Grade 8 Biology Practice Test 2026 - Free Biology Practice Questions and Study Guide

Succession is the process that describes the gradual changes that occur in an ecosystem over time, particularly after a disturbance or the creation of a new habitat. It involves a series of stages where different communities of organisms replace one another, leading to a more stable and diverse ecosystem.

For example, after a forest fire, pioneer species such as grasses and small plants may colonize the area first, followed by shrubs, and eventually larger trees as the soil improves and conditions become suitable for more complex life forms. This sequence illustrates how succession can lead to the development of a mature ecosystem that supports more species and provides greater ecological stability.

In contrast, while climate change can significantly impact ecosystems, it is more of an external force affecting the rates and outcomes of succession. Ecosystem services refer to the benefits that humans derive from ecosystems, such as clean air, water, and pollination, but they do not directly change the dynamics of an ecosystem. Species diversity is important for ecosystem stability and resilience, but it is an outcome of successional processes rather than a driving factor in changing ecosystem dynamics over time.