = high
Total Fertility Rate =high
Life Expectancy = low
Natural Increase Rate = high
MDC (Most Developed Country)
•
•
•
•
•
•
Crude Birth Rate = low
Crude Death Rate =low
Infant Mortality Rate = low
Total Fertility Rate = low
Life Expectancy = high
Natural Increase Rate = low
Population Pyramid
Population Pyramids = graphic device
that represents a population’s age and
sex composition.
Pyramid describes diagram’s shape
for many countries in 1800’s when
was created.
Population Pyramid Overview
• The most important demographic characteristic of a
population is its age-sex structure. Age-sex pyramids
(also known as population pyramids) graphically
display this information to improve understanding
and ease comparison.
• Age-sex pyramids display the percentage or actual
amount of a population broken down by gender and
age. The five-year age increments on the y-axis
allow the pyramid to vividly reflect long term trends
in the birth and death rates but also reflect shorter
term baby-booms, wars, and epidemics.
Population Pyramids
• The shape of a pyramid is primarily determined by the
crude death rate in the community.
• Dependency ratio-the number of people who are too
young or too old to work, compared to the number of
people in their productive years.
• People who are 0-14 and 65-plus normally are classified
as dependents.
• The “graying” of a population refers to the aging of a
community.
• Population pyramids also foretell future problems from
present population policies or practices. Ex. China’s
population policies skewed in favor of males.
Dependency ratio
• Number of people who are too young or too old
to work, compared to the number of people in
their productive years
• Indicates financial burden on a society’s
productive population
• Dependency Ratio = measure of # of dependents –
old and young that each 100 people in productive
years (15 – 64)
© 2013 Pearson Education, Inc.
Sex Ratio
• The number of males per hundred females in
the population is the sex ratio. In Europe and
North America the ratio of men to women is
• In poorer countries the high mortality rate
during childbirth partly explains the lower
percentage of women.
There are three key types
of population pyramids:
Rapid Growth:
This pyramid of
the Philippines
shows a triangleshaped pyramid
and reflects a
high growth rate
percent annually.
There are three key types
of population pyramids:
Slow Growth:
In the United States,
the population is
growing at a rate of
annually. This growth
rate is reflected in the
more square-like
structure of the
pyramid. Note the
lump in the pyramid
between the ages of
about 35 to 50.
In wealthy countries with very slow rate of
population growth – population is nearly equally
divided - so pyramids have
• Almost vertical sides.
• War can be reflected by showing depleted age
cohorts and male – female disparities.
• The % of a country’s population in each age group
strongly influences demand for goods and services
within that national economy.
• Country with high % of young has high demand for
educational facilities and health delivery services.
There are three key
types of population
pyramids:
Negative Growth:
Germany is
experiencing a period of
negative growth (0.1%). As negative
growth in a country
continues, the
population is reduced.
A population can shrink
due to a low birth rate
and a stable death rate.
Increased emigration
may also be a
contributor to a
declining population.
Population Pyramids in U.S. cities
```