Ocean Food Web (page 2)

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Author: Tricia Edgar

Creating a Food Web

Of course, the menu in the ocean is a lot larger than what your food chain shows! Individual animals can eat many other types of plants and animals, not just one. For example, a seal likes to eat other fish like salmon, and seals in turn can be eaten by larger animals such as orca whales.

  1. Create two more labeled push pins that say “orca” and “salmon” and use your string to attach the orca to the seal, the orca to the salmon, and the seal to the salmon. Are there any other connections that you can see?
  2. Your food chain is beginning to look more like a web! Can you research any other animals that might be part of this ocean food web? Add them to push pins and continue building your web.

Creating a Food Pyramid

A food pyramid is different from a food chain or web. How is it different? Think about your herring. How many copepods does it eat in a week? Probably thousands! How many herring does it take to feed your seal? Certainly fewer.

As you move up the food chain, each level, or trophic level, can support fewer animals. Each trophic level represents the position an organism occupies in a food chain. A single seal (ultimate consumer) can eat many herring (secondary consumer), and a single herring can eat many copepods (primary consumer). Each copepod eats hundreds of individual bits of phytoplankton, called producers because these small plants get energy from the sun. This means that thousands and thousands of plankton end up indirectly feeding that seal at the top of the chain. A food pyramid shows the different numbers of organisms that are necessary at each level of the food chain. At the bottom of your food chain you might draw many different bits of phytoplankton, but there will be only one seal in the small triangle at the top.

  1. Let’s build your pyramid! Print out this pyramid template on your cardstock paper, and let’s get started.
  2. First, cut out the template from the image you printed.
  3. Fold the template along the diagonal lines that run through its center.
  4. From bottom to top, label the four parts of one triangle with the following names: producer, primary consumer, secondary consumer, ultimate consumer.
  5. From bottom to top, label the four parts of the second triangle with the names of the plants and animals on your food chain. You’ll begin with the plants at the bottom, and end with the name of the top predator at the top. Remember: The phytoplankton are the producers, the copepods are the primary consumers, the herring is the secondary consumer, and the seal is the ultimate consumer.
  6. On a third triangle, draw a picture of each plant or animal.
  7. To complete your ocean food pyramid, tape the tab on your first triangle to the underside of your third triangle. You’ve made a food pyramid!
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