Food Webs and Food Chains – Grade Five Ohio Standards Connection: Life Sciences Benchmark B Analyze plant and animal structures and functions needed for survival and describe the flow of energy through a system that all organisms use to survive. Indicator 3 Trace the organization of simple food chains and food webs (e.g., herbivores, producers, carnivores, omnivores and decomposers). Lesson Summary: Throughout the lesson, students will be engaged in a variety of experiences to help them understand simple food webs and food chains. Opportunities are also provided for students to internalize the role different organisms play in food chains and food webs and how energy flows in an ecosystem. This lesson should be taught after students have had experience with indicators #1 (Describe the role of producers in the transfer of energy entering ecosystems as sunlight to chemical energy through photosynthesis.) and #2 (Explain how almost all kinds of animals’ food can be traced back to plants.). Estimated Duration: Four hours and 10 minutes Commentary: A food chain shows the linear relationship between organisms in an ecosystem. It shows how organisms are connected to each other according to what they eat. A food web shows how organisms can be part of many food chains. A food chain shows how each organism eats one thing and is eaten by one animal; whereas a food web shows all the organisms an animal eats and is eaten by; food chains do not exist in reality. Students understand scientific concepts best when they have opportunity to explore them actively. A classroom environment can provide students many opportunities to explore ecosystems and interactions which occur between organisms. Classroom terrariums, aquariums, compost bin, rotten log community and/or a river tank system can provide these types of experiences. Taking students to an ecosystem such as a pond, field or a park gives them another excellent opportunity to observe and experience interactions in an ecosystem. Reading books about a variety of ecosystems and other literature will help enrich students’ knowledge. The school library media center can help to provide a class collection of books, children’s literature, videos and research resources about ecosystems. 1 Food Webs and Food Chains – Grade Five Pre-Assessment: Have each student draw food chains using pictures or names of four to five organisms. Give each student the same set of animals. When all students have drawn their food chains, they can share food chains to determine if they are drawn correctly. Scoring Guidelines: Check to determine if food chain shows a correct linear relationship (i.e., producer, primary consumers and secondary consumers). Assure that arrows are pointing from organisms being eaten to organisms eating it. Have students share their food chains with the class. This will provide an opportunity to check students’ understanding about food chains. Post-Assessment: Have students create a food web of an ecosystem (e.g., pond, meadow, forest, river or lake) using the names or pictures of organisms provided by the teacher and write an explanation of their food web. Allow students to cut pictures of the organisms from magazines, draw the organisms, or write names of the organisms. The following information should be included in the food web: arrows indicating the direction of energy flow from one organism to another; labels for all components of the food web (producers, primary consumers and secondary consumers); a detailed written description of food web explaining the flow of energy; a written comparison between food chains and food webs. Scoring Guidelines: See Attachment A, Rubric for Post-Assessment Instructional Procedures: Day One 1. Write on the board, or overhead, a food item from the dinner one of the students ate last night (e.g. salmon, chicken, spinach). Have the class discuss the source of the food item. Have the students then suggest what organism it might have consumed, and thereby, what that organism might have eaten. Trace each food item to either a plant or a tertiary consumer and to the sun’s energy. Complete the food chain. Ask students what they notice about the direction of the arrows in the food chain. Make sure that students understand that the arrows point from the organism being eaten towards the organism eating it. Energy is flowing from the organism being eaten towards the animal that consumes it. Spend a few minutes exploring that the food chain is a way to show how energy passes from one organism to another. Food chains show linear relationships among organisms. 2. Ask students to make a list of food items from yesterday’s school lunch. In groups, have students discuss where these foods came from. Then have students construct food chains individually. Every food item from their school lunch should be traced back to either a 2 Food Webs and Food Chains – Grade Five 3. 4. 5. 6. plant or a tertiary consumer. Students may need to conduct research to complete the chain. Some food chains will be short and some will be long. Remind students to trace each food item to the sun’s energy. To make their food chains, students may cut pictures from magazines, draw organisms, or write the names of the organisms. While students are constructing food chains, facilitate learning by asking questions for clarification, prompting and encouraging critical thinking and clarifying misconceptions. When all students have completed their food chains, allow group members time to review each other’s food chains. Have groups share their food chains with the whole class. Engage the whole class in discussion. Ask students how they know what an animal eats or what eats it. Stretch students’ thinking by asking what might eat a plant or an organism after it dies. It is really important to discuss the role decomposers play in food chains and food webs. Ask students where plants get their energy from (sunlight). It is important to discuss the role of the sun’s energy in an ecosystem. Ask students what will happen if the sun stops shining (everything will die). Ask students what other terms are used to describe organisms at each level in the food chain. Make sure to introduce the terms, plants (producers), herbivores (primary consumers), carnivores (secondary consumers), tertiary consumers, omnivores and decomposers. If students have not labeled their food chains with these terms have them label their food chains with appropriate terms. Have students use the terms orally in order to internalize the vocabulary. Have students write about different parts of a food chain in their journals and explain the role of each component. Day Two 7. Divide the class into groups of four. Assign each group a different area in the schoolyard. Have groups mark their area of study with yarn or string. Have each group study and observe their assigned spot. They can dig in the soil; look in the grass, around plants and up into the trees to discover what kind of plants and animals live in the schoolyard. Encourage students to also look for clues like feathers, furs, tracks, cracked nuts, and eaten leaves. Have the group recorder keep a list of all the organisms the group has discovered. 8. When the students return to the classroom ask students to create food chains using the organism they found in the schoolyard. Students can also use references (text books, teacher, ecosystem books, Internet) to discover other animals that might be in the schoolyard and what each animal eats and what predators eat it. To make their food chains, allow students to cut pictures from magazines, draw organisms or write the names of the organisms. Ask students what might eat tertiary consumers after they die (decomposers-fungi, bacteria). Make sure that the students understand important role decomposers play in an ecosystem. Ask them what could happen if all decomposers disappear from earth. (Dead organisms will pile up and nutrients would not be put back in soil.) 3 Food Webs and Food Chains – Grade Five 9. When complete, have each student share his or her food chains with a partner. Then have students share their food chains with the whole class. Encourage students to use appropriate vocabulary (producers, primary consumers (herbivores), decomposers, secondary consumers (carnivores), and tertiary consumers) while describing their food chains. 10. Have students demonstrate their understanding by writing about food chains in their science journals. See Attachment B, Sample Journal Writing. Day Three 11. Assign the whole class one ecosystem (e.g. pond, woods, school yard, forest). In small groups, students will use references which may include textbooks, ecosystem books, Internet and teachers to find out the names of plants and animals in the assigned ecosystem. Encourage students to use various resources to find out what each organism eats and by whom it is eaten. Tell students to make food chains using the organisms from the ecosystem. Each group will decide how to organize its food chains and how many food chains to make. Groups can also decide if each member makes one food chain or if the whole group works together on each food chains. While students are working on their food chain, facilitate learning by observing, asking questions, clarifying misconceptions and making suggestions to groups who seem overwhelmed and frustrated. Ask guiding questions instead of giving answers. Encourage students to think and to stretch their thinking. Encourage students to ask each other to share how they know what an organism eats and who eats it. When all groups have constructed the food chains, have pairs of students share with each other the food chain they made. 12. Next, have groups share their food chains with the class explaining how they decided what an animal eats and what eats it. (Students can either create a poster of their food chain or act it out.) During the class discussion, students will discover that most organisms are eaten by more than one animal. There can be many different food chains for the same animal. 13. Ask students what will happen if we connect different food chains constructed by the class. This is the time to introduce the concept of food web. A food web shows all things an organism eats and is eaten by. A food chain shows a linear relationship. 14. Write names of animals and plants from the ecosystem the class is studying on index cards or on sticky notes. Make sure to label each organism with the components of the food web it represents. Each student will represent one organism. Using the animal name cards and yarn, have the class stand in a circle to create a food web of the ecosystem. The students will be passing the yarn from an organism being eaten to the organism, which eats it. 15. After the web is created, ask students to trace the direction of energy flow in their food web. Give several students opportunity to give their explanations. (In a food web many food chains connect to form overlapping relationships. Food webs can be very confusing for students. They need experience in constructing food webs.) 16. Create a bulletin board of the schoolyard ecosystem and the ecosystem that the class just studied. Post pictures of both ecosystems’ organisms on two separate bulletin boards and have students use yarn to make the connections. Each group can take turns in connecting 4 Food Webs and Food Chains – Grade Five a part of the web (adapted from NSTA Pathways to Science Standards: Middle School, pg. 74.). This will help students better understand the concept of different organisms eating the same food. 17. End the lesson with journal writing in response to the prompt, “What do I understand about food webs and food chains?” Day Four 18. Start the activity by asking students, “What is the difference between food chains and food webs?” Have a brief discussion with the class. This is an opportunity to review the concepts students have been studying the last few days. 19. Assign each group an ecosystem. Group members will use a variety of resources to make a list of plants and animals that live in their assigned ecosystem. They will also research what each organism eats and is eaten by. (This part of the lesson may be assigned for homework.) To create their web, students can draw pictures of the organisms, cut pictures from the magazines or write names on index cards. Remind them to label the components of their food web. While students are working, listen, observe, ask questions and help clarify any misconceptions. 20. After finishing the group food web, have each member write a description of the food web, explaining the flow of energy in the web, and the function/role of each organism in the web. In their writing, have students compare and contrast food webs and food chains. 21. When finished with the assignment, invite each group to post its web in the designated area. Allow 10 to15 minutes for students to walk around the room to view the webs. This will give groups a chance to review each other’s work. Have students write their comments and questions on sticky notes and post them beside the food webs. 22. Bring the whole class together for a discussion. During the discussion, allow time for each group to explain its web and answer the questions written on sticky notes. a. Ask each group what problems and frustrations they experienced. b. Would the group make any changes to its web? c. What other questions does the group have? Differentiated Instructional Support: Instruction is differentiated according to learner needs to help all learners either meet the intent of the specified indicator(s) or, if the indicator is already met, to advance beyond the specified indicator(s). Students can give their explanations orally or act it out instead of writing. Students can create a poster of their food chains. Extensions: Have students write a food web or food chain song. Make a food chain and food web game. Play food web and food chain games. Have students write about what might happen if there was a disruption in their food web. e.g., If one group of living things was eliminated from an ecosystem or a plant or animal from another ecosystem was introduced to an ecosystem. Monitor the water quality of a local stream and determine the impact on the associated 5 Food Webs and Food Chains – Grade Five food webs and food chains. Read literature which has concerns regarding the importance of taking care of our ecosystems. Invite someone from the local park system or soil and water conservation district to visit the class and share information and activities with students. Homework Options and Home Connections: Borrow a book from the library about an ecosystem. Read it and write a report or prepare a poster of findings. Ask students to visit a local ecosystem (pond, field, river, lake, nature preserve, city park, etc.) with his or her parents. They could share their observations about food chains and food webs with the class. Students could persuade parents to start recycling or start composting yard and kitchen waste. (Parents could access information for local solid waste management agency or teacher may send information home with students about recycling and composting.) Study and read about the compost ecosystem and create its food web. Study the role of non-living things (air, water, soil) in an ecosystem. Materials and Resources: The inclusion of a specific resource in any lesson formulated by the Ohio Department of Education should not be interpreted as an endorsement of that particular resource, or any of its contents, by the Ohio Department of Education. The Ohio Department of Education does not endorse any particular resource. The Web addresses listed are for a given site’s main page, therefore, it may be necessary to search within that site to find the specific information required for a given lesson. Please note that information published on the Internet changes over time, therefore the links provided may no longer contain the specific information related to a given lesson. Teachers are advised to preview all sites before using them with students. For the teacher: Variety of resources about ecosystems; ecosystem books, Internet access, encyclopedias, and any other resources, old magazines. For the students: Ecosystem books, Internet access, encyclopedias, and any other resources, variety of resources about ecosystems, string, small trowels to dig, old magazines, crayons, colored pencils, paper to draw, yarn. Vocabulary: producers carnivores primary consumers secondary consumers tertiary consumers decomposers herbivores omnivores 6 Food Webs and Food Chains – Grade Five Technology Connections: Search the Ohio Department of Natural Resources Web site (http://www.dnr.state.oh.us) or the National Wildlife Foundation site (http://www.nwf.org/ ) for background information for the following activities: Have students research their ecosystem on the Internet; Create a food web on the computer; Research the impact of technology on our ecosystem. Research Connections: Marzano, Robert J., Pickering, Debra J., Pollock, Jane E. Classroom Instruction that Works Research-based strategies for increasing student achievement. Alexandria, Va: ASCD, 2001. Alternative post assessment is used, requiring students to create a product (diagram, build models, etc.) and write a detailed explanation. Instructional strategies also make use of research based effective strategies such as nonlinguistic representations (making physical models, drawing pictures), cooperative learning (small/large group, individual and group accountability), activating prior knowledge and higher level questioning, thinking, and stretches. Students are also given opportunities to organize, elaborate and apply their learned knowledge in various situations. Teacher’s questioning, student journals, and discussions are woven throughout the unit. (Marzano, 2001) National Science Teachers Association. Pathways to Science Standards, Middle School. Editor Rakow, National Science Teachers Association, 2000, p. 74. General Tips: In order to understand food webs and food chains, students need to know what eats what in an ecosystem. It is very important that a variety of resources are available and students are given many opportunities to research and read about living things in a variety of ecosystems and how they interact with each other. Call your local library to get a class collection of books about various ecosystems. Make use of free outreach programs offered by a local zoo, nature preserves, county and city parks, soil and water conservation district, and local environmental agencies. Show videos about ecosystems. Have resources available in the classroom. Attachments: Attachment A, Rubric for Post-Assessment Attachment B, Journal Writing Sample Attachment C, Pond Food Web Attachment D, Food Web for School Yard or Field 7 Food Webs and Food Chains – Grade Five Attachment A Rubric for Post-Assessment 4 3 2 1 Food Web Design Labeling of Component Direction of Energy Flow Explanation of Energy Flow Comparison of Food Webs and Food Chains 8 Food Webs and Food Chains – Grade Five Attachment B Journal Writing Sample In my food web, energy is being transferred from the organism being eaten to the animal that is eating it. Arrows are pointing from the organism being eaten to the organism eating it. The plants at the bottom of the food web are algae and duckweed. They are called producers. They get their energy from the sunlight. They use sunlight to make food. The plants (producers) are giving energy to primary consumers (snails, minnows, tadpoles, insects). Since these animals eat plants they are called herbivores. Arrows are pointing from producers to primary consumers. Primary consumers are eaten by secondary consumers like bullfrogs, dragonfly nymphs, and spotted salamanders. Arrows are pointing from primary consumers to secondary consumers. Secondary consumers eat other animals. They are called carnivores. Tertiary consumers (water snake, snapping turtle) feed on secondary consumers and might also feed on primary consumers. For example a snapping turtle might eat a frog or a small fish. Arrows are pointing from secondary consumers to tertiary consumers. Great blue heron and snapping turtles are usually not eaten by any animals. That is why they are called tertiary consumers. When organisms at all levels of the food web die, decomposers and scavengers such as fungi, bacteria, and earthworms break them down. My food web shows many other organisms can eat that one organism. A food chain shows the linear relationship between organisms in an ecosystem. It shows how organisms are connected to each other according to what they eat. A food web shows how organisms can be part of many food chains. A food chain shows how each organism eats one thing and is eaten by one animal; whereas a food web shows all the organisms an animal eats and is eaten by. Food chains do not exist in reality. Food Web Components- producers, primary consumers, secondary consumers, tertiary consumers, decomposers, herbivores, omnivores, carnivores. 9 Food Webs and Food Chains – Grade Five Attachment C Pond Food Web Producers (green) Tertiary Consumers (blue) Primary Consumers (red) Decomposers (brown) Secondary Consumers (orange) 10 Food Webs and Food Chains – Grade Five Attachment D Food Web for School Yard or Field Producers (green) Primary Consumers (red) Tertiary Consumers (purple) Decomposers (brown) Secondary Consumers (blue) Note: Student created web might not show all these connections. Use this web as a guide to see the possible connections individual students might include in their work. 11