Question

Following are a few organisms

Which among the above can grow on stones and also help in the formation of soil?

Write the mode of their action for making soil.

• A. Lichen
• B. Mosses
• C. Mango tree
• D. Cactus

Answer 1

Answer: (A), (B)

Mosses

The correct options are A and B.

Explanations for the correct option:

Option A

1. Lichens are that is a symbiotic partnership of two separate organisms, a fungus, and an alga.
2. First organism to colonize the area.

Option B

1. Bryophytes are amphibians of the plant kingdom.
2. They occur in damp, humid, and shaded areas.
3. They play important role in plant growth on bare rocks.
4. Mosses belongs to bryophyte .
5. Mosses along with lichens are the first organism to colonize the rocks.
6. They decompose rocks making soils and suitable conditions for the growth of higher plants and their succession.
7. Mosses form a dense layer on soil and prevent soil erosion during falling rain
8. Mosses help in the formation of topsoil.

Mode of action

1. Lichens and mosses release certain extracellular enzymes which break down the stones resulting in the formation of soil.
2. Habitat is first colonized by lichens followed by mosses.
3. Their decay and decomposition lead to an increase in the organic content of the soil
4. It leads to higher plant formation.

Explanations for the incorrect option:

Option C

1. The mango tree belongs to the angiosperm.
2. It is the higher plant that requires well-stabilized soil and environment to flourish.

Option D

1. The cactus belongs to the angiosperm.
2. Angiosperm is the higher plants that require a well-flourished environment and soil to grow and spread.

Final answer: Lichen and mosses help in soil formation on bare rocks.