Ecosystem Question 38

38. Which of the following would appear as the pioneer organisms on bare rocks?

(a) Lichens

(b) Liverworts

(c) Mosses

(d) Green algae

Show Answer

Answer : a

Hints & Solutions

(a) Lichens produce small amounts of carbonic acids from their “roots” and these slowly dissolve the rock, releasing nutrients. Other nutrients are obtained from waterborne or air-borne particles of both organic and inorganic materials. The body of a lichen contains an alga; this is able to photosynthesise sugars, some of which are passed on to the fungal component of the lichen. In return the alga gets a tiny but significant amount of shelter within the tissues of the lichen.