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.
