Shoe Classification: An Intro to Cladistics

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Objective

SWBAT explain the strengths and limitations of the Linnaean classification system.

Big Idea

Students practice their decision making and justification skills as they learn about classification and evolutionary relationships.

Warm-up

10 minutes

I find it challenging to find a variety of activities to use for warm-ups that activate prior knowledge in a way that is time efficient yet motivational for students.  At this point I really want my students to push their thinking as they make connections and develop explanations.  I am hoping that by the end of their 8th grade year this type of thinking is automatic.

To accomplish this goal, as well as to allow students to move and be social (so important at this age, especially by 3rd or 4th hour), I use Warm-up Rotation Questions to activate their thinking.  The students are given the following directions:

  1. Read the question.
  2. Develop a group answer.
  3. Write your answer on the paper using your assigned color (you may NOT repeat what any prior group answered).  **This is a typical direction used often in class during any type of discussion activity.
  4. When time is up, move to the next station and repeat process.

Using these directions, students answer these 4 questions:

  • What is the purpose of classifying objects or organisms?
  • What information does classifying provide that we would not have without classification?
  • Develop an explanation of “classification” that is appropriate for a first grade student.
  • Do you feel classification is important?  Why or why not?

I set this up as 60 second rotations, with one question per lab table in a similar fashion to the one described in a video found in the activity section of A Difference of Mind.  I like only providing students with limited time as it forces them to get right to work without wasting any time on social talk, however this strict limit forces students to use their gut instinct answer which is why I like to use this strategy as a warm-up.  This strategy allows you to gauge what the students know "right now".  Not allowing repetition forces students to read and consider the prior answers and take thinking a bit deeper than they might otherwise.  The following video provides an idea of what this looks like in my classroom and the Student Work Samples allow you to see the answers developed during this time.

Activity

30 minutes

This portion of the lesson is adapted from this activity found on the internet.

For this classification exercise, I have students partner up with what I call their "shadow" tables.  This Classroom Image shows the left half of my classroom; the front two tables are shadow partners as are the back two tables. I use this grouping strategy when I want the brainstorm groups to be larger than 3 or 4 students.  This also provides students with enough shoes to be challenged on the activity described below.

Students begin by each placing their right shoe on the lab table.  Students work together to create a chart that identifies each shoe by 3 separate characteristics, such as white, Nike, sneaker; pink, Ugg, boot.

Students then must create 2 sub-groups to further sort the shoes (example: sneaker and boot).  Students will continue to create sub-categories until there is only 1 shoe in each sub-group. 

To "test" their newly developed classification system, students will select any 3 shoes and pass them clockwise to the next group.  These new shoes represent newly discovered species that must be classified within our current system.  I suggest that students use a different color ink to record this information so it is easy to identify.  Students do this twice.

These directions are clearly stated in the Shoe Classification Student Directions so students can work at their own pace as independently as possible.

Wrap-up

5 minutes

Following the activity I have students answer the Shoe Classification Analysis Questions.  The following questions are in the student handout:

  • What were some of the common characteristics that you used to classify the shoes?
  • What were the challenges you encountered when classifying them?  How did you overcome those challenges?
  • Was it difficult to use the chart you created using the original shoes with the 6 new shoes you received during the rotations?  Explain why or why not.
  • Compare this classification activity with your experience classifying spiders.  How are they the same?  How are they different? (You can use a Venn diagram or T-chart for your answer).
  • Does this type of classification tell you which shoe was created first (the evolutionary history of the shoes)?  Explain.

 

These questions connect the students' prior experience classifying spiders using the Linnaean system to their future experiences using cladistics (phylogenetic trees) to understand the evolutionary relationships between organisms.

If time allows, begin a discussion on what the phrase "evolutionary relationships" mean and why we would want to know such information.