Oceanography: Food Webs

• Define food chain.
• Identify producers, primary consumers, secondary consumers, tertiary consumers, and decomposers within a food chain.
• Define autotroph and heterotroph.
• Define food web.
• Understand that food chains are typically only 3-5 links long because of inefficient energy transfer.
• Know that dominant species, keystone species and ecosystem engineers may impact trophic levels.
• Know that species within a food web may interact with each other through mutualism, predation, parasitism and commensalism.
• Be able to put animals into a simple food chain and draw arrows showing energy transfer.

Energy is needed for aquatic animals to perform basic survival tasks. In animals, energy is obtained through food. Plants obtain energy from the sun and convert it to food, and all living things obtain and transfer energy by participating in food webs. Food webs show the transfer of energy from the sun to producers which then transfer their own food to consumers. In this lesson students will learn the structure of a basic food chain. They will learn the vocabulary involved with producers and consumers. They will then understand how multiple food chains combine to form a more complex food web. Students will have access to IFXs so they can pick out animals and create their own food chain. A 360 video on ecosystems is also included in this lesson.

1. Start out with the 360 video Feasting With Wendy. Show clip up to 2:17.
2. Discuss the basic structure of a food chain.
3. Explain the difference between producers and consumers (carnivore, herbivore, omnivore, decomposer). Provide IFX examples of each and let students manipulate them.
4. Describe the organization of a food web. Explain how energy transfer limits the size of a food chain. Explain how dominant species, keystone species and ecosystem engineers influence trophic structure.
5. Explain examples of common food web interactions and have IFXs available to show and handle (mutualism, predation, parasitism, commensalism).
6. Allow students access to the IFXs so that they can look through them and pick out 4-5 to create a food chain.
7. Have them use their 3D pen to draw arrows.
8. End class by having students explain their food chain and what organisms they chose.

Use animal and underwater IFXS to show examples during discussion. For example, I used a clownfish, shark, whale, octopus, mollusk, starfish, freshwater fish like bass, sea otter and many others.