Population Pyramids The population structure for an area shows the number of males and females within different age groups in the population. This information is displayed as an age-sex or population pyramid.

Population pyramids of Less Economically Developed Countries typically have a wide base and a narrow top. This represents a high birth rate and high death rate. Population pyramids of More Economically Developed Countries typically have a roughly equal distribution of population throughout the age groups. The top obviously gets narrower as a result of deaths.

The horizontal bars show the percentage of male and female in each age group.

1. Which age group has the greatest proportion of people? 2.Which bar includes the students in this classroom? 3. Are there more people in your age group or in the age group below yours? 45-49

A pyramid shows the history of a country's population growth. In the United States from 1945 to 1965, people had larger families. These people are now between the ages of 30 and 50 and are called baby boomers. This pyramid is an example of slow population growth.

Short-term fluctuations often can be traced to such historical events as wars, epidemics, economic booms, or depressions Baby Boom-after WWII Great Depression-decline in birth rate 1930 and 1934 World Wars I and II-deficit of men in Germany The impact of these events emphasizes the interrelationships among population change and economic, social, political, and health factors.

1.How is Congo's pyramid different from that of the U.S.? 2.Which age group in Congo is the largest? 3.What proportion of the population is in this age group? There are more people in the younger age groups Almost 20% (9% female and 9% male)

1.Now look at Germany. How is it different? 2.How is it different from Congo? The age groups are closer to being equal There is a greater proportion of older people

Why do we need this information? Why would a country 's leaders want to know the proportion of the population in different age groups? What difference does the age of the people in a country make? What kinds of products do young people use? What kinds of services do they need? What about older people? Is it important for a government leader or planner to know the age of the population they are serving?

Young people –Schools, and later, jobs Older people- retirement systems and medical facilities As a population ages, needs change from childcare and schools to jobs, housing, and medical care.

Migration also affects pyramid shape Most migrants are in the working ages, and often more males than females Most migrants are in the working ages, and often more males than females In some Middle Eastern countries a large number of men migrated to work in the oil fields, which caused a bulge in one side of the pyramid, while it took a "bite" out of the pyramid of some of the countries from which they came.

Time to make your own Population Pyramids We will use a modified pyramid with only 4 age groups First we will practice with the U.S. After we are done, you will get in groups of 4 and graph pyramids of other countries

US Population by Age 2000 (percent) AGESMALESFEMALES %14% %14% % 60+7%9%

Now get with your partners and make your population pyramids

PolandHaitiThailandItaly Saudi Arabia BrazilAustraliaEthopiaJapanCanadaArgentinaKenyaGermany South Korea IndiaNigeriaCubaLithuaniaEgypt United Kingdom ChinaMexico Dem. Rep. of Congo FranceBangladeshIranIndonesiaIrelandCyprusPakistan Sri Lanka VietnamRomaniaHonduras Papua New Guinea Hungary