In the nature, which of the following is/are most likely to be found surviving on a surface without soil? 1. Fern 2. Lichen 3. Moss 4. Mushroom Select the correct answer using the code given below.
- (a) 1 and 4 only
- (b) 2 only
- (c) 2 and 3 ✓ UPSC's answer
- (d) 1, 3 and 4
Why the answer is (c)
• Lichens (fungus–alga partnerships) are pioneer organisms that colonise bare rock, tree bark and walls, absorbing water and minerals directly from air and rain (item 2).
• Mosses (bryophytes) lack true roots and grow as mats on rocks, tree trunks and roofs, needing only moisture, not soil (item 3).
• Ferns (1) have true roots and generally need soil or a soil-like substrate; mushrooms (4) are fungal fruiting bodies that grow on decaying organic matter or soil, not on a bare surface.
• Lichens and mosses together begin primary succession by weathering rock into soil.
• Hence 2 and 3, option (c).
Why the other options are wrong
- (a) 1 and 4 only
- Ferns and mushrooms need soil or organic substrate.
- (b) 2 only
- Moss also survives on bare surfaces, not lichen alone.
- (d) 1, 3 and 4
- Ferns and mushrooms need soil; lichen is the classic bare-surface survivor.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2021, held on 10 October 2021. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.