Lab Assignment: Ecological Interactions
INSTRUCTIONS
Many factors contribute to whether an organism can thrive in a given environment. Each species has a range of tolerance that can determine whether the species is commonly observed or only observed rarely and under very specific environmental conditions. In this lab, you will explore one of the factors that impacts survival of living organisms: the acidity or alkalinity of soil and water.
IMPORTANT: Seven days of plant growth are needed to complete this experiment.
Additional materials needed:
• Paper towels, scissors, sunny location, tap water.
• Cell phone/digital camera - pictures required
Concepts to explore: Environmental impact on a living organism
Experiments
Experiment 1: Effects of pH on radish seed germination
• Students measure acidity and alkalinity of soil to determine the range of pH tolerance for the seed.
Pre-Lab Questions
1. Would you expect endangered species to be more frequently generalists or specialists? Explain your answer.
2. How does temperature affect water availability in an ecosystem?
3. Choose a species and describe some adaptations that species developed that allow them to survive in their native habitat.
Experiment 1: Effects of pH on Radish Seed Germination
Data Tables and Post-Lab Assessment
Table 1: pH and Radish Seed Germination
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Stage/Day Observations
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Acetic Acid
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Sodium Bicarbonate
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Water
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Initial pH
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1
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2
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3
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4
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5
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6
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7
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Take a picture of your results. Include a note with your name and date on an index card in the picture. Insert picture here:
Post-Lab Questions
1. Compare and construct a line graph based on the data from Table 1 in the space below. Place the day on the x axis, and the number of seeds germinated on the y axis. Be sure to include a title, label the x and y axes, and provide a legend describing which line corresponds to each plate (e.g., blue = acetic acid, green = sodium bicarbonate, etc...).
2. Was there any noticeable effect on the germination rate of the radish seeds as a result of the pH? Compare and contrast the growth rate for the control with the alkaline and acidic solutions.
3. According to your results would you say that the radish has a broad pH tolerance? Why or why not? Use your data to support your answer.
4. Knowing that acid rain has a pH of 2 - 3 would you conclude that crop species with a narrow soil pH range are in trouble? Explain why, or why not, using scientific reasoning. Is acid rain a problem for plant species and crops?
5. Research and briefly describe a real world example about how acid rain affects plants. Be sure to demonstrate how pH contributes to the outcome, and proposed solutions (if any). Descriptions should be approximately 2 - 3 paragraphs. Include at least three citations (use APA formatting).