Primary Ecological Succession Occurs where there is no pre-existing vegetation and often no soil in an area. Example = island formed by lava, area left by the retreat of a glacier. Gradual growth of an ecosystem for the first time over a long period of time.

Primary Ecological Succession Example = Melted Glacier Example = animation of lava flow

Secondary Ecological Succession *A process of gradual change that occurs following the destruction of an existing ecosystem to restore an area to it normal state. *Destruction could be: Fire, flood, plowing, deforestation, construction, tsunami, hurricane, etc.

*During the process, communities are replaced by other communities until the Climax Community is reached = the final stable community of organisms with no significant change. -The climax community is dependant on the BIOME of the area where the succession is occurring!

-Very slow process, may take decades to return to a normal state. - As the producer communities change, so do the consumers. -Very slow process, may take decades to return to a normal state. - The climax community is stable, yet changing slightly.

Mt. St. Helen’s 1980

Example = A plowed field in York County, PA. 1. Destruction = plowing. Pioneer organisms (first organisms to occupy a recently disturbed area ex. Lichens, algae) move in and briefly become established in the area.

2. Pioneer organisms are replaced by grasses and weeds. Example = A plowed field in York County, PA. 2. Pioneer organisms are replaced by grasses and weeds. Intermediate species

Example = A plowed field in York County, PA. 3. Small shrubs grow along with other grasses and weeds = more producers = more consumers move into the community. Intermediate species

Example = A plowed field in York County, PA. Saplings (young trees) grow (=Scrub forest) = less grasses and weeds due to shading = different consumers are attracted to the area. Intermediate species

Example = A plowed field in York County, PA. Forest matures = more canopy = less light to forest floor = different consumers. The climax community has been reached, which, for this example, is a deciduous forest. This community will remain relatively stable until another destructive event occurs.