[Campbell Biology P.255] In a geographic region where the climate becomes significantly hott... | Practice Question

In a geographic region where the climate becomes significantly hotter and drier, but atmospheric CO2 concentration remains unchanged, how would you expect the relative abundance of C3, C4, and CAM plant species to shift over time?

  • A: C3 plants would decrease, while C4 and CAM plants would increase.
  • B: C4 plants would decrease, while C3 and CAM plants would increase.
  • C: CAM plants would decrease, while C3 and C4 plants would increase.
  • D: All three plant types would likely decrease due to the harsher conditions.

Explanation

C3 plants are less efficient in hot, dry conditions due to increased photorespiration and water loss through open stomata. C4 and CAM plants have evolved mechanisms spatial and temporal separation of carbon fixation, respectively to minimize photorespiration and conserve water, making them better adapted to such environments. Therefore, their relative abundance would increase as C3 plants decrease.