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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?