CGS NS 202 Lecture Notes - Lecture 5: Exponential Growth, Introduced Species, Density Dependence

• School: Boston University
• Department: Natural Sciences
• Course: CGS NS 202
• Professor: Millard Baublitz

Document Summary

In a population closed to immigration and emigration: Change in n/change in t = b-d or bn- dn. Change in n/ change in t = the change in n for a given change in time. If r= 0, population size remains the same. If the r is constant, it is an exponential growth. Density dependence: growth rate is a function of population size. Species with small body size usually reach high densities: on a per capita basis, small individuals need less energy o survive than large. Some newly introduced species reach high population densities: in a new region the normal predators and pathogens may be absent. Densities can be much higher than in their native ranges: this was demonstrated by the zebra mussels, introduced into the great lakes in. Logistic model limits growth by incorporating carrying capacity (k) (k): the maximum population size the environment can support fits few real populations, but estimates possible growth.