A hypothetical scenario is introduced in which the class is asked to apply their understanding of the forces that drive natural selection to prepare a proposal along with an environmental consulting company to help clean up an area near their school that is contaminated with trichloroethylene (TCE). Students use the Avida-ED software application to test hypotheses for evolving (engineering) a strain of bacteria that can biodegrade TCE, resulting in a non-hazardous clean-up solution. Conduct this design challenge activity after completion of the introduction to digital evolution activity, Studying Evolution with Digital Organisms.