The student will be able to create a simple food web and classify organisms in the food web. The student will also be to identify the consequences of removing pieces of the food web.
A food chain is a linear model that shows how organisms depend on other for their food. A food web is a diagram that shows the links between multiple species in a particular ecosystem.
1. Find a large open space. Have the students stand in a circle. Have them reach into the middle and grab someone else's hand. Each one of their hands should be grasping someone else's. Make sure that they have not grabbed the same person with both hands. Now give them a certain amount of time to try and unravel their web so everyone is untangled and on the outside of the circle. If you have a large class it may be helpful to divide them up into 3-4 groups of 6-8 people.
2. Debrief the activity. Highlight the fact that the students made up a web. Also point out that every person was dependent upon someone else. For the web to get untangled, they had to work together. Had someone broken the chain of the web then the whole process could have been disrupted.
Start by introducing food webs and showing a food chain. (To make an interactive food chain, go to: http://www.vtaide.com/png/foodchains.htm#create)
Let them know that a food chain is a linear model that shows how organisms depend on other for their food. (The arrow points from the "eaten" to the "eater". This shows the flow of energy through the food web.) A food web is a diagram that shows the links between multiple species in a particular ecosystem. For modeling, create, with the students, a basic food web for some marine animals in the arctic.
Though a basic web, it illustrates how complex food web cans be. ASK: How would this web be changed if one link was removed? What if the Polar Bear lost his sea ice? How would the rest of the web be affected? What kind of food (or organism) is always at the beginning food web? For today's lesson we are going to concentrate on land animals of the Seward Peninsula.
Have students list some animals that live on the Seward Peninsula. Make sure that they list humans as an animal.
For discussion and to assess the student's level of understanding, ask the students what they know about climate change. Ask them to list some ways that climate change is affecting them and also how it is affecting animals on the peninsula.
After the discussion, tell the students that the focus for the lesson will be making a food web for the following:
Emphasize to the students that this list is not comprehensive and that food webs can be very complex. After students have created their list, have them identify the producers and consumers. Remind them that producers are organisms that have the ability to produce their own food. Consumers encompass everything else. Have students break the consumers up into herbivores, omnivores and carnivores.
Break students up into groups of 2-4. Pass out the pictures of the animals in the food web.
Have students assemble their pictures of animals onto their butcher paper. Have them construct their web in pencil to begin with. Help them with the first step. Who eats the lichen, the blue berries, and/or the wild flowers? Name one animal.
Once the students have finished their food webs, compare them. Ask: are they all the same? Discuss the differences. Once you have checked the food webs to make certain they are correct, have them glue the pictures onto the paper.
Now discuss what happens when a member of the food web is removed. (Use the muskoxen as an example. They were threatened by over hunting when Europeans explored Alaska.) Read them the included excerpt about muskoxen. Have the students answer the following questions about muskoxen:
Once you have modeled the muskoxen example, have the students complete the same activity by selecting an animal to remove from the food web and answer the same questions on the worksheet provided. They should carefully remove the picture of the animal and glue it onto the worksheet. (OR the students may "X out" the organism, and you can provide them with another copy of that creature to glue onto the worksheet