Population EcologyPopulation Ecology

CHAPTER 9 NOTESAPES

Ms. Miller

CHAPTER 9 NOTESAPES

Ms. Miller

Key ConceptsKey Concepts

Factors affecting population sizeFactors affecting population size

Species reproductive patternsSpecies reproductive patterns

Species survivorship patternsSpecies survivorship patterns

Conservation biology and human impacts on ecosystems

Conservation biology and human impacts on ecosystems

Population Dynamics and Carrying CapacityPopulation Dynamics and Carrying Capacity Population dynamics—study of how populations change in

size, density, and age distribution

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

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

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

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)

Exponential and Logistic Growth—two models of growth (J curve vs. S curve)

Population Density—number of individuals in a given area Population Density—number of individuals in a given area

J-CurveJ-Curve

S CurveS Curve

Exponential and Logistic GrowthExponential and Logistic Growth

Population DispersionPopulation Dispersion

Fig. 9-2 p. 164Fig. 9-2 p. 164

Factors Affecting Population SizeFactors Affecting Population Size

Fig. 9-3 p. 166

Population Density EffectsPopulation 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-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)

Density-dependent controls—affect population size/growth as plate job population density increases (competition, predation, parasitism, disease transmission)

Natural Population CurvesNatural Population Curves

Fig. 9-7 p. 168

The Role of Predation in Controlling Population SizeThe Role of Predation in Controlling Population Size

Predator-prey cycles Predator-prey cycles Top-down control vs. Bottom-up control Top-down control vs. Bottom-up control

Fig. 9-8 p. 168

Reproductive Patterns and SurvivalReproductive Patterns and Survival

Asexual reproduction Asexual reproduction Sexual reproduction Sexual reproduction

r-selected species r-selected species K-selected species K-selected species

Fig. 9-10 p. 170

Survivorship CurvesSurvivorship Curves

Fig. 9-11 p. 171

Human Impacts on EcosystemsHuman Impacts on Ecosystems

Habitat degradation and fragmentation Habitat degradation and fragmentation

Ecosystem simplification Ecosystem simplification

Genetic resistance Genetic resistance

Predator elimination Predator elimination

Introduction of non-native species Introduction of non-native species

Overharvesting renewable resources Overharvesting renewable resources

Interference with ecological systems Interference with ecological systems

Learning from NatureLearning from Nature

Interdependence—all organisms on earth are dependent on one another

Interdependence—all organisms on earth are dependent on one another

Unpredictability—things we do have unexpected or unintended side effects

Unpredictability—things we do have unexpected or unintended side effects

Recycle wastes—we must find ways to use waste for energy

Recycle wastes—we must find ways to use waste for energy

Dependence on Nature—we need the earth but the earth does not need us

Dependence on Nature—we need the earth but the earth does not need us

Limited resources –we continue to deplete and degrade the Earth’s natural capital

Limited resources –we continue to deplete and degrade the Earth’s natural capital