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Population Growth Of Various Countries. Jose Henson Sam Choi Natalie Wagner Alex Kang. Origins of Population Growth Models. Thomas Malthus proposed that human growth would precede exponentially An essay on the principle of population as it affects the future improvement of society (1798)
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Population Growth Of Various Countries Jose Henson Sam Choi Natalie Wagner Alex Kang
Origins of Population Growth Models • Thomas Malthus proposed that human growth would precede exponentially • An essay on the principle of population as it affects the future improvement of society (1798) • Gave formula: • Growth Rate: • Predicted the world would soon outgrow its resources, with the ultimate destruction of mankind
Exponential Growth Exponential Population Growth: -Used for rapidly growing population - Bacteria, insects, rabbits -Assumptions -All individuals reproduce constantly and equally -Not valid for human population growth - Valid over a short period of time
Growth of Bacteria • Reproductive rate, r, is found from data by finding ratio of 2 • Exponential growth equation can now be used to calculate future populations • At t=100
Revision of the Population Model • Pierre-Francois Verhulst of Belgium - Suggested that there was a limit to population growth in 1838 - Growth Formula: - mu represents mortality caused by high population -as population increases growth is overshadowed
Modern Notation Verhulst’s Logistic growthmodel: Factor from both terms Substitute or
Population Model Population equation can be found by solving the differential equation Algebraic manipulation: Integrate with respect to t: Simplify:
Derivation Continued Exponentiate: Let : Simplify: Solve for P:
Logistic Population Growth Logistic Population Growth : M = Population Capacity A = Initial Population Constant r = Reproductive rate constant Assumptions: - Found via logistic regression line - Only valid over long periods of time
Calculating Regression Equations Linear Regression: - Commonly called “best fit” line Logistic Regression - Creates a “best fit” S-shaped curve
Population of the World Current Population: 6,442,658,699 people Growth Rate: 76,570,430 people per year Estimates: 2020: 7.6 Billion people 2030: 8.2 Billion people 2050: 9.1 Billion People
Analysis of Population Levels Calculated Current Population at t=35 (In Millions) Actual Current Population = 295.734 Million People
Analysis of Population Growth Current Population Growth at t=35 Growth Rate:
Analysis of Population Levels Calculated Current Population at t=35 (In Millions) Actual Current Population = 48.422 Million People
Analysis of Population Growth Current Population Growth at t=35 Growth Rate:
Analysis of Population Levels Calculated Current Population at t=35 (In Millions) Actual Current Population = 127.417 Million People
Analysis of Population Growth Current Population Growth at t=35 Growth Rate:
Analysis of Population Levels Calculated Current Population at t=35 (In Millions) Actual Current Population = 1080.264 Million People
Analysis of Population Growth Current Population Growth at t=35 Growth Rate:
Carrying Capacity Set P=M - .00001 Solve for t Year country will reach the carrying capacity: U.S.A: 2543 Korea: 2305 Japan: 2150 India: 2543
Conclusions There are TOO many people in the world…..Thomas Malthus was right….
Works Cited http://www.library.uu.nl/wesp/populstat/Asia/skoreac.htm http://geography.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=geography&zu=http%3A%2F%2Fwww.census.gov%2Fftp%2Fpub%2Fipc%2Fwww%2Fidbsum.html http://www.library.uu.nl/wesp/populstat/Asia/japanc.htm http://www.ugrad.math.ubc.ca/coursedoc/math100/notes/mordifeqs/logistic.html http://en.wikipedia.org/wiki/Global_Population#Forecast_of_world_population http://www.mnforsustain.org/united_states_population_growth_graph.htm http://www.library.uu.nl/wesp/populstat/Asia/indiac.htm http://www.cia.gov/cia/publications/factbook/geos/in.html#People http://www.cia.gov/cia/publications/factbook/geos/us.html http://www.cia.gov/cia/publications/factbook/geos/ja.html http://www.cia.gov/cia/publications/factbook/geos/ks.html