A Simple ExperimentNovember 14, 2011
This week, my student, Justin Baraboo, and I, will try a simple experiment that may shed some light on whether or not, for Paramecium aurelia, the rate of change of the rate of change of the population is something that is important in understanding how the population changes with time. (Justin is an undergraduate physics major at Truman State University. Unlike Justin, Paramecium aurelia is a one celled organism shaped kind of like a piece of rice. Because Paramecia divide every four to twelve hours, they make a good system for studying population dynamics.
What we are going to do is take some Paramecia and stress half of them by starving them for two days. Then, we will take ten of the stressed Paramecia and ten of the unstressed Paramecia, and put them in separate identical containers with plenty of food, and monitor their populations for about 36 hours. If the population dynamics depend mostly on the rate of change of the population, then, after about four to ten hours (very roughy: one generation), the growth rates of the two samples should be statistically the same. If, however, the growth rates are significantly different after that time period, that would be evidence that the population dynamics depend on the rate of change of the rate of change of the population in an important way. We’ll see how it turns out!