Lichens, which are capable of initiating ecological succession even on a bare rock, are actually a symbiotic association of
Answer & explanation
Answer: (b) algae and fungi
A lichen is a partnership between a fungus and an alga. The alga photosynthesises and makes food for both partners. The fungus shelters the alga, absorbs water and minerals, and anchors the lichen to the surface. This pairing lets lichens colonise bare rock as pioneers of ecological succession.
- ✓ (b) In a lichen, one partner is an autotrophic alga and the other is a heterotrophic fungus, living in a mutual association. The alga makes food and the fungus gives protection and anchorage. Together they can survive on bare rock.
- ✗ (a) A lichen always contains a fungus as its non-photosynthetic partner. The photosynthetic partner is an alga (in some lichens, a cyanobacterium). A pairing of algae and bacteria leaves out the essential fungus.
- ✗ (c) A lichen needs a photosynthetic partner, which is an alga. Bacteria and fungi do not form a lichen.
- ✗ (d) Mosses are separate plants, not a lichen partner. In succession on rock they typically follow lichens, after lichens have begun breaking the rock down.
Remember · Lichen = alga + fungus (mutualism). It is a pioneer species in primary succession on bare rock and a bioindicator of air pollution.
📘 Read it in NCERT: Class 9 Exploration, Ch 12 (practise this chapter) · Class 11 Fundamentals of Physical Geography, Ch 5 (practise this chapter)
Sources
- NCERT Class 9 · Exploration, Chapter 12 “Biologically, these are symbiotic (mutual associations of two organisms) — one partner is an autotrophic alga and the other one is a heterotrophic fungus.”
- NCERT Class 11 · Fundamentals of Physical Geography, Chapter 5 “First, the weathered material or transported deposits are colonised by bacteria and other inferior plant bodies like mosses and lichens.”
Question: UPSC Civil Services (Preliminary) 2014, General Studies Paper I. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·
