Transcript Document

Applying Population Ecology: The
Human Population
G. Tyler Miller’s
Living in the Environment
14th Edition
Modified by Mr. Manskopf
Chapter 10
Population Growth: Key
Concepts
 Factors affecting human population size
 Human population problems
 Managing population growth
Section 1 Key Ideas
• What is demography?
• How is population size affected by birth rates,
death rates?
• How fast is the world’s population growing?
• What is doubling time? Rule of 70
• What are fertility rates? How have they changed?
• What factors affect birth rates and fertility rates?
• What factors affect death rates?
• Impacts immigration has on U.S. population.
What is demography?
Demography: is the study of
the size, composition,
distribution of human
population and the causes
and consequences of
changes.
• How many people live where?
• How long are you expected to
live?
• How many children are you
likely to have.
Factors Affecting Human
Population Size
Population change equation
Population
Change
=
(Births + Immigration) – (Deaths + Emigration)
Crude birth rate (BR): per 1,000
Crude death rate (DR): per 1,000
Population Problems
Average crude
birth and death
rates for various
countries in 2004.
How fast is the world’s population
growing?
• Birth rates and death rates
coming down (death more
quickly)
• 219,000 more daily (97%
in developing countries)
• 80 Million per year
• Exponential growth
1.25% down from 2.2% in
1963
The world’s 10 most
populous countries
• China and India
37% of world
8 Billion people by
2050
Describing Population Changes
Doubling time: time in years it
takes world to
double….RULE OF 70
70/ percent changing
70/1.25 = 56 years to double
Africa growing at 2.8%...how
long to double?
Describing Population Changes
Fertility: number of births that occur to an
individual woman.
Replacement-level Fertility: the number of
children a couple must have to replace themselves.
2.1 developed countries, 2.5 in developing countries
Total Fertility Rate (TFR): the average number
of children a woman typically has during
reproductive years.
Global Avg. = 2.8 (1.5 in developed, 3.1 developing down
from2.5 and 6.5 in 1950)
Fertility
rates for
various
countries.
UN World
Population
Projections
assuming
TFR of 2.5
high, 2.0
medium and
1.5 low
How Have Fertility and Birth
Rates Changed In the U.S.
1900: 76 million
2006: 300 million
• Post WW II Baby Boom, 1946
to 1964 added 79 million TFR
reached 3.7
• 2004: 2.9 million added 59%
due to more births/deaths the
rest from immigration
• Projected: 2050, 420 million
and 2100, 571 million
Births per thousand population
U.S. Birth Rates: 1910-2004
32
30
28
26
24
22
20
18
16
14
0
1910
End of World War II
Demographic
transition
1920
Depression
1930
1940
Baby boom
1950
1960
Baby bust
1970
Echo baby boom
1980
1990
2000
2010
Year
Fig. 10-8, p. 180
U.S. Population Estimates
Comparing U.S., Mexico and Canada
Major changes that took place in the U.S. 1900 - 2000
Factors Affecting Birth Rates
and Total Fertility Rates
 Children in Labor Force
 Cost of raising and educating children
 Availability of pension systems
 Urbanization
 Education and employment for women
 Infant mortality rate
 Average marrying age
 Abortion
 Availability of birth control
Effectiveness of
typical types of
birth control.
Factors Affecting Death Rates
 Life expectancy: the average number of years a
newborn is expected to live.
 Infant mortality rate (IMR): number of babies
per 1,000 that die before 1st birthday.
Life expectancy
1955 to 2004: Increased
48 years to 67 years (76
in developed world, 65
in developing)
U.S. 77 years and
projected 82 by 2050
Poorest countries of
Africa only 49 years
Life expectancy
• Increased food
supplies
• Better nutrition
• Advances in medical
field (vaccines,
antibiotics)
• Advances in
sanitation
• Safe water supplies
Infant Mortality
Infant mortality is viewed as the
single measure of a society’s
quality of life…health care
and nutrition
1965 to 2004: drop 20/1000 to
7/1000 and 118/1000 to
61/1000 in developing world
U.S. 1900: 165/1000 to 2004:
7/1000
Infant Mortality
3 Factors Keep U.S.IM
High:
1) Inadequate health care
for poor and pregnant
woman.
2) Drug Addiction among
pregnant woman
3) High teen birth rate
U.S. Immigration
• What do you think
environmental impacts
of immigration to U.S.
might be?
Legal
immigration
to the U.S.
from 1820 to
2001.
1989: large
increase due
to Act passed
by Congress
Section 2: Population Age
Structure Key Ideas
• What are age structure diagrams? How can you
use them?
• What are some effect of population decline
from reduced fertility?
• What are some effects of population decline
due to rises in death rates?
How does age structure afect
population?
• The number of people
under age 15 is a major
factor in determining
future population.
• 33% developing world
• 17% developed world
1.9 billion set to enter
reproductive age
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
U.S. Population by age 1900, 2000,
and 2050 projected
Population
structure by
age and sex in
developed and
developing
countries.
Comparison of
key demographic
indicators in 2004
for 3
countries…one
highly developed,
one moderately
developed and one
less developed.
Tracking the baby-boom generation in the
U.S.
What are some impacts of population
decline from reduced fertility?
• 40 Countries Populations
Stabilized or Declining
(growth rates below 0.3%)
all in EU Expect Japan
• UN Project by 2050 most
developed countries (not
U.S.)
• Mean more of population
shift to elderly
What are some impacts of population
decline from reduced fertility?
Impacts Social and Economic
of this decline:
• Large elderly population
• Increased medical costs
• Less people in workforce
• More stress on fewer
taxpayers
• Labor Shortages
• All lead to political
changes
What are some impacts of population
from rise in death rates?
AIDS to cause premature
deaths of 278 million
from 2000 to 2050
(almost equal to U.S.
population)…mostly in
Africa
• Remove productive
workers
• Increase in orphans
Global
Aging
Section 3: Solutions Key Ideas
• What are the advantages and disadvantages of
reducing births?
• How can economic development help reduce
birth rates?
• How can family planning help reduce birth
rates and abortion rates and save lives?
• How can empowering woman help reduce
birth rates?
What are advantages and disadvantages
of reducing births: Controversy
Can the world’s resources
support an additional 2.5
billion by 2050?
• Is the Earth
overpopulated?
• Carrying capacity
• If yes, what should b
done?
What is a sustainable
population?
What are advantages and disadvantages
of reducing births
No Need to Reduce
Population
• Life spans increasing
• People free to have as
many kids as want
• Slowing population
growth = economic
decline.
• Increased technology
will provide answers.
Yes, we must reduce
population
• Basic human needs of
people not being met
• Larger population =
larger human ecological
footprint
• Resources being used
up rapidly
How can economic development
reduce birth rates?
History indicates that as
countries become
economically developed, their
birth and death rates line.
This happens in 4 stages:
1) Preindustrial
2) Transitional
3) Industrial
4) Postindustrial
Look up these stages (pg 188) for HW
The Demographic Transition
Fig. 10-20 p. 189
Stage 2
Transindustrial
Stage 3
Industrial
Stage 4
Postindustrial
High
80
70
Relative population size
Birth rate and death rate
(number per 1,000 per year)
Stage 1
Preindustrial
60
50
Birth rate
40
30
Death rate
20
10
0
Total population
Low
Increasing Growth Very high Decreasing
Low
Zero
growth rate
growth rate
growth rate growth rate growth rate growth rate
Time
Low
Negative
growth rate
How can economic development
reduce birth rates?
Transition countries may
get caught:
• HIV/AIDS
• Too much debt
• Lack of skilled workers
• Less economic
assistance
• Not enough or too
much decrease in
population
How can family planning reduce
birth rates?
Family planning has been
a major factor in
reducing the number of
birth and abortions
around the world.
• Provides educational
and clinical services to
help couples choose
how many children they
want
How can family planning reduce
birth rates?
• Responsible for a 55%
drop in TFRs in
developing countries
from 6 in 1960 to 3.1 in
2004.
Still 42% of pregnancies
unplanned and 26%
aborted.
How can empowering women
reduce birth rates?
Women tend to have fewer
kids if they are educated,
have a paying job outside
the home, an do not have
their human rights
suppressed.
Why do you think that is?
Typical workday for women in rural
Africa…how does it compare to your average
day?
Solutions: Influencing
Population Size
Migration
Environmental refugees
Reducing births
Family planning
Empowerment of women
Economic rewards and penalties
Section 4: Case Study: Slowing
Population Growth in India
Generally disappointing results:
Poor planning
Bureaucratic inefficiency
Low status of women
Extreme poverty
Lack of support
Case Study: Slowing Population
Growth in China
Economic incentives
Free medical care
Preferential treatment
Locally administered
Very intrusive and coercive
Section 5: Cutting Global Population
Growth
 Family planning
 Improve health care
 Elevate the status of women
 Increase education
 Involve men in parenting
 Reduce poverty
 Sustainability