Question 88 from UPSC CSE 2021 - Environment

Question

In 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.

IASCODEX · Accepted Answer

Correct Option: C. 2 and 3

Strategy: Identify soil-independent surface dwellers. Eliminate ferns and mushrooms as they require soil or decaying organic matter. Select lichens and mosses, which grow directly on surfaces like rocks and bark.

Key Info: **Lichen:** Lichens are composite organisms formed by a symbiotic relationship between fungi and algae or cyanobacteria. They thrive on bare surfaces, such as rocks, tree bark, and even artificial substrates like glass or metal, requiring minimal substrate and extracting nutrients from the air and rain. They are key pioneers in ecological succession and can survive in extreme environments.

**Moss:** Mosses are small, non-vascular plants (Bryophytes) that absorb water and nutrients mainly through their leaves. They often grow on rocks, tree trunks, or even rooftops, requiring only moisture and shade rather than soil, making them important for soil formation in primary succession and erosion prevention.

**Fern:** Ferns are vascular, spore-producing plants that require anchorage and nutrients from the underlying medium, usually soil rich in organic matter. They do not generally grow on bare surfaces without some substrate for rooting.

**Mushroom:** Mushrooms are the fruiting bodies of certain fungi. Most species grow on decaying organic matter in soil, leaf litter, or wood. Some can be cultivated without soil using substrates, but in nature, mushrooms depend on decomposing organic substrates and are not typically found on bare inorganic surfaces.

IASCODEX · Answer

Option A: 1 and 4 only

IASCODEX · Answer

Option B: 2 only

IASCODEX · Answer

Option D: 1, 3, and 4

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.

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.