100 likes | 105 Views
How Populations Grow. Learning Objectives. Explain the ways ecologists study populations. Identify the factors that affect population growth. Explain what happens during exponential growth. Explain what happens during logistic growth. Describing Populations. Geographic range
E N D
Learning Objectives • Explain the ways ecologists study populations. • Identify the factors that affect population growth. • Explain what happens during exponential growth. • Explain what happens during logistic growth.
Describing Populations Geographic range Density and distribution • Growth rate • Age structure
Geographic Range • The area inhabited by a population is called its geographic range.
Growth Rate Growth rate = 1 Population size is unchanged. Growth rate > 0 Population size is growing. Growth rate < 0 Population size is decreasing. Bacterial population
Population Growth Births Emigration Immigration Deaths
Exponential Growth Under ideal conditions with unlimited resources, a population will grow exponentially. Population is rapidly increasing.
Logistic Growth When a population’s growth slows and then stops, following a period of exponential growth, it is called logistic growth. Phase II Phase III Phase I
Carrying Capacity The maximum number of individuals of a particular species that a particular environment can support Population stabilizes at carrying capacity.