Reproductive Patterns

The Rate Strategy (r-strategists)

This is an adaptation for living in an environment where fluctuations in biotic or abiotic factors occur. These organisms tend to:

• be smaller

• have a short lifespan

• have many offspring in a short time

• invest little to no energy in raising their offspring

• are controlled by density-independent factors

• population numbers are usually not near carrying capacity

Examples: Bacteria, mice, rates, insects

The Carrying-Capacity Strategy (k-strategy)

This is an adaptation for living in an environment that is fairly predictable. These organisms tend to:

• larger organisms

• have a longer life span

• have only a few offspring

• invest energy and resources into raising their young

• are controlled by density-dependent factors

• reach an equilibrium at the carrying capacity

Ex: birds, elephants, other large mammals