The students and I had a great time with this activity. I believe it is important to stress to the students that individual bacteria (or any organism for that matter) do not adapt to a changing environment by making themselves different. Rather, a different genotype already exists in the population that is more advantageous in the new environment and this genetic make-up becomes selected for.

I also used the example of the evolution of peppered moths during England's Industrial Revolution to apply the concept of microevolution to another organism (I've attached the PowerPoint that I used - a skeleton really, but useful pictures as long as you look up and familiarize yourself with the background story). There is potential for making this activity specific and relevant to your students depending on the organism you use for an example.