Comparative Anatomy (4 of 8): The Digestive System

• Students will understand the overall function of the digestive system.
• Students will learn the organs of the human system.
• Students will handle and manipulate human digestive organs.
• Students will observe the differing food capturing techniques of three predatory specimens: squid, dog shark, and cat.
• Students will compare and contrast the digestive system of each specimen.
• Students will work with larger-than-life models of each specimen.

The digestive system ingests food, breaks it down so nutrients can be absorbed, and eliminates what cannot be digested. In the animal kingdom there are a variety of food-capturing methods along with variations in the digestive process. In this comparative anatomy lesson, students will be comparing three predators: the squid, the dog shark, and the cat. Students will compare and contrast their methods of capture and digestion. Students will handle and manipulate digestive organs. In addition, students will walk through the systems in larger-than-life specimens.

1. Start the class with 2D video of the digestive system.
2. Describe each organ of the human digestive system.
3. Give students the organs to manipulate and observe as they are discussed.
4. Have students do a quick activity. Place the human digestive organs in the body in the correct spots.
5. Walk around and give input.
6. Move to outer space where the three specimens will be.
7. Open up squid so all organs are spread out.
8. Start video of squid capturing prey.
9. Have class walk through squid organs, pointing them out and explaining functions.
10. Focus on radula and tentacles for food capture.
11. Open up dog shark so all organs are spread out.
12. Start video of dog shark capturing prey.
13. Have class walk through dog shark organs, pointing them out and explaining functions.
14. Focus on uniqueness of liver and spiral valve.
15. Open up cat so all organs are spread out.
16. Start video of cat capturing prey.
17. Have class walk through cat organs, pointing them out and explaining functions.
18. Focus on canine dentition and stalking method of prey capture.