The Opposable Thumb As A Human Adaptation : Thumb-Taping Lab

Lynda Kiesler, Albert Lea High School, Albert Lea, MN
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Summary

In this biology activity, students will first brainstorm and observe how humans use their hands. They will then conduct a short experiment to determine the importance of the opposable thumb to humans. This experiment involves students taping their thumb to render it useless while they proceed to do an everyday activity. In the end students will have the opportunity to reflect on why the opposable thumb is an adaptation important to humans.

Learning Goals

Students will learn about one adaptation that humans possess through evolution; the opposable thumb. They will use brainstorming, discussion, questioning, observation, and data collecting skills in performing the activity. Students should understand the following vocabulary when finished: adaptation, opposable thumb, evolution and primate.

Context for Use

This activity can be completed at the beginning of the evolution unit when studying adaptations. It may be used for 7th grade Life Science or 10th grade biology. It may be done in a classroom setting at desks and takes about one class period of 50 minutes. Follow-up may be done on the second day. The teacher must remember to have plenty of masking tape handy as well as numerous garbage receptacles. Remind students the day before to wear shoes with shoe laces. If a group does not have shoes with laces, the students in that group may perform a separate activity such as writing their name.

Description and Teaching Materials

The Opposable Thumb As A Human Adaptation : Thumb-taping Lab


BRAINSTORMING SESSION:
1. Divide students into small groups. They should brainstorm ideas about how humans use their hands versus other animals and especially other primates.

2. Discuss as a class their ideas. Create a class discussion summary on the board or overhead. The term "fully opposable thumbs" should be introduced if it hasn't already.

3. Next they will test a question. This will also allow them to experience the use of their own thumbs, possibly something they never think about, as well as appreciate the shape and design of their own hands.

EXPERIMENT:
Question: " Can I tie my shoes faster with or without my thumbs?"
Students should write a lab report that will contain information similar to the following.

TITLE / QUESTION: "Can I tie my shoes faster with or without my thumbs?"
MATERIALS: masking tape, timer or clock, shoe with laces

PROCEDURE:
1. Put students into groups of two. Collect baseline data by having each student tie their shoe while being timed by a partner. This should be done three times to get an average time. Students should put their data in data table in their lab book.
2. Next, using masking tape, tape the thumb down on each hand. For best results, a partner can tape it to the pointer finger to render it useless.
3. Repeat step 1 with the thumbs taped. (NOTE: It is important to follow the same procedure as done in step 1 so that data is consistent.)
4. Have students average their data.
5. Contribute data averages to a class chart.
6. After viewing/discussing the class data, write a conclusion.

Analysis/Conclusion questions:

1. What is special about the hand of humans?

2. The design of the human hand is an adaptation. How does our hand's design allow us to do so many tasks such as writing, texting, and tying shoes?

Teaching Notes and Tips

Students should write down their procedure and data in their lab notebook instead of on handouts. This will save paper. Instruct students on how to tape their thumb to their pointer finger. The teacher may want to practice first to discover problems that students may encounter. Stop watches or a wall clock with a second hand may be used. Instruct students how to safely ensure that discarded tape is thrown into the proper trash can. Be sure to remind students a day ahead to where shoes with laces. If any do not, they can complete a different timed-task such as using a pencil to write their full name.

Assessment

The teacher may collect lab notebooks to review the student data and analysis questions. The same questions may be included on a chapter test.

Standards

9.4.3.3.2 Evolution by natural selection (2009 MN Science Standards)

References and Resources