Age Structures

Age structure diagrams are tools that we use to determine how a community is growing. Developing and developed countries tend to have very different age structures. The population is divided into age brackets. For example ages 0-2, 3-5, and so forth. Then a census is taken to see how many individuals in the country are in each bracket. In the United States a census is taken every 10 years. It can be a very tedious process collecting the population’s ages. The information is then further divided into males and females. Once the population is tallied it can be described by age structure, or the portions of the population in each age class. There are three types of age structure: rapid growth, zero growth, and negative growth. The rapid growth structure has a very wide bottom and it progressively thins out. It looks similar to a triangle. This is considered rapid growth because there are many individuals in the reproductive stage of their life that will continue to contribute to the growth of the population. Countries that have this trend include Nigeria and Guatemala. Zero growth means exactly what it sounds like. There is not any growth occurring in the country. There are equal numbers of individuals in each age bracket. Spain and Austria have a trend like this. The third structure is Negative growth. In this structure there are less individuals in their adolescents and reproductive ages than there are those who are past reproduction. This means that the country will not grow and actually decrease in size in the next few years. Germany and Bulgaria have a trend like this. These structures can give insight into how a country is growing.

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For more information:

http://esa21.kennesaw.edu/activities/populationage/populationage.pdf

http://people.oregonstate.edu/~muirp/agestruc.htm