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Looking Good, Feeling Good: From the Inside Out

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Teacher's Guide

Lesson 1—Engage

It’s Alive! Or Is It?

At a Glance

Overview

Lesson 1 consists of one activity that engages students in the study of bones, muscle, and skin. Through a teacher demonstration and class discussion, students share their prior knowledge about living systems and bone, muscle, and skin. Students then develop a list of characteristics of living things and their own understanding of bone, muscle, and skin as living systems.

Major Concepts

Bone, muscle, and skin are living systems. Some common characteristics of living systems are that they

Objectives

After completing this lesson, students will be able to

Teacher Background

See the following sections in Information about the Musculoskeletal and Skin Systems:

  1. 1 Introduction
  2. 3 Characteristics of Living and Nonliving Systems

In Advance

Web-Based Activities
Activity Web
Component?
Photocopies Materials
1 No Master 1.1, It’s Alive! Or Is It?, 1 copy per student 1 piece of white chalk
1 rubber band
1 piece of heavy paper, wrapping paper, or a report cover
1 chicken breast bone, “wishbone,” or other animal bone that is dried and easily broken
1 piece of raw meat of any kind, although red meat may be more easily associated with muscle
1 piece of chicken skin
1 knife
1 pair of scissors

Preparation

Wash the chicken bone, raw meat, and chicken skin. Keep the meat and skin on ice prior to use. Wear plastic or rubber gloves when handling these items to prevent possible bacterial contamination. Cover an area of a front table or workbench with nonabsorbent material to prevent contamination of the work space. Have necessary materials on hand to dispose of meat and chicken skin in accordance with your school’s regulations. Just before class, pair the materials as follows: chalk with bone; rubber band with muscle; and paper with skin.

Make photocopies.

Procedure


Note to teachers: In this lesson, students develop a list of characteristics of living systems. Defining life is not a trivial task. Life has been defined in many ways for many different purposes, and there is no single definition that works for everyone. The characteristics that we focus on in this lesson were derived with the following in mind:

Proceed through the lesson at a steady pace. The idea is to elicit students’ prior knowledge about living systems and help them appreciate that muscle, skin, and especially bone contain living cells.

  1. Focus student attention on the three pairs of materials on the front table. Begin with the paper and skin. Ask students, “What do these two items have in common?”

Allow only two to three minutes to develop this list. Student responses will vary. They may indicate that both skin and paper are flat and flexible. In addition to observable characteristics, try to focus students on functions. Both items can be used as coverings to contain things or as a protective layer for items beneath them.

Note to teachers: Asking this question requires students to call on their prior knowledge and to engage their thinking. At this point, do not critique student responses. Appropriate teacher comments are short and positive, such as “Good” and “What else?” Other appropriate teacher responses include “Why do you believe that?” or “How do you know that?” Questions such as these allow you to assess current student knowledge about the subject and adjust lessons accordingly. They also provide a springboard to “Let’s find out” or “Let’s investigate.” In general, it is time to move forward when you see that thinking has been engaged.

  1. Ask students, “How are paper and skin different?”

Once again, allow only two to three minutes to develop this list. Student responses again will vary. Although they probably will lack details, they may indicate that paper and skin are made of different things. Try to get students to elaborate on this response. They may also indicate that both came from sources that were alive at one time.

  1. Repeat the questions in Steps 1 and 2 for chalk and bone and for the rubber band and meat.

Developing lists of similarities and dissimilarities for these two pairs should proceed quickly. For each pair, try to have students come up with at least one response relating to what each item is composed of. Note that it is possible that students may not know that meat is animal muscle. If necessary, tell them that meat is muscle tissue.

  1. Break both the chalk and the bone. Cut both the rubber band and the piece of meat. Cut both the paper and the chicken skin. Ask students, “Can these items repair themselves? Why or why not?”

Students will realize that the chalk, rubber band, and paper cannot repair themselves. They also should realize that the bone, meat, and skin cannot repair themselves. Some students, however, may make the leap to bone, muscle, and skin in an intact organism, such as a human, and indicate that these three systems can indeed repair themselves.

  1. Ask students to raise their hands if they have ever broken a bone, injured a muscle, or cut their skin.
  1. Ask students to lower their hands if their injuries healed.

All students should lower their hands unless their injury is very recent or they have a condition that prevents normal healing. Some students may indicate that healing occurred, but it took a long time. All student responses are appropriate for discussions later in this lesson and in subsequent lessons.

Note to teachers: Some students may raise the issue of scars forming at the site of a previous skin injury. Rather than allow this topic to change the focus of class discussion, simply indicate that scar formation is an indication that the tissue has healed.

  1. Ask students, “Why could the bone, muscle, and skin of your body heal while the broken chicken bone, cut piece of meat, and cut chicken skin could not repair themselves?”

While students may understand that there are basic differences between muscle in their body and meat on the table, for instance, they may have trouble expressing what those differences are and why the two function differently. You may have to guide the discussion by asking additional questions:

Try to guide this brief discussion so that students view the bone, muscle, and skin of their bodies as active, changing, and responsive systems that are connected to other body systems, such as nerves and blood vessels.

  1. Divide the class into teams of three or four. Ask each team to make a list of characteristics of living systems.

Give teams just five minutes for this task. If students need help getting started, suggest that they think about finishing sentences that begin, “Living systems are made of …” or “Living systems are able to ….”

National Science Education Standards icon
Content Standard C:
Some traits are inherited and others result from interactions with the environment.
  1. Ask teams to share the items on their list with the class.

Write the responses on the board. Try to summarize the responses like this: living systems

If students respond that living systems can move, for instance, you might indicate that this characteristic is the result of obtaining and making energy and interacting with the environment.

Note to teachers: The ability to reproduce is a commonly listed characteristic of living systems. In this lesson, that characteristic is not listed separately because bone, although it is a living system, does not reproduce itself. Rather, the cells of bone reproduce and carry out those activities (such as making protein and depositing mineral) that allow bone to grow, repair, and remodel itself. If students mention reproduction as a characteristic of living systems, list this response under “function according to a genetic blueprint (the cells contain DNA).”

  1. Provide each student with one copy of Master 1.1, It’s Alive! Or Is It? Ask students to fill in the first column, Characteristics of Living Systems, with the summary items you’ve created from Step 9.
  1. Ask students to consider the class discussion and complete the table. For instance, if the first item in the characteristics column is “Living systems are made of cells,” students should check the “Yes” column if they agree with this statement or the “No” column if they disagree with this statement. They do this for each system—bone, muscle, and skin—for each characteristic of a living system.
  1. Ask students if they believe that bone, muscle, and skin are living systems. Ask for a show of hands.
  1. Ask several students to share their thoughts and reasoning with the class.
  1. Ask students to write an answer to the question at the bottom of Master 1.1, It’s Alive! Or Is It?, Why do you believe bone, muscle, and skin have been grouped together for study in this module?
assessment icon
Assessment:
Collect students’ copies of Master 1.1. They will help you assess how well each student distinguishes between the living and the nonliving.
  1. Ask several students to share their thoughts with the class.

Why bone, muscle, and skin have been grouped for this module may not be obvious to students. Answering this question provides an opportunity for students to reflect on prior knowledge, and it sets the stage for the investigations to follow. Over the course of this module, students will develop the understanding that these systems all have structural functions and they protect the body. Also, these systems simultaneously allow flexibility and strength.

  1. Explain to students that they are about to begin their study of bone, muscle, and skin. As they investigate these three systems, they can reflect on their understanding of bone, muscle, and skin as living systems by comparing their new insights with their responses in this lesson.

Lesson 1 Organizer
Activity 1: It’s Alive! Or Is It?
What the Teacher Does Procedure Reference

Focus students’ attention on the three pairs of materials: paper and skin, chalk and bone, and rubber band and muscle.

  • Ask what each pair of items has in common.

Step 1

Ask how each pair differs:

  • Paper and skin
  • Chalk and bone
  • Rubber band and meat
Steps 2 and 3

Break the chalk and bone. Cut the rubber band and meat. Cut the paper and chicken skin.

  • Ask if these items can repair themselves.
Step 4

Ask students to raise their hands if they have ever broken a bone, injured a muscle or cut their skin.

  • Instruct students to lower their hands if their injuries healed.
Steps 5 and 6

Ask students why their bones, muscle, and skin can heal but the samples on the table cannot.

Step 7

Divide the class into teams of three or four. Instruct teams to

  • make a list of characteristics of living things and
  • share their list with the rest of the class.
Steps 8 and 9

Give each student a copy of Master 1.1, It’s Alive! Or Is It?

  • Ask students to fill in the column labeled “Characteristics of Living Systems.”
  • Ask students to complete the rest of the table.
master iconSteps 10 and 11

Ask students whether they believe that bone, muscle, and skin are living systems.

  • Ask for a show of hands.
  • Have several students share their reasoning with the class.
Steps 12 and 13

Ask students to write an answer to the question at the bottom of Master 1.1, It’s Alive! Or Is It?

  • Have several students share their reasoning with the class.
Steps 14 and 15

Explain that they will now investigate bone, muscle, and skin.

  • They should remember their new insights as the lessons proceed.
Step 16
master icon= Involves copying a master.

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