Biology 2012 JAMB Past Questions - Question 33: The most likely first colonizers of a bare rock are

Correct Answer

C

Explanation

Lichen is an intimate association between a green alga and a fungus. It is an astonishly hard organism which thrives in areas where no other vegetation exists and where algae or fungi alone cannot possibly survive. The unicellular algae are surrounded and protected by fungai hyohae (singular hypha). The special hyphae called rhizoid absorb water andmineral salts used by green algae to synthesize carbohydrate and release oxygen.The rhizoids grow into the rock causing it's disintegration and producing rock particles. Spores of moss plants which establish themselves and drive away the lichen. The rhizoid grow more into the rock causing more disintegration making soil out of the bare rock. Fern plants arrive and drive away the mosses and later grasses and lastly trees