PLANET EARTH: Fresh Water

Transcription

1 PLANET EARTH: Fresh Water Teacher s Guide Grade Level: 9-12 Running Time: 42 minutes Program Description Follow rivers as they course from mountain to the sea, nourishing unique and dramatic wildlife and shaping the land. Recognizing that all life on land depends on fresh water, the presentation emphasizes the importance of rain in the water cycle and how animals from grizzly bears in British Columbia to cichlids in Africa s river valley use fresh water to protect, nurture, and teach their young. A look at South America s Pantanal wetlands and such key animals in the food chain as the red-bellied piranha reveals predator-prey relationships essential to completing the circle of life. Focusing on many of the world s most spectacular lakes, waterfalls, streams, and wetlands, the program uncovers exceptional animal species and adaptations including the crab-eating macaque s amphibious lifestyle, developed while living in the Sunderbans, the world s largest delta in West Bengal, India. Learning Objectives After viewing the program and participating in discussion, students will be able to: Describe the characteristics of fresh water biomes; Understand the importance of fresh water to all organisms; Identify the steps of the water cycle; Relate an organism s adaptations to its surrounding habitat; Recognize the vast biodiversity of fresh water biomes. Classroom Connections Describe the processes involved in the water cycle. Include evaporation and transpiration, condensation, and precipitation in your answer. What types of animals live in mountain rapids? Name some of the species. How are they specifically adapted to their environment? In its food web, at what trophic level does Japan s giant salamander reside? Explain your answer. What dangers do salmon encounter on their journey to spawn? How might their journey relate to the concepts of survival of the fittest and natural selection? What river has created Earth s longest canyon system? Describe how the river transformed the landscape and hypothesize how the river has changed as a result. 1

2 How do members of smooth-coated otter families depend on one another? Incorporate the species role as both predator and prey in your answer. Why are watering holes necessary dangers for wildebeest and other animals migrating across the Serengeti? What large predator do they face? What makes this predator such a successful hunter? Draw and label key steps in the life cycle of a lake fly. How does it compare to the life cycles of other insects? Compare the adaptations and behavior of the crab-eating macaque monkey to those of the smooth-coated otter. What is similar about their behavior? What is different? Describe the characteristics of a mangrove forest. How do mangroves differ from trees growing in a temperate forest? Classroom Activities Observe and compare the diversity of organisms found in two different ponds. To begin this activity, the teacher will need to obtain pond water from two different places, microscopes (light and stereoscope), slides and cover slips, and an identification sheet for pond organisms. Instruct students to place a few drops of water into a Petri dish and observe it under the stereoscope. Have students record and sketch any living things they see. Students should prepare a few slides of pond water from each of the ponds and observe them under a light microscope. Remind students to carefully track their slides in order to make accurate records of their observations. Students should describe and illustrate what they see in a lab notebook. Students should pay special attention to the number of each type of organism they see. Students should use the identification sheet to name as many organisms as possible. Once completed, students should review and reorganize their notes in order to prepare for a discussion about the biodiversity found in each pond. During discussion, students will compare their findings with other classmates and compile a list of generalizations about the quantity and diversity of organisms found in pond water. Using the organisms described, set up a food web of the pond ecosystem. Which organisms do you think are producers? Which do you think are consumers? Ask students: Which pond has the greatest biodiversity? Ask them to use their data to explain their answer. Reveal the limited supply of Earth s fresh water and reinforce the importance of water conservation. To begin this activity, gather 1000-ml beakers, 100-ml graduated cylinders, tap water, vegetable oil, blue food coloring, and stirring rods. Divide students into lab groups of two or three. Provide each group with two 1000-ml beakers, labeled beaker one and beaker two. Beaker one will represent the world s water distribution in terms of fresh water versus salt water. Pour 970 ml of water into beaker one. Add two drops of blue food coloring to the water and stir. This will represent the ocean. Instruct students to add 30 ml of vegetable oil into beaker one. This represents the world s fresh water. Students should note the vast differences between these quantities. To beaker two, students should add the following amounts to represent average U.S. fresh 2

3 water use: 30 ml to represent a dishwasher, 50 ml to represent toilet leaks, 90 ml to represent baths, 120 ml to represent faucets, 210 ml to represent showers, 220 ml to represent washing machines, and 280 ml to represent toilet flushes. Students should pay attention to how full the beaker becomes with each water use. Ask students the following questions: Where is most of the world s water found? Is the water in the ocean suitable for human use? Explain your answer. Based on the proportions of the experiment, what percentage of the world s water is fresh water? Which daily activity uses the most water? Which uses the least? Do any of these results surprise you? How can you conserve water at home and at school? Are there other ways you consume water? Demonstrate how water moves through the steps of the water cycle evaporation, condensation, and precipitation. To begin this activity, gather aluminum pans, crushed ice, salt, clear plastic two-liter bottles, warm water, and ice cubes. Instruct each lab group to fill the aluminum pan with crushed ice, sprinkle with salt, and stir. In about fifteen minutes, students will see snow appear on the outside and bottom of the pan. Have students record their observations. Have students fill the clear plastic two-liter bottle with one-half of a liter of warm water. Place an ice cube on top of the bottle opening and observe. Students will see a cloud (vapor) form. Students should keep observing the bottle until they see water droplets (rain) slide down the side of the bottle. Students should record their observations and explain what they saw in terms of the water cycle. Target Vocabulary* adaptation - modification of an organism or its parts that makes it more fit for existence under the conditions of its environment biome - a major ecological community type (as tropical rain forest, grassland, or desert) ecosystem - the complex of a community of organisms and its environment functioning as an ecological unit erode - to wear away by the action of water, wind, or glacial ice (flooding eroded the hillside) food chain - an arrangement of the organisms of an ecological community according to the order of predation in which each uses the next usually lower member as a food source food web - the totality of interacting food chains in an ecological community freshwater - water that is not salty especially when considered as a natural resource 3

4 habitat - the place or environment where a plant or animal naturally or normally lives and grows predator - an animal that lives by predation (a mode of life in which food is primarily obtained by the killing and consuming of animals) prey - an animal taken by a predator as food rapids - a part of a river where the current is fast and the surface is usually broken by obstructions sediment - material deposited by water, wind, or glaciers sonar - a method or device for detecting and locating objects especially underwater by means of sound waves sent out to be reflected by the objects spawn - to produce or deposit (eggs) used of an aquatic animal wetland - land or areas (as marshes or swamps) that are covered often intermittently with shallow water or have soil saturated with moisture *By permission. From the Merriam-Webster Online Dictionary 2007 by Merriam-Webster, Incorporated ( Academic Standards National Science Education Standards (National Research Council, NAS, 1996) The National Academy of Sciences provides standards for science content and science teaching in grades K 12. Standards specific to this PLANET EARTH program: Grades 9 12: Biological Evolution (p. 185); Interdependence of Organisms (p. 186); Matter, Energy, and Organization in Living Systems (p. 186); The Behavior of Organisms (p. 187); Environmental Quality (p. 198) To view the standards, visit the NSES Web site: AAAS Benchmarks for Science Literacy Developed by the American Association for the Advancement of Science (AAAS), Benchmarks for Science Literacy states what all students should know and be able to do in science, mathematics, and technology by the end of grades 2, 5, 8, and 12. Benchmarks addressed in this PLANET EARTH program: Chapter 5: Diversity of Life (pp ); Interdependence of Life (p. 117); Flow of Matter and Energy (pp ); Evolution of Life (pp ) Chapter 4B: The Earth (p. 69) 4

5 AAAS Benchmarks for Science Literacy is available on the Web at: Published by Discovery Education, Inc., a division of Discovery Communications, LLC All rights reserved. Based on PLANET EARTH BBC. Distributed under exclusive license from Educational Publishers LLP. 5