Human Impact of Selective Breeding

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Objective

SWBAT to construct a scientific explanation on how selective breeding influences the inheritance of desired traits in organisms.

Big Idea

Students explore how selective breeding influences inheritance of desired traits.

Engage

10 minutes

In this lesson I engage students by watching the National Geographic video Meet the Super CowThis video demonstrates the power humans can have in influencing the inheritance of desired traits in organisms, in this case the organism is Belgian Blue cows. (MS-LS4-5. Gather and synthesize information about the technologies that have changed the way humans influence the inheritance of desired traits in organisms.).  These cows are bred for their extreme muscle mass.  

As students watch the video, they answer the following questions:

1.  Describe the physical characteristics of the Belgian Blue Cow.  How does this cow compare to the more common type of cow that we see on farms or commercials?

2.  According to video how is man using science to control nature?  What is this process called?

3.  What specific trait are breeders looking to influence its inheritance?  In other words breeders want the cows to have plenty of ____________________.

4.  What benefit do breeders get out of having cows with great muscle mass?  

5.  What is the science behind the incredible muscle mass in these Super Cows?

6.  What are the steps that scientists take to ensure that this defective gene gets passed on?

Explore

25 minutes

In this section of lesson students will explore selective breeding by completing an online simulation from ExploreLearning.  (Teacher Note:  This is a paid subscription, but you may sign up for a 30 day Free Trial by clicking here).

The Gizmo that I use is titled:  Evolution:  Natural and Artificial Selection

The Evolution: Natural and Artificial Selection Gizmo allows students to explore the process of artificial selection and compare its outcomes to the results of natural selection. (SP2 - Developing and Using Models) 

Learning Objectives:

  • Use artificial selection/selective breeding to develop a new variety of insects. (CCC - Cause and Effect -Phenomena may have more than one cause, and some cause and effect relationships in systems can only be described using probability.)   

Activity Sequence:

Depending on the level of your class, it's important for you to model and clarify any questions that students might have when completing the Gizmo.  ExploreLearning allows you to modify the Student Exploration sheet by downloading it as a word file and modifying it to meet the needs of your students.  It's important that you walk around and check for understanding as students are conducting the Gizmo.  

1.  Complete Prior Knowledge Question as whole class.  This particular question deals with dog breeding, which students are familiar with from prior lesson.

2.  In terms of activities, I only have students complete Activity B that deals specifically with Artificial Selection/Selective Breeding.  By now students have explored the relationship between Genotype and Phenotype and as a result Activity A is not needed to build students' background knowledge.

3. I omit Activity C since it deals with mutation rates which is not part of this lessons learning objectives.

Elaborate

20 minutes

In this section of lesson students complete a reading titled Selective Breeding from ReadWorks*.  

One you have created account type in Selective Breeding in search box to find reading passage.  As students read text they use Marking the Text and Writing in the Margins as reading strategies.   I use these reading strategies to ensure that students interact with text in meaningful and purposeful ways that will increase reading comprehension.  

(These are AVID - Advancement Via Individual Determination - resources. I teach at an AVID school.)

I have students specifically use the Connect strategy for this reading.  Students are able to make many connections to this reading since going to the market to buy produce is a connection we have to selective breeding.

Connect

Make connections within the text, to your own life, and to the world. Making connections will improve your comprehension of the text.

While reading you might ask,

  • How does this relate to me?

  • How does this idea relate to other ideas in the text?

  • How does this relate to the world? 

Once students have completed reading they answer the Text-Dependent Questions included in reading passage.

The non-profit ReadWorks is committed to solving the nation's reading comprehension crisis by giving teachers the research-proven tools and support they need to improve the academic achievement of their students.

ReadWorks provides research-based units, lessons, and authentic, leveled non-fiction and literary passages directly to educators online, for free, to be shared broadly.

The ReadWorks curriculum is aligned to the Common Core State Standards and the standards of all 50 states. Most importantly, ReadWorks is faithful to the most effective research-proven instructional practices in reading comprehension.

Evaluate

5 minutes

Students now gather and synthesize their evidence to construct an explanation of how humans have influenced the inheritance of traits in dogs.  Students are required to gather evidence from this lesson (videos, modeling activity) to construct their explanation. (SP6 - Construct Explanations/WHST.6-8.2 -Write informative/explanatory texts to examine a topic and convey ideas, concepts, and information through the selection, organization, and analysis of relevant content.

Students are required to use CER Graphic Organizer and Transition Words to construct their explanation.