TEKS 7.12D observe and describe the role of ecological succession in ecosystems

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.

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.

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.

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

Misconception Fires are bad.

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.

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.

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

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.

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.

Secondary succession begins with organic material in the soil.

Engage Show a video clip of a forest fire such as the one found at &q=forest+fire&hl=e n &q=forest+fire&hl=e n 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.

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 don’t want to lead students to believe that this is the only way to begin succession.

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. /index.html /index.html

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)

Explain The Heathland Project site at the Woodland Education CentreHeathland Project Woodland Education Centre /second.htmhttp:// /second.htm

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.

1998

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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.

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.