 Orderly, natural changes and species replacements that take place in the communities of an ecosystem.  Follows a predictable, orderly pattern. (Think about your bedroom…)  Two types: Primary and Secondary

 Step 1 - Bare rock (0-1 years) Lichens grow on the bare rock. As they die, the decaying lichens form soil so moss can grow.

 Step 2 - Grassland (2-4 years) Grasses and other small plants grow, out-competing the mosses for sunlight.

 Step 3 - Transitional or shrub (5-20 years) Small shrubs such as dogwood and sumac begin to dominate.

 Step 4 - Coniferous Forest ( years) Pines and fir trees begin to shade out the smaller shrubs

Pine forest

 Step 5 - Deciduous Forest ( years) Large, slow-growing trees such as oak, maple and hickory replace the pines.

 Succession that occurs after a community is disrupted by natural disasters or human activity. Examples = fire, flood… *Occurs in a shorter amount of time because soil and sometimes seeds present.

Jack Pines (boreal forests – Canada/Russia)

Now Yellowstone National Park (after a 1988 forest fire)

 Step 1: Bare rock – lichen – moss – soil making  Step 2: Grasslands  Step 3: Shrubbery/Transitional  Step 4: Coniferous trees  Step 5: Deciduous trees Why do you think some forests remain coniferous and do not transition to deciduous?

 Where does primary succession happen? Totally new bare rock.  When does secondary succession begin? After a fire/flood/landslide/natural disaster.  So, what step is not necessary for secondary succession that is a part of primary succession? Step 1: Creating soil