## Population growth: balance of birthrate, deathrate, emigration, and immigration: r = (b - d) + (i - e)

## Exponential growth: 2 make 4, 4 make 8, 8 make 16, …rN = dN/dt; N increases exponentiallyNOTE: growth rate r remains constant! exponential growth only possible if resources are unlimited; in nature, resources are always finite.

## Carrying capacity: maximum N for given level of resources

## Logistic growth: growth curve is sigmoidal because growth rate r decreases when N approaches carrying capacity K

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