Transcript Document

Transition & Limiting
Human Population
Review: The Ecological Footprint
The cumulative amount of Earth’s surface area
required to provide the raw materials a person or a
population consumes and to dispose of or recycle
the waste that is produced
Ecological footprints
Residents of some
countries consume
more resources—and
thus use more land—
than residents of
Shown are ecological
footprints of an
average citizen from
various nations.
Figure 7.23
The wealth gap
Residents of developed
nations have larger houses,
more possessions, and more
money than residents of
developing nations.
The richest 20% of the
world’s people consumes
86% of its resources, and
has >80 times the income of
the poorest 20%.
Figure 7.25
Demographic transition theory
Demographic transition = model of
economic and cultural change to explain
declining death rates, declining birth rates, and
rising life expectancies in Western nations as
they became industrialized
Proposed by F. Notestein in the 1940s-1950s
Demographic transition: Stages
Figure 7.18
Demographic transition: Stages
The demographic transition consists of several stages:
Pre-industrial stage: high death rates and high birth rates
Transitional stage: death rates fall due to rising food
production and better medical care. Birth rates remain high, so
population surges.
Industrial stage: birth rates fall, as women are employed and
as children become less economically useful in an urban
setting. Population growth rate declines.
Post-industrial stage: birth and death rates remain low and
stable; society enjoys fruits of industrialization without threat
of runaway population growth.
A Proven Solution: Female Education
Female literacy and
school enrollment are
correlated with total
fertility rate:
women have fewer
Figure 7.16
Family planning and Total Fertility Rate (TFR)
Family planning, health care, and reproductive education
can lower TFRs.
A counselor advises African women on health care and
reproductive rights.
Figure 7.17b
Family planning and Fertility Rate
Nations that
invested in
TFRs more
than similar
nations that
did not
Figure 7.17a
Limiting Factors (if we don’t implement a solution, the
population will control itself in a much more dramatic way - Malthus)
Limiting Factor: anything that restricts the growth of a
population in a biological community
•Density-Dependent: relies on the number of people
•Ex. Food/famine, clean water, shelter, build up of
trash/toxic waste, pollution, plague/disease, stress, war,
•Density-Independent: unrelated to the number of people
•Ex. Weather, climate, natural disasters, etc.
HIV/AIDS and human population
AIDS cases are increasing rapidly worldwide.
Figure 7.26
HIV/AIDS and human population
Infects 1 in 5 people in southern African nations
Infects 5 million new people each year
Kills babies born to
infected mothers
Has orphaned
14 million children
Has cut 15 years off
life expectancies in
parts of
southern Africa
Figure 7.27
Population and the environment
Population growth can lead to environmental degradation.
Overpopulation in Africa’s Sahel region has led to
overgrazing of semi-arid lands (leads to starvation).
Figure 7.21
Demographic fatigue and demographic
Many governments of developing countries are
experiencing “demographic fatigue,” unable to meet the
social, economic, and environmental challenges imposed by
rapid population growth.
This raises the question:
Will today’s developing countries successfully pass
through the demographic transition?
The “IPAT” model
Shows how Population, Affluence, and Technology interact
to create Impact on our environment.
I = P  A  T
Further factors can be added to the original equation of Holdren and
Ehrlich to make it more comprehensive.
Conclusions: Challenges
Human population is rising by 79 million people annually.
Many more people are born into poverty than into wealth.
Rich and poor nations are divided by a “wealth gap.”
HIV/AIDS is taking a heavy toll.
Population growth has severe environmental effects.
Conclusions: Solutions
Expanding women’s rights is crucial to encourage the
demographic transition.
Health and reproductive education and counseling can
reduce fertility rates.
Education, medicine, and policies can lessen the toll of
New “green” technologies can help reduce population
growth’s environmental impacts & increase our carrying
What has allowed us to increase Earth’s carrying capacity
for our species?
a. Agriculture
b. Industrialization
c. Tool-making
d. All of the above
Women who are more educated tend to… ?
a. Have higher TFRs.
b. Live in developing nations.
c. Have fewer children.
d. Contract HIV/AIDS.
QUESTION: Weighing the Issues
Should the United States fund family planning efforts in
other nations?
a. Yes, without reservation
b. Yes, in nations whose programs it approves
c. Only if it can influence the nations’ policies
d. Never under any circumstances
QUESTION: Interpreting Graphs and Data
What happens
during the
stage” of the
a. Birth rates rise; death rates drop; population increases
b. Birth rates drop; death rates drop; population decreases
c. Death rates drop; birth rates are stable; population
Figure 7.18
QUESTION: Viewpoints
Do you believe that national governments should implement
policies, subsidies, or other programs to reduce birth rates?
a. No, not at all
b. Yes, but only positive incentives for fewer
c. Yes—penalties for too many children
d. Yes, both incentives and penalties
Central Case: China’s One-Child Policy
• Unfettered population growth posed challenges for
China’s environment, economy, and political stability.
• China tried to control its growth with a system of rewards
and punishments to encourage one-child families.
• The program decreased population growth, but meant
government intrusion in private reproductive choices.
Assignment for “China’s Lost Girls”
You must identify 5 Key Facts AND 5 Unforeseen
Consequences of China’s One-Child Policy
On a sheet of notebook paper:
1. Title your paper “China’s Lost Girls” and write your
name and class period in the top right.
2. Title one section “Key Facts” & number #1-5.
3. Title another section “Unforeseen Consequences” &
number #6-10.
4. Fill in these sections with information from the
documentary “China’s Lost Girls”