Population Pyramids

population pyramid

a bar graph representing the population of a country broken down by age and sex (male or female)

age cohort

age groups represented on the y-axis of a population pyramid (0-4, 5-9, 30-34, etc.)

three shapes of population pyramid

expansive, constrictive, and stationary

expansive pyramid shape

triangle shape: wide base (bottom), narrow top

stationary pyramid shape

rectangular: roughly even bars from top to bottom

constrictive pyramid shape

diamond shape: narrow base (bottom), wide middle and top section

expansive pyramid growth rate

rapid growth

expansive pyramid birth rate

high/very high birth rate

expansive pyramid level of development

underdeveloped

stationary pyramid growth rate

slow or stable growth

stationary pyramid birth rate

low or stable birth rate

stationary pyramid level of development

developed

constrictive pyramid growth rate

negative growth (population is shrinking)

constrictive pyramid birth rate

very low birth rate

constrictive pyramid level of development

highly developed