Describe the stages of succession on bare rocks

Step One

Bare rock, no organisms - Glacier leaves behind bare rock; Volcano produces 
 bare rock with no organisms.

Step Two

Pioneer species begins breaking down rock. Pioneer species: 1st organism to live in an area. Pioneer species, usually lichens, grows on rock. Lichens secrete acids that begin breaking rock into small particles, which mix with lichen remains to begin making soil.

Step Three

More complex plants, usually mosses, begin growing when soil is deep enough, after many years; eventually replace (succeed) lichens. 
 Tiny organisms such as insects move in, add their remains to soil.

Step Four

Larger, more complex plants: As soil gets thicker ferns succeed mosses.
 Grasses and wildflowers may succeed ferns. 
 When enough soil has developed, shrubs and small trees move into the area.

Step Five

Forests: Soil may be deep enough after hundreds or thousands of years for
 pine or hardwood forests.

hope this helps