Biology 2483A Lecture Notes - Lecture 10: Genetic Drift, Habitat Fragmentation, Allele
3 Nov 2017
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Document Summary
The risk of extinction increases greatly in small populations. Population growth patterns include exponential growth, logistic growth, fluctuations and regular cycles. Population size changes in response to four biological processes: Population dynamics: the ways in which populations change in abundance over time. Cattle egret --> immigration from africa: jump dispersal ii. Population size reaches an equilibrium due to limited resources. equilibrium population size fluctuates because k is not constant. Immigration and emigration are so small in natural population. Width is varying of birth and death rate therefore k is going to vary from densities iii. Can be due to density-dependent and/or independent factors. Could be good year for food, bad year for predators, weather, biology, random. Delayed density dependence can cause populations to fluctuate in size. The risk of extinction increases greatly in small populations a) Fluctuations in (or r) can increase the rate of extinction. Small populations are at greater risk of extinction.
