Limits to Population Growth

What slows the growth of populations? Limiting Factors Density-dependent limiting factors: limiting factors that are dependent on population size Density-independent limiting factors: limiting factors that affect the same percentage of a population regardless of its size.

Density-dependent limiting factors Food supply Predation Disease Related to competition and interactions between organisms. Greater effect in larger populations.

Density-dependent limiting factors Populations controlled by density-dependent factors show an S-shaped curve on a graph. Exponential growth at first, then growth slows and stops at the carrying capacity. p.81

Density-independent factors Natural disasters Hurricane Fire Tsunami Limit growth of population by destroying habitat.

Density-independent limiting factors Populations controlled by density-dependent factors show a boom and bust on a graph Exponential growth when conditions are favorable, then many die when conditions change. Thrips, aphids, and other Insects (pg 127)