1. Activity 79Eating for Energy • Challenge: How are the energy relationships among organisms in an ecosystem affected by the introduction of a new species? • Key Vocabulary: • Consumer • Ecosystem • Photosynthesis • Plankton • Producer

2. What foods do humans use as sources of energy? Humans Cow Grass Wheat Consumer: organisms that obtain food by eating other organisms Where does the grass of wheat obtain food?

3. What makes up an ecosystem? An Ecosystem is a group of living organisms, their habitat, and the non-living things they interact with

4. Doing the Activity: Attach Student Sheet 79.1 into your notebooks and answer question #1 We will finish #2-3 after we complete the activity.

5. Stop to Think 1 Brainstorm ways in which zebra mussels might accidentally be spread from one lake to another.

6. Stop to Think 2 Why are producers such as plants, an essential part of any ecosystem?

7. Stopping to think 3 • Copy the food web into your notebooks. • Identify each organism as a producer or consumer. • Add humans to this food web. • In the lake food web, humans are consumers. Are humans always consumers? Explain.

8. Stopping to Think 4 Using the above food web as a guide, create a lake food web that includes zebra mussels. Be sure to show how zebra mussels get their energy AND how other organisms get money from them.

9. Stopping to Think 5 Look at the zebra mussel map. The lines across the U.S. represent large rivers. Where do you predict zebra mussels will be found in the next 10 years? The next 20 years? The next 50 years? Explain your predictions.

10. Are producers a necessary part of the Northern pike’s ecosystem?

11. Analysis Questions 1-3 Answer questions 1-2 in your notebooks. Answer question #3 on the sheet provided.