Population Biology

Under ideal conditions, populations will continue to grow at an increasing rate. The highest rate for any species is called its biotic potential.

Classic examples: rabbits, yeast have a high biotic potential What has a low biotic potential?

The result is a J-shaped curve.

This assumes... Unlimited food Unlimited space NO predation NO competition NO disease NO environmental disruptions NO crowding

However, population growth is usually restricted by limiting factors.

abiotic limiting factors nutrients temperature storms floods drought

biotic limiting factors competition occurs when two organisms occupy the same niche. disease parasitism

When a population is limited by biotic and abiotic factors, it will not grow out of control.

It will grow until it reaches carrying capacity. Carrying capacity is the number of organisms of one species that an environment can support.

A population curve that grows until it reaches carrying capacity will be s-shaped.

Populations at carrying capacity will fluctuate in number. But, overall, birth rate will equal the death rate. (immigration = emigration)

This stable state will remain until some environmental factor changes.

The interaction of predator and prey result in a predator-prey cycle.