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MUSE | Natural Selection | Unit Overview and Materials | Section 1: The Nature of Scientific Arguments | 1A: Unit Introduction | Instructional Notes


Student handouts

Lesson 1B: Sequencing Events (cartoon activity)


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Intended Learning Outcomes

There are no explicit learning outcomes for this day. However, it is an important orientation day.


3 student handouts:

  • Written unit overview
  • Introduction to Written Assignments
  • Galapagos Tortoises Problem Statement

Time frame and sequence

This material will take one class period to complete.

The students will be entering into a new area of study with the commencement of this unit on evolutionary biology. It is important to take time to introduce the unit and set up expectations for student work during the coming weeks. There will also be time during this class period for students to complete a writing assignment that will be an important tool for assessing their prior knowledge about mechanisms of evolution.

There are three handouts that should be given to students today. The first is the written Unit Overview which describes the goals of the unit. The second is the Introduction to Written Assignments handout which describes the expectations for written work. Finally, students will be asked to do a brief written assignment, the Galapagos Tortoises assignment.

Begin the class with a short discussion about evolution. Students will come to the study of evolutionary biology with many ideas that they should have a chance to discuss. Ask students what they have heard about evolution. Many students will likely respond with topics related to the way the evolution/creation science debate is covered in the news. They may make comments about how evolution goes against religious teachings, etc. The point of this discussion is not to enter into a debate about particular issues, but simply to let students share some of the things they have heard. Keep a list on an overhead or the board of some key phrases that are brought up. This will be helpful during the subsequent discussion about topics that will be the focus of this unit.

Once the students have had a chance to share their preliminary ideas, pass out the Unit Overview. Read it aloud or let students read quietly to themselves. In either case, the overview should become the focus of the discussion as you turn away from the student ideas and introduce the unit in a more formal way. Emphasize that evolutionary biology provides the conceptual foundation for much of life science and that the broad goal of the unit is to understand what it means to look at the world from this perspective. At this point refer back to some of the comments made during the earlier discussion and tie them in to the intended outcomes of the unit. This conversation also provides an opportunity to make the point that much of the work in this unit will be at an intellectual level that students may not have had much experience with. Students will be expected to critique one another's arguments and ask for evidence and justification for statements made by others. They will frequently be asked to use the concepts they are learning to construct explanations and because of this they will be asked to be aware of their own learning. Much of this discussion may be somewhat vague, but the important thing to do is set the stage for the challenges ahead in a way that makes those challenges seem exciting and worthwhile.

Move on to the Introduction to Written Assignments page. This handout sets up the expectations for written work during this unit. The major point is that students must share their thinking in several ways. One important way is through their writing. This handout is written as a personal communication from the teacher. It promises to produce an exchange of ideas through assignments that will be key to the success of this unit. It is important to emphasize that their hard work will be matched by yours and that their complete responses to each question will help guide the classroom instruction.

The final task of the day will be to ask students to complete the first written assignment. Hand out the Galapagos Tortoises problem statement. It may be helpful to read this statement aloud and make sure the task is clear to the students before they begin to write. However, do not have students discuss their ideas at this point. This writing assignment is an important tool for assessing students' initial ideas and therefore, you will want to insure that they are giving their own ideas and are not influenced by others before they begin writing. This is one reason we suggest administering this writing assignment during class time. It will be important to emphasize that you are not looking for a right answer here, but rather you are really interested in what they are thinking. They should attempt to thoroughly address the topic.

Student Ideas and Teaching Strategies

The first discussion with students in this unit will set the stage for the unit as a whole. It is important to find out what students think of when they hear the word evolution. Perhaps more than any other subject in the life sciences, students come to the study of evolution with strong ideas and preconceptions. The goal during this introduction day is to find out what some of those are so that you can be prepared for the potential sidetracks and roadblocks these notions may create. There has been a significant amount of education research that has explored the ideas students often bring to the study of evolution. We encourage you to read over the Roadblocks to Understanding section of this site for more information.

Another important function of the initial discussion is to set the stage for much of the unit. Throughout this unit students will need to engage in conversations with one another and with the teacher. This first discussion will allow you to determine their comfort level with whole class discussion. It will help you decide how much work you may have to do to establish classroom norms that can facilitate interaction.

As you transition into an overview of the unit, keep in mind that you are providing your students with a sense of where they are going and how they will get there. Several of the initial activities may appear to students to have very little to do with evolutionary biology. However, if you have set the stage properly you will be able to explain the connection by referring back to this discussion. Emphasize to students that part of the goal of this unit is to be able to analyze scientific arguments on a general level before moving into evolution-specific areas.

Another way in which you will be laying valuable groundwork on this day is by setting up the expectations for written work. Many high school students are accustomed to very short writing assignments that do not ask for their ideas, but simply ask them to restate information they have read or heard in class. The writing assignments in this unit are quite different in that they will often be asking for a glimpse into the individual thinking of the students. There may be times when the information provided is quite limited and the students will need to draw from earlier portions of the class or their own experience to answer. There will also be cases in which there may not be a single correct answer, but instead many acceptable answers. Your job when setting the stage for these kinds of assignments will be to emphasize to your students the value of writing thoroughly about their thinking. You will want to remind them that writing in this way will help you know where they stand and will help them clarify their own ideas as well. While this initial discussion is key in setting high expectations, it will be equally important for you to provide careful feedback on the first several assignments that reinforces the points you make during this discussion.

The final task of the day is for students to respond to the Galapagos Tortoises problem statement. This assignment serves several valuable functions. First, it gives you an opportunity to determine some of the ideas your students have about how populations of organisms change over time. Our experience has been that virtually all of the common misconceptions reported in the education research literature are exposed by this assignment. You will almost surely find many references to Lamarckian ideas such as need and use and disuse. You will likely have many references to a single, dramatic mutation event. Student responses will probably not have many references to variation within populations or populations as the unit of selection. Again, we suggest that you look over the summary of the research on student ideas presented in the Roadblocks to Understanding section of this site.

The second major function this writing assignment serves is as a focus point that students can return to later to see how their thinking has changed. We have woven reflection on their written response to this assignment into the final exam for the unit. This has been a wonderful assessment tool in our classroom. If you will be using the student writing in this way, you will need to make sure that every student completes the assignment and you will have to keep them on file until the end of the unit.


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