Colonization of a bare rock surface is termed primary succession. Primary succession refers to the process of ecological succession that occurs in an area where there was no previous soil or vegetation, such as a bare rock surface, glacier retreat, or lava flow. In these areas, the first organisms to colonize are usually bacteria, lichens, and mosses that can survive in harsh conditions and break down the rock surface to create soil. As the soil layer builds up and organic matter accumulates, larger plants such as grasses and shrubs can begin to grow, which in turn attracts animals and insects. Over time, the ecosystem becomes more complex and diverse, with different species competing and interacting with each other. Therefore, the colonization of a bare rock surface is an example of primary succession, which is a process of ecological change that occurs in areas where there was no previous soil or vegetation.