IB Biology Practice Exam

Ecological succession is primarily characterized by a gradual change in species composition in a habitat over time. This process involves a series of stages where organisms colonize an area, leading to changes in the community structure. Initially, pioneer species such as lichens and mosses may establish themselves in a bare or disturbed environment. As these organisms modify the habitat, they create conditions that allow more complex species to thrive, leading to increased biodiversity. Over time, this dynamic can progress towards a climax community, which is a stable and mature ecosystem. This concept highlights the importance of temporal changes in ecological relationships and how ecosystems evolve in response to both biotic and abiotic factors.