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Population Geography

Population Geography. Counting the Worlds Population. A Lesson In Exponential Growth!. Bacteria Bottles.

vivien-kidd
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Population Geography

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  1. Population Geography Counting the Worlds Population

  2. A Lesson In Exponential Growth! Bacteria Bottles This puzzle illustrates the concept of exponential growth using bacteria. Bacteria multiply by division. One bacterium becomes two. Then two divide into four; the four divide into eight, and so on. For a certain strain of bacteria, the time for this division process is one minute. If you put one bacterium in a bottle at 11:00 p.m., by midnight the entire bottle will be full. John Madden - 2009/10

  3. Bacteria Bottles 1) When will the bottle be half-full? How do you know? 2) Suppose you could be a bacterium in this bottle. At what time would you first realize that you were running out of space? Why? John Madden - 2009/10

  4. Bacteria Bottles Suppose that at 11:58 some bacteria realize that they are running out of space in the bottle. So they launch a search for new bottles. They look far and wide (working at the speed of light). Finally, offshore in the Arctic Ocean, they find three new bottles! Great sighs of relief come from all the bacteria. This is three times the number of bottles they’ve ever known. Surely, they think, their space problems are over. 3) Is that so? Explain why the bacteria are still in trouble. Since their space resources have quadrupled, how long can their growth continue? (Remember it takes an hour to fill up the first bottle) John Madden - 2009/10

  5. Bacteria Bottles Ready For The Answers??? 1) The bottle will be half-full at 11:59 p.m. because the doubling time is one minute and the bottle will be full at midnight. 2) At 11:55 p.m., when the bottle was only 3% full and 97% empty, would it be easy to perceive that there was a space problem? John Madden - 2009/10

  6. Bacteria Bottles 3) With space resources quadrupled, the bacteria have two more doubling times, or two minutes before they will run out of space. • 11:58 p.m. : Bottle 1 is one-quarter full. • 11:59 p.m. : Bottle 1 is half-full. • 12:00 a.m. : Bottle 1 is full. • 12:01 a.m. : Bottles 1 and 2 are full. • 12:02 a.m. : Bottles 1, 2, 3, and 4 are full John Madden - 2009/10

  7. Bacteria Bottles • So, what does this suggest about Human Population Growth?? John Madden - 2009/10

  8. Bacteria Bottles John Madden - 2009/10

  9. Bacteria Bottles John Madden - 2009/10

  10. Bacteria Bottles Human Population Growth! Year John Madden - 2009/10

  11. Why study population? • Over the last 12,000 years of history, population is increasing faster than ever before! • In the last 2000 years, the Earth’s population has increased 10 times • In the last 50 years, Earth’s population has doubled • Will this population growth increase to a level that will cause a global crises?

  12. Population Basics • Demography: the study of human populations • Currently 7 billion people on the Earth • This study is very important because the number of people in a country can influence the infrastructure and support systems of a country • Population Equation • Scale of inquiry: size of a geographic investigation (world, regional or local) important to understand • On global scale, demographers focus on where earth’s populations are increasing fastest and where they are expanding more slowly-least stable areas experiencing the fast growth

  13. Population Facts • About 81% of earth’s population lives in poorer, less developed countries • The only two countries to have more than 1 billion people are India and China • 1 in 3 of earth’s people live in China or India • Nearly 3 of every 5 people live in Asia and Europe • Largest population concentration is East Asia-nearly 25% of earth’s total population: most people subsistent farmers • Third largest population cluster is Europe: most people are urban dwellers

  14. Population Distribution and Density

  15. Population Distribution • Defined: pattern of people across the earth’s surface-where they live • Over history, people have been unevenly distributed-Why? • Few people live in desert/tundra • About 75% of global population lives on 5% of worlds surface • Area people can live is called the ecumene • 50% of earth’s people live in cities

  16. Worlds Population Density http://en.wikipedia.org/wiki/List_of_countries_by_population_density

  17. World Areas of Population Density • East Asia: China, South and North Korea and Japan • 1.5 billion people with 1.3 billion in China • South Asia: India, Pakistan and Bangladesh • Within 50 years, India will pass China as most populace country on planet • Southeast Asia: Vietnam, Indonesia and Thailand • Western and Central Europe: mostly urban • Northeastern United States and Canada: includes megalopolis from Boston to Washington D.C.

  18. Population Density • Defined: number of people in a particular land area • Arithmetic density • Total number of people divided by total land area • Example: Egypt has arithmetic density of 177 people per square mile but only 98% of population lives on 3% of land • Physiological density • Number of people per unit of arable land • Helps in analyzing amount of farmland available to population • U.S. physiological density is 340 people per square mile; Japan is 7,000 people per square mile; Egypt's is 3,000 people per square mile • Agricultural density • Number of farmers per unit of arable land • High density meant many farmers are on each piece of farmland; low density suggests the presence of larger farms

  19. Population Math

  20. Adding up population numbers • Equations exist to allow demographers to determine actual populations • Demographic accounting equations • Global population accounting equation • P1=P0+B-D • P1 is size of population at end of interval of measurement • P0 is size of population at start of interval of measurement • B is number of births during interval of measurement • D is number of deaths during interval of measurement • Subglobal population accounting equation • P1=P0+B-D+I-E • P1, P0, B and D same as above • I is number of immigrants moving into region during interval of measurement • E is number of emigrants moving out of region during interval of measurement • Immigration: people moving into a region/country • Emigration: people leaving a region/country

  21. Math Example • Country A has 1 million people in 1990. Over the next 10 years 75,000 babies are born; 50,000 people die; 10,000 people move into the country; and 5,000 people exit. What would the population be in 2000? • P1=1,000,000+75,000-50,000+10,000-5,000= 1,030,000 people

  22. Population Pyramids • Also known as age-sex structures used to evaluate the distribution of ages and genders in a given population • Shows sex ratio (number of males compared to females in a population) at ANY GIVEN TIME! • Cohorts (people of the same age) are split between men and women on the pyramid • Used to analyze population and/or predict future population • Cannot determine country size from pyramids but can determine placement in DTM

  23. Population Pyramid Algeria’s pyramid has a wide base and a flattened top. What does that mean? Italy’s pyramid is wider in the middle than at the base. What does that mean? What expectations do you have for a population pyramid from 2025?

  24. Expanding Populations Contracting Population Stable Population

  25. 2025 Predictions • Did Algeria’s growth rate decrease? How can you tell? • What happened to Italy’s population? • Graying population: when a population has more middle-aged and older people than young people. Why is this a problem?

  26. South Africa and the United States

  27. Fertility and Mortality • Fertility: reproductive behavior of a population • Impacted by • Fecundity of population • Diet and nutritional intake • Economic and industrialization levels • Sociocultural factors like age of marriage • Mortality: death related behavior of a population

  28. Population Key Terms • Crude Birth Rate (CBR): number of live births per 1,000 people in a year • Crude Death Rate (CDR): number of deaths per 1,000 people in a year • LDC’s average CDR of 20 while MDC’s average CDR of 10 • Infant mortality rate (IMR): number of infant (children who die before their first birthday) deaths per 1,000 live births • Life expectancy: average number of years to be lived by a person • Fecundity: ability of a woman to conceive (usually 15 to 45) • General fertility rate (GFR): number of births per 1,000 women in the fecund years • Total fertility rate (TFR): predicted number of births a woman will have as she passes through fecund years • TFR has declined on every continent but Africa over the last 50 years • Example : in 1975 Mexico’s TFR was 7 but in 2009 had dropped to 2.37 – in China in 1970 TFR was 6 but 1.6 in 2009 • 2006 TFR rate was greater than 3.0 across the globe • 2006 TFR rate in U.S., Europe and China was 2.1 or less

  29. Fertility Rates

  30. Replacement-Level Fertility • A TFR of 2.1 is considered replacement-level fertility meaning parents will produce the number of children needed to replace themselves • TFR of 2.1 causes zero population growth (ZPG) • Rate of Natural Increase (RNI) is growth rate of a population using the formula • CBR-CDR/10 • Does NOT include immigration and emigration • RNI that equals zero means population won’t grow or decline • Global RNI in 2006 was 1.2% • More developed countries had an RNI of 0.1% • Less developed countries had an RNI of 1.5% • Africa’s RNI in 2006 was 2.3% • RNI does NOT include migration

  31. Population Graph Options: S-curves and J curves

  32. Rule of 70 • Defined: time that it takes for a population to double • Equation: Divide 70 by current growth rate of population • 70/ current growth rate = doubling time • Examples • 70/5% = 14 years • 70/2% = 35 years

  33. Population Consequences The good AND the bad!

  34. A Graying Population • What would be the positives and negatives of a graying population? • Dependency ratio: show relationship between dependents and nondependent's • Dependents: people who depend on workers for survival • Nondependent's: people who can support themselves through work • High ratio means more people are dependent than working • Fewer people to pay taxes • Social security dependency • 2000 was first time in history that people under 14 years of age were outnumbered by people over 60

  35. Carrying Capacity and Overpopulation • Carrying capacity: number of people an area can sustain or support • Japan: imports food • Saudi Arabia: desalinizes water to increase carrying capacity • Overpopulation: when a region’s population outgrows its carrying capacity • Resource availability very important but resources can be indigenous or imported • Some areas have resources to produce more than they harvest-lack of infrastructure, political/economic stability, etc.

  36. Other population growth consequences • In China, boys now outnumber girls 119 for every 100 girls born – natural average 105 to 100

  37. Population growth theories • Thomas Malthus • Wrote An Essay on the Principle of Population, 1798 • Argued that global population was growing exponentially while food supplies were growing arithmetically • Advocated birth control and celibacy (positive checks) and warned of war, starvation and disease (negative checks) • Said population growth caused poverty, crime and misery • Karl Marx • Said population wasn’t problem-the problem was unequal distribution of resources and wages • Said population growth was caused by poverty and unequal distribution so if things were distributed evenly, population wouldn’t grow • Ester Boserup • Believed overpopulation problem could be solved by increasing number of subsistence farmers because when humans are faced with starvation, they WILL develop new technology • Neo-Malthusians • Argue that sustainable development hinges on Malthusian idea that human population must reach a “sustainable” level within carrying capacity

  38. Is population growth a problem?Two very different, but supportable ideas • Yes • Most of our increased food availability is tied to non-sustainable resources like oil • Humans bring about environmental destruction • I=PAT • Environmental Impacts= Population size times affluence times technology • Most humans live a lifestyle that is not sustainable • No • Food supplies have increased - in 1970 average caloric intake was 2,435 but in 2000 average was 2,087 • Countries like China have industrialized quickly BECAUSE of increased population that create workers and a market • Humans are the ultimate resource and will continue to advance to support ourselves

  39. Historical Growth The DTM

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