DENDROLOGY

Detailed explanation-1: -Primary succession always starts with a pioneer species. This is the species that first lives in the habitat. If life is to begin on barren rock, which is typical of new land, the pioneer species would be an organism such as a lichen (Figure below (Links to an external site.)

Detailed explanation-2: -The earliest life forms we know of were microscopic organisms (microbes) that left signals of their presence in rocks about 3.7 billion years old. The signals consisted of a type of carbon molecule that is produced by living things.

Detailed explanation-3: -Primary succession occurs in essentially lifeless areas-regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier.