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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.
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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 withunlimited 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
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 • r-selected species • Asexual reproduction • K-selected species • Sexual reproduction 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