POPULATION DYNAMICS

      Why do populations change?
      What patterns do population change follow?
urchen

population: (n) the total number of individuals occupying an area
Darwin's first and second observations



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Population Characteristics

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What Limits Population Growth?

Biotic and abiotic factors


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      EXPONENTIAL GROWTH
      • Nt = N0 * ert)
        • where r is the intrinsic rate of growth
          & N0 is the initial population

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      LOGISTIC GROWTH
      • Nt = K / (1 + be-rt)
        • where b = ln [(K - N0) / N0]
          & K is the equilibrium population

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Population Density affects Species Interactions

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      Predation and Population Density

      The Lynx and the Hare

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      REPRODUCTIVE STRATEGIES

      • r-selected species opportunists
        • high dispersal
        • short lifespan
        • many offspring
        • small, poor competitors
        • selfish
      • K-selected species specialists
        • low dispersal
        • longlived
        • few offspring, but high investment
        • large, good competitors
        • altruistic "relatives"

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