Modeling Logistic Growth with Skittles

As much as possible, I want my students to understand concepts by getting their hands on them, so I'm always on the lookout for new ideas of activities or labs to add to my units. Last year I saw a post  in the AP Bio teacher group in Facebook describing a series of ecology mini labs, and I saved the file to the ecology unit folder in Google drive. As I was planning our Ecology unit, I took a look at new files I had in drive and decided to give this one from Pam Close a try. You can request the whole set of mini labs from Dr. Close's website here.

Students are given a plot of "land" and a set of "organisms" with rules for placing them on the land and guidelines for whether they live or die of starvation. They simulate 8-10 generations and determine the carrying capacity of their land.

Students also added the exponential growth curve to compare it with the logistic growth the lab showed.

I think it was a great way for students to see how the logistic growth curve is formed. Students rolled dice to determine location and the organisms were skittles. The class really got into it. I must confess it was pretty noisy with 7 lab groups all rolling two dice for most of the lab, but I enjoy a lab with some noise, so I didn't mind. By the third generation most groups had a pretty good idea of what the carrying capacity of their land was. I put the information from Dr. Close's lab in this document as well as the "land" grid for the skittles organisms.