Warm-up: Succession

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Warm-up Succession

• Read the Case Study,
• Communities Maintained by Fire
• on pages 130 131.
• Write two things you have learned and
• answer questions 1 2.

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Warm-up Answers

• 1. New things you have learned
• The purple plant Fireweed covers the burned
  
• forest areas of the Rocky Mountains.
• Ecological Communities (Biomes) that are
• maintained by fire are
• Chaparral of California, Temperate
  Grasslands of the Midwest, many Southern and
  Western Coniferous forests.
• Seeds of some species will not germinate
  until
• exposed to temperatures of several hundred
  degrees.

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Warm- Up Answers (contd)

• 1. A young longleaf pine is low to the ground,
  so it can survive fire that sweeps through the
  canopy.
• Deciduous trees may burn because
• they are not as low to the ground.

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Warm-up Answers (contd)

• 2. The tallgrass prairie, have evolved in an
  environment of frequent fires. In these
  communities, controlled fires can kill any
  competitors that try to move in to the ecosystem.
  
• Disadvantages to using fire
• Risk to human property
• Chance that competitive species may not be
  destroyed.

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Changes in EcosystemsEcological Succession
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What is 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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Primary Succession

• Primary succession occurs where there was no
  previous community, such as on bare rock or sand.
• Begins in a place without any soil
• Sides of volcanoes
• Landslides
• Flooding
• Glacial retreat

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• Primary succession begins with
• PIONEER SPECIES.
• Pioneer organisms can tolerate extreme
  conditions hot and cold dry and wet.
• Moss, dune grass, and lichens are pioneer
  organisms.
• First, lichens that do not need soil to survive
  grow on rocks
• Next, mosses grow to hold newly made soil

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Pioneer Species
Low, growing moss plants trap moisture and
prevent soil erosion
Lichens break down rock to form soil.
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Lichens

• Lichens are algae and fungus growing together in
  a mutualistic relationship.
• Algae make the food
• Fungus anchor and capture water.

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Primary Succession

• Soil starts to form as lichens and the forces of
  weather and erosion help break down rocks into
  smaller pieces
• When lichens die, they decompose, adding small
  amounts of organic matter to the rock to make
  soil

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Primary Succession with lichens and mosses.
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Primary Succession

• Simple plants like ferns and mosses can grow in
  the new soil

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Primary Succession

• The simple plants die, adding more organic
  material (nutrients to the soil)
• The soil layer thickens, and grasses,
  wildflowers, and other plants begin to take over

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Primary Succession

• These plants die, and they add more nutrients to
  the soil.
• Shrubs and trees can survive now.

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Primary Succession

• Insects, small birds, and mammals have begun to
  move into the area.
• What was once bare rock, now supports a variety
  of life.

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• Warm-up Primary succession
• Explain some of the adaptations of plants,
  especially in Californias Chapparal Biome.

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Ceanothus americanus (pictured below) has leaves
covered with flammable resins that help fuel a
fire. This adaptation benefits the species
because ceanothus seeds require intense heat for
germination. Fire-resistant roots also enable
the plant to resprout quickly in recently burned
areas.
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Knobcone pine (pictured below) have seed cones
that require the heat of a fire to open. The
seeds are protected from fire behind tightly
closed resin-coated scales, often so well
insulated that even when the outer part of the
cone is charred, the seeds inside are protected.
High temperatures cause the cone to open,
releasing the seeds that fall to the ground into
a cool bed of ash and mineral soil.
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Secondary Succession

• 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

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Secondary Succession

• Newer communities make it harder for the older
  communities to survive.
• Example Younger birch trees will have a harder
  time competing with taller, older birch trees for
  sun, but a shade loving tree may replace the
  smaller birch trees.

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When does secondary succession occur?

• After forest fires
• After cultivated land is abandoned
• Temporary flooding from storms, etc.

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Climax Community

• A relatively stable group of plants and animals
  that is the end result of the succession process
• However, stability never happens for long in
  ecology! The only constant is CHANGE!
• Does not always mean big trees
• Grasses in prairies
• Cacti in deserts

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• The following slide is an example of the
  Secondary Succession of a deep freshwater pond.

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Crash Course video, Succession (1002)
http//www.youtube.com/watch?vjZKIHe2LDP8
Bozeman, Ecological Succession (621)
http//www.youtube.com/watch?vV49IovRSJDs
Succession Song, Mr. Parr (358)
http//www.youtube.com/watch?vrzE6BNNLew0
Animation with bird, Succession (622)
http//www.youtube.com/watch?vk03vxRYsJ4Y