APBI 200 Lecture : Biol 121- 2010.04.09- Ecology- Population Dynamics (Ch. 52).docx
Document Summary
Population dynamics = change in populations through time. Find patterns in natural populations in addition to exponential and logistic growth. Why do all populations stop growing: density-independent factors. When b or d is not influenced by population density. E. g. abiotic environmental changes such as weather patterns and disturbances: density-dependent factors. Increase in d; decrease in b as population density increases negative feedback. There are extrinsic and intrinsic factors that are density-dependent. Sensitivity to some limiting resource which limits reproduction e. g. decrease in the # eggs laid. Territory boundaries need certain space between nests, etc. Crowding increases mortality (e. g. smaller, frailer individuals) Predation more predators leads to less prey. Hormonal changes can lead to aggressive behaviour, delay in sexual maturation time, as population density increases. Density-dependent factors define k for a particular habitat. K depends on the quality of habitat (food, space, accumulation of waste) K varies with time can change year to year.
