TEKS 7'12D

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TEKS 7.12D

• observe and describe the role of ecological
  succession in ecosystems

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Overview

• Ecosystems are constantly changed. Different
  organisms are adapted to certain conditions.
  After an event that can change the ecology of an
  area, the flora and fauna also changes. Students
  will look at what happens after several such
  changing events such as a fire or glacier
  movement.

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Misconception

• As plants grow back after a disturbance, the same
  plants that were there previously grow back.
  They are just shorter because they are growing
  back.

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Science Concept

• Certain types of plants and animals are better
  adapted to grow in certain environments. There is
  a natural succession of life that grows back
  after a disaster.

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Rebuild

• Allow students to explore the online field trip
  about the natural succession in a national park.
  
• And/or view Yellowstone Aflame

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Misconception

• Fires are bad.

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Science Concept

• Fires are natural occurrences and are necessary
  for maintaining a balance and clearing out plant
  debris. When fires can become bad is when humans
  prevent fires for long periods of time, allowing
  debris to build up. The debris acts as fuel to
  intensify the fire. If the fire gets to big,
  then we see the major fires that we have become
  accustomed to hearing about in the news.

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Rebuild

• Allow students to explore some of the positive
  impacts fires have.
• The virtual field trip does a great job of
  reinforcing that fires are neither good nor bad,
  just a part of the natural cycle of things.

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Prior Knowledge

• While the idea of succession is a new one to
  students, the following TEKS should be covered in
  the 7th grade prior to lessons on ecological
  succession. Background on ecosystems is
  imperative to understanding succession.
• 7.12) Scientific Concepts. The student knows that
  there is a relationship between organisms and the
  environment. The student is expected to
• identify components of an ecosystem
• observe and describe how organisms including
  producers, consumers, and decomposers live
  together in an environment and use existing
  resources
• describe how different environments support
  different varieties of organisms

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Teacher Background

• Succession is the process by which communities
  are established.
• The end result is a climax community. A climax
  community is the combination of flora and fauna
  that use the land and its resources most
  effectively.

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• There are 2 types of ecological succession
  primary and secondary.
• Primary Succession occurs on inorganic material
  such as rock. The start of primary succession can
  occur with events such as a volcanic eruption,
  rock exposed by retreating glaciers.
• In order for suitable soil to be made, primary
  succession must begin with a pioneer species, or
  soil forming species. One common such species is
  the lichen.

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• Secondary succession begins with organic material
  in the soil.

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Engage

• Show a video clip of a forest fire such as the
  one found at http//video.google.com/videoplay?doc
  id9039257627990588050qforestfirehlen
• Have student make a T-chart in their notebook or
  journal. On one side have them list possible
  causes of the forest fire. On the other side
  have students brainstorm effects of a forest fire.

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• Alternative to a fire video would be a volcano or
  earthquake.
• One reason for this is that we will be using a
  fire a lot as the catalyst for starting
  succession. We dont want to lead students to
  believe that this is the only way to begin
  succession.

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Explore

• Virtual Field Trip If you have access to a
  computer lab, students can go through the field
  trip at their own speed. If not, the field trip
  can be taken as a class with a projector.
• The field trip is located through the Yellowstone
  National Park website. http//www.windowsintowonde
  rland.org/fire/index.html

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Explore alternative/addition

• View last two chapters of Yellowstone Aflame DVD
  (Firestorm and Aftermath)
• Firestorm shows more of the actual fire and what
  firefighters went through in fighting it. The
  images are amazing and students will likely get
  into it. (approx 5 min)
• Aftermath is more of the succession aspect of
  what happened after the fire. (approx 3 min)

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Explain

• The Heathland Project site at the Woodland
  Education Centre
• http//www.countrysideinfo.co.uk/successn/second.h
  tm

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1993

• In 1993 the land here was cleared purposefully
  and then treated with Roundup to clear the site
  of all plants. The purpose was to observe the
  natural succession.

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1998
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2002
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2004
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Elaborate

• Students will make a film strip of what might
  happen to an area after an ecological changing
  event. Each frame will show the changes that are
  made over time. Students will note pioneer
  species and a climax community. See Black-Line
  masters.

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Evaluate

• Have students make a timeline of at least 4 steps
  leading up to a climax community.
• Timelines should be illustrated with 2 sentences
  about what is going on in their pictures.