Wednesday, November 10, 2010

Students will "gobble" up this food web

Wondering how to make learning about food webs fun for your students? Here's an activity perfect for November (when we're all dreaming up the upcoming turkey dinner) where students will investigate the concepts of food webs and food chains. This is alos a great opportunity for them to learn about and describe the role of wild turkeys, plants and other organisms in cycling energy and matter. Another plus? this activity is easily adaptable for students in kindergarten through 8th grade and addresses science and environmental education national learning standards.

This photo of a Rio Grande subspecies of wild turkey is courtesy of the National Wild Turkey Federation
So what are food webs? Basically, food webs are the feeding relationships among the different species in a community. Each member of a community can be classified as either a consumer or a producer. Producers, well, produce energy—generally from the sun through photosynthesis. Producers harness the sun's energy to make their own food. On the other hand, consumers are those members of the community who consume energy by eating other organisms. Producers are the base of the food chain and very important, because all of the energy in the community originates with them.

Start off by discussing the definitions of producer and consumer and have students list examples of each, Write the name of each producer and consumer on an index card (1 per card) and tape each piece to the chalkboard or whiteboard. To make it even easier, you can print off these printable cards with list numerous members of the community, whether they are a producer or consumer, and what they eat. Younger students might find it easier to understand if each animal were represented by a pictureYou and your students may also be interested in learning more about wild turkey predators in particular for this lesson.

Then have the students come to the chalkboard and draw lines to show the energy chains.  You can also place the cards on the floor and connect them with yard. Students can then physically walk through a specific energy chain in the food web. Students can then record their specific chain on a piece of paper or in a science journal.

Once each student has recorded their chain, the teacher can pull an organism from the web. Have students discuss which food chains the removed organism affected. Repeat with other organisms from the chain and continue to discuss.

To add a fun twist, replace all the organisms in the food web and have students secretly select and record a second energy chain. Once each students has recorded their new secret food chain, the teacher slowly randomly begins to remove and organism. After the first organism is removed, record who is "dead" and who is "alive." Continue to remove organism and record the casualties and survivors until all the energy chains have been eliminated.

Here are some questions for discussion:

  • What did the students notice when all the organisms had died?
  • What strategies to herbivores use to avoid being captured? Answers will vary, but examples might include mimicry, mobbing behavior, camouflage coloration, safety in numbers, physical or chemical combat, etc.
  • What strategies do carnivores use to capture their prey? Again, answers will vary but might include binocular vision, sharp teeth, heightened sense of smell, sharp claws, camouflage coloration, hunting in groups, physical or chemical combat, etc.
  • How do organisms compete for food? Organisms usually compete for food through adaptations, performance, heard-to-head competition, or predatory competition. Students' answers may vary. For more on the adaptions of wild turkeys, be sure to check out our post from last week called "This turkey is staying alive!"
  • What would happen if there were more predators or prey in a particular community? Explain. Answers may vary, but could include overpopulation of species, which would lead to an increase in disease and a decrease in available food and space for that species.
  • How might humans affect the food web? Humans could negatively impact the food web through pollution and habitat destruction. However, humans can also positively impact the food web through habitat creation, establishing wildlife areas, and helping to control overpopulated species. It's important for students to realize not all human intervention is bad.
This lesson was based on and adapted from the "Turkey Web"activity found in the National Wild Turkey Federation's Wild About Turkeys k-12 curriculum and activity guide.

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