In the deserts of Arizona and New Mexico, some tiny creatures show just how quickly natural selection can turn a mutation into an advantageous adaptation. Watch a video about rock pocket mice, who show that one small change can make all the difference in survival when the landscape changes drastically. After watching the video, high schoolers take a look at the Hardy-Weinberg theorem, perform some calculations regarding the frequency of heterozygous genotypes in the rock pocket mouse population, and answer some short analysis questions.