Lesson 8: Abundant Lakes

Florida is fortunate to have more than 7,800 lakes. Approximately 35% are in Lake, Orange and Osceola counties. The largest lake in Florida, Lake Okeechobee, is located in south Florida. Lake George, the largest lake in northeast Florida, is located in Lake, Marion, Putnam and Volusia counties.

The source for most of these lakes is seepage from groundwater or drainage from rain and storm water. Lake levels usually fluctuate due to rainfall, evaporation, runoff and interchange with groundwater. Sometimes landowners living on a lake may use lake water for irrigation.

Lakes have life cycles that last thousands of years. It is natural for lakes to “fill in” as sediment collects on the lake bottom. Sometimes humans speed up this process needlessly by developing too near the edge of a lake. Nutrients such as fertilizers and some detergents cause plants to grow too rapidly. As they decay, this matter settles to the bottom with other debris, and the lake dies before its time.

1. Ask the class if anyone has ever lived on a lake. If any students have, ask them what is different about living on a lake from living anywhere else.

2. Have students read parts 1 and 2 to find out what a lake is.

3. Ask discussion questions for part 1:

• Many of Florida’s lakes began as what?
• What is the primary water source for most lakes?
• What happens to lakes during times of drought?
• Is there a lake near your house?
• How is this lake used by man? By wildlife?

4. Have students look at the map in part 2. Ask them to count how many lakes they can see. Do they all have names on this map?

5. Have students read “Imagine that!” in part 2. Discuss the disadvantages of introducing exotic plant species.

6. Have students read part 3 and part 4 to find out about lake life zones. Ask discussion questions:

(part 3)

• What helps determine where a plant or animal may choose to live?

(part 4)

• Why are the plants in the littoral zone important to animals?
• What is the next zone called? What lives in this zone?
• What is photosynthesis?
• What are decomposers?

7. Have students look at and discuss the drawing in part 4. Would the same plants that grow in the shallow zone grow in the deep zone? Why or why not?

8. Have students read part 5 and part 6. Ask discussion questions:

(part 5)

• What is a food web?

9. Have students look at the illustration in part 5. Ask discussion questions:

• What does the crayfish eat?
• What could eat the crab?
• What happens to the parts of the crayfish that don’t get eaten?
• What could eat the fish?
• What would happen if the fish simply died of old age?
• What could eat the alligator?
• What happens to plants when they die?

10. Have students read and discuss “Imagine that!” in part 6. Have students navigate to Lesson 7 Part 1 and look at the map. Have them locate Lake Apopka, which is the largest lake just to the left of Orlando. Discuss what could happen to a lake if there wasn’t a “balance” among the producers, consumers and decomposers.

FCAT-style questions based on the content of Lesson 8 have been prepared to assist students in preparing for the Florida Comprehensive Assessment Test.

• Lesson 8 FCAT-Style Questions
• FCAT Reading Rubric
• Sample Responses

1. Have students draw a cross-sectional view of a lake and the lake bottom. Have students illustrate and label lake life zones and plants and animals in this freshwater food web.

2. FCAT-Style Questions, Lesson 8 Online Quiz or Lesson 8 Quiz worksheets may be used.*

1. Have students navigate to the Lesson 8 Experiment, “Draining into a lake.”

2. Divide class into cooperative groups and have them read “What you will learn,” “What you will need” and “Here is what you do.”

3. Have each student begin a Make A Prediction lab report worksheet.

4. Have students do the experiment “Draining into a lake” and answer the questions. Make sure that students understand that this experiment shows how untreated sewage would pollute a lake.

5. Have students complete the Make A Prediction lab report worksheets and discuss.

6. Have students read “Make a difference!” and discuss.

7. Have students do the extra activity “What other plants can cause problems?” as a class assignment or as homework.

Answers for the FCAT-style questions and the online and offline quizzes can be downloaded at answers.html. The quiz answer keys are password-protected. You can obtain the password by registering via a short form.