Chapter 2 Key Issue 3Chapter 2 Key Issue 3

Why Is Population Increasing Why Is Population Increasing at Different Rates in Different at Different Rates in Different

Countries? Countries?

Demographic Transition Demographic Transition ModelModel

• The The demographic transition model demographic transition model explains changes in the natural explains changes in the natural increase rate as they relate to increase rate as they relate to economic and industrial economic and industrial development.development.

• It is a process with It is a process with four stages four stages and and every country is in one of them.every country is in one of them.

Stage 1Stage 1

• Stage one of the demographic Stage one of the demographic transition is one of high birth rates transition is one of high birth rates and death rates and consequently and death rates and consequently very low growth.very low growth.

• Most of human history was spent in Most of human history was spent in stage one but no countries remain in stage one but no countries remain in that stage. that stage.

Stage 2Stage 2

• Stage two is one of high growth because Stage two is one of high growth because death rates decline and birth rates remain death rates decline and birth rates remain high.high.

• The demographic transition assumes that The demographic transition assumes that countries enter stage two because they go countries enter stage two because they go through the Industrial Revolution. through the Industrial Revolution. Technologies associated with industry Technologies associated with industry helped countries to produce more food helped countries to produce more food and improve sanitation and health.and improve sanitation and health.

Stage 2Stage 2

• Western European countries and North Western European countries and North America entered stage two about 1800.America entered stage two about 1800.

• Countries in Latin America, Africa, and Asia Countries in Latin America, Africa, and Asia have experienced stage two much more have experienced stage two much more recently, and without experiencing an recently, and without experiencing an industrial revolution.industrial revolution.

• Developing countries have moved into stage Developing countries have moved into stage two because of a medical revolution, the two because of a medical revolution, the diffusion of medical technologies to LDCs.diffusion of medical technologies to LDCs.

Stage 3Stage 3

• Countries will move from stage two Countries will move from stage two to stage three when their crude birth to stage three when their crude birth rates drop sharply as a result of rates drop sharply as a result of changes in social and economic changes in social and economic patterns that will encourage people patterns that will encourage people to have fewer children.to have fewer children.

Stage 4Stage 4

• Countries will reach stage four of the demographic Countries will reach stage four of the demographic transition because their birth rates will continue to transition because their birth rates will continue to decline until the natural increase rate drops to zero. decline until the natural increase rate drops to zero. This is true of countries in Europe together with This is true of countries in Europe together with Canada, Australia, and Japan.Canada, Australia, and Japan.

• The demographic transition assumes that this occurs The demographic transition assumes that this occurs because of more changes in social customs such as because of more changes in social customs such as women entering the labor force in large numbers.women entering the labor force in large numbers.

• It could be argued that some countries, primarily It could be argued that some countries, primarily western and northern European, that are now western and northern European, that are now experiencing population decline, have entered stage experiencing population decline, have entered stage 5.5.

The Age –Sex DistributionThe Age –Sex Distribution

• The age-sex distribution of a country’s population The age-sex distribution of a country’s population can be shown on a population pyramid. It will can be shown on a population pyramid. It will show the distribution of a country’s population show the distribution of a country’s population between males and females of various ages.between males and females of various ages.

• A A population pyramidpopulation pyramid will normally show the will normally show the percentage of the total population in five year percentage of the total population in five year age groups with the youngest group at the base age groups with the youngest group at the base of the pyramid and the oldest group at the top.of the pyramid and the oldest group at the top.

• Males are usually shown on the left and females Males are usually shown on the left and females on the right.on the right.

• Each age –sex group is called a population cohort.Each age –sex group is called a population cohort.

Age-Sex DistributionAge-Sex Distribution

• A pyramid with a wide base shows a rapidly A pyramid with a wide base shows a rapidly growing country with a large proportion of growing country with a large proportion of young people, and is typical of a less young people, and is typical of a less developed country. A pyramid that is more developed country. A pyramid that is more rectangular depicts a country with relatively rectangular depicts a country with relatively even number of young, middle-aged, and older even number of young, middle-aged, and older people, and is typical of a more developed people, and is typical of a more developed country.country.

• The The dependency ratio dependency ratio is the number of people is the number of people in a population under the age of 15 and over in a population under the age of 15 and over the age of 64, compared to the number of the age of 64, compared to the number of working people who must support them. working people who must support them.