45.4C: Age Structure, Population Growth, and Economic Development
- Explain how age structure in a population is associated with population growth and economic development
The variation of populations over time, also known as population dynamics, depends on biological and environmental processes that determine population changes. A population’s growth rate is strongly influenced by the proportions of individuals of particular ages. With knowledge of this age structure, population growth can be more accurately predicted. Age structure data allow the rate of growth (or decline) to be associated with a population’s level of economic development.
For example, the population of a country with rapid growth has a triangle-shaped age structure with a greater proportion of younger individuals who are at or close to reproductive age. This pattern typically occurs where fewer people live to old age because of sub-optimal living standards, such as occurs in underdeveloped countries.
Changing Population Age Structure : This 3:28 minute movie discusses age structures and gives examples.
Some developed countries, including the United States, have a slowly-growing population. This results in a column-shaped age structure diagram with steeper sides. In these cases, the population has fewer young and reproductive-aged individuals, with a greater proportion of older individuals. Some developed countries, such as Italy, have zero population growth. Countries with declining populations, such as Japan, have a bulge in the middle of their age structure diagram. The bulge indicates relatively-few young individuals, and a higher proportion of middle-aged and older individuals.
Globally, less-economically developed countries in Africa and Asia have the highest growth rates, leading to populations consisting mostly of younger people. Improved health care, beginning in the 1960s, is one of the leading causes of the increased growth rates that created the population explosion. For example, in the Middle East and North Africa, around 65 percent of the population is under the age of 30. These high growth rates lead to the so-called “youth bulge,” which some experts believe is a cause of social unrest and economic problems such as high unemployment.
All of the factors above also have an impact on the average life expectancy. As economic development and quality of health care increase, the life expectancy also increases.
Contributions and Attributions
- greenhouse gas. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/greenhouse_gas . License : CC BY-SA: Attribution-ShareAlike
- OpenStax College, Biology. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44875/latest...ol11448/latest . License : CC BY: Attribution
- One-child policy. Provided by : Wikipedia. Located at : https://en.Wikipedia.org/wiki/One-child_policy . License : CC BY-SA: Attribution-ShareAlike
- Population Growth. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Human_population_growth . License : CC BY-SA: Attribution-ShareAlike
- climate change. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/climate_change . License : CC BY-SA: Attribution-ShareAlike
- 1280px-Los_Angeles_Aerial_view_2013.jpg. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/World_..._view_2013.jpg . License : CC BY-SA: Attribution-ShareAlike
- World-Population-1800-2100. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:W...-1800-2100.svg . License : CC BY-SA: Attribution-ShareAlike
- population curve. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Po...tion_curve.svg . License : Public Domain: No Known Copyright
- OpenStax College, Biology. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44875/latest...ol11448/latest . License : CC BY: Attribution
- Measles. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Measles%23Epidemiology . License : CC BY-SA: Attribution-ShareAlike
- density-dependent. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/density-dependent . License : CC BY-SA: Attribution-ShareAlike
- Boundless. Provided by : Boundless Learning. Located at : www.boundless.com//biology/de...ctious-disease . License : CC BY-SA: Attribution-ShareAlike
- vaccine. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/vaccine . License : CC BY-SA: Attribution-ShareAlike
- 1280px-Los_Angeles_Aerial_view_2013.jpg. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/World_..._view_2013.jpg . License : CC BY-SA: Attribution-ShareAlike
- World-Population-1800-2100. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:W...-1800-2100.svg . License : CC BY-SA: Attribution-ShareAlike
- population curve. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Po...tion_curve.svg . License : Public Domain: No Known Copyright
- Measles US 1944-2007 inset. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:M...2007_inset.png . License : CC BY: Attribution
- Countriesbyfertilityrate.svg.png. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Total_...tilityrate.svg . License : CC BY-SA: Attribution-ShareAlike
- OpenStax College, Biology. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44875/latest...ol11448/latest . License : CC BY: Attribution
- Population decline. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Population_decline . License : CC BY-SA: Attribution-ShareAlike
- Population pyramid. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Population_pyramid%23The_Middle_East_and_North_Africa . License : CC BY-SA: Attribution-ShareAlike
- Population pyramid. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Population_pyramid%23Youth_bulge . License : CC BY-SA: Attribution-ShareAlike
- Population dynamics. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Population_dynamics . License : CC BY-SA: Attribution-ShareAlike
- Boundless. Provided by : Boundless Learning. Located at : www.boundless.com//biology/de.../age-structure . License : CC BY-SA: Attribution-ShareAlike
- population dynamics. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/population%20dynamics . License : CC BY-SA: Attribution-ShareAlike
- Boundless. Provided by : Boundless Learning. Located at : www.boundless.com//biology/de...on/youth-bulge . License : CC BY-SA: Attribution-ShareAlike
- 1280px-Los_Angeles_Aerial_view_2013.jpg. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/World_human_population%23/media/File:Los_Angeles_Aerial_view_2013.jpg . License : CC BY-SA: Attribution-ShareAlike
- World-Population-1800-2100. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:World-Population-1800-2100.svg . License : CC BY-SA: Attribution-ShareAlike
- population curve. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Po...tion_curve.svg . License : Public Domain: No Known Copyright
- Measles US 1944-2007 inset. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Measles_US_1944-2007_inset.png . License : CC BY: Attribution
- Countriesbyfertilityrate.svg.png. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Total_...tilityrate.svg . License : CC BY-SA: Attribution-ShareAlike
- OpenStax College, Human Population Growth. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44875/latest...e_45_05_04.jpg . License : CC BY: Attribution
- Changing Population Age Structure. Located at : http://www.youtube.com/watch?v=OpOEHjndywk . License : Public Domain: No Known Copyright . License Terms : Standard YouTube license
- Worldwide Life Expectency. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/World_...za_de_vida.PNG . License : CC BY-SA: Attribution-ShareAlike
- OpenStax College, Human Population Growth. October 17, 2013. Provided by : OpenStax CNX. Located at : http://cnx.org/content/m44875/latest...e_45_05_03.png . License : CC BY: Attribution
Key Points
- Population dynamics are influenced by age structure, which is characteristic for populations growing at different rates.
- Age structure varies according to the age distribution of individuals within a population.
- Fast-growing populations with a high proportion of young people have a triangle-shaped age structure, representing younger ages at the bottom and older ages at the top.
- Slow-growing populations with a smaller proportion of young people have a column-shaped age structure, representing a relatively even distribution of ages.
- Improvements in health care have led to the population explosion in underdeveloped countries, causing a “youth bulge” which is associated with social unrest.
Key Terms
- population dynamics : Variation among populations due to birth and death rates, by immigration and emigration, and concerning topics such as aging populations or population decline.
- youth bulge : Age structure typical of fast-growing populations in which a majority of the population are relatively young.
- age structure : The composition of a population in terms of the proportions of individuals of different ages; represented as a bar graph with younger ages at the bottom and males and females on either side.