Download Ecological Succession

Ecological Succession
Biology Georgia Performance Standard
SB4c. Relate environmental conditions to successional changes in the ecosystem.
What is succession? What are the two types?
(After viewing the video clip, individually answer this question)
Primary Succession
Starts from bare rock, NO soil is present.
Occurs in areas that have not previously been occupied by plants. Disasters such as volcanic eruptions, or an event
like a nuclear power plant disaster causing a city to be abandoned can lead to primary succession.
Basics Steps of Primary Succession
After a geologic event, bare rock is exposed to the environment.
Pioneer species, such as lichens, are the first to inhabit the area. Lichens give off acid which
degrades the rock into soil.
Next mosses come in and as it dies and decays nutrients are added to the soil.
As rock continues to break down, soil thickens. Weeds and grass will start to grow. More
nutrients are added.
When the soil is thick enough, bushes and small trees will start to grow.
Basic Steps of Primary Succession (cont.)
Pine trees are the first tree to grow.
When the soil become rich enough, deciduous trees start to grow. As they shed their
leaves each year, the leaves degrade and add more nutrients to the soil.
Eventually a mature temperate deciduous forest forms. This is known as Climax forest.
(Picture to left is a climax forest).
Secondary Succession
Secondary Succession occurs in areas where soil is left behind.
These areas might have been damaged by natural disasters such as
floods, fires, and hurricanes. In these cases, organic matter and soil
are already present. Abandoned farmland will also go through
Secondary succession.
Because soil is already present in a damaged area (i.e., after fires, etc.) weeds will be the first to start growing here.
Grasses will follow, and then shrubs and trees will begin to grow.
The trees that grow the fastest and tallest will be the most successful. Eventually a climax forest will re-develop in
the area.
Lesson Summary: Compare and contrast primary and secondary succession. Think of how they start, events that
cause them to start, and the steps they each go through.