Bio1b Summer 2008 Eric Harris Ecology Lecture 4 Page 1 of 2 ECOLOGY LECTURE 4 POPULATION BIOLOGY II GROWTH AND REGULATION Reading 7th ed 1143 1158 8th ed 1181 1197 A Exponential Growth Growth in an idealized unlimited environment i Derivation of equation staring with Nt 1 Nt B D I E Births Deaths Immigrants Emigrants ii Discrete time vs continuous time dN dt the population rate of change B Logistic Growth Growth in a limited environment i Four features of competition between individuals shared requirement for a resource resource is in limited supply leads to a reduction in vital rates ii Derivation of the logistic equation dN dt rN K N K K the carrying capacity r the intrinsic rate of increase of the population iii Note The negative effects of small population size the Allee effect iv Life histories K and r selected populations K selected long lifespan low mortality good competitors producing few high quality offspring r selected short lifespan high mortality good dispersers and colonizers producing many small offspring with little parental care C Regulation of population growth i regulation vs limitation ii Population density determined by density dependent factors AND density independent factors Updated on 06 30 08 Bio1b Summer 2008 Eric Harris Ecology Lecture 4 Page 2 of 2 D Population Dynamics variations in the size of populations i Population cycles ii Metapopulation a group of populations of a single species linked by immigration and emigration E Human Population Growth i The population explosion is over ii The demographic transition describes the transition from high birth and death rates to low birth and death rates iii Infant mortality and life expectancy iv Global carrying capacity v Ecological footprint Updated on 06 30 08
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