Plant Essays
1999
1. The rate of photosynthesis may vary with changes that occur in environmental temperature, wavelength of light, and light intensity. Using a photosynthetic organism of your choice, choose only ONE of the three variables (temperature, wavelength of light, or light intensity) and for this variable
a. Design a scientific experiment to determine the effect of the variable on the rate of photosynthesis for the organism:
b. Explain how you would measure the rate of photosynthesis in your experiment:
c. Describe the results you would expect. Explain why you would expect these results.
2. Communication occurs among the cells in a multicellular organism. Choose THREE of the following examples of cell-to-cell communication, and for each example, describe the communication that occurs and the types of responses that result from this communication.
• Communication between two plant cells
2003
2. Regulatory (control) mechanisms in organisms are necessary for survival. For the following examples, explain how each is regulated.
i. Flowering in plants
ii. Water balance in plants
2005
3. Angiosperms (flowering plants) have wide distribution in the biosphere and the largest number of species in the plant kingdom.
a. Discuss the function of FOUR structures for reproduction found in angiosperms and the adaptive (evolutionary) significance of each
b. Mosses (bryophytes) have not achieved the widespread terrestrial success of angiosperms. Discuss how the anatomy and reproductive strategies of mosses limit their distribution.
c. Explain alternation of generations in either angiosperms or mosses.
2006
3. The movement of water through vascular plants is important to their survival.
a. Explain the mechanism of water movement through vascular plants during transpiration. Include a
discussion of how the anatomy of vascular plants and the properties of water contribute to this
process.
b. Explain how gas exchange affects transpiration.
c. Describe TWO adaptations that affect the rate of transpiration in desert plants.
2008
4. Flowering plants have evolved various strategies for fertilization.
a. Describe the process of fertilization in flowering plants.
b. Discuss TWO mechanisms of pollen transfer and the adaptations that facilitate each mechanism.
Some species of flowering plants have evolved mechanisms to prevent self-fertilization.
c. Discuss an evolutionary advantage of preventing self-fertilization.
d. Describe TWO mechanisms that prevent self-fertilization.
2011
2. Organisms utilize a diversity of methods to obtain proper nutrition.
a. Some organisms digest food intracellularly, while others digest food extracellularly.
· Identify ONE nonvertebrate organism that digests food intracellularly and describe the process.
· Identify ONE nonvertebrate organism that digests food extracellularly and describe the process.
b. Describe TWO structural features of the human stomach and/or small intestine. For each, explain how
the structure relates to the function.
c. Plants have a variety of mechanisms for obtaining nutrients. Describe TWO plant structures and explain
how each structure is utilized for nutrient uptake.
4. The regulation of transpiration is an important homeostatic mechanism in plants.
a. Under controlled conditions, a transpiration experiment was conducted using two plant species. The data
collected are shown in the figure below. Using the data from the experiment, calculate the rate of
transpiration for species A and species B between the times of 5 and 15 minutes (show your work).
Summarize the differences between the two transpiration rates.
b. Identify and explain THREE different structural or physiological adaptations that could account for the different transpiration rates of species A and B.
c. Water potential (Ψ) is described by the following formulas.
Ψ = ΨP + ΨS
Ψ = -iCRT
Discuss the variables in both formulas and how they affect water potential.
2007
3. Compared with other terrestrial biomes, deserts have extremely low productivity.
a. Discuss how temperature, soil composition, and annual precipitation limits productivity.
b. Describe a four-organism food chain that might characterize a desert community, and identify the
trophic level of each organism.
c. Describe the results depicted in the graph. Explain one anatomical difference and one physiological
difference between species A and B that account for the CO2 uptake patterns shown. Discuss the evolutionary significance of each difference.