Biology 2483A Lecture Notes - Lecture 10: Cattle Egret, Logistic Function, Exponential Growth
20 Oct 2017
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Topic: population dynamics: population growth patterns include exponential growth, logistic growth, fluctuations and regular cycles, population size changes in response to 4 biological processes: Population dynamics: the ways in which populations change in abundance over time: density independent event changes the population size, four patterns of population growth. After a density-independent population crash: example: fireweed in boreal forest. Population doesn"t go into exponential increase until after . After dispersal to a new geographic area: example: cattle egret (jump dispersal) Growth rate slows due to density-dependent factors. Population size reaches an equilibrium (b=d, i=e) due to limited resources (food and space) no net increase or decrease. Actual populations rarely show logistic growth, ignores density-independent factors. Equilibrium population size fluctuates because k is not constant. Birth rate and death rate are much higher values. Can be small (normal) or large (outbreak/crash) Can be due to density-dependent and/or independent factors. Large fluctuations, doesn"t look anything like logistic growth.
