Succession

1
Succession

• Equilibrium in Ecosystems

2
Changes by Fire

• Volcanoes create new land on which primary
  succession occurs

3
Changes by Fire

• Forest fires create the opportunity for secondary
  succession.

4
??Questions??

• What did the events do to the Earth?
• How did the events do this?
• What part of the Earth was affected?
• What differences were there between the two
  events other than one was caused by a volcano and
  the other by a fire?

5
What is Succession?

• Succession is the series of predictable changes
  that occur in a community over time.
• A community is all the different organisms that
  live together.
• A community in an ecosystem is in equilibrium, or
  a state of balance, when the numbers and species
  of organisms in it do not change suddenly.

6
What causes succession?

• Fires
• Floods

• Volcanoes
• Hurricanes

7
Types of Succession!!

• After a disaster, succession helps an ecosystem
  recover. There are two Main types of ecological
  succession
• Primary succession
• Secondary succession

8
Primary Succession

• Primary Succession- series of changes that occur
  in an area where no ecosystem previously existed.
  
• Example An area might be a new island formed by
  the eruption of an undersea volcano
• Example 2 An area of rock uncovered by a melting
  sheet of ice.
• The first species to populate the area are called
  Pioneer Species.
• Lichens and mosses carried by the wind or water

9
Primary succession - occurs on an area of newly
exposedrock, sand, or lava or any area that has
not been occupiedpreviously by a living (biotic)
community
Glaciers scrape the Earth as it moves. Some land
may have been buried under ice for thousands of
years. Rocks are carried along by the ice.
As the glacier melts, the rocks are left behind.
After about a year, lichens begin to grow on the
rock surface. Lichens slowly break the rock
down. Primary succession areas have no soil.
10
After the lichens create cracks in the rocks,
mosses begin to grow in the cracks. The moss
further breaks down the rock helping to form
soil. Both lichens and mosses are pioneer
species. Pioneer species create soil in primary
succession.
Soil is a thin layer that covers the land. Soil
goes down into the ground a short way. Soil is
more than rock particles. It includes all the
living things and the materials they make or
change.
Herbs and shrubs follow the lichens and mosses.
Then pine trees and aspens are next. The Climax
community are the birches and spruces.
11
Primary Succession

• Primary succession may lead to a community of
  organisms in equilibrium, which does not change
  drastically unless the ecosystem is disturbed.

12
Secondary Succession

• Secondary Succession- the series of changes that
  occur after a disturbance in an EXISTING
  ecosystem.
• Unlike primary succession, secondary succession
  occurs in a place where an ecosystem has
  previously existed.
• Secondary succession restores the ecosystem to a
  state in which equilibrium can be maintained.
• occurs somewhat more rapidly than primary
  succession.

13
Secondary succession - takes place where a
community hasbeen removed, e.g., in a plowed
field or a clear-cut forest
Pioneer Community
The pioneer community is made up of grasses.
Insects, small mammals and reptiles make their
home here. If the soil has been disturbed, weeds
are the first plants to grow. They secure the
soil.
Shrubs and bushes begin to grow. Other mammals,
such as rabbits and birds, join the developing
community.
A climax community of trees can support a wide
variety of larger mammals such as foxes and
badgers.
Climax Community
Weeds appear first, followed by grasses. The next
to appear are shrubs, then a pine forest. The
mature hardwood oak and hickory trees form the
climax community. This is the last stage of
succession. These are plants that can reproduce
successfully beneath their own shade and can
maintain the community indefinitely if conditions
dont change.
14
Secondary Succession

• Secondary Succession occurs when a disturbance
  occurs in an already existing ecosystem. A
  forest fire burns an ecosystem, then it goes
  through to secondary succession to restore the
  ecosystem.

15
(No Transcript)
16
(No Transcript)
17
Wrap Up!

• Succession occurs when a disaster occurs and
  disturbs the equilibrium of a community.
• There are two types of succession
• Primary Succession occurs where no previous
  ecosystem exists and establishes equilibrium.
• Secondary Succession occurs after a disturbance
  and restores equilibrium in an already existing
  ecosystem.

• Vocabulary
• Community
• Equilibrium
• Succession
• Primary Succession
• Pioneer Species
• Secondary Succession

18
SCHOOLYARD SUCCESSION

• Think about how our school campus looks today.
  Imagine that the school will be closed down
  permanently at the end of the day. The building
  will be bulldozed down and all the grass scraped
  off during removal of debris. Most of the soil
  remains. Create a timeline of the succession of
  the area. Assume that the area will remain
  undisturbed by humans.
• In your groups, create a timeline to describe the
  series of changes that restore equilibrium to an
  ecosystem.
• Begin with year 0 and labeL it LAND
  DISTURBANCE. Write a one or two sentence
  description of what the area looks like.
• Imagine you can revisit the area and document the
  changes. Record the year and write a one or two
  sentence description of what the area looks like
  each time you visit. BE SURE TO IDENTIFY THE TYPE
  OF PLANTS THAT ARE GROWING.
• The revisiting points are 1 YEAR, 15 YEARS, 85
  YEARS.
• Label the timeline with the type of succession
  that is occurring and the campus name. i.e.
• THE ______________ SUCCESSION OF _____________
  SCHOOL CAMPUS.