Download Ch 09 Human Population, Factors affecting growth

Ch 09 Human Population,
Factors affecting growth
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A. HUMAN POPULATION GROWTH:
A BRIEF HISTORY
1. The human population has grown rapidly
because of the expansion of agriculture and
industrial production and lower death rates from
improvements in hygiene and medicine.
a) In 2006, the population of developed countries grew
exponentially at 0.1% per year.
b) Developing countries grew (15 times faster at 1.5%
per year.
c) No population, including humans, can continue to
grow indefinitely
2. We do not know how long we can continue
increasing the earth’s carrying capacity for
humans.
a) There are likely to be between 7.2-10.6 billion
people on earth by 2050.
b) 97% of growth in developing countries living in acute
poverty.
c) What is the optimum sustainable population of the
earth based on the cultural carrying capacity?
?
Black Death—the Plague
Time
Hunting and
Gathering
Agricultural revolution
Industrial
Revolution
Fig. 1-1, p. 6
Where Are We Headed?
3. U.N. world
population
projection based on
women having an
average of 2.5 (high),
2.0 (medium), or 1.5
(low) children.
Figure 9-2
B. FACTORS AFFECTING HUMAN POPULATION
SIZE
1. Population increases because of births and
immigration and decreases through deaths and
emigration.
2. Instead of using raw numbers, crude birth rates
and crude death rates are used (based on total
number of births or deaths per 1,000 people in a
population).
Average crude birth
rate
Average crude death
rate
21
World
9
All developed
countries
All developing
countries
Developing
countries
(w/o China)
11
10
23
8
27
9
Fig. 9-3, p. 174
38
Africa
15
Latin and
Central America
21
6
20
Asia
7
Oceania
17
7
United
States
North
America
Europe
14
8
14
8
10
11
Fig. 9-3, p. 174
a) The crude birth rate is the number of live
births per 1,000 people in a population in a
specific year
b) The crude death rate is the number of deaths
per 1,000 people in a population in a specific
year.
3. There are currently more births than
deaths throughout the world
a) The annual rate of natural population change
(%) = birth rate- death rate divided by 1,000
persons multiplied by 100
4. The rate of the world’s population growth has
decreased.
a) The annual population growth dropped by almost half
between 1963 and 2004, from 2.2% to 1.2%.
b) During this same period, the population base doubled
from 3.2 to 6.4 billion.
c) The six fastest growing countries in terms of
population are India, China, Pakistan, Nigeria,
Bangladesh, and Indonesia
5. The populations of China and India comprise
37% of the world’s population.
a) The next most populated country is the United Stated
with 4.5%
1.3 billion
1.5 billion
1.1 billion
1.4 billion
China
India
USA
Indonesia
Brazil
Pakistan
Bangladesh
Russia
Nigeria
Japan
300 million
349 million
225 million
264 million
187 million
229 million
166 million
229 million
147 million
190 million
142 million
130 million
135 million
199 million
128 million
121 million
2006
2025
Fig. 9-4, p. 174
6.
Declining Fertility Rates: Fewer Babies per Women
a) The average number of children that a woman bears
has dropped sharply.
b) This decline is not low enough to stabilize the
world’s population in the near future.
•
•
Replacement-level fertility: the number of children a
couple must bear to replace themselves.
Total fertility rate (TFR): the average number of children
a woman has during her reproductive years.
7. The replacement level to sustain a population is
2.0 children.
8. In 2006, the average global Total Fertility Rate
was 2.7 children per woman.
a) 1.6 in developed countries (down from 2.5 in 1950).
b) 3.0 in developing countries (down from 6.5 in
1950).
9. Fertility and Birth Rates in the
United States
a) Nearly 2.9 million people were added to
the U.S. in 2006:
– 59% occurred because of births
outnumbering deaths.
– 41% came from illegal and legal immigration.
Video: People Explosion
PLAY
VIDEO
 From ABC News, Human Biology in the Headlines, 2006 DVD.
10. From 1946-1964 the United States had a
sharp rise in birth rate, called the babyboom period
a) At its peak the TFR reached 3.7 children per
woman
b) In 2006, the total fertility rate in the United
States was slightly > 2.0
c) The population growth of the United States is
still greater than any other developed country
and is not close to leveling off
d) Other major developed countries have slower
population growth and most are expected to
have declining populations after 2010
11. The baby bust that followed the baby
boom was largely due to delayed
marriage, contraception, and abortion.
47 years
Life expectancy
77 years
8%
Married women working
outside the home
81%
15%
High school
graduates
83%
10%
Homes with
flush toilets
Homes with
electricity
Living in
suburbs
Hourly manufacturing job
wage (adjusted for
inflation)
Homicides per
100,000 people
98%
2%
99%
10%
52%
1900
$3
2000
$15
1.2
5.8
Fig. 9-7, p. 176
12. Factors Affecting Birth Rates and Fertility Rates
a) The number of children women have is affected
by:
– More children work in developing countries; they are
important to the labor force
– The cost of raising and educating them.
– If there are available private/public pension systems,
adults have fewer children because they don’t need
children to take care of them in old age
– People in urban areas usually have better access to
family planning
– If women have educational and economic choices,
they tend to have fewer children.
– Infant deaths, Marriage age, Availability of
contraception and abortion.
13. Factors Affecting Death Rates
a) Death rates have declined because of:
•
•
•
•
Increased food supplies, better nutrition.
Advances in medicine.
Improved sanitation and personal hygiene.
Safer water supplies.
14. Measures of overall health are life expectancy
and infant mortality rates
a) Life expectancy is the average number of years a
newborn can expect to live
b) Infant mortality rate is the number of babies out of
every 1,000 born who die before their first birthday
c)
U.S. infant mortality is higher than it could be
(ranked 46th world-wide) this is due to:
•
•
•
Inadequate pre- and post-natal care for poor.
Drug addiction.
High teenage birth rate.
15. Arguments to limit immigration into the U.S.
are:
a) Limitations would aid in stabilizing the population
sooner
b) Limitations would help reduce the US’s enormous
environmental impact
16. Arguments for generous immigration policies in
the U.S. are
a) Since 1820, the U.S. has admitted almost twice as
many immigrants and refugees as all other countries
combined
Number of legal immigrants (thousands)
1907
1914
New laws
restrict
Immigration
Great
Depression
Year
Fig. 9-8, p. 178
C. POPULATION AGE STRUCTURE
1. Age structure diagrams are visual aids, which
show the distribution of males and females in
each age group.
2. The percentages of male and females in the total
population are divided into the following age
categories:
a) Pre-reproductive ages (0-14)
b) reproductive ages (15-44)
c) Post-reproductive ages (45-up)
3. The number of people in young, middle, and
older age groups determines how fast
populations grow or decline.
4. The number of people younger than age
15 is the major factor determining a
country’s population growth.
a) In 2004, 30% of the planet’s population was
under 15
5. Changes in the distribution of a country’s
age groups have long-lasting economic
and social impacts.
POPULATION AGE STRUCTURE
a) Populations with a large proportion of its people
in the pre-productive ages 1-14 have a large
potential for rapid population growth.
Figure 9-9
POPULATION AGE STRUCTURE
6. 32% of the people in
developing countries
were under 15 years old
in 2006 versus only 17%
in developed countries.
Figure 9-10
Developed Countries
Female
Age
Male
Population (millions)
Fig. 9-10a, p. 179
Developing Countries
Female
Age
Male
Population (millions)
Fig. 9-10b, p. 179
7. Changes in the distribution of a country’s age
groups, like the ‘baby boom’ generation, longlasting economic and social impacts.
a) Such a group can dominate the population’s demands
for goods and services
b) They influence elections and legislation and
economic demand
8. The ‘baby bust’ generation compared to that of
the ‘baby boom’
a) There will be fewer people to compete for education,
jobs, and services
b) It may be more difficult to get job promotions
because a larger baby-boom group will occupy most
upper-level positions.
9. Reduced fertility and population decline can
have long-term consequences, especially if the
decline is rapid.
a) A gradual population decline, its harmful effects can
usually be managed.
10. There can be a sharp rise in the proportion of
older people.
a) Producing a sharp rise in public services’ cost for
health, etc.
b) It may have many fewer working taxpayers & labor
shortages.
c) It may be necessary to raise retirement age, raise
taxes, cut retirement benefits and increase legal
immigration, which are generally unpopular moves.
11. Age structure
predictions based on a
medium fertility
projection.
a) The cost of an aging
population will strain
the global economy.
Figure 9-12
12.If population declines because of deaths,
consequences are serious.
a) Deaths from disease such as AIDS disrupt a
country’s social and economic structure.
b) Large number of people in a particular age are
removed from the country’s future:
c) Life expectancy drops.
13.In the case of AIDS, the deaths are mostly
young adults, those who usually help run
the country and everyday life for millions.
Rapidly Declining
Population Problems
• Can threaten economic
growth
• Less government
revenues with fewer
workers
• Less entrepreneurship
and new business
formation
• Less likelihood for new
technology development
• Increasing public deficits
to fund higher pension
and healthcare costs
Fig. 9-13, p. 182