BIOL 2Q04 Lecture 16: Regulation of Population size
2 Dec 2015
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Document Summary
Competition, predation and disease disrupt the equilibrium, even quality of habitat. Population will increase until it reaches the equilibrium point. Different habitats will have different equilibrium densities: o. Anything that can affect birth rates or death rates. Second principle: always a factor that affects birth or death. Differences between populations in equilibrium density can be caused by variation in either density-dependent or density independent per capita birth and death rates. Anything that alters birth and death rates affect equilibrium density. Extrinsic- pressure by other species or abiotic conditions o. Intrinsic- internal, interactions between individuals inside the population (dependent factors) Diseases can limit a host population if the host population abundance. Limiting factor: factor causes a change in average or equilibrium density o. Regulating factor: % mortality caused by the factor increases with population is higher when the disease is absent.
