BIOB50H3 Lecture 8: BIOB50 Lecture 8-10.pdf
Document Summary
Population size can be determined by density-dependent and density-independent fac- tors. Density independent- does not matter on the size of the populations. Density dependent- matters how abundant the population is. Cause birth/death/dispersal rates to change as the population changes. As densities increase, birth rates often decrease, death rates increase(disease/not enough re- sources) and emigration increases all of which tend to decrease population size. Population regulation occurs when density dependent factors cause populations to increase when there is a low density or decrease with a high density. Ultimately food, space and other essentials are going to be too sparse so pop size will decrease. The logistic equation incorporates limits to growth and shows how a population may stabilize at a maximum size, the carrying capacity. Logistic equation incorporates the carrying capacity and density dependent factors limiting growth. Logistic growth: population increases rapidly at first, then stabilizes at the carrying capaci- ty (maximum population size that can be supported by the environment).
