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Fall 2008 Soc 111. DEmography. Demography. Branch that studies human population patterns and dynamics Size of population, overall age structure, population distribution, and how the structure changes over time
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Fall 2008 Soc 111 DEmography
Demography • Branch that studies human population patterns and dynamics • Size of population, overall age structure, population distribution, and how the structure changes over time • Nearly all demographers are either trained as sociologists, economists, or statisticians
Population pyramids • Snapshot of a population • Depict a population by age and sex
Growth rate • Net change after fertility, mortality, and migration have been accounted for in a population • Basic demographic equation: Growth rate= births- deaths + net migration
Sustainability is a modern concern • Thomas Malthus asked this in the 1790s • Potato increased food supply for lower classes • Population nearly doubled during 1700s • Malthus theorem • Populations grow geometrically (2 to 4 to 8…), but food supplies grow arithmetically (1 to 2 to 3…). • Are there enough resources? • Food, land, fossil fuels, housing units, schools, etc
Exponential growth curve due to increased nutrition and hygiene 8000 BC to 1750… 67,000 people/year ~Every 7 hours 6.7 billion Dec 2008 est Reached first billion in 1804 Adding a billion currently at a rate of about 12 years Outstripping not just food but other resources as well Europe’s transition is more realistic High death/ birth rates (Stage 1) High birth/low death rates (Stage 2) Low birth/death rates (Stage 3) Pop shrinkage: extremely low birth rates (Stage 4) World growth rate slowing Peak in 1963 of 2.2%/year Currently about half this New Malthusians vs. Anti-Malthusians
Prediction • How many social services/what social structures to put in place • Basic demographic equation cannot account for social factors • War, Famine, Economic depressions, Economic booms, Disease epidemics, even government policies
China’s demographic transition China, 2000 China, 2025 China, 2050