Click on the page icon for Lesson 2 in Adobe Acrobat format (80K). Includes Activity Page 2.

Objectives

• Identify the main parts of a coral reef.
• Describe a coral reef food chain.

Materials

• Copies of Activity Page 2.
• Additional reference books with pictures of coral reefs.

Subject

Science

Procedure

1. Using the Introduction as a guide, present the coral reef as an example of a dynamic ecosystem. Within every ecosystem, physical conditions such as temperature and the amount of sunlight affect and are affected by the organisms in an environment, such as plants, animals, and microscopic organisms. Ask students if they have ever visited a coral reef or seen pictures of one. Perhaps they can name some of the fish that live there. (Angelfish and barracuda might be two fish that students can recognize.) If an aquarium or fish supply store is nearby, you might arrange for a class visit. You might also refer students to one of the many reference books with colorful photographs of coral reefs.

2. Tell your students that each dynamic ecosystem consists of many interacting parts, each using energy and producing wastes. Ask them to speculate why coral reefs host an abundance of marine life. (The key is that the coral reef receives a wealth of sunlight, which causes algae within the reef to produce an abundance of food. The waves crashing over the reef distribute oxygen and food throughout the ecosystem, creating a hospitable environment for animals). Tell your students that many kinds of living things make up the coral reef community: producers (plants), filter feeders (animals that take in microscopic plants and animals from the water), grazers (algae eaters), predators (animals that eat other animals), and scavengers (animals that eat the remains of dead creatures). A complex food web connects all of these living things. You might wish to write the five organism types on the blackboard and ask students to suggest an animal that fits into each type.

3. Give each student a copy of Activity Page 2. Tell the class to examine carefully the diagram as you describe some of the following organisms found along a coral reef:

• At the highest point (crest) of the reef, large, dome-shaped, brain coral forms huge boulders. Colorful parrotfish, their large front teeth fused together like a parrot's beak, scrape algae off the coral rock. (Refer to the Introduction to remind students that coral grows with the help of algae.) Nearby, the queen angelfish sports an electric-blue, crown-like growth and eats sponges, which in turn feed on microscopic life.
  
• On the outer reef, Elkhorn coral extends its branches like sign posts and withstands the constant pounding of the waves. Sea fans expose themselves to the prevailing current to receive food, while predators like the barracuda ready themselves for the hunt.
  
• Between the reef and the shore is a quieter environment known as the lagoon. Here the turtle grass is dense, protecting the young members of reef species. Schools of French grunts who stay among the corals all day move to the grass beds at night to hunt for small crustaceans like grass shrimp. Nearby, a pink-tipped anemone floats food its way by waving its tentacles.

4. Ask your students to complete Activity Page 2 by writing their answers on a blank piece of paper. When they finish, discuss the correct answers with them. Be sure to emphasize that all of the organisms depicted in the diagram are related to each other in a vast food web.