The table below lists potential environmental conditions in future climates, related to atmospheric carbon dioxide concentrations ($CO_2$) and mean annual temperature (MAT).
The table also lists potential outcomes with respect to whether conditions will favour grasses with C3 or C4 photosynthetic pathways.
Assuming no other changes in environmental conditions, match the options in the two columns.Environmental conditions Outcomes (P) Increased $CO_2$, no change in MAT (i) C3 performs better than C4 (Q) No change in $CO_2$, increased MAT (ii) C4 performs better than C3 (iii) C3 and C4 perform equally
Conditions and Photosynthetic Pathways
This section determines how future environmental changes affect plants based on their photosynthetic pathways (C3 or C4).
Impact of Increased $CO_2$ (Condition P)
- Response: Higher atmospheric $CO_2$ concentrations benefit C3 plants more than C4 plants. C3 photosynthesis is typically $CO_2$-limited, while C4 plants already concentrate $CO_2$ internally.
- Outcome: This leads to C3 performing better than C4 (outcome i).
Impact of Increased MAT (Condition Q)
- Response: Increased Mean Annual Temperature (MAT) favors C4 plants, which are adapted to warmer climates. C3 plants are often more sensitive to heat stress.
- Outcome: This results in C4 performing better than C3 (outcome ii).
Summary of Matches
Based on the analysis:
- Condition P (Increased $CO_2$) matches Outcome (i) (C3 better than C4).
- Condition Q (Increased MAT) matches Outcome (ii) (C4 better than C3).
The pairing is P-i; Q-ii.
Important Questions from Abiotic factors
- Mean global temperature since pre-industrial times has increased approximately by
- Terrestrial plants conduct gas exchange through stomata. Having only few stomata on the leaf surface is a common adaptation to which one of the following conditions?
- Some air-breathing marine vertebrates such as whales, seals and marine turtles possess adaptations for long, deep dives. Which one or more of the following is/are examples of such adaptations?
- Which one or more of the following is/are greenhouse gas(es)?
- You are a plant ecologist studying a plant in the genus Veronica. You notice that, at open rocky sites, Veronica grows as a creeper spreading low to the ground, whereas in grasslands, the stem stands upright. You collect seeds from multiple populations in each habitat type and grow them under uniform conditions in a greenhouse. You find that all the plants grown in the greenhouse have stems that stand upright. Which one or more of the following explanations best support(s) your observations?
