Biological Classification - Day 1

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Objective

Students will be able to explain the Linnaean system use it to classify living organisms according to a variety of common features.

Big Idea

Ideas about how things are classified prompt questions about relationships.

Hook

10 minutes

Every time that I think about classifying something I am reminded of Sesame Street's One of These (things is not like the others) song. So, to start this lesson I play a mini-video of different "cats" set to that tune.

I then keep the first/last image of the video up and ask the students to look closely at the four cats, and to try to determine which one "does not belong". I ask for volunteers to share their answers, explaining why they believe their choice does not belong. I explicitly state that at this point it is not about whether they are right or wrong, but rather about how they are thinking about classifying these animals.

I then ask, "Why would it be important for scientists to classify anything?", and wait for students to think about an answer and then pair up with an elbow partner to share ideas. At the end of the share, I have students write a complete answer to the question, giving them the frame "It is important to classify things because..." I then ask students to crumple up their paper, and say: 

"When I say go, toss the papers around the room, until I tell you to stop. You can stand up to retrieve a paper, but you cannot have more than one at a time."

Once we stop, I make sure everyone has a paper, and I have the students share out what their paper says, while I chart their ideas on the board. 

I don't tell them that they will be tossing the paper before-hand to avoid having students begin the toss on their own. 

This technique help students recognize that there are different ideas, but relieves the threat of being wrong when they are asked to share. The key idea that I want to elicit from the students is that classification provides a way to sort organisms for easier study.

Note to teachers: After hearing some of the answers, and once the students have come to the understanding of the importance of classification, I also have them write a simple response to the paper they have and return it to its owner. (SW1SW2SW3)

If anybody asks about the cats, I tell the students that I will not actually give them the answer, but rather they fill figure it out on their own in the lessons that follow.

Explain

10 minutes

I continue by presenting the following slide show:

Slides 2-5 include some background information about the Linnean system of classification. As I am talking through those slides, I make sure students understand the meaning of species, know who Linnaeus is, and what we call binomial names. 

I conclude this section by presenting the Linnean System Mind Bite, embedded in slide 6.

This video is a brief excerpt of a full lesson. I only present this introduction to help frame the students thinking about why classification is needed, and give them a purpose to proceed with the interactives, where they will read about and explore the Linnean system. 

Explore

20 minutes

Before the lesson I bookmarked and shared the two websites the students will be using on Edmodo:

Both of these sites are from the American Museum of Natural History, and I find that they do a great job of explaining the concepts in a simple and direct way. As students work through the sites, they are recognizing how patterns help scientists organize different species (CCC Patterns can be used to identify cause and effect relationships), as well as deriving meaning from scientific text (SP8).

I distribute the Biological Classification Guided Notes, and ask students to get their devices and explore the two sites. In the following video I provide some tips for teachers to guide students through the interactives:

 

Note to teachers: When reviewing the student work (SW1SW2SW3), I noticed almost every student missed the ray-finned fish in question 8. This tells me that students need explicit teaching and practice in reading this type of arrangement. A simple explanation of the diverging lines will probably do, but I would recommend that you do this during this lesson in order to avoid seeing the same problem. Did you notice the wonderful comparison made in question 9 by SW1?

Closure

10 minutes

To close this lesson I distribute the ball cladogram, and ask the students to respond to the question, "What scheme do you think was used to classify these items?"

Note to teachers: The scheme I used to create the cladogram is 

  1. balls
  2. balls that bounce
  3. balls that are played using hands (or no equipment)
  4. balls that are bounced on the ground

However, I do not mark answers incorrectly just because they did not identify my scheme. The students could very well identify other schemes (B-SW1B-SW2B-SW3B-SW4). The purpose of this assignment is that students recognize that all members share nested attributes, and that these can be used to classify them. (CCC Patterns Graphs, charts and images can be used to identify patterns in data.)