10 Cwi Population Pyramid

Population Pyramid Intro: Population pyramid is an age-sex pyramid that graphically displays information. A population pyramid vividly reflects long term trends in birthrates and death rates but also reflects wars and epidemics. Typically consists of two back-to-back bar graphs with the population plotted on the X-axis, Y-axis, one showing the number of males and one showing females in five year age groups.

P1 There are 3 kinds of population pyramids: Stationary pyramid: population pyramid shows a constant growth rate Expansive Pyramid: population shows a broad base and rapid growth rate Constrictive Pyramid: population pyramid showing negative growth rate

P2 Uses: Displays information on the age –sex structure in population to improve understanding of long term trends in the birth and death rates but also reflect shorter term baby-booms, wars, and epidemics. Considered the best way to display the age and sex distribution of a given population. It can also be used for displaying future trends in a population Provides a clear picture of population’s age-sex composition P3 Example of Negative growth rate: Germany is experiencing a negative growth (.1%) The population might be shrinking because of the low birth rate and a stable death rate.

Increased emigration can also be a contributor to a declining population Example of Positive growth rate: In the United States: population is growing at 1.7 percent annually High birth rate can be a contributing factor Increased immigration P4 Fertility rate of a population is the single most important influence on the shape of a population pyramid. The broader the base of the pyramid, median age of population will also be younger. A population with lower mortality rates will display a slightly younger age distribution. This is due to the fact that any disparities in the mortality rates of a population are more likely a result of variations within the younger age groups.

P5 Summarize all key points