What is ecological succession?

Ecological succession refers to the gradual and directional change in the composition of biological communities over time. This process involves a series of stages where one community of organisms replaces another, leading to a more stable and mature ecosystem. Succession can occur in various environments, such as after a disturbance (secondary succession) or in previously uninhabited areas (primary succession).

The focus here on the gradual change emphasizes that succession is not a sudden transformation, but rather a slow progression that involves multiple phases, typically beginning with pioneer species and culminating in a climax community with more complex structures and diverse species interactions. This change reflects not just the replacement of one species by another, but also alterations in environmental conditions and ecological interactions that take place over time.

Other choices do not accurately capture the essence of succession. For instance, the evolution of a species over time relates to the genetic changes within a species rather than the community-level changes implied by ecological succession. The establishment of new habitats, although relevant to ecosystems, does not specifically define the process of change in existing communities. Lastly, while competition between species is a significant aspect of ecological interactions, it is not synonymous with the process of succession. The correct answer precisely encapsulates the core concept of ecological succession.