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Population Pyramids


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An introduction to population pyramids

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Population Pyramids

  1. 1. What it is and how it works
  2. 2. <ul><li>Canada 1961 </li></ul>
  3. 3. <ul><li>Consists of two back-to-back bar graphs </li></ul><ul><li>population plotted on the X-axis and age on the Y-axis, in five-year age groups (cohorts). </li></ul><ul><li>Males are shown on the left and females on the right </li></ul><ul><li>Measured by raw number or as a percentage of the total population. </li></ul>Canada 1961
  4. 4. <ul><li>Where are you represented? </li></ul><ul><ul><li>Males? </li></ul></ul><ul><ul><li>Females? </li></ul></ul><ul><li>Oldest at top </li></ul><ul><ul><li>Youngest? </li></ul></ul><ul><li>Each age group called a “cohort” </li></ul>
  5. 5. <ul><ul><li>Stationary </li></ul></ul><ul><ul><li>narrow base and roughly equal numbers in each age group, tapering off at the older ages. </li></ul></ul><ul><ul><li>Scandinavian countries </li></ul></ul>                        
  6. 6. <ul><li>Expansive </li></ul><ul><li>broad base </li></ul><ul><li>rapid rate of population growth </li></ul><ul><li>low proportion of older people. </li></ul><ul><li>A steady upwards narrowing shows that more people die at each higher age band. </li></ul><ul><li>This type of pyramid indicates a population in which there is a high birth rate, a high death rate and a short life expectancy. </li></ul><ul><li>LLDC’s for the most part </li></ul>
  7. 7. <ul><li>Constrictive </li></ul><ul><li>a high proportion of aged persons and declining numbers. </li></ul><ul><li>Germany, Italy </li></ul>
  8. 8. <ul><li>Used to find the number of economic dependents in a population. </li></ul><ul><ul><li>Under 15 (those in k-12 full time, unable to work) and over 65 (those who have the option of retirement) </li></ul></ul><ul><li>Dependency ratio = % under 15 + % over 64 </li></ul><ul><li>% 15-64 </li></ul><ul><li>Used to observe natural increase, birth/mortality rates, breakdown by age range within a population </li></ul>
  9. 9. <ul><li>What do you notice about this pyramid? </li></ul><ul><li>Why do you think there is a “bulge” in the middle? </li></ul><ul><li>Notice the bottom 3 age groups – why is it that they are the largest? </li></ul>