Population Pyramids

Population Pyramids

* A population pyramid shows the age and sex structure of a population. The horizontal bars show the percentage of males and females in each age group. * Shows population in groups starting with the young on the bottom and the old on top.

Demographic Transition

* A process with phases that countries move through as living conditions improve. * A model that helps us understand changes in population growth rates in different countries over time.

How to Read Population Pyramids

Width of base Wide base = high birth rates Narrow base = lower birth rates Symmetry - pyramids should look the same on male side and female side. * Any asymmetrical shapes show differences in male & female population. * Bumps in sides. * Bumps can represent "baby booms", wars, or an influx of male workers into a country.

How we gather population data

* Census - A system for gathering information about members of a society. - Also known as sampling or polling.

How countries are grouped

* Developing - A low living standard, undeveloped industry (lower level of manufacturing goods and services). - A higher living standard, developed industry (high level of manufacturing goods and services).

Population Pyramids: CONTRACTING

* In at bottom. * Lower numbers of young people. * Country has long life expectancy, low death rate and low birth rate, good education, good health care.

Population Pyramids: STATIONARY

* Pyramids that display somewhat equal numbers. * Low fertility, low mortality. * Growth is neutral or stable.

Population Pyramids: EXPANDING

* Wide at the base, narrow at the top. * Indicates high birth rates, and high death rates. * Large numbers of youth, rapid population growth.

3 Types of Population Pyramids

1. Expanding 2. Contracting 3. Stationary

Demographic Transition Stages

Stage I - High birth, High death, Low growth Stage II- High birth, Declining death, Increasing growth Stage III- High birth, Low death, High growth Stage IV- Declining birth, Low death, Declining growth Stage V- Low birth, Low death, Low growth