Population Pyramids and Population Density Maps

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.