Main steps of the activity about natural selection. (A) Place the same number of Smarties per color on the habitat and ask students to write their hypotheses about what could happen to that population over time. (B) Ask students to prey on the Smarties. (C) Simulate the reproduction of the surviving Smarties. (D) Discuss changes in color frequency (and use other habitat to extend the discussion about long-term viability of a population with low levels of genetic diversity).