2. I Demographic Transition
Model
A. Tool designed to show how population
growth is related to economic growth.
B. Traces the changing level of population
growth associated with industrialization
and urbanization
C. Demographic Transition model has 4
stages
3. STAGE 1
A. High birth and high death rates create slow
population growth.
B. Around 8,000 BC the Agricultural Revolution
took place and humans began planting crops, so
population started to grow slowly
C. This was the case for all humans until about
1750
D. All countries have moved passed stage 1, with
African countries the last to move into stage 2
4. Stage 2
A. Death rates drop due to Industrial Revolution
that in part brought new medical and sanitary
practices that created a healthier population.
B. Birth rates remain high resulting in rapid
population growth.
C. USA and Europe moved into stage 2 in the
1800s
D. Africa, Asia and Latin America didn’t enter stage
2 until the 1950s and was caused by the Medical
Revolution. A time when Medical technology
diffused to these areas.
5. STAGE 3
A. Birth rates begin to drop due to family planning,
education, and the increase of economic
demands, so birth rates come closer to death
rates.
B. Population growth slows, yet is still growing.
C. North America and Europe entered into stage 3
in the early 1900s
D. Most Latin American countries like Brazil,
Argentina, Mexico, and Asian countries like
Vietnam, Thailand, and Philippines fit into this
category.
E. A majority of African countries remain in Stage 2
6. STAGE 4
1. Birth and death rates are equally low so
population growth is very limited.
2. Countries often reach a point of ZPG, or Zero
Population Growth, where there is no natural
increase. ZPG is reached when TFR falls below
2.1 replacement levels.
3. Many Western European countries entered into
stage 4 in the 1990s and USA entered around
2000.
5 NEW STAGE. This was added to show that
some countries have birth rates falling well
below death rates and their population is
shrinking.
7. II Western Experience
A. The Demographic Transition model was
developed to show how Western Europe
transitioned from an agricultural economy
to an industrial one.
B. The transition also mirrors what is called
the EPIDEMIOLOGIC transition in which
diseases became less fatal, and people
lived longer, along with a lower infant
mortality rates.
C. The birth rates changed in western
societies because the value of large
families changed. Having kids in an
urban industrial economy is considered a
financial burden rather than an asset.
8. III A Divided World converging
A. Demographic transition does not look the
same everywhere
B. Some Developing countries in recent
history experience lower death rates
because of modern medicine, but do not
achieve economic levels that usually bring
lower birth rates.
C. Sri Lanka. Sprayed DDT to combat
malaria in 1946 and 8 years later life
expectancy jumped from 44 to 60
12. I Demographic Equation
A. The population structure is determined in
part by the demographic equation which is
the combination of natural change and
change through net migration (immigrants
– emigrants)
B There are several ways immigration has
an impact
1. Large migrations can completely change
a population structure
2. Migrations create unbalanced
populations. Most migrants are single
young males
3. Both source and destination of migrants
can have changes in population
structure.
13. III Population Pyramids
A. Population Pyramids are graphic devices that
represent a populations age and sex
B. Pop. Pyramids come in all shapes and sizes and are
often called profiles.
C. They show the impacts of human events such as
disease, war, population controls, and migrations.
D. Different shapes show different population
characteristics and can clearly show
dependency ratios, and future population problems
with the numbers from today.
E. Dependency Ratio is the ratio of people under 15
and over 65 that every 100 people in between those
years support.
14.
15. Population Pyramids
• Inverted bar graphs that show a wide
population base (younger population) with a
narrow top (older population).
• Population Pyramids show:
– Age Distributions
– Dependency Ratios of under 15 and over 65
– Sex Ratio - Male vs. Female
