Answer:
Primary succession occurs in areas without any soil where basically nothing is there. After an event such as a volcanic eruption, pioneer species such as lichens and mosses are able to colonize the land since they can grow without soil and are primitive. Lichens can break down rock to form soil and they can add small amounts of organic matter to the rocks when they decompose to make even more soil. Simple plants like ferns can then grow in the created soil. After these simple plants die, more organic material is added to the soil and the soil thickens, allowing grasses, wildflowers, and other plants to begin to take over. Next, after these plants die, enough nutrients are added to the soil for trees and shrubs to survive. Finally, insects, small birds, and mammals begin to move into the area and form a community, so what was once bare rock can now support a variety of life.