๐ Q.3 IAS Prelims 2021 โ Environment & Ecology (Life Without Soil)๐งท Authentic Classroom Explanation by IAS Monk
๐ 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
โ Correct Answer: (c) 2 and 3
๐ง Classroom Explanation:
๐น Fern โ โ 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.
๐น Lichen โ โ
Correct
Lichens are a symbiotic association of algae + fungi.
They do not require soil at all and can survive on:
โข Rocks
โข Tree bark
โข Walls
โข Glass, metal, plastic
They need only:
โ An undisturbed surface
โ Clean air
โ Time
๐น Moss โ โ
Correct
Mosses are non-vascular plants with no true roots.
They absorb water and nutrients directly from air and rain.
They can grow on:
โข Rocks
โข Tree trunks
โข Walls
๐น Mushroom โ โ Not correct
Mushrooms (fungi) generally need organic substrate like soil, wood, or decaying matter for nutrition.
๐ Hence, only Lichen and Moss can survive on surfaces without soil.
๐ Curiosity Raiser:
Why are lichens called โpioneer speciesโ?
Because they are often the first life forms to colonize bare rocks, slowly helping in soil formation over centuries.
๐ Enrich Notes (Prelims Gold):
โข Lichen = Bio-indicator of air quality
โข Moss + Lichen โ Non-vascular, no true roots
โข Ferns โ Vascular, soil-dependent
โข Mushrooms โ Saprophytic fungi
One-Line Memory Hack:
๐ โNo soil, no roots โ Think Moss & Lichenโ
๐ชถ IAS Monk Whisper:
When life finds a way on bare stone, resilience becomes biology.















