Changes in Ecosystems: . Ecological Succession

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Changes in Ecosystems.Ecological Succession
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• Do all ecosystems stay the same all the time?
• What are some things that cause changes to
  ecosystems?
• Natural and unnatural (Quickly and slowly)

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Ecological succession

• Natural, gradual changes in the types of species
  that live in an area can be primary or secondary
  
• The gradual replacement of one plant community by
  another through natural processes over time

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Ecological succession

• Series of predictable changes that occur in a
  community over time. Caused by
• Physical environment
• Natural disturbance
• Human disturbance

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Primary Succession

• Begins in a place without any soil
• Sides of volcanoes
• Landslides
• Glacier melting
• Starts with the arrival of living things such as
  lichens that do not need soil to survive, called
  PIONEER SPECIES.

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Pioneer species

• Lichens

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http//www.life.uiuc.edu
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Primary Succession
http//www.uncw.edu
http//uisstc.georgetown.edu
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• Reaching a mature community can take CENTURIES.

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Secondary Succession

• Begins in an area where the ecosystem has been
  disturbed, but where soil and organisms still
  exist.
• Occurs faster and has different pioneer species
  than primary succession

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• Succession following a disturbance that destroys
  a community without destroying the soil
• Fires - Forest clearing Natural Human
  disturbance
• Hurricane - Farming

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Secondary succession

• Unlike primary succession, secondary succession
  occurs in a place where and ecosystem currently
  exists.
• And occurs more rapidly than primary succession.

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http//www.geo.arizona.edu
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http//www.ux1.eiu.edu
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Climax Community

• A stable group of plants and animals that is the
  end result of the succession process
• Does not always mean big trees
• Grasses in prairies
• Cacti in deserts

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Think-Pair-ShareShoulder Partners

• PAGE 408-410

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References

• http//www.slideshare.net/radhakrishnan1962/ecolog
  ical-succession-1
• Science explorer Prentice Hall. Environmental
  Science

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Succession in Marine Ecosystems

• Deep and dark
• Can succession happen?
• 1987 dead whale off of California
• Unique community of organisms living in remains
• Represents stage in succession in an otherwise
  stable, deep-sea ecosystem
• Whale-fall community

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Whale-Fall Succession

• Begins when large whale dies
• Sinks to barren ocean floor
• Scavengers and decomposers flock to carcass , our
  first community
• Amphipods
• Hagfish
• sharks
• After a year, most tissues have been eaten
• Now, second small community of organisms live
  here
• Body is decomposing, releasing nutrients into the
  water
• Small fishes
• Crabs
• Snails
• worms
• Only skeleton remains
• Third community moves in
• Heterotrophic bacteria
• Decompose oil in bones? release of chemical
  compounds
• Who uses these chemical compounds?
• Chemoosynthetic autotrophs