Pop. Dynamics


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Pop. Dynamics

  1. 1. World Population Dynamics
  2. 2. Population Distribution <ul><li>Population distribution is where people live, this can be on a global, regional or local scale. </li></ul><ul><li>Places with lots of people usually have habitable environments they either: </li></ul><ul><li>wealthy and industrial e.g. Europe, Japan etc. </li></ul><ul><li>poor with rapidly growing populations e.g. India, Ethiopia </li></ul><ul><li>Places with few people are usually hostile environments, e.g. Antarctica, Sahara Deserts, Alaska etc. </li></ul>
  3. 4. Areas of Large Population <ul><li>River Valleys. </li></ul><ul><li>e.g. Ganges valley in India, Rhine valley in Germany, Indus Valley in Pakistan. </li></ul><ul><li>Lowlands Plains. </li></ul><ul><li>e.g. Denmark (very low lying and famous for dairy farms), East Anglia in the UK (good location for growing cereals) </li></ul><ul><li>Area rich in natural resources. </li></ul><ul><li>Coastal Plains. </li></ul><ul><li>e.g. New York in the U.S.A. </li></ul>
  4. 5. The Population Explosion
  5. 6. Population Explosion a recent event <ul><li>Last 200 years or less for MDCs </li></ul><ul><ul><li>Industrial Revolution </li></ul></ul><ul><ul><li>Improvement in sanitation and medicine </li></ul></ul><ul><li>Last 50 years or less for LDCs </li></ul><ul><ul><li>Transfer of technology, i.e. medical, agricultural (Green Revolution) </li></ul></ul>
  6. 7. Components Influencing Pop. Growth <ul><li>The Pop. of a country changes because of the relationship between: </li></ul><ul><li>the birth rate — number of live births per </li></ul><ul><li>1000 of the population per year. </li></ul><ul><li>the death rate — number of deaths per 1000 </li></ul><ul><li>of the population per year. </li></ul><ul><li>migration — number of people moving into </li></ul><ul><li>or out of a country. </li></ul>
  7. 8. Rates of Global Pop. Change <ul><li>CBR (crude birth rate) = number of births per 1000 population </li></ul><ul><ul><li>1990: 24 Today: 21.3 </li></ul></ul><ul><li>CDR (crude death rate) = number of deaths per 1000 population </li></ul><ul><ul><li>1990: 9 Today: 8.93 </li></ul></ul><ul><li>growth rate = birth rate - death rate (often in %) </li></ul><ul><ul><li>1990: 1.5% Today: 1.3% </li></ul></ul><ul><ul><li>growth rates have come down </li></ul></ul>
  8. 9. Special Kinds of Fertility and Mortality Rates <ul><li>TFR (total fertility rate) = </li></ul><ul><ul><li>number of children born to a woman during her reproductive years (or life time) </li></ul></ul><ul><ul><li>1990: 3.1 2000: 2.8 </li></ul></ul><ul><li>IMR (infant mortality rate) = </li></ul><ul><ul><li>infant deaths per 1000 live births (infant < 1 yr) </li></ul></ul><ul><ul><li>1990: 62 2000: 56 (1900: 200) </li></ul></ul>
  9. 10. Pop. Growth and Resources <ul><li>The relationship b/w the population grwoth and the resources can be understand by the following three key concepts: </li></ul><ul><li>Overpopulation — when pop. is more than the available resources. </li></ul><ul><li>Under population — when pop. is less than the available resources. </li></ul><ul><li>Optimum population — when population is a/c to the available resources. </li></ul>
  10. 11. Factors Affecting Pop. Growth <ul><li>2. Leading to a high </li></ul><ul><li>death rate </li></ul><ul><li>Health Care </li></ul><ul><li>Infant mortality rate </li></ul><ul><li>Better hygiene </li></ul><ul><li>Life expectancy </li></ul><ul><li>HIV/AIDS </li></ul><ul><li>1. Leading to a high birth </li></ul><ul><li>rate </li></ul><ul><li>Health Care </li></ul><ul><li>Preference for sons </li></ul><ul><li>Early marriages </li></ul><ul><li>Need for human labor </li></ul><ul><li>Lack of information on family planning </li></ul>
  11. 12. <ul><li>3. Migration </li></ul>
  12. 13. Percentage Population Change 1900-1990 5 7 10 11 16 23 27 25 33 33 Death rate 27 34 42 45 46 44 39 31 32 34 Birth rate                     MEXICO 7 7 7 8 9 10 11 13 13 16 Death rate 14 15 17 27 27 22 24 29 34 27 Birth rate                     CANADA 9 9 9 10 10 11 11 13 15 17 Death rate 15 16 16 23 25 20 22 27 30 33 Birth rate                     USA 1990 1980 1970 1960 1950 1940 1930 1920 1910 1900 COUNTRIES
  13. 14. Consequences of Pop. Growth Benefits Problems
  14. 15. <ul><li>Benefits: </li></ul><ul><li>Problems: </li></ul><ul><li>Competition for jobs </li></ul><ul><li>Competition for housing </li></ul><ul><li>Educational opportunities </li></ul><ul><li>Shortage of food supply </li></ul><ul><li>Sanitation and sewage </li></ul><ul><li>Transportation </li></ul><ul><li>Health care </li></ul><ul><li>Controls: </li></ul><ul><li>Incentives and penalties </li></ul><ul><li>Family planning </li></ul>
  15. 16. Population, population change, growth rates <ul><li>Population: number of persons </li></ul><ul><li>Population change: increase in the number of persons (per year) </li></ul><ul><li>Growth rates: rate of change (per year) </li></ul>
  16. 20. Doubling Time <ul><li>Number of years in which a population reaches twice its size </li></ul><ul><li>doubling time can be approximated using growth rates </li></ul><ul><li>doubling time = 69 : growth rate </li></ul><ul><ul><li>rate: 1.4 doubling time: 49 </li></ul></ul><ul><ul><li>rate: 2.0 doubling time: 34.5 </li></ul></ul><ul><ul><li>rate: 0.5 doubling time: 138 </li></ul></ul><ul><ul><li>rate: -0.5 doubling time: ???? </li></ul></ul>
  17. 21. 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>
  18. 22. The Demographic Transition
  19. 23. Five Stages of the Demographic Transition <ul><li>birth rates, death rates and growth rates systematically change through time as societies change: </li></ul><ul><ul><li>modernize, urbanize </li></ul></ul><ul><ul><li>gain access to technology </li></ul></ul>
  20. 24. 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>
  21. 25. Stage 2 <ul><li>high birth rates, declining death rates, rising growth rates </li></ul><ul><li>improvements in sanitation (water) 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>
  22. 26. Stage 3 <ul><li>continued decline of death rates, declining birth rates, growth rates decline from 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>E.g. Mexico, China </li></ul>
  23. 27. Stage 4 & 5 <ul><li>Stage 4: low birth rates, low death rates, low 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>Western Europe, Japan </li></ul></ul>
  24. 28. Population Pyramid with young cohorts
  25. 29. 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>
  26. 30. Population Pyramid and Demographic Transition <ul><li>Stage 2: wide base </li></ul>
  27. 31. Population Pyramid and Demographic Transition <ul><li>stage 3: wide middle </li></ul>
  28. 32. Population Pyramid and Demographic Transition <ul><li>stage 4: slender </li></ul>
  29. 33. Population Pyramid and Demographic Transition <ul><li>stage 5: narrow base </li></ul>
  30. 34. Population Dependency in LEDCs & MEDCs <ul><li>Population dependency is a ratio comparing the number of working age (16-64)* with the number of dependents (0-15 and over 65)*. </li></ul><ul><li>It’s normally written as a single number which is the number of dependents for every one hundred people of working age. </li></ul><ul><li>* The range of these age group can be vary. </li></ul>
  31. 35. Dependency Ratio = no. of children(0-15) + old people(65+)x100 no. of people of working age (16-64) <ul><li>Example: </li></ul><ul><li>The dependency ratio for the UK (1995) </li></ul><ul><li>in millions == 11,360 + 9,029 x100 == 53.84 </li></ul><ul><li>37,867 </li></ul><ul><li>This means that for every 100 economically active </li></ul><ul><li>people , there are nearly 54 people are dependent. </li></ul><ul><li>Note that: D.R.  50-60  MEDCs </li></ul><ul><li>D.R.  60-100  LEDCs </li></ul>
  32. 37. use: International Data Base http:// www.census.gov/ipc/www/idbnew.html , then Online Demographic Aggregation
  33. 38. Frequency of Vital Events: The Population Clock <ul><li>Population Clock </li></ul><ul><li>http://www.census.gov/main/www/popclock.html </li></ul><ul><li>Vital Events (per time unit) </li></ul><ul><li>http://www.census.gov/cgi-bin/ipc/pcwe </li></ul><ul><li>The global population reached 6 billion in fall of 1999 </li></ul>
  34. 39. Population Pyramids <ul><li>Population Pyramids on the Web </li></ul><ul><li>http://www.census.gov/ipc/www/idbpyr.html </li></ul>