Download Succession study guide

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The change of an ecosystem over a period of
time. This includes Primary and secondary
succession
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We would not have ecosystems without them
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Primary and secondary

Primary succession is the
series of changes that occur in
an area where no soil or
organisms exist. It takes an
average of 2000 years for the
ecosystem to become a climax
community.

Secondary succession is the
changes that occur after a
disturbance in an existing
ecosystem. It takes on average
of 200 years for an ecosystem
to become a climax
community.

Primary succession occurs after
a newly formed volcanic island is
formed. It can also occur after
ancient ice sheets or glaciers
melt, leaving bare rock exposed.
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Fire
Flood
Earthquake
Hurricane
Mudslide
War
Mining
Logging
Development
Pollution
Farming

Primary succession takes
longer because there is no
existing soil. Soil takes a long
time to develop.

Pioneer species are the first
organisms to populate an area
where primary succession
occurs.

Mosses, Ferns, and lichens are
examples of pioneer species.

Large trees, such as oak, birch and maple trees.
Larger animals are also some of the last
organisms to inhabit an area.

A Climax Community is the name for a
mature, stable ecosystem. Change is very slow,
and nothing major will happen unless a natural
disturbance occurs.

Primary succession occurs in an
area where there is no soil or
organisms. Secondary
succession occurs in an area
where an existing ecosystem has
been disturbed.

A disturbance is when an
ecosystem is changed
drastically so the organisms
that lived either die or
emigrate.

Soil is formed when pioneer species
break down rock. The moss and
lichen then die and their decomposed
remains enrich the soil.

Seeds can be dispersed by
 Blowing in the wind
 Movement by water
 Animal assisted

Shrubs and small trees are the
first to grow in an abandoned
field, HOWEVER… after a fire
grasses and weeds are the
first to grow.

Mt. St. Helen’s erupted in 1980.
It killed 57 people and
destroyed the ecosystem in a
50 kilometer radius. Life came
back to the area within 3 years
of the disaster.

There are 4.5 deer for every square mile within
the forest

There are about .63 students for every square
foot within the classroom

There are about 3913 birds for every square
mile

There are about 23 dinosaurs for every square
mile

There are about 11.3 ants per square foot

There are about 42 people for every square
mile.

The mouse population may increase since they
won’t have to compete with the sparrows for
food.

The grass population would probably increase,
but everything else may decrease.

The hognose and Garter Snake populations
would increase, since they have no predators.

The hawk population would probably
decrease, since the food source has decreased.