Which type of succession occurs on surfaces where no soil previously existed?

• A. Ecological succession
• B. Primary succession
• C. Secondary succession
• D. Climax community

Answer: (B)

Primary succession occurs on surfaces where no soil exists. When bare rock or newly exposed land first appears, there’s no seed bank or substrate to support established plants. Pioneer organisms like lichens and mosses move in first, tolerating harsh conditions and slowly breaking down the rock while adding organic material. As these pioneers die and decompose, a thin layer of soil forms, enabling grasses and herbs to establish, then shrubs, and eventually trees. This gradual buildup of soil and shifting species composition is the defining path of primary succession. In contrast, secondary succession happens after a disturbance that leaves soil intact, so the starting point is different. Ecological succession is the broad process, and a climax community is the stable end point that can result after ongoing change.