Which scenario best illustrates primary succession?

• A. Forest regrowth after logging
• B. Lava flow creating bare rock
• C. A coral reef forming
• D. A field undergoing seasonal changes

Answer: (B)

Primary succession is the gradual building of a biological community on a surface that starts without soil or life. It begins with hardy pioneer organisms, like certain microbes or lichens, that can tolerate bare rock and begin to break it down and add organic matter. Over time, this initial soil formation allows more plants to establish, followed by larger grasses, shrubs, and eventually trees, creating a developing ecosystem from scratch.

A lava flow creating bare rock is the classic example because it starts with totally lifeless rock and no soil, so the succession process must begin with pioneers and the slow accumulation of soil before other organisms can thrive.

Forest regrowth after logging isn’t primary succession since soil and many seeds or remnants remain, so the ecosystem develops on existing material. A coral reef forming involves building a ecosystem in a marine environment that already has substrate and existing life processes, not the creation of a community from bare ground. A field undergoing seasonal changes reflects ongoing fluctuations within an established ecosystem rather than a new community assembling from scratch.