Beacon Lesson Plan Library

The Mysteries of Twins

Melinda Dukes
Washington County Schools


How can twins help us uncover important information about hereditary? Students are taught how to read science content through the modeling of proper summarization techniques using the article, "Mysteries of Twins." Then, they practice the same reading techniques using another section of the same article.


The student uses background knowledge of the subject and text structure knowledge to make complex predictions of content, purpose, and organization of the reading selection.

The student uses strategies to clarify meaning, such as rereading, note taking, summarizing, outlining, and writing a grade level-appropriate report.

The student knows ways organisms are adapted to their environment.


This is lesson two of three for the unit, Twin Traits

Day 5
-Student journals
-“Mysteries of Twins” series by Arthur Allen (see Weblinks) one copy per student
-Transparency of “Mysteries of Twins”
-Extra transparencies and suitable markers
-Journal Entries handout (Optional-See Extensions)
-Exit Slips (Optional-See Extensions)

Day 6
-Student journals
-“Mysteries of Twins” series by Arthur Allen (see Weblinks) one copy per student
-Chart paper and markers one per group of students
-Journal Entries handout (Optional-See Extensions)
-Exit Slips (Optional-See Extensions)

**If integrating this unit with the language arts unit, Jacob Have I Loved, then the materials needed are as follows:
-Daily Integration Ideas (See Extensions)
-Chart Paper and appropriate markers
-Masking tape


This is lesson two of three for the unit, Twin Traits

Day 5
1. Obtain a classroom set of an article like “Mysteries of Twins” series by Arthur Allen. (See Weblinks) If you cannot obtain classroom sets of this article, find articles that deal with the subject matter at hand- DNA, nature/nurture, twins, etc. Article ideas include
***[Discover Magazine]. November 2003. "You Are What Your Mother Ate."
***[Discover Magazine]. July 2003. Entire magazine filled with genetic testing information, new tests for newborns, and DNA sequencing for discovering inherited diseases.
***[Time Magazine]. June 2, 2003. "What Makes You Who You Are?"

NOTE: you will need four sections of whatever article you choose to use. One portion will be for teaching instruction and student practice, while the other three sections will be for students.

2. Create a transparency of the first page of the article you choose to use, plus have on hand additional blanks for use with the summarizing activity.

3. Familiarize yourself with the reading strategies, summarizing, think-aloud, and semantic map techniques used on this day. Even though you may feel that your students can read the information on their own, take this opportunity to review "reading to learn" with your students. The review will help them understand the content better and more effectively. Use the reading strategies links found in Weblinks.

4. Decide which review activities you will use with students. See Extensions and Weblinks for additional information.

5. Read the article, "Mysteries of Twins." Practice the techniques listed in the Procedures for this day. (Or use the article of your choice.)

(This lesson assumes that "Mysteries of Twins" is the article that will be used. If using another article, use the same concepts outlined in the lesson.

6. Consider using exit slips as another opportunity to formatively assess students. Exit Slips available from the unit's attached files. (See Extensions.)

7. Download and determine how (or if) you will use the Journal Entries handout.

Day 6
1. Since a portion of the article will be used to model reading strategies with students, have on hand the remainder of the article for use with students.

2. Collect chart paper and markers. There should be enough for each group of students. Numbers will vary according to class size. If using non-stick chart paper, also have on hand masking tape.

**If integrating this unit with the unit, Jacob Have I Loved, then read and use the Daily Integration Ideas (See Extensions)

3. Consider using exit slips as another opportunity to formatively assess students. Exit slips are available from the unit's attached files. (See Extensions.)

4. Download and determine how (or if) you will use the Journal Entries handout.


This is lesson two of three for the unit, Twin Traits

**A note about reading strategies.
The science vocabulary and content contained within this unit are probably being presented to students for the first time. Reading selections, such as magazines and text books, are probably written at a higher reading level than 8th grade. In order to assist students, reading strategies are being taught in conjunction with the science content.

**Remember that this lesson assumes the teacher has been able to procure copies of the Arthur Allen article. If unable to obtain enough copies, use another article that deals with the same subject matter and use the same process but different content.

Day 5

1. Review the standards that you have been covering the past few days. Use the ideas listed in Extensions or Weblinks to make the review entertaining AND educational.
**Discuss as a class how dominant and recessive traits are inherited and that variations within a species are the result of genetic information or DNA being passed from parent to offspring.

**Ask the students to think again about the essential question, “Which is a more important factor in how your personality develops – nature or nurture?” Have them write their current thoughts in their journals, and discuss any changes that may have occurred from their original ideas.

2. Tell students that they are going to read an article about “real life” nature versus nurture situations. Explain that as they read the article you want them to consider their current views on nature versus nurture and question whether or not they need to make changes in their views.

3. Explain to students that you are going to read the article together. Explain that they are going to use strategies before they read. These are called prereading strategies. They will also be using strategies while they read (during) and after they read (post). All of these strategies will improve their comprehension of the text. (For more information on pre, during, and post reading strategies, see the Just Read Now link in Weblinks.)

4. Then they will read other articles in groups and on their own using the same methods for summarizing that you are going to model. Explain that these articles will help them understand the nurture or environmental side of heredity. Have students open up their packet to the first section of the article in the “Mysteries of Twins” series by Arthur Allen (see Weblinks).

5. Ask students if they know any prereading strategies, during reading strategies, and post reading strategies. Categorize as you list them on the board.

6. Then, post the transparency of the first page of the article and begin prereading the article by reviewing the structural aids such as titles, bold-faced headings, vocabulary, and illustrations. Remind students to notice transition words or phrases that indicate main points. Make a note of key vocabulary, repetition of ideas, and clueing phrases for main ideas. As students are participating in this activity, make it clear that they are using a prereading strategy. (Explanation of summarizing can be found in Weblinks along with other pre, during, and post reading strategies.)

7. Model for students the reading process by making predictions about what you think you will learn from the selection. Encourage students to add predictions of their own. Point out that this is also a prereading strategy. Add it to the board if it is not already there.

8. Read the a short piece of the selection out loud to the students and describe your own thinking processes (For the think aloud procedures see Weblinks) for sorting through main ideas and details. Reread and then take notes on the board, including key words from topic sentences that express main points of each paragraph. Explain that they are now using a during reading strategy.

9. From the notes, organize the ideas. Allow the students to work with you as you model the process. You might cluster ideas that seem to go together or organize your ideas into a semantic map (see Weblinks). Tell students that they are now using postreading strategies.

10. Then write your summary as the students observe your process. As you write, cross out any information that does not seem important. Be sure to verbalize your thoughts. The choices we make as we decide what to exclude are as important as the choices we make about what to retain. Emphasize that the summarizing process is a postreading strategy.

11. Now explain that students will work on using the reading strategies on their own. Divide students into cooperative groups. Have students read through the same portion of the “Mysteries of Twins” article first, underlining main ideas and details.

12. Then, on a separate sheet of paper, have students take notes to use for developing their summaries.

13. Have them convert their notes to a summary. Ask them to reread their summaries and cross out any unnecessary words or ideas. Have groups exchange summaries and evaluate.

14. Once students have practiced as a whole class and as cooperative groups, have them develop their own summaries independently in their journals. This summary will serve as a formative assessment. Assess the students’ ability to accurately and concisely retell the main idea of the articles and their knowledge of how nature effects development. If the affects of nature on human development are not apparent in the paragraph, you will need to ask students questions to determine their understanding of the standard.

15. Have students look back at their views of nature versus nurture in their journals and make any changes in opinion they may have made through reading the article.

16. (Optional: Exit slips are available from the unit's attached files. See Extensions.)

Day 6

1. Once again have students review their nature versus nurture views as well as all concepts to date. Remember to use another strategy than Q and A to add interest. As a class, discuss changes that were made in individual views from reading the article yesterday.

2. Briefly review the steps to summarizing that you presented the day before.

3. Remind students of the pre-, during, and post- reading strategies that they used the day before. On the board, create three columns labeled pre, during, and post reading strategies. Ask students to list different pre, during and post strategies, using the ones they learned yesterday and others they may already know about.

4. Divide students into pairs or cooperative groups of about four students. Assign each group one of the other three sections of the article. (There will be some groups reading the same article.) Explain that they will follow the procedures for summarizing as they read their article. Let them know that they will be sharing their summary with the rest of the class upon completion. (Note: Do not expect students to become totally independent immediately. Summarizing is always dependent upon the difficulty of the material. If the material contains unfamiliar content or is poorly written, you will need to continue to work together. With well-written and familiar material, some students can begin developing summaries independently.)

4. As students work with their groups to read and summarize the articles, walk around providing coaching with the reading strategy as needed. This is also a good opportunity to formatively assess students’ understanding of the reading strategy. You are looking for their abilities to identify the main idea and details and use them to write an effective summary paragraph.

5. When all groups have completed their assignment, allow groups that read the same article to join each other and compare summaries. They may make revisions to their summaries if they feel it is necessary.

6. Have each group write their final summary on a large sheet of paper to post on the wall.

7. Have each group present their summary to the class. The rest of the class may have questions for each group after they present.

8. Before beginning the next day's lesson, use review techniques appropriate for your students to check for understanding. Students should be gaining an understanding of the following-
*Dominant and recessive genes and how are they inherited
*Variations in a species due to genetic information being passed from parent to offspring and that interactions occur in the process
*Ways organisms are adapted to their environment
*How to use background knowledge, text structure to make complex predictions of content, purpose, and organization of the reading selection
*Use strategies to clarify meaning (rereading, summarizing, etc.)

9. (Optional: Exit slips are available from the unit's attached files. See Extensions.)


Formative assessment is ongoing each day. Within each day’s procedural steps, formative assessment criteria is included. Please see procedures for more information.


1. This unit integrates with the Beacon units, Jacob Have I Loved and Announcing World War II. Jacob Have I Loved is a language arts unit in which Sara Louise, a twin, struggles with the differences between her and her twin sister, Caroline. Is it nature or nurture that has made them the way they are?

Additionally, another unit, Announcing World War II, was written to help students understand the time period of the novel. If they can understand the world around the characters, then they will gain further insight into the character's minds. Students hear radio broadcasts from the time period and create their own.

Integrated units provide multiple opportunities for students to gain insight into complex issues. By researching the nature vs nurture controversy, students gain a deeper understanding of the science content and of the characters in the novel. Consider teaching this unit in conjunction with your history and language arts counterparts. You will see increased interest on behalf of your students as they make connections among all three subjects.

2. The Beacon Unit Plan associated with this lesson can be viewed by clicking on the link located at the top of this page. Once you select the unit’s link, scroll to the bottom of the unit plan page to find the section, Associated Files. This section contains links to the Unit Plan Overview, Diagnostic and Summative Assessments, and other associated files (if any).

3. A word wall may be beneficial in helping students remember complex vocabulary. Create vocabulary word posters by writing the vocabulary down on construction paper and posting on blank wall space. Posters will act as visual cues which may aid student understanding.

4. Instead of the usual Q and A, try different review techniques. Play games like Jeopardy or Who Wants To Be a Millionaire? Use ideas like the ones listed in the Weblink section. Also, puzzlemakers or worksheet generators could be used as discussion starters for the daily review.

5. ESE students may need additional assistance. Hard copies of the instructional steps, additional organizational handouts, guiding questions, key terms and using additional visuals may be necessary. Respond to the needs of your students accordingly.

6. Your science textbook may be an excellent source for content. It is not suggested that the science textbook be used for the reading activity, however, it is a good resource to use as a supplemental material. Additionally, this may be a good resource to use to review the reading strategies with students.

Other Resources:

Bill Nye, [The Science Guy-Genes]. Disney. 1997. Product ID= 68C75Nl00.
[ScienceSaurus]. Great Source Education Group. 2002. Book number- 0-669-48191-2

7. If you or your students need additional help with reading strategies, Beacon Learning Center has three reading strategy courses that may be useful. Pre-, During-, and Post Reading Strategies can be found at the Reading Strategies link in Weblinks.

8. It may be useful to incorporate instruction and assessment on Punnet Squares. While they were not included in this unit, they are a part of the standard selected. You may wish to use the lesson, Dare to be [Punnet] Square (See Weblinks)

Web Links

Use this four-part article for student research and for students to learn about the reading process.
Mysteries of Twins

Use this link to obtain more information about Semantic Webbing.
Semantic Webbing

Use this link to obtain more information about summarizing.

Use this link to obtain more information about Think Aloud.
Think Aloud

Use this link to explore and define different reading strategies.
Reading Strategies

Use this link to obtain a puzzlemaker and worksheet generator that can be used as a discussion starter for the daily review.

Use this link if you would like to incorporate Punnet Squares into your instruction.
Dare to be [Punnet] Square

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