Before You Begin
Question #46642
The Question
During hydrarch succession, a shallow lake transitions through the reed-swamp and marsh-meadow stages before eventually reaching a climax forest community. A population of open-water piscivorous birds suffers local extinction during the late seral stages, even though the total secondary productivity and prey biomass of the habitat have significantly increased. According to the principles of community structure and optimal foraging, which of the following best explains this local population decline?
Options
- A.
The climax forest exhibits lower total biomass and gross primary productivity than the pioneer phytoplankton stage, reducing the energy available to top predators.
- B.
The increased vertical stratification of the later seral stages alters spatial complexity, drastically increasing the bird's search and handling time to an energetically unviable level.
- C.
The climax community shifts entirely to a detritus food chain (DFC), which lacks the trophic levels necessary to support tertiary consumers like predatory birds.
- D.
The climax community is characterized by lower species diversity and reduced niche specialization, leading to the competitive exclusion of the bird species.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Zooplankton|Detritus Food Chain|Mineralization Rate
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the NCERT fact that 'biomass and diversity increase during succession' but fail to synthesize how the physical architecture (stratification) dictates behavioral ecology.
The trap assumes that if total prey biomass increases, predators will naturally thrive, ignoring the mechanical and energetic constraints of foraging (search-to-handling time ratio) in a newly stratified environment.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Organisms and Populations - Class 12 |
| Concept | Diapause vs Hibernation vs Aestivation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |