The Lessons on the Lake Logo Chapter 7: Ecosystems in Delicate Balance
Lesson 7.4 Lesson 7.5 Lesson 7.6 Lesson 7.7 Lesson 7.8 Lesson 7.9 Lesson 7.10
Lesson 7.1 Lesson 7.2 Lesson 7.3
Lessons on the Lake -> Chapter 7 -> Energy Flow

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As a result of evolution, manatees have pelvic bones but they are not connected to the rest of the manatee’s bone structures. Body parts that were once used by a species’ ancestors but no longer serve a purpose are called vestigial structures.


  1. Ch. 7 Intro
  2. Essential Questions
  3. Ecosystems
  4. Energy Flow Through an Ecosystem
  5. Healthy vs. Unhealthy Ecosystems
  6. Biodiversity
  7. Threatened and Endangered Species in the Basin
  8. Decision Making and Issue Analysis
  9. Ecosystem Tumble
  10. Activity: I'm a Survivor