Worksheet #1 Ecology and Ecosystem Service

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Florida International University *

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3013L

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Biology

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Apr 3, 2024

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EVR 3013L Ecology of South Florida Lab Worksheet #1 Ecology and Ecosystem Service Fill in your answers to the questions and problems on this worksheet. Submit the worksheet to the Worksheet #1 Canvas assignment dropbox by Tuesday September 11 at 11:59 pm. View the following videos prior to working on the worksheet. It might also be helpful to access other reliable websites for additional information to answer the questions.  Food chains http://www.odysseyearth.com/videos/the-food-chain/  Food webs http://www.odysseyearth.com/videos/the-food-web/  Feedback in ecological systems http://ed.ted.com/lessons/feedback-loops-how-nature- gets-its-rhythms-anje-margriet-neutel  Creating and interpreting graphs https://www.youtube.com/watch? v=9BkbYeTC6Mo  Lecture video for this week in Canvas. 1. How is a food web different from a food chain? A food web is different from a food chain because a food web shows multiple food chains and how they all interconnect. A food chain shows a direct path of how specific species in a community are eaten sequentially for nutrients. 2. Examine the food web below . a. Which organisms are producers? The Bladderwort, Sawgrass and Periphyton (algae) are producers. b. What role do producers play in an ecosystem? In an ecosystem, producers are always as the start of the food web. They provide the initial nutrients for primary consumers. c. Why do many arrows point to the American alligator at the top of the food web? Many arrows point at the American Alligator because they are the sole predator in this food web. This means that practically all the nutrients or organisms in the food web end up as the alligator’s food. d. What do you think would happen to the food web if the alligators disappeared from the Everglades? If the alligators disappeared from the Everglades, the ecosystem would go out of balance. The Wood Stork, Racoon, Gar, Bass, Apple snail and Limpkin would lose the only predator in the ecosystem and potentially have a rapid increase in population which would deplete other species from over consuming. Additionally, the Wood Stork, Racoon, Gar and Bass would lose a vital source of food from the baby alligators. e. What would be the result if apple snails disappeared from the Everglades? If apple snails disappeared from the Everglades, the Limpkin and Snail Kite species would be at risk of extinction because it is their only source of food and nutrients. The rest of the ecosystem might be a little disrupted but would still manage to survive.

f. Why is periphyton important in the Everglades? The Periphyton is important to the Everglades because they provide the majority nutrients to different organisms. They are the base producers in this food web. 3. What is the difference between positive and negative feedback. Given an example of each . Positive feedback is when different events cause a chain reaction. Whether positive or negative each event leads to the magnification of the other. Negative feedback is when different events or actions cancel each other out. Whether positive or negative each event balances the other out. An example of a positive feedback loop would be the release of carbon dioxide into the atmosphere from burning trees causes the ozone layer to deteriorate which causes harmful UV rays to enter Earth’s atmosphere, which cause the earth to overheat which creates more wildfires that burn trees down. An example of a negative feedback loop would be whenever someone exercises, they sweat, this leads them to drink water to hydrate and then exercise again to get rid of liquids and toxins. 4. Examine the graph below. The red bars represent the abundance of snowshoe hares (the prey). The blue dots show the abundance of lynx (the predator). a. How are the populations of hares and lynx related over the time from 1980-2010? For the most part they are directly proportional. b. Is the abundance of the lynx related to the abundance of the hares? Yes, as the population of hares decreases, the population of lynx eventually follows suit. c. Is this an example of positive feedback or negative feedback? What are your reasons? This is a negative feedback loop because it is a common predator-prey relationship. The growth in hare population causes the lynx population to grow, which causes the hare population to decrease and then the

lynx population to decrease. Once the lynx population decreases, the hare population increases, and the loop starts all over again. Graph showing abundance of hares and lynx from 1980-2010 Year 5. Examine the graph below. The Everglades ecosystems are very sensitive to phosphorus levels. Excess phosphorus results in degradation of the ecosystem. Farms located north of Everglades National Park are required to have management plans to reduce phosphorus levels. The laws require that the farms have at least a 25% reduction in phosphorus levels each year. A 25% reduction in phosphorus is shown by the black line on the graph. a. What is wrong with this graph based on the video about making graphs that you watched? There are no labels on the x and y axis, and the title should more directly compare the variables on the graph. b. Did the farms meet the required percentage reduction in phosphorus every year? If not, what years did they not meet the requirement? The farms did not meet the required percentage reduction in phosphorus every year. In 2007 the phosphorus percentage reduction did not meet the 25% minimum.

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