Investigating Alternative Mechanisms of Carbon Fixation
Because we dedicate a large amount of time on the "typical" photosynthetic pathways, students often forget about alternative mechanisms of photosynthesis. It is important that our students are aware of C4 and CAM pathways because they play a large role in society and human activity. In this activity, students will investigate the noticeable differences between C3, C4, and CAM plants and think about the impact C4 and CAM plants can have on human society, especially with climate change being a serious matter in the world today.
MATERIALS
- Leaf samples of C3, C4, and CAM plants
- (Optional) fruit samples of C3, C4, and CAM plants
- Three mystery plants, along with some of its features written on cue cards and taped to the vase
- Record sheet and writing utensils
PROCEDURES
- Students will observe the leaf (and perhaps fruit) samples of C3, C4, and CAM plants. Ideally there should be three groups of students but you can group students based on what works best in your own classroom
- Students will record any similarities within the three plants and differences between the three groups of plants
- Students may look at their notes or textbooks to answer some of the questions on the record sheets
- After students have finished working on their handout, students will be handed a mysterious plant in the box
- Using the features written on cue cards and the physical appearances of the plants, students try to hypothesize the carbon fixation mechanism their plants rely on the most to produce carbohydrates (i.e. is it a C3, C4, and CAM plant?)
- Students will present their hypothesis and explain their reasoning. The class must agree or disagree with the groups
EXTENSIONS
Ask students to answer one of the following question:
"If the greenhouse effect persists and gets worse, which photosynthetic pathway (C3, C4, or CA) would benefit the environment the most? How will escalation of the greenhouse effect (a result of increased atmospheric carbon dioxide concentrations) affect the competition between C3 and C4 plants in terms of crop productivity and weed control"
AND/OR
"Converting C3 plants to C4 plants can increase crop productivity. If you were a government looking to allocate some money to researching genetically engineering plants to be C4 crops, which three C3 crops would you choose to turn into C4 plants. What are the disadvantageous and advantageous of genetically engineering plants?"
Ask students to answer one of the following question:
"If the greenhouse effect persists and gets worse, which photosynthetic pathway (C3, C4, or CA) would benefit the environment the most? How will escalation of the greenhouse effect (a result of increased atmospheric carbon dioxide concentrations) affect the competition between C3 and C4 plants in terms of crop productivity and weed control"
AND/OR
"Converting C3 plants to C4 plants can increase crop productivity. If you were a government looking to allocate some money to researching genetically engineering plants to be C4 crops, which three C3 crops would you choose to turn into C4 plants. What are the disadvantageous and advantageous of genetically engineering plants?"
REFERENCES
Questions are from the Nelson Biology grade 12 textbook
Questions are from the Nelson Biology grade 12 textbook