University Of Central Florida (UCF) BSC1005 Biological Principles Practice Exam 1

Primary succession is defined by its occurrence in environments that are initially devoid of soil, such as bare rock or areas left after a volcanic eruption or glacial retreat. This process begins with pioneer species, like lichens and mosses, that colonize these harsh environments and help in soil formation over time. In contrast, secondary succession takes place in areas where soil is present, typically after disturbances such as wildfires, floods, or human activities like farming. Because secondary succession takes place in already developed ecosystems with pre-existing soil and nutrients, it usually progresses much faster than primary succession, which has to start from scratch. Therefore, the significant characteristic that distinguishes primary succession from secondary succession is that primary succession initiates in barren environments without soil, while secondary succession occurs in disturbed environments that already have soil. This fundamental difference helps to explain the distinct processes and timelines associated with each type of ecological succession.