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Question #46930

Difficulty: 8/10 | 🟢 Free

The Question

In a stable lake ecosystem, energy flow to higher trophic levels is primarily mediated by ectothermic herbivores and primary carnivores. If the lake experiences a sustained thermal pollution event that raises the water temperature by $10^\circ C$ (remaining just within the upper thermal tolerance limits of the species), what will be the most immediate ecological consequence leading to the starvation of the top carnivores, assuming Gross Primary Productivity (GPP) remains constant?

Options

A.
The GPP to Respiration (GPP/R) ratio of the ecosystem will increase significantly, causing an energy bottleneck at the producer level.
B.
The respiratory costs (R) of the ectotherms will increase exponentially due to the $Q_{10}$ effect, drastically reducing net secondary productivity.
C.
The primary producers will undergo rapid denaturation of RuBisCO, immediately halting all Net Primary Productivity (NPP).
D.
The assimilation efficiency of the ectothermic consumers will double, leading to the rapid and total exhaustion of producer biomass.

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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

Thermal Tolerance Ranges|Productivity Ratios|Key Analytical Nature

Why This Question Is Tricky

Common Mistakes

Conceptual Pivot: Students often memorize the equation $NPP = GPP - R$ strictly for plants (primary productivity) but fail to apply the same thermodynamic partitioning (Assimilation - Respiration = Production) to consumers.

This question requires synthesizing the $Q_{10}$ metabolic rule from 'Organisms and Populations' with the energy flow principles from 'Ecosystem'.

The common misconception is assuming that as long as the temperature is non-lethal and producer biomass is stable, the food web remains intact, ignoring the 'hidden metabolic tax' that starves higher trophic levels.

Quick Facts About This Question

Question Information

Subject	Biology
Chapter	The Living World - Class 11
Concept	Key Analytical Nature
Difficulty	8
Cognitive Load	5
Target Solve Time	120 sec
Access	Free