1. THEME 1: POPULATIONS IN TRANSITION

2. World Population Growth  Currently 7.2 billion people in the world  www.census.gov/popclock www.census.gov/popclock  How many people can the earth support?

3. Population Changes  Changes are caused by:  Birth rates = number of live births per 1000 people  Death rates = number of deaths per 1000 people  Fertility rates = number of children each woman has  Migration – into or out of an area

4. Statistics  90% of the increase in population will be in developing countries  80% of population lives in less developed areas  Each baby born in the USA consumes 80x more resources in their life than a baby in India  By 2050 India will pass China in population

5. Local Statistics  United States population:  TODAY = 321 million  1950 = 152 million  Virginia population:  2014 Estimate = 8.3 million  Prince William County Population  2013 Estimate = 438,000

6. Population Structure  Population Pyramids - also called age- sex diagrams  Graph is divided in half between male and female  From the bottom up are age groups  Starting from the middle and extending outward on each side is the percent of population in that age group that is male or female

7. US Population Pyramid Source: www.census.gov/population/metro/data/pop_pyramid.html LINK

8. Population Pyramids  Pyramids with a wide base = usually developing countries – means birth rate is high  Pyramids with a narrow base = usually developed countries – or ageing population

9. Rate of Natural Increase  Birth Rate – Death Rate  Example:  Birth rate = 15 per 1000  Death rate = 8 per 1000  15 – 8 = 7  7/1000 =.7% rate of increase

10. Demographic Transition Model  Every society will pass through 4 stages.  1. Birth and death rates high = small increase in population  2. Death rates start to fall = population grows rapidly  3. Fall in birth rates after a fall in death rates = rate of increase slows  4. Birth and death rates are low = slowly growing OR slowly declining