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: Effects of pH on Radish Seed Germination
Natural soil pH depends on the parent rock material from which it was formed and processes like climate. Soil pH is a measure of the acidity or alkalinity of the soil. Acidic soils are considered to have a 5.0 or lower pH value whereas 10.0 or above is considered a strong basic or alkaline soil. The pH of soil affects the solubility of nutrients in soil water and thus it affects the amount of nutrients available for plant uptake. Different nutrients are available under differing pH conditions.
In this experiment we will look at the effect of pH on the germination and growth rate of radish seeds in order to determine the range of pH tolerance for the seed. Acidic or basic water will be used in order to stimulate acidity or alkalinity in soil.
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).