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Human Population : Growth, Demography and Carrying Capacity.

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Presentation on theme: "Human Population : Growth, Demography and Carrying Capacity."— Presentation transcript:

1 Human Population : Growth, Demography and Carrying Capacity

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3 Current World Population Global population was 6,629,514,472 On November 7, 2007 at 08:05 pm The global population grows by: –Nearly 2.3 persons per seconds –Nearly 8,343 persons per hour –Over 200,234 persons per day –Over 73 million persons per year

4 Human Population Dynamics There are just three sources of change in population size —  Fertility – number of children born  Mortality -"natural decrease" refers to population decline resulting from more deaths than births  Migration - Net migration is the number of immigrants minus emigrants

5 Human Population Dynamics Replacement fertility rate (RFR) –The number of children a couple must have to replace themselves Total fertility rate (TFR) –The average number of children born to a woman during childbearing years (15-49) –Average in developed countries = 1.6 (1950 2.5) –Average in developing countries = 3.1 (1950: 6.5)

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7 Infant Mortality Rate (IMR ) infant deaths per 1000 live births (infant < 1 yr) –1990: 62now: 52 (normal in 1900: 200) –Current US IMR: 6.9% (69/1000)

8 Maternal Deaths per 100,000 Live Births Source: WHO, UNICEF, UNFPA Maternal Mortality in 1995: Estimates Developed by WHO, UNICEF AND UNFPA, 2001.

9 Overall, the world population is growing at a rate of about 1.7%; if this rate continues, the population will double in 42 years.

10 Population Pyramids Graphic device: bar graph shows the age and gender composition of a region horizontal axis: gender –male: left-handfemale: right-hand –absolute number of people or % vertical axis: age –5-year or 10-year age groups

11 Population Pyramid with young cohorts

12 Population Pyramids High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Austria or Italy

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14 Population Pyramids Population Pyramids on the Web High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Austria or Italy

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16 Population Pyramids Population Pyramids on the Web High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Austria or Italy

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18 Population Pyramids Population Pyramids on the Web High Growth: Afghanistan Moderate Growth: Mexico Zero Growth: U.S. Negative Growth: Italy

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20 Movement of a nation from high population growth to low population as it develops economically Transition as a result of four stages –Stage 1—Birth and death rates are both high –Stage 2—Death rates fall; birth rates remain high; growth rate rises –Stage 3—Birth rates fall as standard of living rises; growth rate falls –Stage 4—Growth rate continues to fall to zero or to a negative rate Demographic Transition

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22 Population Pyramids and Demographic Stages characteristics shapes of ‘pyramids’ –wide base (true pyramid) –wide middle (bulge), somewhat wider base –urn- or bottle-shaped –reversed pyramid different shapes--different dynamics

23 Population Pyramid and Demographic Transition Stage 2: wide base stage 3: wide middle stage 4: slender stage 5: narrow base

24 Population Pyramid and Demographic Transition Stage 2: wide base stage 3: wide middle stage 4: slender stage 5: narrow base

25 Population Pyramid and Demographic Transition Stage 2: wide base stage 3: wide middle stage 4: slender stage 5: narrow base

26 Population Pyramid and Demographic Transition Stage 2: wide base stage 3: wide middle stage 4: slender stage 5: narrow base


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