Question

Lichens are well known combination of an alga and a fungus where fungus has

(a) a saprophytic relationship with the alga

(b) an epiphytic relationship with the alga

(c) a parasitic relationship with alga

(d) a symbiotic relationship with alga.

Answer 1

Lichens are formed by fungi that live with photosynthetic algae or cyanobacteria by the symbiotic (mutualistic) relationship.The fungus grows around the bacterial or algal cells. The fungus benefits from the constant supply of food produced by the photosynthesizer. The photosynthesizer benefits from the water and nutrients absorbed by the fungus.The lichen can be quite large and conspicuous, more closely resembling a moss or small plant than either a fungus or an alga.Most lichens are members of the Ascomycota and reproduce by means of asci and ascospores.Lichens are found on the ground in deserts, on the sides of the dry rock, hanging from the branches of trees and even growing on the backs of turtles. They are nearly as easy to find and study in the middle of winter as during the warmer months.

Benefits of a symbiotic relationship between fungi and algae:

• Fungus provides shelter (Ascomycota)
• Algae provides food (Cyanobacteria or Green Algae)