Difficulty: Easy
Correct Answer: they serve as key decomposers of dead organic matter
Explanation:
Introduction / Context:
Food webs depend on energy flow and nutrient cycling. Decomposers break down complex biomolecules, returning nutrients to the system. Understanding the primary ecological function of fungi explains their omnipresence in soils, leaf litter, and decaying wood, as well as their importance in biotechnology and agriculture.
Given Data / Assumptions:
Concept / Approach:
Fungi secrete extracellular enzymes to degrade polymers such as cellulose, hemicellulose, and lignin, converting them into small molecules that can be absorbed and reused by other organisms. This decomposition liberates carbon, nitrogen, phosphorus, and micronutrients, closing biogeochemical cycles. While fungi do produce antibiotics, that is not their central ecological role and is more about competition than ecosystem nutrient flow.
Step-by-Step Solution:
Discard photoautotrophy: fungi lack chlorophyll and chloroplasts.
Discard prokaryotic cell structure: fungi are eukaryotic.
Identify decomposition as the keystone ecological function.
Select the option emphasizing decomposition of dead organic matter.
Verification / Alternative check:
Field studies show fungal hyphal networks colonizing litter and wood; enzyme assays detect cellulases and ligninases; stable isotope tracing highlights fungal roles in nutrient turnover.
Why Other Options Are Wrong:
Common Pitfalls:
Overemphasizing secondary metabolite production (e.g., antibiotics, toxins) rather than the fundamental role in decomposition.
Final Answer:
they serve as key decomposers of dead organic matter
Discussion & Comments