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Human Populations Chapter 9
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Demography… the study of populations births, deaths, income, economics, incidence of disease, social structure,… 7 Billion – NatGeo http://www.youtube.com/watch?v=sc4HxPxNrZ0&list=PL3072BF316D74A1 DF&index=2http://www.youtube.com/watch?v=sc4HxPxNrZ0&list=PL3072BF316D74A1 DF&index=2 – 3 min
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Demographers group countries as.... DEVELOPED high average incomes slow population growth industrial economies good social systems good health care DEVELOPING low average incomes fast population growth agricultural economies poor social systems poor health care
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The Human Population…. grew slowly for 1000’s of years 1800’s – population reached 1 billion 1800’s to today - rapid (EXPONENTIAL) growth today – population over 7 billion
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For most of our human existence our ancestors led precarious lives as hunter- gatherers (some people still live like this)… this kept our population under 1 billion
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The Industrial Revolution (1760’s) brought about better living conditions and advancements in medicine, education, sanitation,…..our population has grown to over 7 billion
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Graph Source: www.census.gov & www.wikipedia.orgwww.census.gov 10,000 BC - about 1 million of us 1800’s AD - about 1 billion of us 10,000 BC 1800’s AD
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Graph Source: www.census.gov & www.wikipedia.orgwww.census.gov TODAY, we are “off the chart” with a population of OVER 7 billion Exponential Growth – J curve In just 213 years (1800’s to 2013) our population has grown from 1 billion to over 7 billion)
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TODAY…the U.S. Census Bureau estimates the World population at… World Population 7,071,548,673 18:35 UTC (EST+5) Mar 11, 2013
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What’s your number? World Population Counter hyperlink http://populationaction.org/Articles/Whats_Your_Number/Summary.php
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World population reached… 1 billion in 1800’s 2 billion in 1927 (123 years later) 3 billion in 1960 (33 years) 4 billion in 1974 (13 years) 5 billion in 1987 (12 years) 6 billion in 1999 (12 years) 7 billion in 2011 (12 years) 8 billion in ? 9 billion in ? Do you see a pattern? TAKEN FROM… http://bioweb.wku.edu/courses/Biol115/wyatt/Population/pop1.htm
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What About The Future… The projected estimates for 2050 are…. 10.7 billion (high) 8.9 billion (middle) 7.3 billion (low) the world is adding about 78 MILLION more people every year
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Remember Carrying Capacity? What is the Earth’s carrying capacity? estimates - 10 -15 billion Why do these estimates vary? difficult to determine scientists use different methods to get estimates
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Our impact is increasing. LANDSAT Images 1973, 2000, 2006 Las Vegas, Nevada
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Human Impact on The Environment year 1700, 2002, (projected) 2032 Source: Hugo Ahlenius. 2003. UNEP/GRID-Arendal. Global Environmental Outlook 3, 2002. Human Impact on the Environment, 1700Human Impact on the Environment, 2002Human Impact on the Environment, 2032
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Forecasting/Projecting Population Size Demographers make predictions about populations using… Age Structure Survivorship Fertility Rates Migration
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Age Structure distribution of ages in a population at a certain time can be graphed using a population pyramid (seen below) Sweden and US have slow growth while Mexico has rapid growth
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Survivorship percentage of individuals likely to survive to a given age Centre County, Pennsylvania What was survivorship in 1819? 1859? 1879?
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Survivorship Curve Type I – most individuals live to an old age – developed nations Type II – similar death rates at all ages Type III – most individuals die at early age – many developing nations
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Fertility Rate… Fertility Rate = # of babies born each year per 1,000 women Total Fertility Rate = average number of children a woman gives birth to during her lifetime Total Fertility Rate varies from… 1+ - Japan and Italy - developed nations 7 - Niger and Mali - developing nations 2.1 - United States – developed nation
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Total Fertility Rate Developed countries – average 1.6 children per woman Developing countries – average 3.1 children per woman Why is this number higher in developing countries? REPLACEMENT RATE - the rate at which a population neither grows nor shrinks 2.1 is generally regarded as the replacement rate in the developed world
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Palestinian TerritoriesFertility Rate 1975-19807.39 1980-19857.00 1985-19906.43 1990-19956.46 1995-20005.99 2000-20055.57 Africa Fertility Rate 1975-19806.60 1980-19856.45 1985-19906.11 1990-19955.67 1995-20005.26 2000-20054.97 U.K. Total fertility rate 1975-19801.72 1980-19851.80 1985-19901.81 1990-19951.78 1995-20001.70 2000-20051.66 Do you notice any trends? TOTAL http://video.cnbc.com/gallery/?video=3000137717 – 2 min http://video.foxnews.com/v/2266634659001/declining-fertility-rate-the-biggest-threat-to-america/http://video.foxnews.com/v/2266634659001/declining-fertility-rate-the-biggest-threat-to-america/ - 5 min
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Total Fertility Rate = # of babies per woman
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Migration MIGRATION = movement of individuals between areas o Immigration - movement into an area (or population) o Emigration – movement out of an area (or population) Map shows first migratory routes taken by humans, based on surveys of different types of the male Y chromosome. "Adam" represents the common ancestor from which all Y chromosomes descended. Research based on DNA testing of 10,000 people from indigenous populations around the world. Source: The Genographic Project
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Other Factors Affecting Population Growth Declining Death Rates Life Expectancy Infant Mortality
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Declining Death Rates…. have allowed human population to increase more people have access to…. adequate food clean water sewage disposal vaccines/immunizations and antibiotics
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Life Expectancy… - is increasing throughout the world - average # of years individuals of a population are likely to live Because of… antibiotics immunization/vaccines improved standards of living adequate food clean water better sanitation Life Expectancy Worldwide 67+ years Developed Countries 80+ years
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Life Expectancy
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Life Expectancy is most affected by… Infant Mortality (rate) = death rate of infants less than a year old (per 1000 live births) Infant Mortality varies … as low as 3 - Singapore + Iceland as much as 150 - Sierra Leone + Afghanistan just over 6 – United States High infant mortality tends to result in higher fertility rates as families seek “insurance” for the loss of children.
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Infant Mortality Infant Mortality (death) is DECLINING in most countries Infant Mortality is MOST AFFECTED by the parents access to…. education, adequate food, fuel, clean water Expensive medical care is not as important
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Infant Mortality
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Demographic Transition F model that describes how economic and social changes affect population growth
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Women and Fertility… Decline in birth rates due to … Increased education Economic independence for women
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Influences on Birth Rates Family planning programs Contraceptive technology Role of mass media Government Billboard, Indonesia
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Rapid Population Growth... 1. BRINGS ENVIRONMENTAL PROBLEMS 2. USES RESOURCES AT AN INCREASED RATE 3. CAN OVERWHELM INFRASTRUCTURE
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Environmental Problems I = P x A x T Impact = Population x Affluence x Technology Population-influenced environmental problems…. Global Warming Habitat Loss / Endangered Species Resource Depletion Food Shortages? Not globally, but regionally..
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Use of Resources at an Increased Rate (Resource Consumption) vegetation, water, land - most affected resources In chapter 1 we talked about the 2 root causes of environmental problems. What are they?
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Shortage of Fuel Wood Fuel Wood = firewood, charcoal, chips, sheets, pellets, sawdust often it is the most available form of fuel – for cooking + heating
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Unsafe Water Local water supply may be used for drinking, washing and sewage disposal
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Barren Land loss of Arable Land ( land used to grow crops)
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Much of the World’s Population is undergoing URBANIZATION URBANIZATION = movement of people from rural areas to cities URBAN = cities and towns SUBURBAN = residential area outside an urban area RURAL = outside cities and towns = “country” What are some problems associated with urbanization?
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Infrastructure INFRASTRUCTURE = basic facilities and services that support a community public water, sewer, power plants, roads, schools, hospitals,… Overcrowded Schools Inadequate Housing
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What might limit the human population? F Lack of resources – food, water, shelter F Emerging Diseases – Ebola, Hanta Virus, Lassa Fever, SARS,….
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Population Growth is Slowing Challenges to Population Control –manufacture/distribution expense –religion –low female status u fastest way to reduce fertility rate is to educate women –preference for male children –female Infanticide
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Human Population Forecasts/Projections How many people will the planet eventually support? it is thought that … world population will level off somewhere between 9 and 11 billion people
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Overpopulation When consumption of natural resources by people outstrips the ability of a natural region to replace those natural resources.
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