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Published byRose Rogers Modified over 9 years ago
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The study of populations
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Developed Countries Developed Countries -Ex. United states -Have higher average incomes -Slower population growth -Diverse industrial economies Undeveloped Countries -Ex. South Africa -Have lower average incomes -Simple and agriculture- based economies -Rapid population growth -
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Population growth rates increased during each decade Due to increases in food productions and improvements in hygiene with industrial/scientific revolutions.
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Demographers looks at these properties to predict population changes: 1. Age Structure 2. Survivorship 3.Fertility Rates 4.Migration
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Age Structure Diagram Age Structure Diagram = Type of double sided bar graph Typically the more young people than older people leads to an increase in population size.
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= the percentage of members of a group that are likely to survive to any given age. Demographers study groups of people born at the same time and notes when each person dies.
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Type I – Wealthy countries like Japan and Germany bc people live to old age. Type II – populations have similar death rate at all ages. Type III – Poor countries in which many children die early.
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= the number of babies born each year per 1,000 women in a population. Total fertility rate = average number of children a woman gives birth to in her lifetime. - Replacement Level =
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Replacement Level = the average number of children each parent must have in order to “replace” themselves. The average is about 2.1 (since not all children will survive)
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= “the movement of individuals between areas” Two types: 1. Immigration – movement into an area 2. Emigration – movement out of an area Quick check: The population of the U.S. and other developed countries might be DECREASING if not for which? Immigration!
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The dramatic increase in Earth’s human population in the last 200 years has happened because death rates have declined more rapidly than birth rates. Reasons: 1.Access to adequate food 2.Access to clean water 3.Safe sewage disposal
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Look at the chart on page 238 Figure 7 What kind of regions have the highest life expectancies? MORE DEVELOPED COUNTRIES
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“ the average number of years members of a population are expected to live” Most affected by: INFANT MORTALILTY RATE = “ THE DEATH RATES OF INFANTS LESS THAN 1 YEAR OLD ” I N 1900, WORLD WIDE LIFE EXPECTANCY WAS ABOUT 40 YEARS AND THE INFANT MORTALITY RATE WAS VERY HIGH. B Y 2000, THE RATE OF INFANT MORTALITY WAS LESS THAN 1/3 OF THE RATE IN 1900 L IFE E XPECTANCY A VERAGE : A VERAGE = 67 YO D EVELOPED COUNTRIES = 80 YO
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Most affected by parents’ access to: 1.education 2.Fuel 3.Food 4.Clean water *notice it is NOT health care!
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…CONTAGIOUS DISEASES! Tuberculosis AIDS *South Africa’s life expectancy has been reduced due to an AIDS epidemic
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“A model that describes how economic and social changes affect population growth rates.” It has 4 stages:
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Stage 1 “ Preindustrial” Birth and death rates are about equal Most of the world was here until 1700 when stage 2 hit.
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A Population explosion occurs! (may double in ≥ 30 years) Death rates decline: due to hygiene, nutrition, and education improve. Birth rates remain high, so the population grows quickly!
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Birth rate decreases Populations begin to stabilize But the population has quadrupled in size due to the transition.
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The birth rate drops below replacement level, so the size of the population begins to decrease. This has taken 1-3 generations to occur in a developed country.
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Factors that lead to decline in death rates: 1. increasing education 2. economic independance Education: Educated women KNOW they don’t need lots of kids in case a few will die. Family planning $ brings freedom -Contribute to family -Spend less energy bearing/caring for kids
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Traditionally: Some communities children work Kids take care of elderly Modernization: 1.If women work, kids need daycare which is expensive, so less is better. 2. Working creates PENSIONS so elderly support themselves. This is lowering the birth rate!
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Developed: 1.6 children per woman Developing Countries: 3.1 Children per woman
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