How to Make a Food Web Chain for Biomes
Environmental science, biology, and ecology have given us a new understanding of how living organisms coexist and interact within larger systems known as biomes. Biomes are described by abiotic (nonliving) features like geography, geology, climate, and nutrient resources. Biomes are also described by the characteristic living organisms that they contain. Food chains are used to understand how food energy moves through different organisms. A more accurate depiction of the flow of energy is given with food webs that are able to describe more complex interactions among organisms.
Things You'll Need
- Separate pictures or name cards of organisms in the biome
- Display or projection of the organisms without food energy arrows (alternative to above)
- List of feeding relationships (can also be put individually on separate cards)
- Display board
Instructions
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Antarctic Food Web
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1
Identify the organisms in a biome, for example, an Antarctic marine biome. Simplified:
light and nutrients, bacteria, phytoplankton, macroalgae (seaweed), zooplankton, copepods, krill, squid, crabs, mollusks, seabirds, pelagic fish, benthic fish, penguins, fur seal, leopard seal, killer whales, sperm whale, baleen whales.
(http://www.intandem.com/NewPrideSite/Asia/Lesson7/FoodWebs.JPG) -
2
Arrange the organisms on the display board according to estimated level in the food web, with predators at the top and producers at the bottom. Explain how light and nutrients are converted to food energy by phytoplankton and macroalgae. Draw arrows from light and nutrients to phytoplankton and macroalgae to show the direction the food energy is going. Note that these organisms are known as the "primary producers."
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3
Explain how bacteria, zooplankton, and mollusks eat the phytoplankton, and crabs feed on the macroalgae. Draw the appropriate arrows showing the flow of food energy. Note that these organisms are called "primary consumers" because they eat the primary producers.
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4
Read the list or cards to fill in the rest of the feeding relationships. Draw an arrow from the food source to the consumer. Example: "The leopard seal eats fish, squid, seabirds, penguins, other seals and fish." Draw lines from each of the food sources to the leopard seal. Note that these organisms are carnivores. Carnivores are secondary consumers, and carnivores that eat carnivores are, tertiary, quaternary, etc., depending on how high up the food chain they are.
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5
Explain that a simple food chain, like phytoplankton--zooplankton--copepods--krill--fish is not really so simple. While adult fish eat adult krill, adult krill eat fish larvae, so the arrows go back and forth between those species. This is how a food web differs from a simple food chain--it takes more relationships into account.
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Tips & Warnings
Note that when organisms die, even top predators, they are eaten by detritivores, like crabs and sharks. Read the list of relationships to show where the food energy goes. Note that decomposers (bacteria) break down animal waste as well as dead animals into nutrients that can be used by the primary producers to make food, and the cycle is repeated.
