What is an example of primary succession?

Primary succession refers to the development of an ecosystem in a previously uninhibited area where soil has not yet formed. This process occurs after events that leave the environment devoid of life, such as volcanic eruptions or glacial retreats. The correct example of primary succession is the development of life in a newly formed volcanic island.

When a volcanic island emerges, it starts from bare rock, with no soil or any living organisms. Over time, weathering begins to break down the rock, and pioneer species, such as lichens and mosses, colonize the area. These organisms help in the soil formation process, allowing for more complex plants and animals to eventually inhabit the area, illustrating a sequential progression toward a more complex ecosystem. This is the hallmark of primary succession, as it begins from a lifeless substrate.

In contrast, the other scenarios, such as regrowth in burned forests or renewal after agriculture, represent secondary succession. These processes occur in areas where life has previously existed and soil is already present, thus allowing for a quicker recovery of the ecosystem compared to primary succession. Formation of coral reefs does involve ecological development, but it is a different process influenced by marine biology and geology, and does not exemplify primary succession in a terrestrial context.