world demography the study of the human population

World DemographyThe study of the human population

Objectives Describe how size and growth rate of

human pop has changed in the past 200 years

Define 4 properties that are used to predict population sizes

Describe 4 stages of demographic transition

Explain why different countries may be at different stages of demographic transition

Make predictions about population trends

Populations The study of human populations has its

own term: Demography

Demographers study many factors of a population to predict its future size

One factor is whether the country is developed or developing.

Do you recall…

Developing Countries

Lower average incomes

simple/farm-based economies

Rapid population growth

Developed Countries

Higher average incomes

Diverse/industrial economies

Slower population growth

Forecasting Population Size There are 4 properties we can use to

predict changes to a population

1. Age Structure Definition: the distribution of ages in a specific

population at a certain time.

Q: What will happen to Scotland’s population in 20 years?

2. Survivorship Definition: the percentage of group members that

are likely to survive to a given age. Type I: Wealthy, developed nations; populations are

healthy and many live to old age Type II: similar death rate at all ages Type III: poor populations; high infant/children

mortality rate

3. Fertility Rate Definition: The number of babies born

each year per 1,000 women

What would cause a change in number of babies born?

Fertility with replacement level

The Replacement Level is the number of children that must be born to replace their parents. Which populations

are shrinking?

Which populations are still growing?

Trick Question! None will grow!

4. Migration Definition: The movement of individuals

between areas. Immigration: movement coming into an

area Emigration: movement coming out of

an area

Natural Increase + Migration

Factors that change

populations

Many historic factors have changed populations

Industrial Revolution led to access to

Food Clean water Safer work-

places Advancements

in medicine

Life Expectancy These historic factors changed our

nation’s life expectancy

Life expectancy is the average number of years people are likely to live.

The Demographic TransitionAn eventual change in population

Population Transition What causes a population to stop

growing and startdecreasing?

Population Transition Definition: a model that describes how

economic and social changes affect population growth rates.

Scientists base this on observations and statistical data of other factors.

Demographic transition happens in 4 stages.

Stage 1: Preindustrial Condition Birth rate – high Death rate – high Population size is stable

Stage 2: Population explosion Birth rates – high Death rates – drop due to social

improvements Population grows very fast

Stage 3: Birth Rate Drops Birth Rate – decreases Death rate – still low Population size stabilizes to steady

Stage 4: Transition Birth rate – drops below replacement

level Death rate – still low Population size starts to decrease since

not enough children are born to replace the older generations

What type of graph is this?