This practical activity can be done with a ruler or be adapted for use with a stage micrometer. Prepared microscope slides should be used, but it can also be done with freshly prepared slides. Because this is such a complicated concept, students will need plenty of guidance. Excellent learner centered activity.

This is an Ecology worksheet with questions to test understanding and make watching the video clip"How wolves change rivers" more active. It also requires a flow diagram and develops interpretation and critical thinking skills. The video shows how removing an organism from a foodweb impacts the whole ecosystem.