Check out this article about Rapid Plant Evolution. Not only is this neat research but it is very accesible, easily understood by students and it should be very transferable to your own particular teaching environment. The researchers are only reporting on one particular plant’s rapid adaptation to a patchy urban environment but there are many other plants that may have similar adaptations ripe for study in similar environments.
Though the study only examined C. sancta, its findings, detailed in the March 3 issue of the journal Proceedings of the National Academy of Sciences, likely would apply to any plants or other organisms that can make a similar reproductive trade-off, Cheptou told LiveScience.
The original research in PNAS will be freely available in a couple of months