A special type of bar chart that shows the distribution of the population (within a country, region, or the world) by gender and age, usually with the younger ages at the bottom and with males on the left and females on the right. Slowly growing populations (such as the USA) typically have a relatively large elderly population, so they have a population pyramid of reasonably uniform width from bottom (young) to top (old). Rapidly growing populations (such as Kenya) have a disproportionately large number of young people and thus more of a true pyramid shape, becoming narrower towards the top. The pyramid for a population that is not growing, or is decreasing, often has a bulge in the middle‐age range, with relatively few young and old people. Population pyramids for all countries can be seen on the website of the US Census Bureau (http://www.census.gov/ipc/ www/idbpyr.html).
Subjects: Environmental Science.