Food Web and Trophic Level Lesson Plan

Pre-MacModS

Hognose Carolina Wren Barred Owl

Lubber Grasshopper Grass Bobcat

Above are a few common organisms found in the wilds of South Carolina. Using words or diagrams, organize these into logical predator/prey relationships.

If possible, use the terms a) food chain and b) trophic level in your description or drawing. Food Web and Trophic Level Lesson Plan

Purpose: Following completion of this lesson plan, students should be able to construct food webs and explain trophic levels and understand how the scientific method leads to these conclusions.

Standard 8-1: The student will demonstrate an understanding of technological design and scientific inquiry, including process skills, mathematical thinking, controlled investigative design and analysis, and problem solving.

Teachers: Stomachs can be made with plastic bags filled with toys and/or Swedish fish. 1 stomach (A) should have 3 small fish and 3 small shrimp or crab. 1 stomach (B) should have 1 large fish, 1 small fish, and 1 squid/octopus. 1 stomach (C) should have 2 large fish, 1 squid and 1 small shark labeled ‘A’ (representing that this is shark A from which stomach A was pulled from). It is optional to fill the stomachs with jello to add a touch of realism.

Materials: (1 set of the following materials for each group)

- 1 dissecting tray - 1 pair of scissors - 2 pairs of latex or vinyl gloves - 3 'shark stomachs' labeled A, B, and C

Procedure: Begin by explaining that often to understand feeding behavior and ecology, scientists will often analyze the food items found inside an organism's stomach. These findings help scientists understand where a particular animal falls in food chains and food webs.

1) In front of you there are 3 stomachs removed from 3 different species of shark found in these waters. It is your job to figure out where these sharks and their prey items fall in a food web. Possible prey items may include large fish, young fish, shrimps, squids, or possibly other sharks. 2) Start with shark stomach ‘A’. Carefully cut open the stomach and search inside for prey items. Make note of what you find. Do the items vary in type or number?

3) Now let’s try stomach ‘B’. Again, cut open and record prey items. Do these vary in type or number?

- How do these items compare with items from stomach ‘A’?

- Do you think that all the various prey items found in shark ‘B’ occupy the same level on the food chain? Why or why not?

- Do you think that the prey items in shark ‘B’ occupy the same level as compared to the prey items found in shark ‘A’? Why or why not?

4) And now open up stomach ‘C’. Once more, make note of what prey items you find. In terms of prey size, how does this stomach’s contents compare with ‘A’ and ‘B’? 5) Now take your observations from #s 2 – 4 and list and record the number of what you found in the table below.

Shark Stomach

- Considering the prey items found in ‘A’ vs ‘C’, do you believe shark ‘A’ and ‘C’ are on the same level? Why?

- Do you believe shark ‘B’ is on the same level as ‘A’ and ‘C’ or on a different level? Why?

6) What do you notice about the different prey items in the different stomachs? Are they similar or different? Below, using words or pictures, try to order the different prey items and sharks into appropriate levels based on whom is feeding upon whom. - If we were to assign numbers to each level, where might we start and end with?

Post MacModS

Shrimp Tiger Shark Blacktip Shark

Spot Young Spot Squid

Above are a few animals found off of our coastal waters. Below, using words or diagrams, organize these organisms according to predator/prey relations. If possible, use the terms a) food chain and b) trophic level in your description or drawing.