📘 Q.3 IAS Prelims 2021 — Environment & Ecology (Life Without Soil)🧷 Authentic Classroom Explanation by IAS Monk
📌 The Question:
In nature, which of the following is/are most likely to be found surviving on a surface without soil?
- Fern
- Lichen
- Moss
- Mushroom
Select the correct answer using the code given below:
(a) 1 and 4 only
(b) 2 only
(c) 2 and 3
(d) 1, 3 and 4
✅ Correct Answer: (c) 2 and 3
🧠 Classroom Explanation:
🔹 Fern – ❌ Not correct
Ferns are vascular plants. Though they reproduce via spores, they require moist soil, indirect sunlight, and nutrients absorbed through roots or rhizoids connected to soil.
🔹 Lichen – ✅ Correct
Lichens are a symbiotic association of algae + fungi.
They do not require soil at all and can survive on:
• Rocks
• Tree bark
• Walls
• Glass, metal, plastic
They need only:
✔ An undisturbed surface
✔ Clean air
✔ Time
🔹 Moss – ✅ Correct
Mosses are non-vascular plants with no true roots.
They absorb water and nutrients directly from air and rain.
They can grow on:
• Rocks
• Tree trunks
• Walls
🔹 Mushroom – ❌ Not correct
Mushrooms (fungi) generally need organic substrate like soil, wood, or decaying matter for nutrition.
👉 Hence, only Lichen and Moss can survive on surfaces without soil.
🔍 Curiosity Raiser:
Why are lichens called “pioneer species”?
Because they are often the first life forms to colonize bare rocks, slowly helping in soil formation over centuries.
📚 Enrich Notes (Prelims Gold):
• Lichen = Bio-indicator of air quality
• Moss + Lichen → Non-vascular, no true roots
• Ferns → Vascular, soil-dependent
• Mushrooms → Saprophytic fungi
One-Line Memory Hack:
👉 “No soil, no roots → Think Moss & Lichen”
🪶 IAS Monk Whisper:
When life finds a way on bare stone, resilience becomes biology.