exam –next friday (feb 6) –1 essay, 50 multiple-choice, t/f, matching – #2 pencil –study...
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• Exam– Next Friday (Feb 6)– 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 ??
Some Topics Discussed
• Population growth
• Limits to growth
• Human demography
• Demographic transition
• Family planning and fertility control
• The future of human populations
ESC110 Chapter 4. Human Populations
• World pop:World pop: – 2003 = 6,271,470,983– 2004 = 6,345,338,406
• US pop:US pop:– 2003 = 290,131,722– 2004 = 292,484,293
http://www.census.gov/main/www/popclock.html
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
P = number of peopleA = affluence or average resource-use per personT = technology or the beneficial & harmful environmental effects of the
technologies used to provide & consume each unit of resource
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
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.
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
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
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)
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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