Population Pyramidsand
Population Density Maps
Population
• Two useful ways that geographers can graphically display population information include:
• Population Maps to depict population density
• Population Pyramids to depict population distribution
Population Density…
• …is a measure of how many people live in a certain unit area
• Take the population of a region and divide it by its square area
• Ex.: The population density of Texas is 79.6/mi²
• On average, 79.6 people live in a square mile in Texas
One type of population map shows one dot for every certain number of
people who live in a place:
Another type shows population as color coded regions:
Population Pyramids
• A population pyramid is a bar graph, usually in the shape of a pyramid, used to compare different age groups of men and women.
Population Pyramids
• These graphs show how a population is distributed between age groups and sexes by percentages or numbers.
• Lower age groups are at the bottom
• Men are left of center
• Women are right of center
• In this pop. pyramid, the majority of the population is young, because there is a high birth rate and a high death rate
India, year 2000: large young population, high birth rate, high death rate
India, year 2025: death rate decreases, the younger population grows older
India, year 2050: the population has bulged in the 25-39 age groups
China: 1950-2050
South Korea’s Population Boom
The Aging of Japan
Low Death Rate and Dropping Birth Rate
Triangle
• Developing
• Rapid Growth
Box
• Developed
• Slow Growth
Modified box, glass or cup
• Higly Developed
• Negative Growth
Population Growth Theories
Malthusian Theory
• In 1798 Thomas Malthus published his theory• The population will continue to
grow until it surpasses the food supply
• People will starve reducing the population back to a sustainable level
Neo-Malthusian Theory
• The population is growing faster than Malthusian anticipated• Beyond the capacity of food and:
• Clean air
• Living space
• Fuel
According to these theories, a catastrophe is imminent to reset the
population• World population since 500
A.D.
• Evidence:• Starvation in Africa
• Loss of farmland in China, South America, and Africa
• Natural disasters worldwide
What do you think is going on in each U.S. city? Write down your guesses in your important books.