AP BIOLOGY

Detailed explanation-1: -Complete answer: Lichens are the first organisms to colonize bare rock. They are, therefore, called the pioneer species in primary succession .

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: -The first organisms appearing in the regions of primary succession are pioneer species (usually lichens or mosses). They are the first species present. They must be strong and hardy. The development of a new community is succession.

Detailed explanation-4: -The first species to colonize an ecosystem are called pioneer species.

Detailed explanation-5: -The first species to colonize a disturbed area such as this are called pioneer species (see the Figure below). They change the environment and pave the way for other species to come into the area. Pioneer species are likely to include bacteria, lichens, and mosses that can live on bare rock.