Genetic Modification

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Objective

Students will be able to describe the relationships between changes in DNA and potential appearance of new traits.

Big Idea

There are advantages and disadvantages to genetic modification of organisms.

Warm-Up

5 minutes

Warm-up: What words or images come to mind when you hear the term, genetically modified?

Expect that students will need assistance developing the meaning of the term before responding to the question. If this is the case, first guide students to practice their decoding skills by looking for known word parts to help them determine the meaning of the term, genetically modified.

Look for students to identify that genetically means that it involves the genes, or DNA code. Ask, “What word part do you see in the term, modification and what does it mean?”  Look for students to identify that modify means to change.   Lead students to put the two meanings together to derive that genetically modified means changes to the DNA of an organism.  Once this is established, ask students what words or images come to mind.

This question allows students to activate prior knowledge about genetic modification.  Even if they have no prior knowledge, having gone through the word identification, they will all now possess some knowledge.

Introduce New Material

20 minutes

Inform students of the learning targets:

  • I can explain how the genes of organisms are altered.
  • I can form and defend (in writing) a position on the social, moral, ethical or legal issues related to the use of genetic engineering.

Introduce the vocabulary associated with the lesson: genetic engineering, cleavage, recombinant DNA, plasmid, gene therapy.   Plan to explicitly teach the vocabulary associated with the lesson at the appropriate times within the lesson as students often struggle using the vocabulary of genetics correctly.

Begin the lesson with a video clip, what is genetically modified food?

Before viewing the video, establish the viewing purpose by telling students that they should know at the end of the video.  Display the question they should consider while viewing:

  • Is this video more of a factual video clip or persuasive video clip?
  • Do you think the producer of this clip is in favor or against genetically modified food?

After viewing the clip, ask students to respond to the questions. Expect that students’ interest will be heightened after the video as it is intended to engage students in the discussion. Look for students to identify the video is more of a persuasive video than a factual video given how the information was presented. They also should be able to identify that the clip is not in favor of genetic modification of foods.

At this point in the instruction, do not allow the class  to veer off into a discussion about students’ thoughts on genetically modified foods.  They will have time later in the class to formulate opinions after learning more information about the topic.

Because there are not a lot of notes, instruct students to use a note-taking format that has been taught. 

Provide instruction about the process of genetic engineering, using several real-world applications of the process in the discussion

Share a listing of currently genetically modified foods to help students comprehend that we all have likely eaten genetically modified food.

Explain how genetic modification works and display a recombination image to support the instruction.  Also, show an animation of the process to help students comprehend how it works.

Make sure that students understand both sides of the issue by sharing information on both sides of the genetic modification issue.  Then, engage students in the development of a list of pros and cons.    Explain how brainstorming works and allow students to brainstorm a list advantages and disadvantages of genetically modifying food.   Be sure to present basic brainstorming rules:

  • Generate as many ideas as possible.
  • Let your imagination soar.
  • No criticism or debate.
  • There are no wrong answers.

Use a whiteboard to capture students’ thoughts.  Set the timer for 2 minutes and allow students to share their ideas.  At the end of the timed period, review the list with the class to make sure that all thoughts were captured.  Display a list of Pros and Cons that was collected from a review of information on the internet.   Allow students to compare the list that was developed by the class to the list developed from the internet.  Identify any ideas that are consistent from either list, as well as those that are different.

Ask students if there are implications for genetic modification beyond food?  Allow students to share their thoughts then introduce some of the scientific work using genetic modification:

Growing organs using pigs as the host

Harvesting human insulin from e.Coli.

Ask students to consider whether the advantages/pros outweigh the disadvantages/cons.  Instruct them to turn and talk with a seatmate about their thoughts.

Guided Practice

15 minutes

Distribute computers.  Allow students to explore three sites that will give them a better understanding of the issue and how genetic engineering works:

Engineer a Crop 

Guess what’s coming to dinner 

Viewpoints

Set the timer for 10 minutes to ensure that students use their time efficiently to peruse the sites.  Walk around while they work to provide assistance or redirection, as needed.

After the time has ended, inform students that they now have enough information to write a position essay on genetic engineering.   Explain that a position paper is written from the writer’s position or viewpoint about a topic.  Explain that students will need to consider all that they have learned today about genetic engineering and respond to a writing prompt:

Based on what you now know, do you think we should raise genetically modified (GM) crops?  Defend your answer. Cite specific examples to support your position.

Share the Defending a Position Rubric with students to allow them to review each of the four components that will be used to evaluate their writing:

  • Focus
  • Organization
  • Elaboration
  • Fluency

Instruct students to use the RACE (Re-state, Answer, Cite and Explain) writing strategy that was taught in a previous lesson to guide them in constructing their responses.  Caution should be used if an exemplary writing sample is shared with the class.  Sharing a finished work product with the class will sometimes lead students to write a response that reflects more of what was shared with them than their own ideas and original writing style.

Independent Practice

20 minutes

Release students to work independently on the writing prompt.  Consider preparing a modified writing prompt for those students who may need added support to complete the task.

Walk around the room to monitor students as they work and ensure that all students are actively engaged in the completion of the writing prompt. 

When all students have completed the task, inform them that they will perform peer review of one another's work.  Assign numbers to each student and replace the names so that the work will not unidentifiable.  

Again, quickly review the rubric components with the class.  Inform students the rubric is intended to make the grading "equal" for everyone.  Explain that the rubric should guided the scoring, and not whether or not they agree with the writer.

Collect the completed work.  Remove all identifiers on the work and number each paper.  Keep a record of the number assigned to each student.  Distribute a rubric and numbered writing response to each student. Instruct students to write the number of the paper on the rubric. Explain that students will participate in a peer review of another student’s work.  Instruct students to first read the response.  The, use the rubric to evaluate how well the work meets each of the four components of the position paper: focus, organization, elaboration and fluency.

Student work 18 was evaluated to exceed the standard for organization and elaboration. The student reviewer felt the writer met the standard for focus and fluency.  While I would grade organization and elaboration below a rating of exceeds, I think I understand the reasoning of the reviewing student, who likely did not elaborate as much on his/her work, thus graded this work as "exceeds" for elaboration.

Student work 1 was evaluated below the standard for organization, elaboration, and fluency; but found to meet the standard for focus.  In my opinion, the student reviewer did follow the rubric and accurately scored the paper based on the rubric guidelines.

 

 

Close

5 minutes

If time permits, ask if any students changed their mind about genetic modification from the beginning of class to the end of class.  For those students who changed their position on the issues, ask them to explain why their opinions changed.  Listen to their comments and evaluate how well students are able to cite evidence to support their opinions.