Populations

Objective Students will be able to define population and explain important characteristics of a population.

What is a population? Group of individuals of the same species that live in the same area.

Important Characteristics of a Population Geographic Distribution Density Growth Rate

Geographic Distribution Range: describes the area inhabited by a population Can range from a few cubic centimeters to millions of square kilometers Ex: Rotting Apple vs. Pacific Ocean

Population Density Number of individuals per unit area Can vary depending on the species and its ecosystem Ex: Saguaro Cactus vs. smaller desert plants

Population Growth Rate A population will increase or decrease in size depending on how many individuals are added to it or removed from it 3 Factors affect population size: # of births # of deaths # of individuals that enter or leave the population

Population Growth Rate Immigration: movement of individuals into an area Emigration: movement of individuals out of an area Exponential Growth: individuals in a population reproduce at a constant rate Logistic Growth: Population’s growth slows or stops following a period of exponential growth.

Carrying Capacity The largest number of individuals of a population that a given environment can support