1. 1 Chapter 8 Human Population

2. 2 China’s One-Child Policy In 1970, the average Chinese woman had about six children. In 1970, the average Chinese woman had about six children. Since 1979, China has used a system of rewards and punishments to enforce a one-child limit to slow population growth. Since 1979, China has used a system of rewards and punishments to enforce a one-child limit to slow population growth. In 2005, there were 32 million more males than females in China under the age of 20 In 2005, there were 32 million more males than females in China under the age of 20 Write About It Is it ethical for governments to limit or encourage human population growth?

3. 3 Why did it take so long to reach 1 billion? Why do you think it took off around the late 1880s? Interesting Fact: Of all the humans ever born, approximately 6-7% are alive today.

4. 4 Studying Human Populations Demography: the study of human population How many people live where? How many people live where? How long are you expected to live? How long are you expected to live? How many children are you likely to have. How many children are you likely to have.

5. 5Demography Population size: Number of people Population size: Number of people Population density: Number of people living per mi 2 (or per km 2 ) Population density: Number of people living per mi 2 (or per km 2 ) Population distribution: How people are distributed within an area Population distribution: How people are distributed within an area

6. 6 Exponential Growth Exponential Growth: rapid growth often seen as J-Shaped curve on a graph Can that growth continue?

7. 7 Forecasting Population Size Will new schools be needed? Will new schools be needed? Should we be building more housing? Should we be building more housing? Should farming practices be improved? Should farming practices be improved? Predictions like this often wrong because human behavior changes Predictions like this often wrong because human behavior changes

8. 8 Forecasting Population Size Age Structure: the distribution of ages in a population Age Structure: the distribution of ages in a population Age Structure Diagrams also known as population pyramids Age Structure Diagrams also known as population pyramids What is useful about these diagrams? What is useful about these diagrams?

9. 9 What are these age-structure diagrams showing? What are the “reproductive years” Why is that important in forecasting future population growth?

10. 10 Which “type” of countries are going to see most of the population growth? Which “type” of countries do people live longer lives? Survivorship: percent of population likely to survive a given age

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12. 12 Fertility and Women Two main factors impact fertility rates worldwide Two main factors impact fertility rates worldwide Education level of women (knowledge of family planning) Education level of women (knowledge of family planning) Economic level of women Economic level of women Generally, on average, more education, more wealth = lower fertility rates

13. 13 What does this graph show? How has U.S. fertility rates changed?

14. 14 Migration: movement INTO – immigration or OUT of emigration an area Population Change = (births + immigration) – (deaths + emigration) U.S. growth continues because of both births and immigration

15. 15 Death rates on the decline… people living longer Death rates on the decline… people living longer Why? Why? Population Change = (births + immigration) – (deaths + emigration) Better hygiene, sewage disposal, clean water, medicines, education, access to food, nutrition

16. 16 Demographic Transition Every Country Goes Through It Explain what you see on this chart

17. 17 Stage 1 : High Birth AND Death rates = little population change Stage 2 : Death Rates Fall, Birth Rates Still High = Population Growth Stage 3: Death Rates Low, Birth Rates Drop = Population Growth Slows Stage 4: Death Rates Low, Birth Rate Low = Population Declines DESCRIBE EACH STAGE: WHAT DO YOU SEE?

18. 18 Calculations A town currently has a population of 20 people. If 10 people are born, 8 people die, 3 immigrate and 1 emigrate, what is the population? A town currently has a population of 20 people. If 10 people are born, 8 people die, 3 immigrate and 1 emigrate, what is the population?

19. 19 Calculations USA currently has a population of 320,000,000 people. If 5,000,000 people are born, 2,000,000 people die, 200,000 immigrate and 50,000 emigrate, what is the population? USA currently has a population of 320,000,000 people. If 5,000,000 people are born, 2,000,000 people die, 200,000 immigrate and 50,000 emigrate, what is the population?

20. 20 Rule of 70: Doubling Time 1. Currently, a city has a population of 10 million. When will it reach 20 million if the population is growing at 10% per year (growing 10% every year)? 2. How long will it take a population to go from 200 to 400 if it grows at 5% a year?

21. 21 Rule of 70: Doubling Time 1. Currently, a city has a population of 10 million. When will it reach 20 million if the population is growing at 10% per year (growing 10% every year)? 2. How long will it take a population to go from 200 to 400 if it grows at 5% a year?

22. 22 Review Describe how the size and growth rate for human population has changed over history Describe how the size and growth rate for human population has changed over history What factors lead to population changes What factors lead to population changes Analyze populations using Age Structure Diagrams Analyze populations using Age Structure Diagrams Terms: Demography, Age Structure, Survivorship, Fertility, Migration, Life Expectancy Terms: Demography, Age Structure, Survivorship, Fertility, Migration, Life Expectancy

23. 23 Ages 0-14 Ages 15-44 Ages 45-85+ Rapid Growth Guatemala Nigeria Saudi Arabia Rapid Growth Guatemala Nigeria Saudi Arabia Slow Growth United States Australia Canada Slow Growth United States Australia Canada Male Female Zero Growth Spain Austria Greece Zero Growth Spain Austria Greece Negative Growth Germany Bulgaria Sweden Negative Growth Germany Bulgaria Sweden Population Age Structure Fig. 10-14 p. 184

24. 24 Problems With Rapid Growth Lack of infrastructure to support population Water supplies Water supplies Sewers Sewers Roads Roads Schools Schools Powerplants Powerplants Hospitals Hospitals Housing Housing

25. 25 Problems With Rapid Growth Using up resources too quickly Water supplies Water supplies Food Supplies, Vegetation Food Supplies, Vegetation Wood/fuels : wood supplies critical to life in many regions Wood/fuels : wood supplies critical to life in many regions

26. 26 Problems With Rapid Growth Unsafe water supplies Sewage mixing with water supplies Sewage mixing with water supplies Cholera, Dysentery, Typhoid Cholera, Dysentery, Typhoid 1 Billion lack clean water 1 Billion lack clean water 3 million/yr die 3 million/yr die

27. 27 Clean Water Lacking If the millions of women who haul water long distances had a faucet by their door, whole societies could be transformed.

28. 28 Problems With Rapid Growth Land becomes scarce Arable land : land that can grow crops Arable land : land that can grow crops Tradeoffs made : agriculture, housing, natural habitats Tradeoffs made : agriculture, housing, natural habitats Which do you think typically wins out? Which do you think typically wins out?

29. 29 Problems With Rapid Growth Urbanization: movement of people from rural areas to cities Much of world is going through Much of world is going through Increased demand on infrastructure Increased demand on infrastructure

30. 30 Problems With Growth In U.S. Suburban sprawl: work in cities live in suburbs Decay of inner cities Decay of inner cities Increased traffic Increased traffic Loss of farmland Loss of farmland Decreased wildlife habitat Decreased wildlife habitat

31. 31 Comparing a developed country to Moderately Developed to Developing (lesser developed) Did You Know? On average, 1 American consumes as much natural resources as 5 Chinese or 13 Pakistanis.

32. 32 Diverse World Population Developing (lesser developed) Developing (lesser developed) 5.2 billion people 5.2 billion people living with very little living with very little 97% of population growth. 97% of population growth.

33. 33 Percent of World’s Developing countries Developed countries Population Population growth Wealth and income Resource use Pollution and waste 19 81 0.1 1.6 85 15 88 12 75 25

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35. 35 Growth Is Slowing but still growing