Populations Bell-Ringer 1. List the 3 criteria that must be met in order for a group of organisms to be considered a population? 2. Here is an example of a population. Create two of your own examples. A Pack of Gray Wolves in Yellowstone National Park.

3 Population Keys Population Size: # of individuals in a population. --Small Pop. size problems: --More likely to become extinct --More likely to inbreed

Population Keys (cont.) Population Density: number of individuals that live in a given area --Low density, small populations are less likely to reproduce.

Population Keys (cont.) Dispersion: the arrangement of populations. --Random—Pine trees mixed with hardwoods --Even distribution—Birds on a wire or crops --Clumped—Buffalo herds or cities

Exponential Curve P. 322 Rate of population growth stays the same Result: steady population growth P. 322

Logistic Growth: P. 323 Exponential Growth is limited by carrying capacity. Density Dependent Factors: food, water, shelter, etc.

Density Independent Factors Weather, Climate, and Natural Disasters (for example: summer mosquitoes, spring azaleas, forest fires, etc.)

Pop. Growth R-Strategists: organisms that grow exponentially (Short life, Low parental care, Rapid growth). K-Strategists: organisms that exist near carrying capacity (Long life, High parental care, Slow growth).

Organisms/Populations/Communities Choose an external stimulus and describe how it will affect an organism, a population, and a community.