24 - BIO LECTURE NOTES (3/6/09) Population ecology In...

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BIO LECTURE NOTES (3/6/09) Population ecology In crowded populations, survival and fertility decline o Food affects both survival and fecundity Space is the important limiting resource for some populations Density-regulated populations do not grow without bound o Population rate high = reproductive rate declines Linear decline per capita Logistic equation o In an analogy to exponential growth let Nt+1 = λ (Nt)Nt o A simple assumption is that the per-capita rate of reproduction changes linearly with density so, λ(Nt) = 1+r-(rNt/K) o 1+r is the y-intercept and –r/K is the slope o from this we arrive at the logistic equation, Nt+1 = {1+r-(rNt/K)Nt (rate population growth in terms of density) when Nt is equal to K, then the population size does not change over time o r is called the intrinsic rate of increase and K is called the carrying capacity population dynamics with the logistic equation o K is an equilibrium of the logistic o The stability of the equilibrium K, depends on the value of r
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This note was uploaded on 11/16/2009 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.

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24 - BIO LECTURE NOTES (3/6/09) Population ecology In...

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