Sun provides energy to producers, which transfer it unidirectionally to primary consumers, then secondary consumers in ecosystems.​

Question Breakdown

This GATE Life Sciences question tests the unidirectional energy flow in ecosystems via trophic levels. Energy originates from sunlight, captured by producers (plants), then passes to herbivores (primary consumers) and carnivores (secondary consumers), with ~90% loss at each step as heat.​

Option Analysis

(A) Producers → Primary consumers → Secondary consumers

Incomplete; omits sunlight as the primary energy source for producers via photosynthesis.​

(B) Sun → Producers → Secondary consumers → Primary consumers

Incorrect sequence; secondary consumers eat primary consumers, not vice versa—violates trophic order.​

(C) Sun → Producers → Primary consumers → Secondary consumers

Correct; follows the standard grazing food chain: sunlight → autotrophs → herbivores → carnivores.​

(D) Secondary consumers → Primary consumers → Producers → Sun

Reversed flow; energy moves forward only, never backward to producers or sun.​

Flow of energy through ecosystem starts with sun powering producers, then primary consumers (herbivores), and secondary consumers (carnivores) in a unidirectional path.​

Energy Flow Principles

Producers convert ~1-2% solar energy to biomass via photosynthesis. Primary consumers get ~10% of that energy; secondary consumers even less per the 10% rule. Decomposers recycle nutrients but not energy.​

Comparison Table

GATE Exam Relevance

Core ecology concept for XL papers. Visualize as energy pyramid: widest at producers, narrowing upward. Study 10% law and food webs for related questions.​