WEEK 5 POP #3 Population Pyramids A population pyramid is a demographic snapshot of a society or state at any given time o They give us a wealth of information about the characteristics of the people in this state o The shape of the pyramid gives us great insight into what’s happing in this society The Sex o The pyramids divide the country into male and female (much like you junior high school dance floor) o Males (blue) on the left and females (pink) on the right o X-axis In the middle it starts at zero and moves out to bigger numbers to show the population number Brazil, Greenland, and China in 2010 look completely different China was in millions and Greenland was in thousands o Y-axis this is in 5 year age increments (age cohorts or age brackets) o His definition of 3 brackets of folks “old bracket” the folks that are above 50 or 55ish years of age Once you get to that age, the pyramid gets smaller and smaller as you go up These are folks that don’t do anything; no babies, they don’t work, they don’t contribute to the economy, they don’t pay as many taxes The older they get, they start to be a drain on the resources of the rest of society “bearing brackets” age cohorts 15 to mid-late 40’s Important because they bear the load of the entire society and they’re the most important peeps in the entire state The have kids, they make money, they work the most, they pay most of the taxes, they keep the government functioning They bear the load of all the old folks above them and the young folks below them “baby brackets” under 15 year olds They are a drain on the resource of the bearing brackets They don’t work, they don’t make many, they don’t do anything o The old brackets don’t change much when the baby brackets are wider than the bearing brackets That means that those folks in the middle have a fertility rate of 2.1 = replacement level
The inverse holds true as well Three types of basic pyramids based on shape o Classic pyramid shape i.e. Senegal 2010, Madagascar 2010 o Cool column shape I.e. US 2010
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- Fall '08
- Demography, population growth rate