Populations

Describing Populations Geographic Range: Area inhabited by population Density: Number of individuals per unit area Distribution: How individuals are spaced within a population Random Uniform Clumped Growth Rate: population numbers changing Age Structure: Number of males and females of each age Why is this important?

Random, Uniform, or Clumped??

Population Growth Rate What factors affect growth rate?? Birthrate Death rate Immigration Emigration

Exponential Growth Definition: The larger a population gets, the faster it grows When does this occur? Under ideal conditions, unlimited resources

Logistic Growth Definition: When a population’s growth slows and then stops, following a period of exponential growth. Carrying Capacity: The maximum number of individuals of a species that a particular environment can support

Limiting Factors Definition: Factors that control the growth of a population and determine the carrying capacity Density-Dependent Factors: Affect populations significantly only when population reaches a certain size Density-Independent Factors: Affect all populations in similar ways, regardless of size and density