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Exam Next Friday (Feb 6) Review 3:30 Wed (Feb 4) in ??
1 essay, 50 multiple-choice, T/F, matching #2 pencil Study questions available on the class web site Review 3:30 Wed (Feb 4) in ??
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ESC110 Chapter 4. Human Populations
Some Topics Discussed Population growth Limits to growth Human demography Demographic transition Family planning and fertility control The future of human populations
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Population Growth World population now over 6 billion
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World pop: 2003 = 6,271,470,983 2004 = 6,345,338,406 US pop: 2003 = ,131,722 2004 = ,484,293
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Current Birth and Death Rates
Every second: 4 or 5 children are born, while 2 other people die Net gain: 2.5 humans added to the world population every second 78 million added every year
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Effect of Birth Rate and Death Rate on Population Size
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Human Population Levels Throughout History
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Growth to a Stable Population
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Overshoots and Diebacks
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Basic Causes of Environmental Problems
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(McKinney & Schoch)
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P x A x T Environmental Impact =
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P = number of people A = affluence or average resource-use per person T = technology or the beneficial & harmful environmental effects of the technologies used to provide & consume each unit of resource
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Projected Population Growth
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Table 4.3
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Limits to Growth Varying Perspectives
Overpopulation causes resource depletion and environmental degradation Human ingenuity and technology will allow us to overcome any problems - more people may be beneficial Resources are sufficient to meet everyone's needs - shortages are the result of greed, waste, and oppression
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Decisions on how many children to have are influenced by many factors, including culture, religion, politics, need for old-age security, and immediate family finances.
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Human Demography Demography - vital statistics about people, such as births and deaths Two demographic worlds Less-developed countries represent 80% of the world population, but more than 90% of projected growth Richer countries tend to have negative growth rates
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By 2050, India will probably be the world’s
most populous country.
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World Population Density
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Fertility and Birth Rates
Fecundity - physical ability to reproduce Fertility - the actual production of offspring Crude birth rate - number of births per year per thousand people Total fertility rate - number of children born to an average woman during her reproductive life Zero population growth (ZPG) - occurs when births + immigration just equal deaths + emigration
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Regional Declines in Total Fertility Rates
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As incomes rise, so does life expectancy.
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Population Growth - Opposing Factors
Pronatalist pressures Factors that increase people’s desires to have children (eg, enjoy family, help earnings, high death rate, help when older, males valued, male pride, etc) Birth reduction pressures Factors that tend to reduce fertility (eg, educated women & careers, higher family earnings, etc)
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U.S. Birth Rates:
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Demographic Transition Accompanying Economic and Social Development
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Demographic Transition
Optimistic view - world population will stabilize during this century Pessimistic view - poorer countries of the world are caught in a "demographic trap" - helping poor countries will only further threaten the earth's resources Social justice view - overpopulation due to a lack of justice, not resources
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Infant Mortality and Women's Rights
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Birth Control Methods Family Planning
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The Future of Human Populations
U.N. Projections
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Fig. 4.13
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Summary: Population Doubling Times Role of Technology
Two Demographic Worlds Fertility and Birth Rates Mortality and Death Rates Population Growth Factors Demographic Transition Future of Population Growth
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