The Human PopulationChapter 9
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Section 1:Studying Human Populations 2
Studying Human Populations
• Demography – the study of (ANY!!) population• But usually only human populations
• Demographers (people who study populations) have two categories for countries - Developed and Non-Developed
• Developed – • High incomes, slow population growth, lots of industry• Can you name one?
• Non-Developed – • Low incomes, fast population growth, agriculture based economy• Can you name one?
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Human Population Over Time
• Exponential Growth – Rapid increase in a population• Due to better food production, medicine, hygeine• Can we sustain this growth?
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Forecasting Population Size
• Age Structure diagrams – can give a forecast of future issues• Lots of children now, means a population increase in 10-15
years when those kids start having kids.
• Population Pyramids – • Two sided – male and female• Developed and Non-Developed countries have distinctive
looking pyramids
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• Survivorship Curves – the percentage of that population that will survive at any given age
Type I – Few offspring, but they live a long time
Type II – Equal chance of living or dying every day
Type III – Most offspring die young with few surviving to older age
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• Fertility Rates: Number of babies born each year per 1000 women• Total fertility rate: average number of children a woman will give birth to in
her lifetime• Replacement Level – The number of children a couple needs to have to replace
themselves• In developed countries this is 2.1 (why the .1?)
• Women are the biggest factor in controlling growth• Education (jobs and childcare leads to not needing as many children)• Birth Control
• Population can also change due to:• Immigration – people moving in• Emmigration - people moving out
• Death Rates are delining all over the world. Why?• Life expectency – the average number of years someone will live • Life expectency worldwide has risen to 67 years • Factors affecting life expectency• Contagious diseases, AIDS and tuberculosis
Demographic Transition Model 9
Phase 1 – Agrarian - high birth AND death ratesPhase 2 – Low death rates, high birth rate – POPULATION EXPLOSIONPhase 3 – Birth rate is declining but population is very largePhase 4 – low birth AND death rates
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That’s all for 9.1
• Time for a reading quiz
Section 2:Changing Population Trends 11
Problems of Rapid Growth
• Infrastructure: basic facilities/services that support a community• Public water, sewer, roads, hospitals, power plants
• Shortage of fuel wood• Clean water, heat, and edible food come from a reliable heat source• Expanding populations increase need/decrease availability of fuel wood
• Unsafe Water• No sewers or water treatment plants• Water sources (rivers) used for drinking, cooking, washing, AND sewage• 1 billion people unsafe water worldwide/ 3 million died of water diseases• Right here in US – Rio Grande river in Texas
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Problems of Rapid Growth
• Land Impacts • Arable Land –land where crops can grow• More people need homes leads to less
arable land• Less arable lands leads to less food grown. • Less food + more people = starvation• Urbanization – people moving from rural
to city• Suburbs – sprawl, still taking up arable land• Harsh environments –people live near
resources - Egypt
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Diverse World
• Not all countries are following the demographic transition model• Some industry, but still low incomes• High education, but low industry
• Least Developed Countries – a focus of world community and United Nations• Still have high death rates, high birth rates, and little industry
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• Countries working to slow population growth because of demands on environment and resources• China – One Child
Policy• Family planning
policies• Financial Incentives• Improving status of
women
• Population growth is slowing • We just hit 7 BILLION
people15
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That’s all for 9.2
• Time for a reading quiz