Transcript Slide 1

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!
- 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.
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.
4. 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.
5.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.