Studying the Primate Hand: The Opposable Thumb

Adaptations: The Opposable Thumb Lab
Introduction: The opposable thumb was caused by a beneficial
mutation, which gave some primates an advantage in their
environment. This thumb became a successful characteristic
that was passed to subsequent generations. The human hand
has a totally opposable thumb adapted for refined movements.
Purpose: The purpose of this investigation is to compare the
ability to perform simple operations with and without the use of
an opposable thumb.
In this lab exercise, you will perform several common
actions. Then you will change your hand so that it
resembles that of a non-primate animal. You will
determine whether or not you can successfully perform the
same actions.
Materials:
Masking tape, a text book, lab sheet, pencil, shoe with laces, jelly beans, cup of water, plastic spoon, and phone
timer.
Procedure:
Do each of the following activities and have your partner time how long it takes to do each of them in seconds.
a. remove one shoe
b. put on your shoe again, & tie the lace
c. eat 2 jelly beans
d. spoon water like soup and drink it
e. write your name
f. write the numbers 1 through 10
g. find page 55 of a text book
h. copy the first two lines on this page
2. Using masking tape, have your partner tape each of your thumbs to its adjacent index finger.
3. After your thumbs are securely taped, try each of the activities again. Have your partner time how long it
takes to do each. If an activity takes longer than 5 minutes, record the word "unsuccessful" on the data table.
4. Based on your observations, summarize your conclusions about the movements of your hand and the
usefulness of your thumbs.
Adaptations: The Opposable Thumb Lab
Names:___________________________________
Data Table
Action Performed
Time (sec) with thumb
person 1
person 2
Time (sec) without thumb
person 1
person 2
Remove shoe
Put on shoe & tie laces
Eat 2 jelly beans
Spoon water like soup & drink it
Write your name
Write numbers 1-10
Find page 55 in a text book
Copy the first 2 lines of lab
Analysis and Conclusions:
In this investigation:
1. What was the independent variable?
2. What was the dependent variable?
3. What was the control?
4. Which task did your group expect to be the easiest?
5. Which task did you group expect to be the most difficult?
6. Which task was the easiest?
7. Which task was the most difficult?
8. Which task(s) were so difficult that they couldn’t be completed?
Conclusion:
Based on your observations, summarize your conclusions about the movements of your hand and the usefulness
of your thumbs. **