A Ravine's Web of Life
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RAVINE RA Aquatic INE Life in Streams and Nearshore Education Education Program Program A Ravine’s Web of Life RA INE Education TIMERA: VINE40-60 minutes Program Education Program GRADES: 5-8 Freeman © Carol LOCATION: Indoors or outdoors Ebony jewelwing damselfly SAFETY: When outside, stay in groups SUMMARY KEYWORDS: Students learn about food chains and food webs in the context of their local community. After discussing the different aspects of a Food chain, food web, food web, students model the food web of a Highland Park ravine producer, primary and learn how the food web changes following a disruption. consumer, secondary consumer, decomposer, herbivore, omnivore, OBJECTIVES carnivore, biotic, abiotic, Students are able to: trophic level 1. Explain how energy and matter move through a food web; 2. Describe how a change in one section of a food web affects MATERIALS: the rest of the web; and Printed Food Web 3. Identify examples of producers, consumers, and decomposers in a ravine ecosystem. Cards Ball of yarn Permanent markers BACKGROUND Hole punch Energy and matter naturally cycle through the biotic (living) and 4x6 note cards abiotic (non-living) parts of every ecosystem; this cycle is called a food web. Food webs can be divided into simple individual food chains, like the chain below. This example demonstrates four different feeding levels, also known as trophic levels, in the food GREEN TIP chain. Laminate Food Web cards for future reuse. DAMSELFLY FROG SNAKE HAWK RAVINE EDUCATION PROGRAM 59 www.pdhp.org/hpravines Aquatic Life in Streams and Nearshore A Ravine’s Web of Life PREPARATION PRIMARY SUNLIGHT CONSUMER There are two sets of Food Web Cards for this lesson. Set A includes the basic SECONDARY categories of a food web. PRODUCER CONSUMER Set B includes organisms that have been observed in the ravine ecosystems. SOIL DECOMPOSER Select a set to print for this activity. Be sure to print In nature, many food chains fit The chart above illustrates a cards double-sided. together to create a complex simple food web. Food webs food web. Producers (plants) are important because plants Print enough cards so that use the energy and nutrients and animals cannot create (or each student receives one. from sunlight and soil to destroy) extra energy. They If you print duplicate cards, create their own food. Primary can only change energy from be sure there is only one consumers (also called one form to another. sunlight card per group. herbivores) eat these plants (or particles of organic matter Every ecosystem has its own Punch holes in the top left or detritus). unique set of producers, and right corners of the primary consumers, secondary cards. Weave a piece of yarn Secondary consumers consumers, and decomposers. through the holes in each (carnivores – flesh eaters) Below is a list of energy card to make a necklace. eat the primary consumers, or sources, organisms and groups other secondary consumers. of organisms that may inhabit Note: Illustrations on food Some secondary consumers ravines in Highland Park. web cards are not to scale. are omnivores, so they eat both producers and Using this list and the consumers. Decomposers procedure below, students will break down dead plant and create a food web exclusive to animal matter. this ecosystem. Primary Secondary Consumers Energy Source Producers Consumers (omnivores and Decomposers (herbivores) carnivores) Sunlight Leaf litter Zooplankton (scuds Water strider Bacteria Organic matter Phytoplankton daphnia, copepods) Dragonfly (suspended in water) Algae Bloodworm/Midge Broadwing damselfly Blue-green algae Mayfly Rainbow trout (cyanobacteria) Riffle beetle Lake chub Longnose dace White sucker Mosquito Great blue heron RAVINE EDUCATION PROGRAM 60 www.pdhp.org/hpravines Aquatic Life in Streams and Nearshore A Ravine’s Web of Life PROCEDURE INTRODUCTION 1. Ask students: • What do they know about food chains? [who eats who, energy transfer from one organism to another] • What are the levels of a food chain called? [trophic levels] • What do we call an animal that eats another animal? [predator] • An animal that is eaten? White suckers in ravine stream [prey] • How does a plant get 3. Introduce the idea of a 6. Sit or stand in a circle (or its food? [they create food web, where each living multiple circles based on their own food through organism links to several food groups if using Set A). photosynthesis] chains. Explain that while food chains may appear simple, in 7. Instruct students to hold 2. As a class, define the nature the transfer of energy their cards facing outward and following science words, and between organisms is more visible to the group. Hand the ask students for examples of complicated. Each plant or ball of yarn to the students these: animal eats or is eaten by with the Sunlight Card. Producer: an organism that several others. creates its own food 8. Direct students to hold 4. Define food web: many onto the yarn with one hand Consumer: an organism that food chains linked together. eats other living things and toss the ball of yarn to whomever they think is the Carnivore: an organism that FOOD WEB next step of the food web. For eats animals (secondary MODELING example, the student with the consumer) sunlight card should pass the Note to instructors: If using Omnivore: an organism that yarn to a producer, showing eats both plants and animals Set A, divide class into groups the transfer of energy (secondary consumer) of 10-12 students. If using Set between them. If the group B, do not split the class into disagrees with their selection Herbivore: an organism that groups. eats only plants/producers then the person should try (primary consumer) 5. Give each student a Food again. Students should not Web Card. After they receive toss the ball of yarn to the Decomposer: an organism a card, they “become” that same person every time. that eats dead things and organism or ecosystem breaks them down into component. They may be nutrients biotic or abiotic. RAVINE EDUCATION PROGRAM 61 www.pdhp.org/hpravines Aquatic Life in Streams and Nearshore A Ravine’s Web of Life 9. After five minutes, ask 15. Consider the following PRESENTING student to count how many questions as a class: FOOD WEBS other organisms they are • How did the web differ Students create a short skit connected to (i.e., their food after one person stepped or multimedia presentation web connections). Some out of the group? Was that reenacts an aquatic students may not receive the the food web more or less food web. The story should ball of yarn. complicated? include producers, primary • Is it healthier to have a consumers (herbivores), 10. Ask a student to roll complicated or a simple secondary consumers up the yarn, hand it to the food web? [Complicated (carnivores and omnivores), student with The Sun, and food webs are stronger] and decomposers. start again. After a couple minutes, remove a primary • If using Set B of the Food Web Cards, ask students Students should include a consumer from the food situation where their food web by asking him or her to if they thought their food webs included every species web goes out of balance. step out of the circle. Before Encourage students to be they step out have them tug in their ecosystem? [No, because land plants and creative and have fun with on their part of the yarn. this activity! Anyone else who feels the animals, as well as species tug should step out as well. that live only in Lake Michigan, are not included] VOCABULARY QUIZ 11. Explain that this is an • What are some of the exaggerated model of the limitations of this model? Quiz students on the ripple effect of changes made • How might matter or energy meaning and spelling of to an ecosystem. Changes leave the ravine ecosystem? vocabulary words, in the food web could be caused by numerous factors, ASSESSMENT EXENSIONS including changes in weather TROPHIC PYRAMIDS or climate, disease, pollution, FOOD WEB (Grades 6-8) overharvesting by people, FLIP BOOKS and introduction of exotic Using 4”x6” note cards, Explore an alternative species. students create small books visualization of a food web: explaining the different the trophic pyramid. 12. Repeat Step 9. elements of a food web - producers, primary consumers 13. The person with the (herbivores), secondary HAWK Decomposer Card should consumers (carnivores and SNAKE wrap up the yarn. The class omnivores), and decomposers. can return inside. FROG After the definitions are DISCUSSION written, encourage students to DAMSELFLY draw examples on each card. 14. Have a representative Students should label the from each group explain the drawings and list the plants yarn’s journey through their and animals that eat or are food web. eaten by this organism. RAVINE EDUCATION PROGRAM 62 www.pdhp.org/hpravines Aquatic Life in Streams and Nearshore A Ravine’s Web of Life TERRESTRIAL FOOD WEBS Encourage students to create a terrestrial food web which occures on land. Compare the similarities and differences between the aquatic and terrestrial food webs. To learn more, visit: Food Chain Game (4th and Adult Mayfly found in Highland Park 5th grade) www.sheppardsoftware.com/ content/animals/kidscorner/ D.S. White and W.U. Brigham. 1996. White sucker life history: www.dnr. games/foodchaingame.htm Aquatic Coleoptera. pp 399-473 state.oh.us/portals/9/pdf/pub172.pdf in An Introduction to the Aquatic Great blue heron life history: http:// Food Web (6-8th grade) – Invertebrates of North America. animaldiversity.ummz.umich.edu/ when all arrows are clicked Eds. R.W. Merritt and K.W. accounts/Ardea_herodias/ Cummins. Kendall/Hunt Publishing Midge life history: http:// into place the activity is Company, Dubuque, Iowa.