Students will describe how a system reaches equilibrium. Students will be able to describe primary and secondary succession. Objective:

Succession

Succession Vocabulary Pioneer species - a group of hardy organisms that begin the soil-building process. Climax Community - Stable, end stage of ecological succession in which organisms use resources efficiently and balance is maintained by disturbances such as fire. Succession - natural, gradual changes in the types of species that live in an area.

Primary Succession  When a volcano erupts and molten lava flows from the eruption, it replaces everything in its path with bare rock.  No soil is present at the beginning of primary succession.  Primary species such as lichen and mosses appear.  Overtime the weathering and decaying pioneer species create soil.

Secondary Succession  Starts with bare soil (dirt).  Seed sprout and grasses begin to grow.  In areas able to support shrubby and trees shrubs appear.  Trees are the last plants to appear in an area undergoing succession.  An area that has become stable is considered to be a climax community.

Primary Succession Pioneer species growing on the bare rock. Lichen

Secondary Succession Secondary succession has soil. Common after excavations and forest fires. Forest fire Excavation

Primary vs. Secondary Succession As you look at the following images, write down your observations on the table provided by your teacher.

Journal Entry: Describe primary and secondary succession.