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What is Ecological Succession?
Changes in Ecosystems:
Ecological Succession
Primary Succession
• Begins in a place without any soil:
• Natural, gradual changes in the types
of species that live in an area
• Can be primary or secondary
Pioneer Species
» Sides of volcanoes
» Landslides
» Flooding
• First, lichens that do not need soil to
survive grow on rocks
• Next, mosses (nonvascular plant---does
not have xylem or phloem) grow to hold
newly made soil and are known as a
PIONEER SPECIES
(1st to inhabit an area)
Lichens break down rock to
form soil.
Low, growing moss
plants trap moisture
and prevent soil
erosion
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Primary Succession Steps
Secondary Succession
1.  Simple plants (ex: mosses and ferns) grow
in the new soil
2.  Simple plants die (adding more nutrients to
the soil) thickening the soil and other
plants begin to grow
3.  Process repeats; shrubs and trees survive
4.  Insects, small birds, mammals, etc move
into an area and now can support a variety
of life
• Begins in a place that already has
soil and was once the home of
living organisms
• Occurs faster and has different
pioneer species than primary
succession
• Example: after forest fires
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Ecological Succession Recap
2 types of ecological succession:
Primary Succession
(no soil; ex: volcano lava flow with a
pioneer species; longer process)
Secondary Succession
(existing soil; disturbance;
faster process)
Ecological Succession
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