The Cell Theory: An Evidence-Based Argument

Before Strategy/Engage: 15 minutes

1. Give students two to three minutes to brainstorm a list of characteristics that all living things have in common.  NOTE: An online mind mapping tool such as MindMeister may be used for this step.  

2. Ask for student volunteers to share one idea from their brainstorm and create a class list on the board.

3. Allow students to move into groups of two to four students. Tell students their group should attempt to narrow down the class list created in step one to just three items. Allow students to discuss this task with their group members for about five minutes.

4. After students complete their discussion, tell students that scientists have narrowed down the list to just three items, and this list is called the cell theory. According to this theory, these three characteristics apply to all living things.

• All living things are made of cells.
• Cells are the basic units of structure and function of living things.
• Living cells come from other living cells.

During Strategy/Explore & Explain: 60+ minutes

1. The teacher should give each student a copy of the Cell Theory Research Graphic Organizer (see attachments). 

2. The teacher should show the following video clip. Students should add notes to their graphic organizer while viewing the video clip. Students will listen for the names of the three scientists who are credited with developing this theory and write their names in the top box of the graphic organizer. The students should also record the discoveries that support each tenet of the cell theory in the boxes at the bottom of the graphic organizer. 

"The Wacky History of Cell Theory" from TED-Ed on youtube.com (6:11)

3. Students will need access to the articles listed in the materials section. Students may use a printed copy of the article or access the article online using an Internet-capable device.

• "Discovery of Cells and the Development of Cell Theory" from smithlifescience.com
• "Cell Theory" from saylor.org
• "Cell Theory" from the University of Miami Department of Biology

4. Students will read the articles while continuing to add information to the Cell Theory Research Graphic Organizer (see attachments). This graphic organizer will require students to research the scientific evidence and discoveries that support the claims of the cell theory.

Note: Depending on students’ abilities, the teacher may wish to read the articles and complete the graphic organizer as a whole class, or model this skill one time before allowing students to read the articles independently or with a partner or small group. In addition, the teacher may wish to require students to cite the articles used during the lesson in MLA or APA format to include in a bibliography page for students' final essay.

After Strategy-Explain & Elaborate-60+ minutes

1. After reading the articles and completing research notes using the graphic organizer, students will begin to develop their argumentative three-paragraph essay. The teacher may wish to present the students with the grading rubric before they begin writing: Persuasion Rubric from readwritethink.org. The teacher should decide in advance if he or she will allow students to present their personal opinion of the cell theory or require a strictly scientifically-based argumentative essay. The rubric does require students to state a personal opinion. The teacher could remove this from the rubric if needed.

Note: Depending on students’ experiences in writing in an argumentative format, the teacher may wish to provide more or less scaffolding during this portion of the lesson.

2. Students will begin the writing process by planning in their essay using the Persuasion Map Graphic Organizer from readwritethink.org. Alternatively, the students may complete this persuasion map in an online format using this website: Persuasion Map Student Interactive from readwritethink.org.

Note: This graphic organizer was developed for a five paragraph essay. To modify it for a three paragraph essay, the teacher or students can cross off the "b" and "c" boxes for "Facts or Examples". With this modification, students will be required to explain one discovery that supports the cell theory. The "thesis" should contain a statement about the cell theory and list the three main tenets of the cell theory. The "main reasons" and "facts or examples" should be the discoveries that scientists have made to support the claims of the cell theory that students learn during their research. The "conclusion" should summarize the most important details of the student's argument.

3. After completing the Persuasion Map, students should begin writing their essay. The teacher may require students to hand write or type their rough draft.

4. After completing the rough draft, students should review their own writing using the Evidence-Based Argument Checklist from readwritethink.org. Students should also switch papers with a partner to allow a classmate to complete the same checklist. (The teacher may wish to make a two-sided copy of the Evidence-Based Argument Checklist, so students can use one side for a self-check and one side for a peer-check.) As students review their essay and their peer's essay, they should also be editing spelling and grammatical mistakes.

5. After each student has revised and edited their own essay and had at least one peer revise and edit their essay, the student should complete a final draft of their essay that details the evidence that supports the cell theory. The teacher could require this to be handwritten or typed.

Before Strategy/Engage: 15 minutes

1. Give students two to three minutes to brainstorm a list of characteristics that all living things have in common.  NOTE: An online mind mapping tool such as MindMeister may be used for this step.  

2. Ask for student volunteers to share one idea from their brainstorm and create a class list on the board.

3. Allow students to move into groups of two to four students. Tell students their group should attempt to narrow down the class list created in step one to just three items. Allow students to discuss this task with their group members for about five minutes.

4. After students complete their discussion, tell students that scientists have narrowed down the list to just three items, and this list is called the cell theory. According to this theory, these three characteristics apply to all living things.

• All living things are made of cells.
• Cells are the basic units of structure and function of living things.
• Living cells come from other living cells.

During Strategy/Explore & Explain: 60+ minutes

1. The teacher should give each student a copy of the Cell Theory Research Graphic Organizer (see attachments). 

2. The teacher should show the following video clip. Students should add notes to their graphic organizer while viewing the video clip. Students will listen for the names of the three scientists who are credited with developing this theory and write their names in the top box of the graphic organizer. The students should also record the discoveries that support each tenet of the cell theory in the boxes at the bottom of the graphic organizer. 

"The Wacky History of Cell Theory" from TED-Ed on youtube.com (6:11)

3. Students will need access to the articles listed in the materials section. Students may use a printed copy of the article or access the article online using an Internet-capable device.

• "Discovery of Cells and the Development of Cell Theory" from smithlifescience.com
• "Cell Theory" from saylor.org
• "Cell Theory" from the University of Miami Department of Biology

4. Students will read the articles while continuing to add information to the Cell Theory Research Graphic Organizer (see attachments). This graphic organizer will require students to research the scientific evidence and discoveries that support the claims of the cell theory.

Note: Depending on students’ abilities, the teacher may wish to read the articles and complete the graphic organizer as a whole class, or model this skill one time before allowing students to read the articles independently or with a partner or small group. In addition, the teacher may wish to require students to cite the articles used during the lesson in MLA or APA format to include in a bibliography page for students' final essay.

After Strategy-Explain & Elaborate-60+ minutes

1. After reading the articles and completing research notes using the graphic organizer, students will begin to develop their argumentative three-paragraph essay. The teacher may wish to present the students with the grading rubric before they begin writing: Persuasion Rubric from readwritethink.org. The teacher should decide in advance if he or she will allow students to present their personal opinion of the cell theory or require a strictly scientifically-based argumentative essay. The rubric does require students to state a personal opinion. The teacher could remove this from the rubric if needed.

Note: Depending on students’ experiences in writing in an argumentative format, the teacher may wish to provide more or less scaffolding during this portion of the lesson.

2. Students will begin the writing process by planning in their essay using the Persuasion Map Graphic Organizer from readwritethink.org. Alternatively, the students may complete this persuasion map in an online format using this website: Persuasion Map Student Interactive from readwritethink.org.

Note: This graphic organizer was developed for a five paragraph essay. To modify it for a three paragraph essay, the teacher or students can cross off the "b" and "c" boxes for "Facts or Examples". With this modification, students will be required to explain one discovery that supports the cell theory. The "thesis" should contain a statement about the cell theory and list the three main tenets of the cell theory. The "main reasons" and "facts or examples" should be the discoveries that scientists have made to support the claims of the cell theory that students learn during their research. The "conclusion" should summarize the most important details of the student's argument.

3. After completing the Persuasion Map, students should begin writing their essay. The teacher may require students to hand write or type their rough draft.

4. After completing the rough draft, students should review their own writing using the Evidence-Based Argument Checklist from readwritethink.org. Students should also switch papers with a partner to allow a classmate to complete the same checklist. (The teacher may wish to make a two-sided copy of the Evidence-Based Argument Checklist, so students can use one side for a self-check and one side for a peer-check.) As students review their essay and their peer's essay, they should also be editing spelling and grammatical mistakes.

5. After each student has revised and edited their own essay and had at least one peer revise and edit their essay, the student should complete a final draft of their essay that details the evidence that supports the cell theory. The teacher could require this to be handwritten or typed.