Human population


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Human population

  1. 1. Human Population : Growth, Demography and Carrying Capacity AP Environmental Science Chapters 9, 12 & 13
  2. 2. Human Population Growth Historically <ul><li>Early Hunter Gatherers </li></ul><ul><ul><li>Nomadic, with a strong sense of the earth </li></ul></ul><ul><ul><li>Practiced intentional birth control </li></ul></ul><ul><li>Rise of Agriculture </li></ul><ul><ul><li>Necessary for Survival </li></ul></ul><ul><ul><ul><li>Animals became extinct via predation and altered habitat </li></ul></ul></ul><ul><ul><ul><li>Humans began to cultivate own food </li></ul></ul></ul>
  3. 3. <ul><li>C. Agriculture Gives Rise to Cities </li></ul><ul><ul><li>Food produced in country, consumed in city </li></ul></ul><ul><ul><ul><li>Food wastes are no longer returned to soil </li></ul></ul></ul><ul><ul><ul><li>Soil becomes less productive </li></ul></ul></ul><ul><ul><li>Waste of populations concentrated in cities </li></ul></ul><ul><ul><li>Population control in medieval societies </li></ul></ul><ul><ul><ul><li>Infanticide </li></ul></ul></ul><ul><ul><ul><li>Plagues </li></ul></ul></ul>
  4. 4. <ul><li>D. Industrialization </li></ul><ul><ul><li>View of children during early phases of industrial growth </li></ul></ul><ul><ul><ul><li>Valued as cheap source of income and cheap labor </li></ul></ul></ul><ul><ul><ul><li>Exponential growth of populations </li></ul></ul></ul><ul><ul><li>By 1900s, Birth Rate in Industrialized World Dropped </li></ul></ul><ul><ul><ul><li>Rise in standards of living </li></ul></ul></ul><ul><ul><ul><li>Safe and inexpensive means of birth control introduced </li></ul></ul></ul><ul><ul><ul><li>Increase in the cost of child rearing </li></ul></ul></ul>
  5. 5. Increasing our carrying capacity <ul><li>Technology has allowed us to raise Earth’s carrying capacity for our species time and again. </li></ul><ul><li>Tool-making, agriculture, and industrialization each enabled humans to sustain greater populations. </li></ul>
  6. 7. MI L L I O NS
  7. 8. Population Projections Over 95% of this increase will take place in “Developing Countries”
  8. 10. Current World Population <ul><li>Population Clock Vital Events (per time unit) </li></ul><ul><li>Global population was 6,669,203,826 </li></ul><ul><li>On February 27, 2007 at 6:13 am </li></ul><ul><li>The global population grows by: </li></ul><ul><ul><li>Nearly 2.3 persons per second </li></ul></ul><ul><ul><li>Nearly 8,343 persons per hour </li></ul></ul><ul><ul><li>Over 200,234 persons per day </li></ul></ul><ul><ul><li>Over 73 million persons per year </li></ul></ul>
  9. 11. Human Population Dynamics <ul><li>There are just three sources of change in population size — </li></ul><ul><li>fertility </li></ul><ul><li>mortality </li></ul><ul><ul><li>&quot;natural decrease&quot; refers to population decline resulting from more deaths than births </li></ul></ul><ul><li>migration </li></ul><ul><ul><li>Net migration is the number of immigrants minus emigrants </li></ul></ul>
  10. 12. Factors affecting population growth rates <ul><li>Population growth depends on rates of birth, death, immigration, and emigration. </li></ul><ul><li>(birth rate + immigration rate) </li></ul><ul><li>– (death rate + emigration rate) </li></ul><ul><li> = population growth rate </li></ul>
  11. 13. Rates of Global Pop. Change <ul><li>CBR ( crude birth rate ) = # births / 1000 population </li></ul><ul><li>CDR ( crude death rate ) = # deaths / 1000 populatio </li></ul><ul><li>Growth Rate = (b + i) – (d + e) </li></ul><ul><ul><li>growth rates have come down </li></ul></ul>
  12. 16. Human Population Dynamics <ul><li>Total fertility rate (TFR) </li></ul><ul><ul><li>The average number of children born to a woman </li></ul></ul><ul><ul><li>Average in developed countries = 1.5 </li></ul></ul><ul><ul><li>Average in developing countries = 3.8 </li></ul></ul><ul><ul><li>Worldwide 1990: 3.1 now: 2.76 </li></ul></ul><ul><li>Replacement fertility rate (RFR) </li></ul><ul><ul><li>The number of children a couple must have to replace themselves </li></ul></ul><ul><ul><li>A TFR of 2.1 for developed countries with low infant and child mortality rates </li></ul></ul><ul><ul><li>Africa RFR = 2.5 </li></ul></ul>
  13. 17. Female education and TFR <ul><li>Female literacy and school enrollment are correlated with total fertility rate. </li></ul><ul><li>More-educated women have fewer children. </li></ul>
  14. 18. What Is Family Planning ? <ul><li>Definition </li></ul><ul><ul><li>Measures enabling parents to control number of children (if they so desire) </li></ul></ul><ul><li>Goals of Family Planning </li></ul><ul><ul><li>Not to limit births </li></ul></ul><ul><ul><li>For couples to have healthy children </li></ul></ul><ul><ul><li>For couples to be able to care for their children </li></ul></ul><ul><ul><li>For couples to have the number of children that they want </li></ul></ul>
  15. 20. Poorer countries will experience most future population growth <ul><li>98% of the next billion people born will live in developing nations. </li></ul>
  16. 21. <ul><li>China’s Program </li></ul><ul><ul><li>Nation With Best Known Population Control Program </li></ul></ul><ul><ul><li>Reasons Chinese Government Initiated Population Control Measures </li></ul></ul><ul><ul><ul><li>Freshwater and food at a premium for nation’s population </li></ul></ul></ul><ul><ul><ul><li>Country experiencing population momentum </li></ul></ul></ul><ul><ul><li>Government Perks / Coercive Measures for Citizen Compliance </li></ul></ul><ul><ul><ul><li>Free education and health care </li></ul></ul></ul><ul><ul><ul><li>Increased personal and family incomes </li></ul></ul></ul><ul><ul><ul><li>Increased legal marrying age for women </li></ul></ul></ul><ul><ul><ul><li>Contraceptives, abortions, and sterilizations free of charge </li></ul></ul></ul><ul><ul><ul><li>Preferential housing and retirement income </li></ul></ul></ul>
  17. 22. What Methods are Used to Control Births? <ul><li>Preconception Birth Control Methods </li></ul><ul><ul><li>Barrier Methods </li></ul></ul><ul><ul><ul><li>Condom </li></ul></ul></ul><ul><ul><ul><li>Vaginal sponge </li></ul></ul></ul><ul><ul><ul><li>Diaphragm </li></ul></ul></ul><ul><ul><ul><li>Spermicides </li></ul></ul></ul><ul><ul><li>Hormonal Contraceptives </li></ul></ul><ul><ul><ul><li>Pill </li></ul></ul></ul><ul><ul><ul><li>Injections and implants </li></ul></ul></ul><ul><ul><li>Sterilization </li></ul></ul><ul><li>Postconception Birth Control Measures </li></ul><ul><ul><li>Intrauterine Device </li></ul></ul><ul><ul><li>RU-486 Pill </li></ul></ul><ul><ul><li>Abortion </li></ul></ul>
  18. 23. Contraceptive Use Worldwide <ul><li>People in industrialized countries enjoy easy access to contraceptives while those in LDCs do not. </li></ul><ul><li>In the U.S., teens and poor women are least likely to use contraceptives. </li></ul><ul><li>Severe problems are associated with teen pregnancy. </li></ul>
  19. 24. Human Population Dynamics <ul><li>infant mortality rate </li></ul><ul><li>IMR </li></ul><ul><li>infant deaths per 1000 live births (infant < 1 yr) </li></ul><ul><ul><li>1990: 62 now: 52.4 (normal in 1900: 200) </li></ul></ul>
  20. 25.
  21. 26. chem-enc-1.html
  22. 27. Maternal Deaths per 100,000 Live Births Source: WHO, UNICEF, UNFPA Maternal Mortality in 1995: Estimates Developed by WHO, UNICEF AND UNFPA, 2001 .
  23. 28. HIV/AIDS and human population <ul><li>Infects 1 in 5 people in southern African nations </li></ul><ul><li>Kills babies born to infected mothers </li></ul><ul><li>Has orphaned 14 million children </li></ul><ul><li>Has cut 19 years off life expectancies in parts of southern Africa </li></ul>
  24. 29. Migration Net migration is the number of immigrants minus emigrants
  25. 31. <ul><li>Overall, the world population is growing at a rate of about 1.7 percent; if this rate continues, the population will double in 42 years. </li></ul><ul><li>Unabated, such a rate would lead to a point about 2000 years hence when the mass of humanity would weigh more, and be larger, than the Earth. </li></ul><ul><li>But, the growth rate is decreasing </li></ul>
  26. 32. Rule of 70’s <ul><li>Predicting long-term population growth- </li></ul><ul><li>70/ growth rate = doubling time </li></ul><ul><li>If a population of a country grows at a rate of 5% a year, the number of years required for the pop to double is what? </li></ul>
  27. 34. Population Pyramids <ul><li>Graphic device: bar graph </li></ul><ul><li>shows the age and gender composition of a region </li></ul><ul><li>horizontal axis: gender </li></ul><ul><ul><li>male: left-hand female: right-hand </li></ul></ul><ul><ul><li>absolute number of people or % </li></ul></ul><ul><li>vertical axis: age </li></ul><ul><ul><li>5-year or 10-year age groups </li></ul></ul>
  28. 35. Population Pyramid with young cohorts
  29. 36. Population Pyramids <ul><li>Population Pyramids on the Web </li></ul><ul><li>High Growth : Afghanistan </li></ul><ul><li>Moderate Growth : Mexico </li></ul><ul><li>Zero Growth : U.S. </li></ul><ul><li>Negative Growth : Austria or Italy </li></ul>
  30. 38. Population Pyramids <ul><li>Population Pyramids on the Web </li></ul><ul><li>High Growth : Afghanistan </li></ul><ul><li>Moderate Growth : Mexico </li></ul><ul><li>Zero Growth : U.S. </li></ul><ul><li>Negative Growth : Austria or Italy </li></ul>
  31. 40. Population Pyramids <ul><li>Population Pyramids on the Web </li></ul><ul><li>High Growth : Afghanistan </li></ul><ul><li>Moderate Growth : Mexico </li></ul><ul><li>Zero Growth : U.S. </li></ul><ul><li>Negative Growth : Austria or Italy </li></ul>
  32. 42. Population Pyramids <ul><li>Population Pyramids on the Web </li></ul><ul><li>High Growth : Afghanistan </li></ul><ul><li>Moderate Growth : Mexico </li></ul><ul><li>Zero Growth : U.S. </li></ul><ul><li>Negative Growth : Italy </li></ul>
  33. 44. <ul><li>Movement of a nation from high population growth to low population as it develops economically </li></ul><ul><li>Transition as a result of four stages </li></ul><ul><ul><li>Stage 1 —Birth and death rates are both high </li></ul></ul><ul><ul><li>Stage 2 —Death rates fall; birth rates remain high; growth rate rises </li></ul></ul><ul><ul><li>Stage 3 —Birth rates fall as standard of living rises; growth rate falls </li></ul></ul><ul><ul><li>Stage 4 —Growth rate continues to fall to zero or to a negative rate </li></ul></ul>Demographic Transition
  34. 45. Demographic transition: Stages
  35. 46. Population Pyramids and Demographic Stages <ul><li>characteristics shapes of ‘pyramids’ </li></ul><ul><ul><li>wide base (true pyramid) </li></ul></ul><ul><ul><li>wide middle (bulge), somewhat wider base </li></ul></ul><ul><ul><li>urn- or bottle-shaped </li></ul></ul><ul><ul><li>reversed pyramid </li></ul></ul><ul><li>different shapes--different dynamics </li></ul>
  36. 47. Stage 1 <ul><li>high birth rates, high (at time erratic) death rates, low growth rates </li></ul><ul><li>stage for much of human history, traditional societies </li></ul><ul><li>practically no country today </li></ul>
  37. 49. Stage 2 <ul><li>high birth rates, </li></ul><ul><li>declining death rates, </li></ul><ul><li>rising growth rates </li></ul><ul><li>improvements in </li></ul><ul><li>sanitation (water) </li></ul><ul><li>and medicine </li></ul><ul><li>in Europe during Industrial Revolution </li></ul><ul><li>in developing countries since the 50s/60s </li></ul><ul><li>much of Africa today, some countries of Asia (Afghanistan, Nepal, etc.) </li></ul>
  38. 50. Population Pyramid and Demographic Transition <ul><li>Stage 2: wide base </li></ul><ul><li>stage 3: wide middle </li></ul><ul><li>stage 4: slender </li></ul><ul><li>stage 5: narrow base </li></ul>
  39. 51. Stage 3 <ul><li>continued decline of death </li></ul><ul><li>rates, declining birth rates, </li></ul><ul><li>growth rates decline from </li></ul><ul><li>high to lower levels </li></ul><ul><li>change in behavior: adaptation to lower death rate, in particular infant mortality rate </li></ul><ul><li>economic change: urbanization (incentive to have fewer children) </li></ul><ul><li>Mexico today </li></ul>
  40. 52. Population Pyramid and Demographic Transition <ul><li>Stage 2: wide base </li></ul><ul><li>stage 3: wide middle </li></ul><ul><li>stage 4: slender </li></ul><ul><li>stage 5: narrow base </li></ul>
  41. 53. Stage 4 & 5 <ul><li>Stage 4: low birth rates, </li></ul><ul><li>low death rates, low </li></ul><ul><li>growth rates </li></ul><ul><ul><li>United States today </li></ul></ul><ul><li>Stage 5: low birth rates, rising death rates, declining growth rates (if birth rates drop below death rates: negative growth rates) </li></ul><ul><ul><li>several countries of Europe today (Austria) </li></ul></ul>
  42. 54. Population Pyramid and Demographic Transition <ul><li>Stage 2: wide base </li></ul><ul><li>stage 3: wide middle </li></ul><ul><li>stage 4: slender </li></ul><ul><li>stage 5: narrow base </li></ul>
  43. 55. Population Pyramid and Demographic Transition <ul><li>Stage 2: wide base </li></ul><ul><li>stage 3: wide middle </li></ul><ul><li>stage 4: slender </li></ul><ul><li>stage 5: narrow base </li></ul>
  44. 56. <ul><li>Population Path of Most Less-Developed Countries (LDCs) </li></ul><ul><li>“ Trapped” in Stage 2 of Demographic Transition </li></ul><ul><ul><li>Before 1970, LDCs seemed poised to make transition thanks to economic growth </li></ul></ul><ul><ul><li>Since 1970, economic growth has not kept pace with population </li></ul></ul><ul><ul><li>High birth and low death rates result in explosive population growth </li></ul></ul><ul><ul><li>Downward spiral in standard of living </li></ul></ul>Demographic Trap
  45. 57. Demographic Fatigue <ul><ul><li>Condition characterized by a lack of financial resources and an inability to deal effectively with threats such as natural catastrophes and disease </li></ul></ul><ul><ul><li>Possibility that countries suffering from demographic fatigues could slip back into Stage 1 of demographic transition </li></ul></ul>
  46. 58. Age Structure & Population Projections <ul><li>Baby boomers - half of U.S. population; use most of goods and services; make political and economic decision </li></ul><ul><li>baby-bust generation - born since 1965; may have to pay more income, health care and social security to support retired baby boomers; but face less job competition </li></ul><ul><li>Better health may --> later retirement of baby boomers --> keep high-salary jobs </li></ul>
  47. 59. Tracking the baby-boom generation in the United States
  48. 60. Effects of Population Decline <ul><li>As percentage of 60+ aged people increases, population begins decline </li></ul><ul><li>60+population increase --> severe economic and social problems because 60+ consume </li></ul><ul><ul><li>more medical care </li></ul></ul><ul><ul><li>Social Security </li></ul></ul><ul><ul><li>costly public services </li></ul></ul><ul><li>Labor shortages require automation & immigration </li></ul>
  49. 62. The Graying of Japan <ul><li>Family-planning access, cramped housing, expensive land, late marriage, education cost --> voluntary decrease in birth rate </li></ul><ul><li>Low immigration rate </li></ul><ul><li>Health insurance and pension - 45% of national income; could -->low economy </li></ul><ul><li>Illegal immigration bolsters work force </li></ul>
  50. 64. Influencing Population Size <ul><li>Most countries restrict immigration </li></ul><ul><ul><li>Canada, Australia, U.S. - most immigration </li></ul></ul><ul><li>Involuntary immigration results from </li></ul><ul><ul><li>armed conflict </li></ul></ul><ul><ul><li>environmental degradation </li></ul></ul><ul><ul><li>natural disaster --> environmental refugees </li></ul></ul><ul><li>Migration from rural to urban areas </li></ul>
  51. 66. F amily P lanning: reduce births and abortions <ul><li>59% contraceptive use in developed countries -46% overall, up from 10% in 60s </li></ul><ul><li>FP reduces children's social services needs </li></ul><ul><li>FP reduces risk of childbearing deaths </li></ul><ul><li>FP effectiveness depends on program design and funding: </li></ul><ul><ul><li>good in some counties with good program </li></ul></ul><ul><ul><li>poor in other counties </li></ul></ul>
  52. 67. F amily P lanning: reduce births and abortions -2 <ul><li>Services not always accessible; add female teenagers and sexually active unmarried </li></ul><ul><li>Add birth control for men (sperm-killing device used in China) </li></ul><ul><li>If developed countries provided $17 billion/ year, and each person pays $4.80/year, average family size would be 2.1 and world population would be 2.9 billion </li></ul>
  53. 68. Rewards and Penalties to reduce births <ul><li>What might work: </li></ul><ul><ul><li>encourage, rather than coerce, people to have fewer children </li></ul></ul><ul><ul><li>reinforce existing customs and trends toward smaller families </li></ul></ul><ul><ul><li>don’t penalize for already existing larger family </li></ul></ul><ul><ul><li>increase poor family’s economic status </li></ul></ul>
  54. 69. Empowering women to reduce births <ul><li>Women tend to have fewer, and healthier children when: </li></ul><ul><ul><li>they have access to education and paying jobs outside home </li></ul></ul><ul><ul><li>their society doesn’t suppress women’s rights </li></ul></ul><ul><li>But women do most of the work </li></ul><ul><ul><li>not shown in GDP because of lower pay </li></ul></ul><ul><ul><li>Women excluded from economic and political decision making </li></ul></ul>
  55. 70. Case Studies - India <ul><li>Family planning efforts began in 1952; fertility rate declined from 5.3 to 3.4 but population grow is still exponential -1.9% </li></ul><ul><li>Disappointing results due to: </li></ul><ul><ul><li>poor planning </li></ul></ul><ul><ul><li>bureaucratic inefficiency </li></ul></ul><ul><ul><li>low status of women </li></ul></ul><ul><ul><li>extreme poverty </li></ul></ul><ul><ul><li>lack of administrative & financial support </li></ul></ul>
  56. 72. Case Studies - China <ul><li>Family planning efforts began in 1970; TFR fell from 5.7 to 1.8; infant mortality and illiteracy rates 1/3 to 1/2 of India’s rates </li></ul><ul><li>Population control program is extensive, intrusive and strict: </li></ul><ul><ul><li>postpone childbearing </li></ul></ul><ul><ul><li>only one child/family -->benefits </li></ul></ul><ul><ul><li>effect b/c China is dictatorship; limited resources would have mean disaster </li></ul></ul>
  57. 73. Cutting Global Population Growth <ul><li>U. N.Conference on Population and Development, Cairo, 1994 </li></ul><ul><ul><li>8 goals to be met by 2015 (p. 276) </li></ul></ul><ul><ul><li>are these goals wishful thinking? </li></ul></ul><ul><li>Replacement level fertility can be met in 15-30 years as shown by Japan, Thailand… </li></ul><ul><li>Invest in family planning, reduce poverty, and elevate status of women </li></ul>
  58. 74. Population and the environment <ul><li>Population growth can lead to environmental degradation. </li></ul><ul><li>Overpopulation in Africa’s Sahel region has led to overgrazing of semi-arid lands. (China obviously also an ex.) </li></ul>
  59. 75. Affluence and the environment <ul><li>Poverty can lead to environmental degradation… </li></ul><ul><li>BUT </li></ul><ul><li>wealth and resource consumption can produce even more severe and far-reaching environmental impacts. </li></ul>
  60. 76. The wealth gap <ul><li>Residents of developed nations have larger houses, more possessions, and more money than residents of developing nations. </li></ul><ul><li>The richest 20% of the world’s people consumes 86% of its resources, and has > 80 times the income of the poorest 20%. </li></ul>
  61. 77. Food and Hunger <ul><li>840 million people are hungry </li></ul><ul><li>799 million of those are in developing countries </li></ul><ul><li>The other 40 million are in developed countries </li></ul><ul><li>½ of the US population relies on food stamps </li></ul>
  62. 78. Food and Hunger <ul><li>1.2 billion are overweight </li></ul><ul><li>30% of the U.S. population is obese </li></ul><ul><li>Why does this dichotomy exist? </li></ul><ul><li>POVERTY </li></ul>
  63. 79. Poverty in Developing Nations <ul><li>Trade imbalances exist between developed nations and developing nations. </li></ul><ul><li>U.S. has outsourced production to these poverty-stricken nations. </li></ul><ul><li>Many will work under terrible conditions and long hours because it is a better alternative to continued poverty. </li></ul>
  64. 80. Cage People of Hong Kong
  65. 83. FAIR TRADE <ul><li>www. / watch ?v=NZpUwCfINh8 </li></ul>
  66. 84. <ul><li>What's Behind the Chocolate? </li></ul>
  67. 85. Ecological Footprints <ul><li>Environmental Impact Equation (Paul Ehrlich Formula) </li></ul><ul><li>I = P x A x T </li></ul><ul><li>I= Total Impact </li></ul><ul><li>P= Population size </li></ul><ul><li>A= Affluence </li></ul><ul><li>T= Level of technology </li></ul>
  68. 86. Ecological Footprints <ul><li>The amount of the earth’s surface that’s necessary to supply the needs of, dispose of the wastes of a particular population. </li></ul><ul><li>U.S. requires 9.7 hectacres/ person </li></ul><ul><li>Indonesia requires 1.1 hectacres/ person </li></ul>
  69. 87. EcoTopia <ul><li>Boulder, Colorado </li></ul><ul><ul><li>Provide bike trails throughout the city </li></ul></ul><ul><ul><li>Citizens voted to increase their taxes to pay for community use green space </li></ul></ul><ul><ul><li>Busses are available to commute throughout the urban sprawl </li></ul></ul><ul><ul><li>Carpools are encouraged </li></ul></ul><ul><ul><li>Strong recycling programs </li></ul></ul>
  70. 88. KNOW THESE FORMULAS! <ul><li>Doubling Time = ___ 70_____ </li></ul><ul><li>% growth rate </li></ul><ul><li>Population Density = # of Individuals </li></ul><ul><li>area sampled </li></ul><ul><li>%Growth Rate= b-d + i-e X 100 </li></ul><ul><li>population size </li></ul>
  71. 89. <ul><li>The Human Population </li></ul>
  72. 90. <ul><li>Short of thermonuclear war itself, rampant population growth is the gravest issue the world faces over the decades immediately ahead. If we do not act, the problem will be solved by famine, riots, insurrection and war . </li></ul><ul><li>Robert S. McNamara </li></ul>