Host population Regulation - Lecture 16

What does it mean for a population to be regulated?

It means that the growth of the population has changed from exponential growth to logistic growth due to a factor that created a carrying capacity

What is exponential growth?

uncontrolled density-independent growth that does NOT regulate populations

What is logistic growth?

density dependent growth with a carrying capacity that CAN regulate populations

What is the effect of density-dependent factors on populations? Provide example.

a population’s per capita growth rate to change with increasing population density

• ex.) competition within a pop, predation, disease/parasites

What is the effect of density-independent factors on populations? Provide example.

a population’s per capita rate is not related to population density

• ex.) natural disasters

How does a carrying capacity(k) affect logistic growth?

• growth increases when n<k

• growth decreases when n>k

Why are density-independent factors still important for popuatlions?

• can still reduce population growth rate by acting on birth and death rates

What causes regulation?

• greater mortality at greater density

• lesser fecundity at greater density

Density-dependent cycling