BIOL 12100 Lecture Notes - Lecture 21: Exponential Growth, Doubling Time, Water Scarcity
31 Aug 2018
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7 billion served, growth surge due to agriculture, ~1650 another growth surge do to science, rate of increase- humans reproduce exponentially, for humans, b=21/1000/year d=9/1000/year r= b/d 0. 012/year. N= 6*109 * e0. 012* 18 years= 7. 5 * 109: growth patterns, in 70"s r=0. 02 so doubling time= 35 years, we can conclude a couple things from the data r>0 is increasing, developed nations are getting lower r"s. Slight r lowering in developing nations: by 2050 26 african countries will have doubled. In asia: 1. 4 billion people in china, 1. 3 billion people in india, to stop population growth (zpg) b=d so that r=0 and there must be stable age distribution, causes of growth, demographic transitions. Age structure: mexico- broad based age distribution lots of future reproducers, sweden- very even distribution pretty much r=0, usa- in the middle of these two, human population growth, evidence of increasing death rates.
