Nature’s Laboratory: Ecology in Your Backyard and Beyond Developed by the University of Wyoming Science Posse Grade Level: 7-8 Topics Covered: Diversity of Organisms Behavior and Adaptation Interrelationships of Populations and Ecosystems Standards and Benchmarks: This lesson plan includes topics covering the following Wyoming Science Academic Content Standards for Grade Span 5-8: CONTENT STANDARD 1. CONCEPTS AND PROCESSES In the context of unifying concepts and processes, students develop an understanding of scientific content through inquiry. Science is a dynamic process; concepts and content are best learned through inquiry and investigation. ACADEMIC CONTENT STANDARD 1. CONCEPTS AND PROCESSES Students learn about scientific content through inquiry. 8.A.S.1.1 Students relate different organ systems with their specialized function. 8.A.S.1.3 Students describe interconnectedness of diverse organisms within an ecosystem. CONTENT STANDARD 2. SCIENCE AS INQUIRY Students demonstrate knowledge, skills, and habits of mind necessary to safely perform scientific inquiry. Inquiry is the foundation for the development of content, teaching students the use of processes of science that enable them to construct and develop their own knowledge. Inquiry requires appropriate field, classroom, and laboratory experiences with suitable facilities and equipment. ACADEMIC CONTENT STANDARD 2. SCIENCE AS INQUIRY 8.A.S.2.1 Students use science reference materials to answer science questions and present findings. 1 8.2 Students use inquiry to better understand the world in which they live. 8.A.S.2.2.a Students ask questions about objects, organisms, or events in the environment. 8.A.S.2.2.b Students conduct a simple investigation using simple technology and tools to collect and organize data. 8.A.S.2.2.c Students communicate results of an investigation and match connections to daily life. CONTENT STANDARD 3. HISTORY AND NATURE OF SCIENCE IN PERSONAL AND SOCIAL DECISIONS Students recognize the nature of science, its history, and its connections to personal, social, economic, and political decisions. Historically, scientific events have had significant impacts on our cultural heritage. ACADEMIC CONTENT STANDARD 3. HISTORY AND NATURE OF SCIENCE IN PERSONAL AND SOCIAL DECISIONS Students use scientific knowledge to make personal decisions. 8.A.S.3.2.a Students identify and perform a task associated with a local problem regarding natural resources. Overview of Lessons: Lesson Plan 1: Habitat Is Where the Heart Is - Introduction to animals and their habitats - Use of field equipment to study animal-habitat relationships - Development of Environmental Impact Assessment Lesson Plan 2: Food Webs in the Backyard and Beyond - Introduction to food webs and trophic levels o Producers, consumers, decomposers - Description of backyard food webs - Introduction to adaptation and biomes - Comparison of skull and track features with biomes - Additional Options o Keystone species o Discussion of invasive species effects Lesson Plan 3: Predator or Prey: Who’s in Control? 2 - - Introduction to population growth o Exponential vs. logistic growth o Predator-prey population cycles o Top-down vs. bottom up effects Working with data o Predator-prey data o Tree-ring data Discussion of what drives population cycles Notes: The lessons contained in this unit could be used as stand-alone lessons to supplement material covered in class. Alternatively, they could be used sequentially. The lessons are meant to cover ecology at levels from the individual to the ecosystem. Though these fields of ecology are present in all 3 lessons, Lessons 1 and 2 focus more heavily on community and ecosystem ecology, while Lesson 3 leans more towards population ecology. 3 Lesson Plan 1: Habitat Is Where the Heart Is Estimated Time: 80 minutes Objectives (Enduring Ideas): Students will learn how scientists study an animal’s relationship with its environment – this is the definition of the field of ecology Students will learn what makes up an animal’s habitat requirements Students will learn how animals are adapted to their environment Students will learn how to use radio telemetry as a method in wildlife research Students will learn how to identify local animal species from their tracks Students will learn that animals are differentially affected by humaninduced changes to habitats Vocabulary: Biodiversity: a measure of diversity that increases with species evenness and species richness (also “species diversity”) Community: all of the living organisms living in a specific area Digitigrade: walking on your toes Ecosystem: a biological community plus all of the abiotic (non-living) factors influencing that community. Habitat: the arrangement of food, water, shelter or cover, and space suitable to animals’ needs Habitat generalist: a species that can survive in many types of habitats Habitat fragmentation: the conversion of once continuous tracts of habitat to smaller, interrupted patches Habitat specialist: a species that requires a specific type of habitat to survive Plantigrade: walking on the soles of your feet Population: a group of individuals of a single species inhabiting a specific area 4 Shannon-Wiener Index: a quantitative index of species diversity (see Molles 2008 for equation) Species evenness: the relative abundance of species in a community Species richness: the number of species in a community Materials and Preparation: PowerPoint presentation on animals and habitat (Appendix 1) Radio telemetry equipment (may be available from local Game and Fish office) Thermometer Animal tracking guide books Data sheets for habitat descriptions (Appendix 2) Clipboards to record data Rubber animal tracks for making tracks in soil or snow (Available online through Acorn Naturalists) Stuffed/plastic animals or flash cards Lesson Overview: Part1: o Habitat Selection Background Briefly discuss of how we can learn what habitats animals use Part2: o Search for different animals with telemetry and tracking Split students into teams and locate transmitters attached to different “herds/groups” of animals Other groups of students will locate animals based on track imprints in the soil Have students write up habitat descriptions for each animal Part3: o Discuss potential human effects on habitat loss and which of our study animals is most likely to be affected by habitat loss Work though a problem set Background Information: (for teachers) This activity involves considerable set-up time before class. The main idea is that different species of animals are connected with different environments. In this lesson, students will locate animals in their corresponding habitat types. Some species will be habitat generalists (e.g., deer) and will be found in more than one habitat. Other species (e.g., marten) will be habitat specialists. You 5 will need to place the stuffed/plastic animals, with transmitters attached, in several habitat-types. For example, a plastic mountain lion w/ transmitter could be hidden in a wooded area and deer w/ transmitters in wooded and meadow area. In addition, if there aren’t wild animal tracks in the area, then rubber tracks should be imprinted into the dirt. The teacher should make note of where the tracks and transmitters are located so they can find them later if the students can’t! This lesson plan is probably best done after students have covered concepts such as ecosystems and food webs in the classroom. General ecology books such as Molles 2008 provide information on these concepts. This is especially important for Part 3 so they can make predictions about what might happen to a predator if one of its prey sources is depleted. Procedures: I. Engage Show PowerPoint presentation (Appendix 1) on how to determine an animal’s preferred habitat. Discuss with students some potential methods for studying wildlife/habitat relations Following the presentation, give the students instructions for the outdoor portion of the activity. Tell them that they will look for several wildlife species by using radio telemetry (from an airplane) and by looking for tracks on the ground. II. Explore/Explain How do we tell animals’ preferred habitat Students will go outside. This could be a schoolyard, a city park, wilderness area, etc. Part1: Put students into groups of 2-3. Some groups will “fly” and look for animals with radio telemetry gear. These students will search for and locate transmitters attached to plastic animals. Other groups will look for tracks and identify the animal with an animal tracking field guide. Part2: Have students use a habitat evaluation form (Appendix 2) to evaluate which species are found in which habitat. On this worksheet, “overstory” refers to all the coniferous and deciduous tree species in the habitat while “understory” refers to the plants growing beneath this tree canopy. In the “notes” section the students can write any other observations they make that they might think are interesting about the habitat they’re describing. Explain to the students that this type of worksheet is similar to habitat evaluation forms that scientists use in real wildlife research. 6 III. Elaborate Ask which animal species will be most impacted by a development project in a particular habitat type (make Environmental Impact Assessment) or by impacts to other species in the food web. Have students return to the classroom. While remaining in their groups, give them a worksheet (Appendix 3) and tell them to evaluate the impact of alterations to their study ecosystem. Scenario 1 should be used when more time is available (approximately 15 minutes), while scenario 2 can be completed more quickly. In scenario 1, tell them that a grocery store is being planned for the forested portion of their study ecosystem. Recall that the students’ study area encompasses several habitat types, only one of which is forested. The students will need to develop an Environmental Impact Assessment to determine which species are most likely to be affected by the removal of forest. In scenario 2, a disease, such as chronic wasting disease, has begun to spread within the deer population. Ask the students to determine which other animal species are likely to be impacted by changes to the deer population. In this way the students are reminded that habitat includes food, so the predators may be impacted by disease in deer. If time allows, students can work through both scenarios. IV. Have students will present their opinions on scenario 1 and/or 2 to classmates. Students will turn in worksheet (Appendix 3) with their answers to scenario 1 and/or 2. V. Evaluate Enrichment If time allows, this lesson would be an ideal place to introduce the concept of biodiversity. Numbers of “animals” could be varied within each habitat type, and students could be asked to calculate species richness and evenness for each community. This would require that students be familiar with the distinction between “population” and “community”. A measure, such as the Shannon-Weiner Index (Molles 2008), could be used to compare species diversity between the different habitats. 7 References: Vocabulary Council for Environmental Education. 2004. Project Wild: K-12 Curriculum & Activity Guide. Council for Environmental Education, Houston, TX. Molles, M. C. 2008. Ecology: concepts and applications, 4th Edition. McGraw-Hill, New York. Acknowledgments: The use of telemetry equipment to find transmitters was adapted from a laboratory taught by Merav Ben-David and Elizabeth Flaherty in their Wildlife Ecology course at the University of Wyoming. The application of habitat data to an EIA was adapted from Karin Westerling’s “Design an Ecosystem” lesson: http://www.accessexcellence.org/AE/ATG/data/released/0079KarinWesterling/index.php 8 Lesson Plan 2: Food Webs in the Backyard and Beyond Objectives (Enduring Ideas): Students will learn about producers, consumers, and decomposers Students will learn about the interconnectedness of ecosystems Students will learn about adaptation, and specific adaptations animals have to their environment Students will learn about keystone species (if enrichment portion is used) Students will learn about the potential effects of invasive species Vocabulary: Adaptation: a trait that increases the ability of an individual to survive and reproduce compared with individuals without the trait Biome: usually large areas distinguished by their predominant plants and associated with particular climates Carnivore: an animal that consumes other animals. Consumer: organisms that obtain energy by consuming other organisms. Decomposer: a consumer that gets its energy from the remains and waste products of organisms. A detritivore. Ecosystem: a biological community plus all of the abiotic factors influencing that community. Food web: a complex model of interconnected food chains in which there are multiple links between species. Herbivore: an animal that eats only plants. Keystone species: species that, despite low biomass (or abundance), exert strong effects on the structure of the communities they inhabit. Omnivore: an animal that has the ability to eat and survive on both plant and animal products. Producer: an organism, such as a plant, that converts light energy to chemical energy. An autotroph. 9 Trophic level: each feeding level in a food chain. Materials and Preparation: Skulls and tracks of several mammals (may be available at local Game and Fish office or through natural history museums) PowerPoint slides of different biomes Rubber animal tracks for making tracks in soil or snow (available online through Acorn Naturalists) Soil sampling kit (Available online through Carolina Biological) Compound and dissecting microscopes Flash cards of different plants, animals, fungi, etc. in Wyoming Lesson Overview: Part1: o Use PowerPoint slides (Appendix 4) to discuss ecosystems and food webs o Define biotic and abiotic factors (also introduced in Lesson 1) Part2: o Construction of food webs Have students go outside and catalogue all the living organisms they can find. If weather doesn’t permit, give students flash cards with different Wyoming species. Define producer, consumer, and decomposer. Have students construct food webs for the organisms they catalogued or were given as cards. Part3: o Use of skulls to describe adaptation to the environment Have students examine features of skulls and tracks. They’ll try to group animals together that appear similar (for example carnivores, herbivores, etc.) Have students define each study specimen as an herbivore, carnivore, or omnivore. Students will also be shown different biomes and asked to assign skulls to the correct one. Background Information: (for teachers) The second part of this lesson would best be done after the students have learned about evolution by natural selection in the classroom. Otherwise the concept of adaptation may be difficult to grasp. The Brooker et al. (2008) text 10 shown in the references section provides a good resource to the teacher for this information. This lesson could easily be split into two 45 minute class periods. In this first part, students develop food webs and classify organisms as producers, consumers, and decomposers. In the second part, students look at actual adaptations that some of these organisms have that put them in such categories. If students go outdoors but find few organisms, collecting soil samples and examining them under a microscope may give them additional organisms to add to their food webs. The same idea goes for making tracks with the rubber casts. Students could identify the tracks and add these species to their food webs. During the skull lab, the teacher can vary the number of skulls that the students look at based on available time. It would be useful to have a few skulls from the same family so that students can group them together (e.g., bobcat and mountain lion skulls). There should at least one skull each representing an herbivore (e.g., elk), carnivore (e.g., wolf), and omnivore (e.g., black bear). Pictures of different ecosystems should coincide with the available skulls (e.g, desert, ocean, forest, mountain). Procedures: I. Engage PowerPoint presentation (Appendix 4) on food webs and the difference between a population, community, and ecosystem. Ask students to differentiate between the level of population, community, and ecosystem. When it is clear that they understand what a community is they will move to the outdoor portion of the lesson. II. Explore/Explain Part 1: Get students into pairs. Each pair will have 10 minutes to write down all the living creatures they can find in their schoolyard, local city park, etc. Encourage students to include organisms such as fungi. If time permits, students can take soil samples for analysis of microscopic organisms in the classroom. Part 2: Have students return to the classroom and create a food web from their lists. Part 3: Ask thee students to think of useful ways that these organisms could be classified. At this point list the definitions of producer, consumer, and decomposer (Appendix 4). Part 4: Ask students to classify the organisms in their food webs as producers, consumers, and decomposers. At this point the food webs can be turned into concept maps as the students add the action that each species is having on its adjacent member in the food web. For 11 example, an arrow would be drawn from a plant to an herbivore. Along this arrow will be written the interaction happening along this arrow (for example “herbivore eats plant and gets energy from the plant”). III. Elaborate The next part of the lesson involves examining mammal skulls, skins, and tracks. This should be left for a second class period if classes are only 45-50 minutes. Ask students to describe which members of their food webs are herbivores, carnivores, or omnivores. Then tell them that where a species fits into a food web is partially determined by adaptations it has for feeding. At this point give the definition of “adaptation”. Discuss with the students the difference between a carnivore, herbivore, and omnivore. Ask students to form pairs and rotate through stations that contain mammal skulls, skins, and imprints of tracks placed at the back of the room. In addition, pictures of different types of biomes will be given. Have students answer questions from a worksheet (Appendix 5). After students correctly identify all the specimens, have them evaluate the range of the different species with Google Maps. End this lesson with a discussion of what allows some species to have larger/smaller ranges. For example, animals that are adapted to live in old growth forests are unable to live in newly planted forests. IV. Evaluate Rubric There should be an open discussion of the answers to the worksheet. Then collect the students’ concept maps and/or worksheets from the skull identification lab. VI. Enrichment If time allows, the concept of a “keystone species” could be introduced. Appendix 4 has slides showing a classic example of a keystone species, the seastar Pisaster. The keystone species concept was developed by Paine (1969). In rocky intertidal zones, Pisaster is a major predator of the mussel Mytilus californianus. When the predator is removed the mussels overtake the shoreline. When the seastar is present it keeps the mussels in check and allows other species to flourish. Once students understand this concept they can brainstorm to think of other potential keystone species. A famous local example is wolves 12 keeping ungulate herds in check and potentially reducing herbivory on plants. References: Vocabulary Brooker, R. J., E.P. Widmaier, L.E. Graham, and P.D. Stiling. 2008. Biology. McGraw-Hill, New York. Molles, M. C. 2008. Ecology: concepts and applications, 4th Edition. McGraw-Hill, New York. Keystone species Paine, R.T. 1969. A note on trophic complexity and community stability. American Naturalist 103: 91–93. Power, M. E., D. Tilman, J. A. Estes, B. A. Menge, W. J. Bond, L. S. Mills, G. Daily, J. C. Castilla, J. Lubchenco, and R. T. Paine. 1996. Challenges in the quest for keystones. Bioscience 46:609-620. Acknowledgments: The use of skulls in this lesson plan was adapted from Elizabeth Flaherty’s What Is Alive?: http://www.scienceposse.org/displayfaculty.asp?facultyid=2170 13 Lesson Plan 3: Predator or Prey: Who’s in Control? Grade Level: 7-8 Estimated Time: 45 minutes Objectives (Enduring Ideas): Students will learn about predator/prey cycles Students will learn about bottom-up and top-down forces in food chains Students will learn how tree rings can be used to study fluctuations in environmental conditions Students will hone basic graphing skills Vocabulary: Bottom-up forces: Regulation of food-web components by either primary producers or the input of limiting resources (e.g., nutrients, space). Predator: a heterotrophic organism that kills and eats other organisms for food. Usually an animal that hunts and kills other animals for food. Top-down forces: Regulation of lower food-web components by an upper-level consumer. Trophic cascade: Reciprocal predator-prey effects that alter the abundance, biomass or productivity of a population, community, or trophic level across more than one link. Materials and Preparation: Tree increment borer (available from Forestry Suppliers or local Forest Service office) ruler Tree cores Paper simulations of tree-rings Data with numbers of wolves and moose on Isle Royale from 1950-2000. Computer with Microsoft Excel Lesson Overview: Part1: 14 o Discuss how historical records can tell us about long-term ecological changes o Discuss what factors drive populations of predators and prey o Discuss how tree rings can be used to reconstruct past environmental conditions Part2: o Examine population data and tree rings Students will examine real tree rings Students will count tree rings from strips of paper designed to simulate real trees Students will compare these to predator and prey population data Part3: o Enrichment Discuss what might drive these cycles – abiotic factors, predators, prey? Or a combination? Background Information: (for teachers) Teachers should read McLaren and Peterson (1994). This paper describes a long-term study on Isle Royale National Park. Populations of wolves and moose have fluctuated for several decades, and there are 2 competing hypotheses as to what drives these cycles. The bottom-up hypothesis says that plant growth is limited by climate, thereby limiting forage available to moose. The availability of moose then determines the number of wolves. The top-down, or trophic cascade, hypothesis says that wolf predation on moose depresses moose numbers and releases plants from herbivory. In addition, a lesson plan designed for undergraduate college students is available online that makes use of this case study: http://ublib.buffalo.edu/libraries/projects/cases/Isle.html In this lesson, students will be given several decades of census data on the wolf and moose population on Isle Royale. They will graph these data. Then the students will measure tree-ring widths from balsam fir trees on the island. These data will be compared with the graphs for the moose and wolves to evaluate which of the competing hypotheses is best supported. There is a great deal of information on tree rings and tree ring research at the “Ultimate Tree Ring Web Pages” http://web.utk.edu/~grissino/. Procedures: I. Engage Give PowerPoint presentation (Appendix 6) on what controls population growth. 15 Ask students about factors that control population growth. It is likely that someone will come up with predation, but if not, introduce this as one factor. Tell them that predation will be the topic today. Introduce students to the idea of top-down vs. bottom-up forces in food webs (see vocab and Appendix 6). Give students a brief background on the ecology of Isle Royale National Park. They will be informed that the park has a unique long-term record of wolf and moose populations. II. Explore/Explain Part1: Have students form pairs. Give each pair data on wolf and moose numbers, from 1950-2000. Part 2: Give students graph paper and ask them to decide on which axes to put numbers vs. time. Part 3: Show students how an increment borer works. For a picture demonstration see: http://www.cnr.vt.edu/dendro/forsite/incre.htm. Then examine a real tree core and discuss how rings form. Rings form due to variation in the rate of growth with changing seasons. Part 4: Give students a strip of paper that simulates ring widths on a tree and will count these widths from 1950-2000. Part 5: Have students compare graphs from wolves and moose with tree ring data. III. Elaborate Discuss what the driving force is in these cycles. In the end the students will see that the answer varies depending on densities of moose, wolves, or climate factors. IV. Evaluate Rubric Collect students’ graphs and discussion of predator/prey cycles. References Fortier, G. M. 2000. The wolf, the moose, and the fir tree. Journal of College Science Teaching 30:92-95. McLaren, B. E., and R. O. Peterson. 1994. Wolves, moose, and tree rings on Isle Royale. Science 266:1555-1558. Molles, M. C. 2008. Ecology: concepts and applications, 4th Edition. McGraw-Hill, New York. 16 Pace, M. L., J. J. Cole, S. R. Carpenter, and J. F. Kitchell. 1999. Trophic cascades revealed in diverse ecosystems. Trends in Ecology & Evolution 14:483-488. Power, M. E., D. Tilman, J. A. Estes, B. A. Menge, W. J. Bond, L. S. Mills, G. Daily, J. C. Castilla, J. Lubchenco, and R. T. Paine. 1996. Challenges in the quest for keystones. Bioscience 46:609-620. 17