AP HUG Unit 2.5

Demographic transition model (DTM)

A model that explains how birth rates, death rates, and population growth change as a country develops economically.

What does the DTM try to explain?

Why populations grow or decline over time as countries move from agrarian to industrial economies.

What three lines are shown in the DTM?

Birth rate, death rate, and total population.

What shape does total population usually form in the DTM?

An S-shaped curve.

Stage 1 of the DTM

High stationary stage.

What is Stage 1 like?

A pre-industrial society with high birth rates and high death rates, so population growth stays very low.

Why are birth rates high in Stage 1?

Children are useful for labor and families have many children because survival is uncertain.

Why are death rates high in Stage 1?

Disease, famine, poor sanitation, and limited medical care.

Stage 2 of the DTM

Early expanding stage.

What happens in Stage 2?

Death rates fall quickly while birth rates stay high, causing a population explosion.

What kind of countries are often in Stage 2 today?

Many countries in sub-Saharan Africa.

Stage 3 of the DTM

Late expanding stage.

What happens in Stage 3?

Birth rates begin to fall while death rates stay low, so population still grows but more slowly.

Stage 4 of the DTM

Low stationary stage.

What happens in Stage 4?

Birth rates and death rates are both low, so population growth is slow or stable.

Why do Stage 4 countries have low birth rates?

Urban lifestyles, women’s education and employment, contraception, and higher costs of raising children.

Stage 5 of the DTM

Natural decrease stage.

What happens in Stage 5?

Death rates exceed birth rates, so the population begins to decline.

What major problem do Stage 5 countries often face?

An aging population and labor shortages.

How does migration affect the DTM?

Migration can change population growth even if the natural increase is low or negative.

What is the epidemiological transition model?

A model that explains demographic change through changes in disease and causes of death.

Stage 1 of the epidemiological transition model

Famine and infectious disease stage.

What characterizes Stage 1 of the ETM?

High death rates from disease, poor nutrition, and famine; low life expectancy.

Stage 2 of the epidemiological transition model

Receding pandemic stage.

Stage 3 of the epidemiological transition model

Degenerative and human-created disease stage.

Stage 4 of the epidemiological transition model

Delayed degenerative disease stage.

Stage 5 of the epidemiological transition model

Re-emergence of infectious disease stage.

What is one weakness of the ETM?

It oversimplifies demographic change by focusing mainly on disease and death rates. It does not fully account for poverty, even though poverty strongly affects health and life expectancy.