Biology Regents Practice Exam

The return of plant life on Mount St. Helens is an example of which process?

1. Humans degrading an ecosystem

2. Loss of genetic variation in a species

3. Growth of a forest through ecological succession

4. Biological evolution of wildflowers

The correct answer is: Growth of a forest through ecological succession

The return of plant life on Mount St. Helens is an excellent example of the growth of a forest through ecological succession. Ecological succession refers to the gradual process by which ecosystems change and develop over time, often following a disturbance. After the volcanic eruption in 1980, the landscape was drastically altered, creating an environment that was initially barren. In the aftermath, pioneer species such as mosses and lichens were among the first to colonize the area. These organisms can thrive in harsh conditions and help to improve the soil quality. As these pioneers die and decompose, they contribute organic material to the soil, making it more suitable for subsequent species. Over time, a variety of plants, including shrubs and eventually trees, began to establish themselves, leading to the development of a mature forest. This process showcases the resilience of ecosystems and the ability of life to rebound after significant disturbances, highlighting the stages of succession from pioneer species to a more complex community. Understanding this process is critical when studying how ecosystems recover and the importance of biodiversity in maintaining ecological balance.