AP BIOLOGY

Detailed explanation-1: -Primary succession occurs when new land is formed or bare rock is exposed, providing a habitat that can be colonized for the first time. For example, primary succession may take place following the eruption of volcanoes, such as those on the Big Island of Hawaii. As lava flows into the ocean, new rock is formed.

Detailed explanation-2: -Secondary succession occurs when the starting point is bare soil that already exists. It is similar to primary succession, however, the pioneer species are often fast-growing plants and often come from pre-existing groups of organisms in the area.

Detailed explanation-3: -Primary succession begins with soil formation. The first stage of succession involves pioneer species. In primary succession, pioneer plants are those that can grow without soil, such as lichens. Lichens begin breaking down a rock.

Detailed explanation-4: -Succession on bare rock is called Xerosere. The lichens are the pioneer species and invade the bare rocks. They secrete acids which dissolve the rocks, help in their weathering and formation of soil. Mosses grow in with the lichens to form a mat over the substratum.

Detailed explanation-5: -Primary succession is ecological succession that begins in essentially lifeless areas, such as regions in which there is no soil or where the soil is incapable of sustaining life (because of recent lava flows, newly formed sand dunes, or rocks left from a retreating glacier).