Presentation on theme: "Chapter 9 The Human Population Mr. Manskopf Notes also at"— Presentation transcript:
Chapter 9 The Human Population Mr. Manskopf Notes also at http://www.manskopf.com http://www.manskopf.com
Chapter 9 Big Idea The 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.
Section 1: Studying Human Populations Describe how the size and growth rate for human population has changed over history What factors lead to population changes Analyze populations using Age Structure Diagrams Terms: Demography, Age Structure, Survivorship, Fertility, Migration, Life Expectancy
Describe what you see on this graph How long did it take to get to 1 billion, than 2, 3,4,5,6 How many people are living today?
Why do you think it took off around the late 1880s?
Studying Human Populations Demography: the study of human population How many people live where? How long are you expected to live? How many children are you likely to have.
Exponential Growth Exponential Growth: rapid growth often seen as J-Shaped curve on a graph Can that growth continue?
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
Forecasting Population Size Age Structure: the distribution of ages in a population Age Structure Diagrams aka population pyramids What is useful about these diagrams?
What are these age-structure diagrams showing? What are the “reproductive years” Why is that important in forecasting future population growth?
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
What causes population to rise? Population Changes = (births + immigration) – (deaths + emigration) For world population growth we are only concerned about births and deaths.
Fertility Rates Fertility Rates: number of babies born each year per 1,000 women Total fertility rate Replacement rate fertility
Fertility and Women Two main factors impact fertility rates worldwide Education level of women (knowledge of family planning) Economic level of women Generally, on average, more education, more wealth = lower fertility rates
What does this graph show? How has U.S. fertility rates changed?
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
Death rates on the decline… people living longer Why? Population Change = (births + immigration) – (deaths + emigration) Better hygiene, sewage disposal, clean water, medicines, education, access to food, nutrition
Life Expectancy Life Expectancy: average number of years members of a population are expected to live Improvement in most of world Lower INFANT MORTALITY
Demographic Transition Every Country Goes Through It Explain what you see on this chart
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?
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?
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?
Rule of 70: Doubling Time Currently, 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?
Section 1 Review Describe how the size and growth rate for human population has changed over history What factors lead to population changes Analyze populations using Age Structure Diagrams Terms: Demography, Age Structure, Survivorship, Fertility, Migration, Life Expectancy
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
Section 2 : Population Trends What 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.
Problems With Rapid Growth Lack of infrastructure to support population Water supplies Sewers Roads Schools Powerplants Hospitals Housing
Problems With Rapid Growth Using up resources too quickly Water supplies Food Supplies, Vegetation Wood/fuels : wood supplies critical to life in many regions
Problems With Rapid Growth Unsafe water supplies Sewage mixing with water supplies Cholera, Dysentery, Typhoid 1 Billion lack clean water 3 million/yr die
Clean Water Lacking If the millions of women who haul water long distances had a faucet by their door, whole societies could be transformed.
Problems With Rapid Growth Land becomes scarce Arable land : land that can grow crops Tradeoffs made : agriculture, housing, natural habitats Which do you think typically wins out?
Problems With Rapid Growth Urbanization: movement of people from rural areas to cities Much of world is going through Increased demand on infrastructure
Problems With Growth In U.S. Suburban sprawl: work in cities live in suburbs Decay of inner cities Increased traffic Loss of farmland Decreased wildlife habitat
Section 2 Review What 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.