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