Biology 2003 JAMB Past Questions - Question 37: The pioneer organisms in ecological succession are usually the

Correct Answer

B

Explanation

BLichens are association of unicellular algae and fungi.They are usually the first organism to grow and establish themselves on a bare-rock during primary succession because they make little demands on thehabitat. The lichens together with abiotic factors like rain, diurnaltemperature changes and wind crumble the rock surface resulting in soilformation. Algae and mosses are replaced by lichens. They make more soil andincrease the fertility of the soil through their activities. They are laterreplaced by ferns.