A Natural History of our Local Park: Geology and Ecological Succession

Transcription

1 Overview This lesson provides an opportunity for students to apply foundational ecological and geological concepts to investigate the natural history of their own local environment. Using field investigation and research skills, they are able to dig beneath the surface (literally) to uncover how the land was formed, why its current inhabitants are able to live there and why the land can support its current human uses.. Objectives Students will: Use open inquiry, field observations, controlled investigations and research to support their own interpretations of the geological and ecological history of their local environment. Create and defend their findings through a public presentation that incorporates their research and conclusions. Materials and Resources Setting Dependent on student needs. A variety of teacher-generated readings on local geology. Geology lab resources such as stream tables if possible. Presentation materials that best fit your available resources (for example, posters, Prezi presentation, research paper). Research and presentations will be enhanced with access to the Internet. Be sure to use any scholarly databases your district might subscribe to (such as EBSCO), though other options like Google Scholar work well. High School Campus, Local Park or Nearby Natural Area Natural Cities Lesson 4 A Natural History of our Local Park: Geology and Ecological Succession By Johnny Devine SUBJECTS Biology Geology Earth Science Urban Ecology Physical Environment Time Needed 1 to 2 days for preparation, 3 to 6 class periods for teaching 5 lessons Glossary Terms: Weathering Erosion Glaciations Sediment Grain-size Ecological succession 39

2 Background Information This unit was designed as a means for students to apply the scientific process and open inquiry to geology and ecology. Students are told that every rock and landscape has a story to tell; we just need to know how to hear it. The idea is for students to expand their perspective on the world, to move from seeing the strip mall, to seeing the hill that the mall is on, to asking how is it that that hill came to be here. This activity begins with a question: What is the natural history of our local environment? The ecology and geology are trying to tell us a story that goes back millions of years. Students use this guiding question to focus their observations. These observations are then used to create a hypothesis about our area s past. Students design controlled scientific investigations to generate data that supports their hypothesis, and they use research from the larger scientific community to strengthen their argument. In the final presentation part of this activity, students must defend their interpretation of our area s past. They practice making solid, evidence-based scientific arguments and participate in a scientific community. Urban Relevance Students begin to discover that the very ground under their feet has a story to tell and science is the means to discovering that story. They gain perspective on their urban environment, realizing that it has changed through a series of natural and human-made processes. This lesson provides an opportunity for students to explore science concepts such as geology and ecology inside the city as opposed to having to travel to a more rural area. This is important as it emphasizes that cities are not places where nature stops working, even though it may not be as easy to see. Students may gain a new perspective of a field science career path that does not have to take them far away. Procedure Preparation Familiarize yourself with the geology and ecology of your local environment before your students begin this activity. Use the Internet or your library to discover what resources and information students are likely to encounter as they conduct their investigation. What is the accepted history of your area according to professional geologists and ecologists? What are major human impacts that are likely to arise during your students investigations? 1. Ask students how they think urban development impacts geology and ecological succession. Students answer this in their journal or science notebook and discuss it in small groups before sharing their thoughts in a class discussion. 2. Make sure students have some basic background information about ecology and geology. The terms in the glossary should be well understood by the time this lesson happens and are included for review purposes. A methodology for teaching these concepts is not included here. It is assumed that these topics have been thoroughly covered and that students have 40

3 Dan Strauss/The Nature Conservancy communicated mastery of them. Based on their own knowledge and research of the local environment, the teacher should design some classroom activities that will re-introduce students to important terminology they may want to use when observing nature. For example, I re-introduce the ideas of weathering, erosion, glaciations, sediments, and grainsize before taking my students out to observe an exposed cliff band. Don t lecture students about what they are going to find! Let them generate questions and make their own observations and arguments. Similarly, you would want to introduce concepts related to ecology and ecological succession (what types of species are present, what does the ph of the soil tell us, what type of density do we observe in the vegetation, what are the age and size of key plants, how does the canopy relate to the understory, etc.). 3. Take students to a nearby location where they can see some native species in as undeveloped an area as possible. Be careful of overly developed city parks that may be relatively young and full of nonnative species. 4. Provide students with some examples of questions to ask about the ecology and geology that they observe. Students should be able to return to class with a collection of questions that they can investigate/research. (see attached document Geology Observations. You could prepare a similar guide for the biological aspects of the environment). 5. Back in the classroom provide students with targeted resources (reading, Internet sites, library books) that will help direct them down the correct path as they attempt to answer the questions they generated in the park. 6. Lead students through an activity that will help them create one or more educated guesses about the local environment s history. For example, a good educated guess could be, I think that at one time, rivers deposited the sediments that now make up the rocks in our park, because I found poorly sorted, rounded grains in the exposed cliff band. Students should create a similar guess about the ecology, such as, The area of the park that we observed is in an early stage of ecological succession because of the presence of species X, the low ph in the soil and the thin cover of soil. Their educated guess should include room for a controlled scientific investigation, such as using a stream table to Outcroppings can often be seen in urban parks. 41

4 Dan Strauss/The Nature Conservancy observe how rivers deposit sediments, or using soil ph probes to investigate the chemistry of different types of environments. 7. Do some front loading for students about what their final presentation must accomplish. Create and provide a rubric that meets your needs. You will be providing students time to conduct research and investigations that will add evidence to their claims about the area s past; it s really important Sites of park maintenance are often great spots to see beneath the surface. that they know how much time they have. This is a great time to talk about constraints, validity and scientific argumentation. Depending on your modifications, students should support their claim with at least one data-centered investigation and a minimal amount of research. Some students will try to do too little work and some may try to do too much; it s your job as the teacher to coach them along to the optimal amount. 8. Guide students through an open inquiry process where they design at least one controlled scientific investigation that will add data-based evidence to their educated guess about the local environment s past. They may need to modify their story about the geology or ecology as they work through their experiment. Examples of investigations mentioned above included using stream tables to investigate weathering and erosion rates. Students could also conduct data-generating investigations that don t involve a controlled variable but still help support their story, such as measuring the density of certain trees or comparing tree size to tree age. 9. Guide students through a research process. This requires some front loading and structuring, depending on the abilities of your students and the time you have available. The end goal is that students have information and/or data from other scientists that they can correctly cite and use to support their own interpretation of the local environment s past. Students may want to modify their own interpretation of the area s past as they read information from other scientists, but it s important that they don t abandon their own thinking. You could scaffold this activity by providing a limited number of readings, books or internet sites that are appropriate for the reading level of your students and do not wander too far from the reality of your area s past. 10. Provide groups time to discuss questions/hypotheses to share their answers. This allows students to practice their presentation/communication skills and receive feedback from their peers. 11. Finally, students should present and defend their interpretation of the area s geological and ecological past in a format that makes the most sense for your time and resources. Their presentation should be a scientific argument that uses evidence from their investigations and cites other scholarly information from their research. My students prepared large 42

5 posters as part of their presentations, but other visual aids could be used, such as creating a website or preparing a Prezi presentation. Peer evaluation was a big part of my class, so I had students evaluate the soundness of other students arguments. Presenters had to respond to these critiques. Assessment It is important to chunk and scaffold this project so that students receive critical feedback at all steps along the way. Be sure to assess students work during observations, background lessons, research and final presentation. Do not wait until the final presentation to give your students a grade! The final presentation was the largest portion of my students overall grade for this project, but they had received enough intermediate feedback that most students were very successful with their final products. Dan Strauss/The Nature Conservancy Some parks, like Prospect Park in Brooklyn, NY, have signage to help visitors learn a little geology. 43

6 Natural History of Your Local Park Geology observations SAFETY Your actions and words must promote the safety of yourself and others. Loss of privilege or reduction in grade may result from a violation of this prime expectation. OBJECTIVE You are to take observations of geology in the park and generate questions to investigate back in the classroom. You must write in your journal and use an effective organization scheme. ASSESSMENT You will be assessed on how well you organize your notes in your journal. Be sure to include headings for any new notes and include the location (a description and latitude and longitude) of any observations. OBSERVATIONS Address these points, using an organizational scheme that you think is most effective. What types of rock do we find in the park? What types of sediment do we find in the park? What evidence is there to determine how these sediments were deposited? What are the grain sizes and textures of sediments we find? Are the sediments well sorted or poorly sorted? What are examples of transportation and erosion that you see? Which of Steno s Principles do we see in the park? [In 1669, Nicolaus Steno ( ) formulated a few basic rules that helped him make sense of rocks and the various objects contained within them. His short preliminary work, De Solido Intra Solidum Naturaliter Contento Dissertationis Prodromus (Provisional report on solid bodies naturally embedded in other solids), included several propositions that have since become fundamental to geologists studying all kinds of rocks. Three of these are known as Steno s Principles, and a fourth observation, on crystals, is known as Steno s Law. More on Steno s Principles can be found in geology textbooks and on the Internet. (Source: About.com/Geology) QUESTIONS Record in your notes at least three questions that you would like to investigate. For example, some questions may be similar to these (you may use one of these as a question you would like to investigate): What areas of the park have been altered by humans, possibly disrupting the geology? I found a layer of sediment with grain size of up to 5 cm. What kind of transportation media could move grains that size? I found a layer of sediment with a number of round pebbles. How did these pebbles get round? I found a sedimentary layer with other rocks in it. Are these rocks igneous, metamorphic or sedimentary? 44

7 Natural History of Your Local Park Geologic column SAFETY Your actions and words must promote the safety of yourself and others. Loss of privilege or reduction in grade may result from a violation of this prime expectation. OBJECTIVE You will create a geologic column of the park based on the outcrops we observe. You need at least three distinct layers. For each layer you should describe the sorting (poor, well, etc.), largest grain size (microscopic, 5 cm, etc.), texture of grains (angular or rounded), color and thickness. These should be approximations based on your visual observations. ASSESSMENT You will be assessed on how well you organize your notes in your journal. Be sure to include headings for any new notes and include the location of any observations. Example: Top Layer Poorly sorted Angular grains Light color Pebbles up to 5cm 30 feet thick Second Layer Better sorted than top layer Rounded grains Light color with dark pebbles Occasional grain up to 2cm 20 feet thick Bottom Layer Grain texture not visible Very well sorted Dark green/brown Fine grain 10 feet thick 45

8 S U B M I T T E D B Y THE NEW YORK BOTANICAL GARDEN Bronx, New York Through comprehensive education programs, the New York Botanical Garden s Children s Education Department seeks to engage children and their families and enhance the skills and knowledge of students and teachers in science, gardening and nature exploration.