AP BIOLOGY

Detailed explanation-1: -The first organisms appearing in the regions of primary succession are pioneer species (usually lichens or mosses). They are the first species present.

Detailed explanation-2: -The first organisms to appear in areas of primary succession are often mosses or lichens. These organisms are known as pioneer species because they are the first species present; pioneer species must be hardy and strong, just like human pioneers.

Detailed explanation-3: -Primary succession begins with the appearance of pioneer species – lichen, mosses, and fungi – all organisms that can grow on rocks and exposed land. These are small, simple organisms that can survive harsh conditions, fix inorganic carbon and nitrogen into usable nutrients and accelerate the process of weathering.

Detailed explanation-4: -Lichens are considered as pioneer species in primary succession on rocks because they can easily grow on rocks where other plants cannot grow. They produce oxalic acid which induced the weathering of rocks and thus soil is formed.

Detailed explanation-5: -2 Most primary succession begins with lichens. Acids from the lichens begin breaking the rocks into small particles. These particles mix with the remains of dead lichens to start forming soil. Because lichens are the first organisms to live on the rock, they are called pioneer species.