Question

Why are lichens called pioneer colonizers? Name the lichen which is popularly called reindeer moss.

Answer 1

Hint: Lichens are a symbiotic association between fungus and algae.

Complete answer: Lichens are the first organisms to colonize bare rock.
They are, therefore, called the pioneer species in primary succession.
1. Many organisms require soil in order to colonize an area. Lichens that colonize bare rock secrete acids and enzymes that break down the rock and start the process of soil-production. 2. Also, when lichens die, they provide some organic matter that also contributes to the soil. 3. Mosses are then able to colonize the thin layer of soil. When mosses die, the soil thickens more, thereby allowing other hardy species to colonize. The process continues until a mature forest forms, which happens, sometimes, centuries later.
4. Symbiotic association: It is defined as an interaction between individuals of different species that results in positive or beneficial effects on the reproduction or survival of the interacting populations.
The image below shows a cross-section of lichen. They are half fungi and half protest (or algae).

5. Primary succession: Successional dynamics begin with the colonization of an area that was not previously occupied by an ecological community, such as newly exposed rock or sand surfaces, newly exposed glacial tills, etc. are termed as primary succession. The stages of primary succession include pioneer community, plants (lichens and mosses), grassy stage, smaller shrubs, and trees.
Reindeer moss is the common name of Cladonia rangiferina.

Note: Animals begin to inhabit the areas when their food is there to eat.
When it is a fully functioning ecosystem, it is said to have reached the climax community stage.