When an existing ecological community is disturbed, __ describes the sequential reappearance of species in the community.
The correct answer and explanation is:
Correct Answer: Ecological succession
Explanation (300 words):
When an existing ecological community is disturbed—such as by fire, flood, human activity, or natural disasters—the process known as ecological succession describes the sequential reappearance of species and the gradual rebuilding of the ecosystem.
Ecological succession is a natural and predictable process through which ecosystems recover from a disturbance. It involves changes in species composition, community structure, and ecosystem processes over time. There are two main types of ecological succession:
- Primary Succession – This occurs in areas where no life previously existed, such as after a volcanic eruption or glacial retreat. In primary succession, organisms colonize bare rock or soil for the first time.
- Secondary Succession – This occurs in areas where a community has previously existed but was disturbed or destroyed. Common examples include abandoned farmland, areas after wildfires, or deforested land. In secondary succession, the soil is usually still intact, allowing for faster recovery compared to primary succession.
In the case of a disturbed community (e.g., a forest cleared by fire), secondary succession typically begins with fast-growing plants such as grasses and weeds (called pioneer species). These plants improve soil conditions and make it suitable for other species to move in, such as shrubs and small trees. Over time, more complex plant and animal species establish themselves, leading to a mature or climax community, which is stable and diverse.
Succession helps restore biodiversity, stabilize ecosystems, and maintain ecological balance. While the process can take years or even centuries, it is essential for the resilience and sustainability of the environment.
Thus, ecological succession is the correct term that describes the natural, orderly process of species re-establishing themselves after a disturbance in an ecosystem.