Transcript
ECO-COLUMNS – An APES Extended Ecology Project Pupose: The purpose of this tab is to create simulated ecosystems in an effort to learn about ecosystems in the real world. Part 1: Setup of your eco-column Steps 1-3 you should conduct in class with your eco-column group members. Steps 4-6 you should do at home. First identify what you are trying to discover through the creation of your eco-column. Look over the demonstration and assembly diagram to understand each chamber. Decide what background sources of information will you use (which parts of the textbook or what other references). Decide what components to include in each section (which organisms, type of soil, etc.) See the list on the backside of this page for ideas. Write a hypothesis for each of the three habitats: aquatic, decomposition, and terrestrial. Draw a diagram of your eco-column and identify the biotic and abiotic factors present in each habitat. Draw the (potentially connected) food webs you anticipate taking place within your eco-column. Make every effort to identify the species you have added as specifically as possible. If an organism is unidentifiable, include a drawing of it (you may use the stereo microscopes to help with this). Part 2: Observation and Data Collection Each week you will make observations of your eco-column. Each observation should include: The date of your measurement The number of days your eco-column has been running pH Temperature Dissolved oxygen content of the aquatic chamber Qualitative observations (turbidity, plant growth, decomposition rate, fish status, odor) Additional measurements as conducted (analysis of NPK content, etc.) Part 3: Lab Write-up Part of the scientific method involves disseminating what you have learned. You will do this in the form of a tab write-up following the guidelines I have given you. Make sure to keep good records during the investigation so that you are not missing anything when it comes time to write. IDEAS FOR CHAMBER COMPONENTS: Terrestrial Chamber: Soil: You will probably want a mixture of planter mix and soil. For the soil, consider what types you have available between your group members. Do you want dry and rocky? Sandy? Soil that has had plants growing in it recently? Seeds: Since you have a small growing space, think small in terms of your plants. Fast growing plants like beans are out. Read the seed packets in the classroom as you think about what to plant. A few seedlings may be available. Decomposition Chamber Organic Matter: Some mix of leaves, grass, planter mix and easily decomposed food such as fruit (no citrus, no peels) should constitute the material in this chamber. Consider what fraction you think each of these components should be. Insects: You should be able to support a number of insects in your decomposition chamber. Insects like Drosophila (fruit flies) can fly back and forth between the terrestrial and decomposition chambers and help degrade the food. What other insects can you think of to include? Do you want to put them in the terrestrial or decomposition chamber? Aquatic Chamber: Water: Not all water is the same. Do you want to include fresh tap water? Old tap water? Distilled water? Pond water? What is your reasoning? Solid material: Choose gravel or sand or a mix to go in the bottom of your aquatic chamber Organisms: Fish, snails, and Elodea (water plants) are available to go in your aquatic chamber. Be especially careful to limit the number of larger organisms in this chamber as you will not open it to add food. Add only the number of consumers you think this chamber can support. Eco-column Write-up Requirements The following are more detailed instructions for your eco-column write-up. Except for drawing and labels, your write up should be typed (double spaced). 1. Write a hypothesis for each of the habitats (aquatic, decomposition, terrestrial). Your hypothesis should state what you think will happen in each one of these ecosystems. You should briefly describe why you think this will be the case. Put in hypothesis section of report. 2. Draw a diagram of your eco-column and identify the biotic and abiotic factors present in each habitat. Put in procedure section of report. Your eco-column has a unique structure. Draw a diagram that shows your eco-column and what is in each section. You can list the biotic and abiotic factors along the side or in separate paragraphs. 3. Draw the (potentially connected) food webs you anticipate taking place within your eco column. Make every effort to identify the species you have added as specifically as possible. If an organism is unidentifiable, still include a drawing of it (you may use a stereo-microscope to help with this). Put in the hypothesis section of report. Draw each organism in a circle. Give the name if at all possible. Binomial nomenclature is best (most unique) plus common name. Identify the role of each organism by putting one of the following letters just beneath the name of the organism: P producer C consumer D decomposer S scavenger Draw the energy arrows. These lines should go from the energy source towards the organism that gets that energy. For example from the sun to algae in the water (if you chose pond water), or from a secondary consumer to a tertiary consumer that eats it. Within your food web(s), circle three separate food chains. For these food chains, label at least two levels of consumers and the overall trophic levels. 4. Write a discussion of your food web. Within your discussion include the following: What are the top level consumers in your eco-column? What would happen to these consumers if all the primary consumers were to die? If the secondary consumers in one of your food chains consumed 4,200 kcal, what amount of energy would you assume was available to the primary consumer? What amount would you speculate will be available to tertiary consumers? What would happen if the decomposers were removed? What do you think is more resilient (i.e. damage resistant), a food web with many species or a food web with just a few species? Explain your answer fully. If you can think of arguments on both sides, discuss both. Apes ECO-COLUMN WRITE-UP INSTRUCTIONS In this eco-column write-up, your job is to clearly present the information about your eco-column to your reader. Your report should include each of the sections below (plus a good title). The heart of your report should be your analysis and conclusion. Don't just answer questions: use this write-up as an opportunity to demonstrate your knowledge and ideas. This is a formal lab report and should follow our formal lab write-up guidelines. Background Information What is an eco-column and why is it a useful tool? How is it like or unlike an ecosystem outside? Is it a closed or open system? These are just a few ideas to get you started on introducing eco-columns. (Use information from the articles you have read.) Hypothesis Briefly summarize the hypothesis you made regarding each segment of your column. Now, how did your actual eco-column results compare to each of your hypothesis? Results (data) Include a table with your eco-column's data for the 34 major testing sessions and attach your daily observation log. Include qualitative information from the disassembly of your eco-column (and the results from your soil test). Did you discover any unexpected organisms (for example: fungus grew or new microorganisms appeared)? Did you not see any new organisms? Be specific on where you looked and what you found. BIG HINT!!! A before and after table would be a useful way to present information like numbers of snails found, etc. Analysis Discuss the data for your eco-column with regard to your setup. What does your data say about what has gone on in your eco-column? What conclusions or generalizations can you make about your eco-column and what connections can you make to other natural systems? Choose one of the nutrient cycles (C, N, or P) and diagram and explain how you think it would occur in your eco-column. Be careful not to include aspects of these cycles that wouldn't occur in your eco-column discuss how your selected biogeochernical cycle affected the organisms living in your column. Conclusions What conclusions can you make about your eco-column? What connections can you make between your eco-column and a natural ecosystem or community? more information for your eco-column write-up Write out an explanation and diagram of your experimental setup. Be sure to identify all of the abiotic and biotic factors in each of your three habitats. Make sure to include all your weekly observations as raw data. All such observations should be properly dated. Also, make sure to include the date when you set up your eco-column, and the dates and descriptions when changes were made. Identify the number of days your eco-column has been in operation. Identify the pH, temperature, dissolved oxygen, nitrate, and phosphate content of your aquatic habitat and the point during the experiment when those measurements were taken. You should also have comparison data from other eco-columns in the classroom. Look for such things as plant growth, decomposition rate, and water turbidity. Conclusion and analysis: this is the most important part of the report. You should identify food chains and food webs in each of your habitats. Identify any biogeochemical cycles that are present. Try to figure out how the three habitats have affected each other. Answer the question: why are there such large differences between the eco-columns in the classroom? Make sure to identify the roles of the various biotic factors such as decomposers, producers, consumers, etc. Identify changes that occurred in your eco-column, such as the water going from murky to clear in the aquatic habitat, and why such changes occurred and their implications as far as the health of the ecosystem is concerned. Compare your artificial ecosystem to real ones outside the classroom. How are they similar? How are they different? Was your eco-column a closed system or an open system or something in-between and how does that affect it? What kinds of niches were available to the various organisms and did you notice any instances of competitive exclusion occurring? Did you observe the law of tolerance in action? What were the limiting factors in your habitats? Was there any form of succession taking place in your eco-column or in the eco-columns of other students? Plant life seemed to have a difficult time in the terrestrial habitats. Why do you think this was so? Various colors sprang up in several of the habitats? There were splotches of red and black on the sand and gravel in the aquatic habitats. Yellow, white, and beige goo and fuzz seemed to invade several of the decomposition habitats. What do you think was causing all these various color changes? Please comment about the stability and sustainability of the various eco-columns in the classroom. Do some eco-columns appear to be more stable than others? Why is this so? Finally, please explore any analogies that can be made between your mini-worlds (eco-columns) and the real world. Do the eco-columns teach us anything about real world ecosystems? ECO-COLUMN REPORT – Examples Here are some examples of conclusions and observations that students may make in the analysis part of their eco-column reports. Decomposition in the aquatic chamber increases turbidity which reduces incoming light and decreases plant photosynthesis. If the fish and snails die, then their will be less carbon dioxide available for the plants. The carbon cycle was demonstrated by the absorption of carbon I dioxide by plants and their eventual decomposition. The hydrologic cycle could be observed and was driven by the heat lamp. The eco-column was a good example of the delicate balance between abiotic and biotic factors. Fungus and bacteria in the decomposition chamber help break down organic matter into inorganic nutrients. Abiotic factors such as soil and air serve as nutrients for biotic factors. Several food chains were observed such as light to plants to protists to fish to decomposers. Net primary productivity is not high enough to maintain a complex, viable ecosystem. The fish die when the DO2 level falls below 5ppm. Real ecosystems are more complex and thus more resilient than the "artificial" eco-column. A limiting factor for the fish was the amount of DO2 in the water. High levels of nitrates in the water let to eutrophication. Low pH levels will affect the viability of the eco-column.
