It is a model of a simple social-ecological system consisting of various numbers of individuals and a regrowing resource (trees). The individuals are of two types – modest (green) or greedy (red) and they harvest from the trees at a certain rate depending on their type. Agents produce offspring that inherit their type/harvest rate. A “mutation rate” changes the probability with which offspring change their type/harvest rate. A parameter “living costs” determines the harvested units that agents lose in each iteration.

Students observe how the agent population and resource change over time as influenced by the parameters of harvest level, living costs, mutation rate, resource regrowth rate and carrying capacity.

The model simulations and concepts can be discussed with the whole class, or alternatively, students work individually or in groups using a worksheet.