Each student should have their own microscope, however, they can work in pairs having one student observe and call out information while the partner records the data. Log on to the web and read through the web site for Bdeltoid rotifers. The site has good information and pictures of rotifer anatomy. If facilities permit, you may want students to look at the site as well. The Bdeltoid rotifers are the ones with which I worked in Lake Hoare.
Extensions can be at the discretion of the teacher.
Some students may want more individual time to explore other ideas. Perhaps one or two students can assume the role of class recorders. Students can also document the discussion in their lab notebooks. Ask students to share their ideas about food webs and food chains in their local area. Then ask students to discuss in small groups what they think might be part of the food web in the perennially ice covered Lake Hoare in the Taylor Valley in the trans-antarctic mountains.