Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?
- Before students complete the writing assignment for the summative assessment, review the responses to the text-dependent questions completed earlier by the students. Make sure the misconceptions are corrected and the key points (as found in the sample answer key) are discussed.
- After students' written responses have been graded and returned with feedback, teachers might wish to use the sample response, provided at the end of the text-dependent questions, with the class. Students who are struggling writers can benefit greatly from seeing a well-organized, detailed written response. The teacher can show the sample response on an overhead or with anLCD projector and discuss some of the following:
- How the topic is introduced in the opening sentences of the introductory paragraph; have students identify the main point of the piece. Brainstorm with students other ways the writer could have opened the piece.
- Have students examine each of the body paragraphs and explain how each supports the main point of the piece.
- Have students identify where the writer effectively uses textual evidence from the article for support of his or her points.
- Have students identify the use of transition words or phrases that make the ideas flow.
- Ask students to identify where domain-specific vocabulary is used accurately and effectively.
- Have students read the final paragraph to see how the writer wrapped up the piece and connected back to the main point established in the introduction.
Have students read the following article from the Smithsonian: ."
Using knowledge gained from the lesson and the information found in the Smithsonian article, have students respond to the following question: "What findings from this study have scientists concerned about the forest ecosystems of Chernobyl?"
Sample answer: It has been over thirty years since the Chernobyl nuclear plant exploded, yet the impact on the environment is still being felt by the organisms living there. It comes as no surprise to scientists that plants and animals still have signs of radiation poisoning. Around the epicenter of the blast, birds have been discovered with smaller brains, there are fewer trees, and there are fewer insects than you would expect to see in a stable ecosystem. However, what has taken scientists by surprise is the effect the explosion has had on the decomposers in the area.
An essential element in every ecosystem is the process of decomposition. Normally organisms such as bacteria, fungus, and insects are involved in the breaking down of decaying matter and returning the nutrients back to the soil. As scientists began observing the ecosystem within the blast area, they realized there was a lot of leaf litter and trees that had fallen, but had not begun the process of decay.
To determine exactly what was occurring with the decomposition process, a team decided to run field tests to record the amount of time it took for leaves to decay. They stuffed over 600 mesh bags with either oak, maple, birch, or pine leaves, making sure there were no insects in the bags. They lined some of the bags with panty-hose as well to prevent insects from getting into the leaves over the course of the experiment. The scientists scattered the bags across various sites that had experienced different amounts of radiation. The bags were left out for approximately a year to study the process that normally should have occurred: the breakdown of the organic matter.
The results showed that in areas where no radiation was present, most of the material had broken down. In areas where there was radiation, a majority of the organic material remained. Both insects and the bacteria and fungus played a large role in the decay process, but it was determined that fungi and bacteria were most important for breaking down the leaf litter on the top of the soil. The role of decay is an essential part of a stable ecosystem. As organisms die, the nutrients need to be returned to the soil for the plants in the area. If the plants are not receiving the nutrients they need, other components of the ecosystem will be affected also. As long as the decomposers are affected by the radiation, the areas surrounding Chernobyl will have a difficult recovery.