The panel on the right shows a graph of lynx and hare populations over a number of generations.

Click 'ENLARGE' to see a larger version of the graph. Click the blue buttons under the graph to plot the lynx and snowshoe hare populations.

Click 'NORMAL VIEW' to return to this page.

Additional teacher's notes

Get the students to work in pairs or small groups to discuss one of the questions and then to come and draw their predictions over the graph. Ask the group to explain why they think the graph will take the shape they've shown, and what parameters will contribute to the shape.

This plenary works particularly well when used with an interactive whiteboard. A sample lesson plan (PDF 82kB) is included in the Links section.

When you have discussed the graph, you can click through the tabs at the top of this panel: 'Inform', 'Question', 'Challenge' and 'Hypothesise'. These sections contain questions you may like to use in your plenary session. The 'Links' section has some useful websites.

Finally, click the link at the top of the screen to move on to Predator–Prey.

The aim of the Plenary is to focus students on what they have learned and to encourage discussion of energy and the ecosystem. Ensure that the students recognise the graph of populations of snowshoe hares and lynxes over a 50-year period, and that the vertical (population size) axes have significantly different scales.

Ask students to share their own interpretations of the graph and take verbal feedback from them. Emphasise the key features of the graph: the contrast in size of lynx and hare populations, the time lag between their peak populations and the cyclical nature of the graph. Relate these features to the research students have undertaken in earlier sessions, particularly in terms of energy and limits on reproduction.