Human Populations

Human Population Growth Like other organisms, the human population increases with time For most of human existence, growth rate was slow Life was harsh, food was scarce, incurable diseases 50% of children didn’t survived to adulthood 500 years ago: population began to grow rapidly Agriculture and industry Reliable food supply Sanitation, medicine, and health care

Patterns of Population Growth Demography – study of human population growth Birthrates, death rate, age structure of a population Demographic Transition: dramatic change in birth and death rates

Demographic Transition Begin Demographic Transition Death rate begins to fall, and birthrates remain high Rapid Growth: births greatly exceed deaths South America, Africa, and Asia Growth Slows: birth falls Increased levels of education Higher standards of living Families have fewer children

Demographic Transition Cont. Growth Stops: demographic transition is complete birthrate falls to meet the death rate US, Japan, much of Europe Most of the population growth occurs in 10 countries India & China

Age Structure Diagram Graphs of # individuals in each age group Used to predict future growth United States: slow growth Rwanda: double in 30 years

Future Growth Prevalence of life-threatening diseases AIDS, Malaria, and cholera 2050: 9 billion people