Primary Succession On Solid Rock Starts With Which Organisms?

• A. Grasses
• B. Trees
• C. Lichens And Moss
• D. Algae

Answer: (C)

On solid rock, primary succession begins with organisms that can live without soil and start building it. Lichens (a partnership of a fungus and photosynthetic partner) and mosses are classic pioneers because they can survive harsh, nutrient-poor surfaces. Lichens chemically and physically weather rock and, as they die, contribute organic material that slowly forms a thin soil. Mosses help retain moisture and add to this soil buildup. Once a tiny layer of soil is established, it becomes possible for other plants to take root, and grasses and eventually trees can grow. Algae may appear on rock too, but the durable first colonizers that kick-start soil formation are lichens and mosses, making them the best answer.