The Human
Population
Big Idea
 The
size and growth rate of
human population has changed
drastically over the last 200
years. Those changes have led to
profound changes to almost
every place on Earth.
Questions to Ponder
 What
is the world’s population?
– http://www.census.gov/popclock/
– http://www.worldometers.info/worldpopulation/
 Do
the factors that affect other
populations affect humans as well?
– Why or why not?
JQ: If 2.4 humans are born every
second, then how many are born each
day?
207,360 people born each day
This is AFTER we factor in
deaths
over 75,000,000 people born each year
JQ: Which of the following graphs do you
think represents the world’s population
growth over the next few hundred years
(population in vs. time)? Explain.
-or-
Section 1: Studying Human
Populations
 Describe
how the size and growth rate for
human population has changed over
history
 What factors lead to population changes
 Analyze populations using Age Structure
Diagrams
 Define demographic transition
• Describe what you see on this graph
•How long did it take to get to 1 billion, than 2,
3,4,5,6
Did You Know? Basic sanitation was rare even in the medical profession
•How
many
people
are living discovered
today? that doctors’ hand
until
1861,
when Dr.
Ignaz Semmelweis
washing greatly reduced patient mortality.
•Why did it take so long to reach 1 billion?
•Why do you think it took off around the late 1880s?
Interesting Fact: Of all the humans ever born,
approximately 6-7% are alive today.
 Rapid
population growth has led to
serious environmental problems
Studying Human Populations
 Demography:
the
study of human
population
How many people live
where?
 How long are you
expected to live?
 How many children
are you likely to
have.

2 General Categories of
Populations

Developed Countries
– Higher average income
– Slower population
growth
– Diverse industrial
economies
– Stronger social
support systems

Developing Countries
– Lower average incomes
– Rapid population growth
– Simple, agriculturebased economies
Exponential Growth
Exponential Growth: rapid growth often seen
as J-Shaped curve on a graph
Is exponential growth sustainable?
Forecasting Population Size
Will new schools be
needed?
 Should we be
building more
housing?
 Should farming
practices be
improved?
 Predictions like this
often wrong because
human behavior
changes

POPULATION SIZE
http://www.worldometers.
info/world-population/
Forecasting Population Size
Age Structure: the
distribution of ages
in a population
 Age Structure
Diagrams aka
Population Pyramids
 What is useful about
these diagrams?

•What do age structure diagrams show?
•What are the “reproductive years”?
•Why is that important in forecasting future
population growth?
•Which “type” of countries are going to see
most of the population growth?
•Which “type” of countries do people live
longer lives?
Population Age Structure
Male
Female
Rapid Growth
Guatemala
Nigeria
Saudi Arabia
Ages 0-14
Slow Growth
United States
Australia
Canada
Ages 15-44
Zero Growth
Spain
Austria
Greece
Negative Growth
Germany
Bulgaria
Sweden
Ages 45-85+
Fig. 10-14 p. 184
Forecasting Population Size
•Survivorship: percent of population likely to
survive to any given age
•Survivorship Curves – show how much of
the population survives for a given age
•Type I
•Wealthy, developed countries
•Most people live to be very old
•Type II
•Similar death rates at all ages
•Type III
•Very poor, undeveloped countries
•Many children die
PROJECTED WORLD POPULATIONS
What causes population to rise?
Population
Changes =
(births + immigration) – (deaths + emigration)
For world population growth we are only
concerned about births and deaths.
Many developed countries would have
negative population growth without
immigration.
Population
Change = (births + immigration) – (deaths + emigration)

Migration:
movement INTO
(immigration) or OUT
of (emigration) an
area
U.S. growth
continues
because of both
births and
immigration
Population
Change = (births + immigration) – (deaths + emigration)
 Death
rates on the
decline… people
living longer
 Why?
Better hygiene,
sewage disposal,
clean water,
medicines,
education, access to
food, nutrition
Life Expectancy
 Life
Expectancy:
average number of
years members of
a population are
expected to live
 Improvement in
most of world
 Lower INFANT
MORTALITY
Compared to our neighbors
Major changes in U.S. over last 100+ years
Fertility Rates
 Fertility
Rate:
number of
children born
each year per
1,000 women
 Total fertility
rate (lifetime)
 Replacement
level
•
What does this graph show?
•Total Fertility Rate – average number of births in one woman’s
lifetime
• How have U.S. fertility rates changed?
Fertility and Women
Two main factors
impact fertility rates
worldwide
 Education level of
women (knowledge of
family planning)
 Economic level of
women
 Generally:

more education = more wealth = lower fertility rates
Rule of 70: Doubling Time


Currently, a city has a population of 10 million.
If the population is growing at 10%, when will
it reach 20 million?
(70/rate = doubling time)
What is the growth rate if the population
increases from 200 million to 400 million in 14
years ?
(70/doubling time = rate)
Section 1 Review
Describe how the size and growth rate for
human population has changed over
history
 What factors lead to population changes
 Analyze populations using Age Structure
Diagrams
 Terms: Demography, Age Structure,
Fertility, Migration, Life Expectancy

China’s One-Child Policy
•
•
•
In 1970, the average Chinese woman had
about six children.
Since 1979, China has used a system of
rewards and punishments to enforce a
one-child limit to slow population growth.
In 2005, there were 32 million more males
than females in China under the age of 20
Talk About It Is it ethical for
governments to limit or
encourage human population
growth?
Diverse World Population
Developed Countries
US, Canada, Japan,
Australia, New
Zealand and most of
Europe. High Per
Capita GDP. (1.2
billion people)
Comparing a Developed Country
to a
Moderately Developed
to a
Developing (Least Developed)
Diverse World Population
 Developing
(lesser
developed)
 5.2 billion people
 living with very little
 97% of population
growth
Percent of
World’s
19
Population
81
Population
growth
0.1
1.6
85
Wealth and
income
Resource
use
15
88
12
75
Pollution
and waste
25
Developed
countries
Developing
countries
World Growth Rates
Strategies for Controlling Growth
 Public
Advertisements
 Economic
Incentives
 Legal Punishments
 Empowering
Women
 Investments in
Education and
Family Planning
Worldwide fertility rates are dropping
Growth Is Slowing but still growing
Medium growth rate – fertility rates decline to replacement level by 2050
Section 2 Review
 How
do developed and developing
(less developed) countries compare?
 What are some strategies for
reducing population growth?