Population Ecology CHAPTER 9 NOTES APES Ms. Miller

Key Concepts Factors affecting population size Species reproductive patterns Species survivorship patterns Conservation biology and human impacts on ecosystems

Population Dynamics and Carrying Capacity Population dynamics—study of how populations change in size, density, and age distribution Biotic potential--a populations capacity for growth (intrinsic rate of increase [r])—rate of growth with unlimited resources Environmental resistance—all factors that limit the growth of a population Carrying capacity (K)—maximum number of individuals of a given species that can be sustained indefinitely in a given area Exponential and Logistic Growth—two models of growth (J curve vs. S curve) Population Density—number of individuals in a given area

J-Curve

S Curve

Exponential and Logistic Growth

Population Dispersion Fig. 9-2 p. 164

Factors Affecting Population Size Fig. 9-3 p. 166

Population Density Effects Density-independent controls—affect a population’s size regardless of its density (climate, fire, natural disasters, meteor impacts, unseasonable weather, deforestation, etc) Density-dependent controls—affect population size/growth as plate job population density increases (competition, predation, parasitism, disease transmission)

Natural Population Curves Fig. 9-7 p. 168

The Role of Predation in Controlling Population Size Predator-prey cycles Top-down control vs. Bottom-up control Fig. 9-8 p. 168

Reproductive Patterns and Survival Asexual reproduction r-selected species Sexual reproduction K-selected species Fig. 9-10 p. 170

Survivorship Curves Fig. 9-11 p. 171

Human Impacts on Ecosystems Habitat degradation and fragmentation Ecosystem simplification Genetic resistance Predator elimination Introduction of non-native species Overharvesting renewable resources Interference with ecological systems

Learning from Nature Dependence on Nature—we need the earth but the earth does not need us Interdependence—all organisms on earth are dependent on one another Unpredictability—things we do have unexpected or unintended side effects Limited resources –we continue to deplete and degrade the Earth’s natural capital Recycle wastes—we must find ways to use waste for energy