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PROBLEM SET #2: Plants
AP Biology
Reminder: Problem Sets are individual assignments. You are welcome to discuss these questions with your classmates, however your answers should be your own. Use your own words. Any academic code violations will result in a zero on this assignment and a note in your academic record.
- In order to test osmosis, a potato cell is placed in a beaker of pure water. What direction would you expect water to move? What changes would you predict in this experiment after 10 minutes? Where is the water potential the lowest? The highest?
- Years ago, when your parents were dating, they went on a romantic date to the redwood forest. On an impulse, they carved their initials in the trunk of one of the trees. Twenty years later, your family returns to the redwood forest. Where on the tree would you expect to find the initials that your parents carved? Consider tree growth in your answer.
- Girdling is the process of removing a ring of bark from a tree that is still living. What effect will this have on the tree? What structure(s) in the tree are being affected? A diagram of a girdle is shown below.
- Water is crucial to a plant, but at the same time, one must be careful not to overwater a plant. Normally, there are air spaces in the soil that allow the plant to survive. Why would overwatering harm a plant? Specifically, which cellular processes would this overwatering interfere with?
- You forget to water your plant for several days and find it wilted by the windowsill. You cut off a branch of your plant and put it in a vase filled with water. After that, you water the rest of the plant (still in the soil). Which of the plants, the cut branch or the remaining plant in the watered soil, will be revived (not wilting anymore) faster? Explain your answer based on your knowledge of plant structures.
- A scientist creates two new plants. One plant is able to keep its stomata open all of the time, the other plant, always keeps its stomata closed. Much to her dismay, both plants die. For each plant, explain why each plant dies.
- Pollination is the process in which pollen is transferred to the stigma of the same species of plant. Pollination is often achieved with the help of pollinators such as birds and insects as well as air or water currents. Birds and insects suck the nectar from flowers for food and in the process they pick up pollen grains and transfer them to other flowers.
a)Certain plants tend to have only one pollinator. For example, butterflies are attracted to daisies and other fragrant flowers while birds are attracted to red and yellow flowers without a fragrance. Beetles are attracted to flowers that smell like rotting meat. Why would it make sense for each type of plant to have a specific pollinator rather than attracting any random pollinator?
b)Coevolution refers to two species jointly evolving as a result of interactions between the two species. Suppose a plant has structures that allow it to attract pollinating insects better. How will this drive the evolution of both the plant and the insect?