Presentation on theme: "Chapter 8 Human Population"— Presentation transcript:
1 Chapter 8 Human Population Mr. ManskopfNotes also at
2 Chapter 8 Big IdeaThe size and growth rate of human population has changed drastically over the last 200 years. Those changes have led to profound changes to almost every place on Earth.
3 China’s One-Child Policy 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.In 2005, there were 32 million more males than females in China under the age of 20Talk About It Is it ethical for governments to limit or encourage human population growth?
4 Studying Human Populations Describe how the size and growth rate for human population has changed over historyWhat factors lead to population changesAnalyze populations using Age Structure DiagramsTerms: Demography, Age Structure, Survivorship, Fertility, Migration, Life Expectancy
5 Describe what you see on this graph How long did it take to get to 1 billion, than 2, 3,4,5,6How many people are living today?Did You Know? Basic sanitation was rare even in the medical profession until 1861, when Dr. Ignaz Semmelweis discovered that doctors’ hand washing greatly reduced patient mortality.
6 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.
7 Studying Human Populations Demography: the study of human populationHow many people live where?How long are you expected to live?How many children are you likely to have.
8 Demography • Population size: Number of people Population density: Number of people living per mi2 (or per km2)Population distribution: How people are distributed within an area
9 Exponential GrowthExponential Growth: rapid growth often seen as J-Shaped curve on a graphCan that growth continue?
10 Forecasting Population Size Will new schools be needed?Should we be building more housing?Should farming practices be improved?Predictions like this often wrong because human behavior changes
11 Forecasting Population Size Age Structure: the distribution of ages in a populationAge Structure Diagrams aka population pyramidsWhat is useful about these diagrams?
12 What are these age-structure diagrams showing? What are the “reproductive years” Why is that important in forecasting future population growth?
13 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
17 What causes population to rise? Changes =(births + immigration) – (deaths + emigration)For world population growth we are only concerned about births and deaths.
18 Fertility RatesFertility Rates: number of babies born each year per 1,000 womenTotal fertility rateReplacement rate fertility
19 Fertility and Women Two main factors impact fertility rates worldwide Education level of women (knowledge of family planning)Economic level of womenGenerally, on average, more education, more wealth = lower fertility rates
20 How has U.S. fertility rates changed? What does this graph show?How has U.S. fertility rates changed?
21 Migration: movement INTO (immigration) or OUT of (emigration) an area PopulationChange =(births + immigration) – (deaths + emigration)Migration: movement INTO (immigration) or OUT of (emigration) an areaU.S. growth continues because of both births and immigration
22 Death rates on the decline… people living longer PopulationChange =(births + immigration) – (deaths + emigration)Death rates on the decline… people living longerWhy?Better hygiene, sewage disposal, clean water, medicines, education, access to food, nutrition
23 Life ExpectancyLife Expectancy: average number of years members of a population are expected to liveImprovement in most of worldLower INFANT MORTALITY
26 Demographic Transition Every Country Goes Through It Explain what you see on this chart
27 DESCRIBE EACH STAGE: WHAT DO YOU SEE? Stage 1 : High Birth AND Death rates = little population changeStage 2 : Death Rates Fall, Birth Rates Still High = Population GrowthStage 3: Death Rates Low, Birth Rates Drop = Population Growth SlowsStage 4: Death Rates Low, Birth Rate Low = Population DeclinesDESCRIBE EACH STAGE: WHAT DO YOU SEE?
28 CalculationsA 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?
29 CalculationsUSA 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?
30 Rule of 70: Doubling TimeCurrently, a city has a population 10 million. When will it reach 20 million if the population is growing at 10%?How long will it take a population to go from 200 to 400 if it grows at 5% a year?
31 ReviewDescribe how the size and growth rate for human population has changed over historyWhat factors lead to population changesAnalyze populations using Age Structure DiagramsTerms: Demography, Age Structure, Survivorship, Fertility, Migration, Life Expectancy
32 Population Age Structure Rapid GrowthGuatemalaNigeriaSaudi ArabiaSlow GrowthUnited StatesAustraliaCanadaMaleFemaleZero GrowthSpainAustriaGreeceNegative GrowthGermanyBulgariaSwedenFig p. 184
34 Population TrendsWhat are problems associated with rapid human population growth?Compare developed and developing (lesser developed) countries.Investigate strategies for reducing population growth.Terms: arable land, urbanization, suburban sprawl, developed and developing countries.
35 Problems With Rapid Growth Lack of infrastructure to support populationWater suppliesSewersRoadsSchoolsPowerplantsHospitalsHousing
36 Problems With Rapid Growth Using up resources too quicklyWater suppliesFood Supplies, VegetationWood/fuels : wood supplies critical to life in many regions
37 Problems With Rapid Growth Unsafe water suppliesSewage mixing with water suppliesCholera, Dysentery, Typhoid1 Billion lack clean water3 million/yr die
38 Clean Water LackingIf the millions of women who haul water long distances had a faucet by their door, whole societies could be transformed.
39 Problems With Rapid Growth Land becomes scarceArable land : land that can grow cropsTradeoffs made : agriculture, housing, natural habitatsWhich do you think typically wins out?
40 Problems With Rapid Growth Urbanization: movement of people from rural areas to citiesMuch of world is going throughIncreased demand on infrastructure
41 Problems With Growth In U.S. Suburban sprawl: work in cities live in suburbsDecay of inner citiesIncreased trafficLoss of farmlandDecreased wildlife habitat
51 ReviewWhat are problems associated with rapid human population growth?Compare developed and developing (lesser developed) countries.Investigate strategies for reducing population growth.Terms: arable land, urbanization, suburban sprawl, developed and developing countries.