Pond Ecosystem Gizmo Answer Key

Name: Chaim Wong Date: 03-19-2022 Student Exploration: Pond Ecosystem Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: abiotic factor, algal bloom, biotic factor, concentration, eutrophication, mean, oxygen, parts per million, photosynthesis Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. All animals need oxygen. We get oxygen from the air we breathe. How do fish get theirs? using their gills, fish must extract oxygen molecules that are dispersed in water. 2. Where does the “fizz” in soda come from? gaseous CO2 (carbon dioxide) escapes. You can see bubbles and hear fizzing. Gizmo Warm-up The Pond Ecosystem Gizmo lets you study ponds as an ecologist would. Each of the tools can be dragged to the pond to take measurements. 1. Drag the Thermometer to the pond at 6:00 am. What is the water temperature? (°C) 4.04 2. Click Fast-forward ( and then click Pause ( ) until about 12:00 pm, ). What is the water temperature now? (°C) 5.22 3. Just as soda contains dissolved carbon dioxide, pond water contains dissolved oxygen. The unit for measuring the concentration (amount) of oxygen is parts per million (ppm). Drag the Oxygen gauge to the pond. What is the concentration of oxygen? 4.04 4. Drag the Fishing pole to the pond, and click Play ( ). Fish for about four hours. How many catfish did you catch? 4 How many trout? 0 Activity A: A day in the life of a pond Get the Gizmo ready: ● Click Reset ( the pond. ). Remove the Fishing pole from Introduction: The fish in a pond are affected by biotic factors such as other fish, aquatic plants, insects, and bacteria. They are also affected by abiotic factors, or nonliving factors such as temperature and the concentration of dissolved oxygen. Question: How does the amount of dissolved oxygen in a pond change during one day? 1. Observe: Use the Oxygen gauge to measure the concentration of dissolved oxygen at several different times. How does the oxygen concentration change over a single day? As the sun rises, the oxygen levels rise, and they fall at night. The sun directly affects the cycle of the oxygen levels. 2. Predict: At what time should the amount of oxygen in a pond be lowest? Place an “X” in the box. 6:00 AM x 12:00 PM (noon) 6:00 PM 12:00 AM (midnight) 3. Test: Measure the dissolved oxygen at four times during the day: 6 AM, 12 PM (noon), 6 PM, and 12 AM (midnight). Then click New pond and repeat the test for two more ponds. Record your results in the table below. 6:00 AM 12:00 PM 6:00 PM 12:00 AM Pond 1 4.04 5.26 6.43 5.56 Pond 2 3.37 4.43 5.28 4.32 Pond 3 4.13 5.32 6.41 5.32 4. Analyze: Was your prediction correct for all three ponds? Explain. My forecast came true because the data showed that the oxygen level is always lowest at 6:00am for all three ponds. 5. Draw conclusions: The dissolved oxygen in a pond is produced by pond plants and algae (small, plant-like organisms) in a process called photosynthesis. A. At what time of day does photosynthesis take place? in the morning B. What source of energy is present during this time? sun C. Why does the level of dissolved oxygen go down after sunset? because there is less energy once the sun goes down Activity B: Get the Gizmo ready: ● Click Reset. Go fish! Question: How do concentrations of dissolved oxygen affect fish? 1. Explore: To investigate the question, measure the oxygen concentration and go fishing in several ponds. (To fish, drag the Fishing pole into the pond, click Play, and wait several hours.) Observe the oxygen concentration and the numbers and types of fish you catch. 2. Form hypothesis: How does oxygen concentration affect the fish that live in a pond? Lower ppm levels in ponds make fish less active and eat less, which eventually leads to their demise. However, fish are more active and will consume more if the ppm is higher. Therefore, it will be much simpler to catch more fish in places with higher oxygen concentrations than in ponds with lower oxygen concentrations. 3. Predict: If you fish in four ponds, will more fish be caught in the two ponds with the lowest oxygen concentrations, or the two ponds with the highest oxygen concentrations? Explain. In fact, the ponds with the highest concentrations will yield more fish. this is due to the fact that fish become more active and eat more when there is a higher oxygen content, making it simpler to catch more fish. However, fish are less active and consume less in ponds with lower oxygen concentrations, which could eventually lead to the fish dying and make it difficult to catch fish. 4. Test: Investigate four ponds. For each pond, measure the dissolved oxygen concentration at 6:00 AM. Fish for six hours and record how many catfish and trout you catch in each pond. Hint: To find a pond with relatively high levels of dissolved oxygen (above 5 ppm), select No farms. To find a pond with low levels of oxygen (below 4 ppm), uncheck No farms. Oxygen (6:00 AM) Number of catfish Number of trout Pond 1 5.09 (one farm) 4 3 Pond 2 2.54 (a lot of farm) 3 0 Pond 3 4.49 (no farm) 3 2 Pond 4 4.37 (no farm) 5 1 5. Analyze: What does your data show? The research indicates that there are more fish to be caught in ponds without farms. 6. Draw conclusions: Which type of fish can survive better in low-oxygen conditions? Explain. Catfish can survive better in low-oxygen environments; this is proven by the fact that catfish were the most often caught fish in low-oxygen ponds. Since more catifish were taken, it may be concluded that the catfish are still active in spite of the low oxygen situation. Fish in low oxygen ponds typically become inactive, eat less, and even perish. Activity C: Dissolved oxygen Get the Gizmo ready: ● Select No farms. ● A calculator is recommended for this activity. Question: How does temperature affect the concentration of dissolved oxygen? 1. Explore: Measure the temperature and concentration of dissolved oxygen in several ponds. Temp:15 celsius dissolved oxygen:5.82ppm, 25c 2.44ppm 2. Form hypothesis: How does temperature affect oxygen concentrations? A pond's hotter temperature results in a reduction in the amount of dissolved oxygen that the pond can contain. compared to cold water, which has a higher capacity to store dissolved oxygen 3. Predict: Which ponds will have a higher average oxygen concentration, ponds cooler than 20 °C or ponds hotter than 20 °C? more than -20 °C 4. Test: For each pond, measure the temperature and oxygen concentration at 6:00 AM. If the temperature is below 20 °C, record your results in the left table. If the temperature is above 20 °C, record your results in the right table. Continue until each table is filled. Ponds cooler than 20 °C 6:00 AM Temp. 6:00 AM Oxygen 15 5.93 Ponds hotter than 20 °C 6:00 AM Temp. 6:00 AM Oxygen 26 4.82 18 5.54 27 4.72 20 5.29 23 5.00 5. Calculate: Find the mean (average) oxygen concentration for the cold ponds and for the hot ponds. To find the mean, add the three oxygen concentrations and then divide by three. Mean oxygen level for cold ponds: 5.586 Mean oxygen level for hot ponds: 4.846 6. Draw conclusions: How does the temperature of water affect its ability to hold oxygen? A pond's water cannot store much oxygen at higher temperatures, but it may hold more oxygen at lower temperatures. 7. Infer: Based on this data and what you learned in Activity B, do you think trout will be more common in warm or cool ponds? Explain. In chilly waters, trout will be more prevalent. this is due to trouts' inability to endure low oxygen levels. Therefore, because there is a low oxygen concentration, trout will be less prevalent if you are fishing in a warm pond. It implies that trout will inhabit cooler ponds more frequently. 8. Predict: How do you think the presence of farms will affect the oxygen concentration in the ponds? Explain why you think so. this because if farms are situated next to ponds, the pond's temperature will rise as a result, resulting in low oxygen concentrations in the ponds? (This is inaccurate) 9. Test: Check that No farms is on and the thermometer and oxygen monitor are still in the pond. Click New pond until you find a pond with a starting temperature between 20 °C and 25 °C. Record the temperature and oxygen concentration for this no-farm pond. Now, turn off the No farms checkbox. Click New pond until you get another pond with a starting temperature between 20 °C and 25 °C. Record the temperature, number of farms, and dissolved oxygen for this pond. Repeat until you have looked at five ponds. Temp. (6:00 AM) Number of farms Oxygen (6:00 AM) Pond 1 22 0 5.14 Pond 2 25 2 3.70 Pond 3 23 0 5.07 Pond 4 23 5 2.53 Pond 5 25 0 4.88 10. Analyze: In the table, circle the pond with the lowest dissolved oxygen and the pond with the highest dissolved oxygen. What do you notice about the number of farms for these ponds? I observe that the ponds' temperatures are nearly identical at both their highest and lowest concentrations of dissolved oxygen. But the number of farms is different. Whereas the lowest dissolved oxygen contains five farms, the highest dissolved oxygen has zero. 11. Draw conclusions: Based on your data, how do farms affect oxygen levels in the pond? Fertilizers are used by farmers to promote crop growth. Additionally, a lot of farms generate a lot of animal waste. Excess garbage and fertilizer may wash into surrounding ponds and streams during heavy rain. Algal blooms, which are characterized by a fast growth in algae, may result from the nutrients in these substances. Farmers use fertilizers to increase crop growth. Many farms also produce large amounts of animal waste. When it rains, excess fertilizer and waste can run off into nearby ponds and streams. The nutrients in these substances can cause a rapid increase in algae known as an algal bloom. When algae die, bacteria break down their remains, using up the dissolved oxygen in the water. The rapid loss of oxygen, or eutrophication, can kill fish and other wildlife living in the pond or stream.