Genetic Drift

In the basic lab, student teams set up two islands composed of equal proportions of genotypic alleles. In this simulation the islands will be bowls, one large and one small.  Each bowl will be populated with beans of the same shape and size, but of different colors.  Students will blindly sample half of the beans on each island to reproduce and the non-reproducing beans are eliminated.  After students have recorded the number and proportion of alleles in each new population, they blindly resample each population again and again record the new proportion of alleles left on each island.  After five iterations, the students can stop and compare the initial vs. final proportions of alleles left on each island.  Genetic drift should have occurred much more dramatically on the small island than on the large island. Great teacher notes and directions, good student directions, and the inclusion of analysis of tables and graphs to develop conclusions makes this a great web site. This simulation builds student understanding of processes other than natural selection that can influence evolution.