2/22

This week, we reinforced our ideas about natural selection by doing a "peppered moth simulation." We reviewed the experiment that was done in Manchester, England with the pale and dark peppered moths. Before the 1850's, the pale variety of moths were more common because they blended in with the lichen-covered trees. As the industrial revolution began in the 1850's, the trees became covered in smoke and soot, and gradually, the dark variety of moth became more common. In our lab, we used two different colored backgrounds to represent the non-polluted (pale) and the polluted (dark) tree trunks. Small circles were cut out to represent pale and dark moths. Students became predators (birds), and had to use tweezers pick up as many "moths" off of each background as they could in 20 seconds. While some students struggled as predators (I know it was difficult!), others excelled! Great job to everyone for putting in a good effort!

Next week we will wrap up our evolution chapter. We will discuss other evidence for evolution (the fossil record, comparative structures, vestigial structures, and plate tectonics). We will also do a lab that will test the students' ability to determine the relative age of fossils. We will have our chapter test on Friday!