population pyramids

Today in class we talked about population pyramids and how they are set up. We use them to analyze growth of the fertility, mortality, and migration in cities. They are set up according to the stats for that area it focuses on. One side of the chart are men and one side of the chart are women. I noticed that the amount of women in the old age section is relatively larger then the men. There are three shapes of the charts. The three are the x-mas tree, the box, and the cup. The x-mas tree represents developing  nations. They have slow growth rates and a short life expectancy. The box shape represents a developed nation with a slow birthrate. They have low infant mortality, slow population growth, and a long life expectancy. Last, the cup shape is a developed nation with a negative growth rate.  It has a low brith rate, a shrinking population, and a long life expectancy.