Population Pyramids

Today we started a new unit, and it is called population pyramids.  We use more population pyramids to analyze growth (or decline) of fertility, mortality and migration in cities.  60+ are called oldies, they are old people, or the elderly.  The ages 20-59 are economically active, or adults.  the ages 0-19 are kiddos, kids, or children.  the basic shapes of any pyramid are a triangle (Christmas tree), a square/rectangle, (the box), and a trapezoid (the cup).  What do they all mean though?  the Christmas tree pyramid is a developing nation. The growth rates are slow, high birth rate, and have a short life expectancy.  Namibia and Bangladesh are some examples of the Christmas tree.  The box pyramid means that the nation is developed, and they have a low infant mortality, slow population growth, and long life expectancy.  Some examples of that pyramid are Sweden and the U.S.   The cup pyramid is a developed nation.  Low birth rate, shrinking population, but a long life expectancy.  Italy and Japan are some examples of this.