Natural vs Artificial Selection

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Objective

SWBAT define artificial selection and explain how humans have influenced the passing of traits using selective breeding methods throughout history.

Big Idea

Students get all worked up at the thought of genetically modified organisms, but are those any different from what we have created using selective breeding?

Warm-up

10 minutes

I begin the lesson by showing students the narrated slide show Artificial vs. Natural Selection from the Genetic Science Learning Center: Learn.Genetics site.  This is a great way to review the basics of natural selection and introduce the concept of humans altering genetics in a low tech manner prior to introducing the topic of genetically modified organisms.

After going through the slide show, I ask students to discuss the following questions with their table groups and to record their answers in their science journals:

  • What are the benefits to artificial selection? 
  • Can you identify any potential negative impacts? 

As always, students are reminded to explain and/or justify their responses.  The Benefits and Costs of Artificial Selection - Student Work provides a sampling of responses.

Activity

25 minutes

Once students are familiar with what artificial selection/selective breeding means, students are given 25 minutes to use research to create list of organisms that are associated with/created by artificial selection/selective breeding.  

Your task is to use the next 25 minutes to create a list of organisms whose genetics have been influenced using selective breeding.  I encourage you to be secretive and creative as you put your list together because this is a challenge and the winning team will win a prize.  

The rules:

1. All items on your list must be living organisms that are capable of reproduction (no manufacturing does not count)

2. You must cite your sources for each item on your list so we can look it up if needed (just copy and paste the url to your document)

3. All subgroups of a larger group will only count as 1 item (huskies and poodles are both dogs so they would only count as 1 item)

4. Be creative, you will only get points for items that are on your list but NOT on anyone else's list

Students work in small groups to complete their list and compile their information on a shared Google doc.  

Wrap-up

10 minutes

Once the research time is over, students return to the classroom and sit with their research group.  I like to use the scoring method from the board game Scattergories.  This method involves having one student group read their answers slowly one by one.  If the answer they state is on anyone else's list, everyone crosses it out and no one gets credit for that answer.  The only answers that earn points are the ones that exist only on a single list.  Be aware, there are times when that means there will be no winner (those are my favorite) but typically this process allows for a single winning group.

During the reading of the list, I like to have a student write all qualifying answers on the board so students can see the amount of organisms that have been influenced using selective breeding (and it helps with scoring).

After scoring, I have students respond to the following question:

Do you respond differently to these organisms knowing that they have been created by humans using artificial means?  Explain your thinking in detail.

The Student Work - Do You Respond Differently? provides a sampling of student responses to this question.  I like to have students respond to this question prior to learning about GMOs, especially altered crop products.  Most of the time, students have no problem with any organisms altered using selective breeding but they do not respond well to using modern technology to insert genes directly into the DNA.  By having students respond to the prompt above, they have clearly stated their opinion prior to fully considering how this is any different from modern creation of GMOs.