Group Challenge Food Chains and Food Webs

• Significant idea: Feeding relationships in a system can be modeled using food chains and food webs

• By the end of this lesson: a clear distinction between food chains and food webs. In addition, be able to explain trophic level and which organisms occupy each trophic level. You will apply your knowledge and explain why trophic levels are limited to 3-4 levels in a food chain.

• ATL: Thinking

• Making a connection between food chains, food webs, and trophic levels and why food chains can only have 3-4 trophic levels.

• https://www.youtube.com/watch?v=mCHdhXMFhcU

• Trophic levels

• https://www.youtube.com/watch?v=LVJ5BKcAhAg

• Food web of the Monterey Bay Ocean

Food Chains• Food chain = the flow of energy from one organism to the

next• Shows the feeding relationships between species in an ecosystem• Arrows show the direction of energy flow

Trophic Levels• Trophic Level = feeding

level in a food chain.

Food Webs• In ecosystems, there are many

food chains that are interconnected.

• Limits of food chains – only show each organism eating one other organism. In reality, organisms eat many other species as food!

•Food webs = complex network of interrelated food chains in an ecosystem

Food Webs• Arrows point towards the

direction of energy flow (arrow goes into the organism that is eating it)

• Show the complex feeding relationships that trophic pyramids and food chains cant show.

• (ex. A grizzly bear is a top predator but also eats plants)

Food Webs• Read and annotate Arctic Food Web article.

• Create a food web using only the animals mentioned in the article.

• Use the cut outs and a large whiteboard to draw arrows between the organisms.

• After you have made the food web, color code each organism as:

• Tertiary consumer• Secondary consumer• Primary consumer• Primary producer• Decomposers• Detritivores