Evolution in action: Experimental evolution of biofilms with Pseudomonas fluorescens

Authentic research experiences that include a wet-bench laboratory component have been implemented into undergraduate introductory classes and have improved scientific understanding while simultaneously attracting students to science, technology, engineering and mathematics (STEM) fields. However, a gap still exists in many high school curricula, when implementation of active learning approaches that spark interest in STEM fields is crucial because career aspirations often take shape before college. A high-quality education in all areas of science at the high school level is crucial for understanding and for recruitment into STEM disciplines. Evolutionary biology in particular should be strongly emphasized because it underlies understanding of a broad range of science topics, yet it is a topic in which students display a great deal of misunderstanding. To address this challenge, we developed a series of engaging short-term evolutionary experiments for classroom use that give students the chance to visualize the effects of evolution in real time. These experiments provide empirical evidence that leads to a deeper understanding of evolutionary processes by providing an opportunity to study evolution in action. Pre- and post-test assessments given throughout the program demonstrated that students who experienced this laboratory curriculum improved test scores by nearly 40% while those exposed to a traditional evolution unit increased their scores by only 20%. The assessments also identified areas for improvement by revealing concepts that students had difficulty with following the laboratory experiments. These achievements set the stage for the implementation of this curriculum in many high school classrooms, with the aim of improving student understanding of evolution and more importantly promoting scientific inquiry and motivation for pursuing STEM careers.