Human Population Growth How has the size of the human population changed over time? Vocabulary Demography Like the populations of many other living organisms the size of the human population tends to increase with time. Human population is growing exponentially. The scientific study of human populations is called demography.

Why do populations growth rates differ in countries throughout the world? Birthrates, death rates and the age structure of a population help predict why some countries have high growth rates while other countries grow more slowly. Population growth in the U.S. Japan and much of Europe has slowed dramatically.

Demographic Transition Vocabulary Demographic transition Birthrates and death rates fall during the demographic transition. Demographic transition is a change in a population from high birth and death rate to low birth and death rates. U.S. Japan and most European countries have reached demographic transition

Age Structure U.S. Population This age structure predicts a slow but steady growth rate for the near future. Rwandan Population This age structure predicts a population that will double in about 30 years.