Demographic Transition

And Population Patterns

I Demographic Transition

ModelA. 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

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

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.

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

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.

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.

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

Demographic Equation

I Demographic EquationA. 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.

III Population PyramidsA. 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.