MathBench > Population Dynamics

Mystery of the Missing Housefly

Applet: once more with mortality

Here's one possible way to write the equation (there are other ways you could write it as well):


On the applet below, you can control both the growth rate and the mortality rate. How does this kind of population dynamics compare to the simple exponential growth model we studied above?


housefly caught in a venus fly trap


Do the results look at all familiar? In fact the shape of the graph is exactly the same as the regular exponential growth model. What gives?

Under exponential-growth-with-mortality, the population grows more slowly, but ultimately the result is the same: either the population "takes off" or it dwindles to zero. We'll discuss why on the next page.