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How has size of human population changed over time? Why do population growth rates differ in countries throughout the world?

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Presentation on theme: "How has size of human population changed over time? Why do population growth rates differ in countries throughout the world?"— Presentation transcript:

1 How has size of human population changed over time? Why do population growth rates differ in countries throughout the world?

2 Back in the day….. opopulations grew slowly ofood scarce oincurable diseases oOnly ½ of children survived to adulthood oFamilies had many children Then……. oHuman population grew rapidly oImprovements in agriculture, medicine, sanitation, and technology reduced death rates. oHuman population grew exponentially

3 Demography- study of human populations by examining characteristics of human populations and attempting to explain how those populations change over time. Reasons why some countries have high/low growth rates: 1.Birthrates 2.Death rates 3.Age structure of a population

4 Age structure diagrams- (or population profiles) model which graphs the numbers of people in different age groups in population. Used to predict future growth

5 Demographic transition-dramatic change in birth/death rates Steps of demographic transition: Throughout most of history: high birthrates and high death rates As countries begin to modernize: lower death rate, population grows and begin demographic transition More modernizing: families have fewer children (birthrate falls), population growth slows Demographic transition complete: when birthrate falls to meet death rate and population growth stops

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