More on Population Growth Some alternative models

Logistic Growth We have been using the logistic growth model:

Logistic Growth This model has some unique properties: As the population approaches K, population growth either levels out or osscilates about K. The model also produces an unexpected result: chaos.

Logistic Growth Clearly, the model is more dynamic than we thought. What are the assumptions of the model, and is the model appropriate? The population exists in a stable age distribution. (that is, all age classes are growing at the same rate). All age classes have equal fecundity and survival.

Logistic Growth Are these assumptions reasonable? If they are not reasonable, we need an alternative model to understand population growth. We need a model that takes into account the the realities of death and reproduction.

Age Structured Population Growth The renewal equation: