Interactions Between Organisms & the Environment

Examples of Density-Independent Factors

Weather, Sunlight, Pollution

Density-Independent

Referring to any characteristic that is not affected by population density.

Density-Dependent

Referring to any characteristic that varies with population density.

Dynamic Equilibrium

A state of balance between continuing processes

Examples of Density-Dependent Factors

Competition, Predation, Parasitism

Age Structure Diagrams

Graph of the numbers of males and females within different age groups of a population

Prey

Organisms that are hunted and killed by other organisms

Predators

Organisms that kill and eat other animals

As prey population increases...

Predator population increases

As predator population increases..

Prey population decreases

Competition

The struggle between organisms to survive in a habitat with limited resources