Set the stage for the lesson by briefly discussing the questions posed in the first paragraph of the student sheet. Then have the groups work on their own to conduct the activity. In this activity, students poke six different-sized holes in the bottom of the bowl. They create a generation by choosing five of each kind of bean to put in the bowl. The population that is left in the bowl is the first generation of parents.
Students then add beans only of the survivors and shake again.
This process is repeated and students watch the population change. Although students work in groups, each student will create a lab report as they do the activity. Be sure students do not think that the environment dictated the changes, rather the environment dictated who would survive. Keep students in their same groups and instruct each group to create their own experiments that demonstrate natural selection. Encourage students to be creative.