Name
Class
Date
Activity: Comparison of Primates
Background Information:
In the 19th century, English naturalist Charles Darwin startled the scientific community by
announcing his hypothesis: Humans and primates, such as the apes, evolved from a common
ancestor. In Darwin’s time, many people criticized his ideas about evolution. Today, scientists
know that primates and humans share many identical amino acids in their DNA sequence,
supporting Darwin. In this activity you will measure and analyze structural differences between
humans and their relatives. Darwin observed that traits among human beings and other primates
differ in many ways. These differences include cranium size (skull), skeletal structure and hand
movement.
Objectives:
 To observe, compare and measure several characteristics of primates.
 To infer the identity of primates based on observations and comparisons.
Materials: Masking tape, ruler.
Procedure: Part A
1. First carry out every activity in Data Table 1 using your thumb. For example, as your
partner observes, write your name, class period and date in the space provided. Write a
check mark in the “Using Thumb” column. Do the same for each activity you complete.
2. Ask your partner to tape the thumb of your writing hand securely to your index finger and
repeat the activities. Your partner will place a zero (0) in the “Without Thumb” column if
you have difficulty with the task.
3. Remove the tape from your thumb and trade places with your partner and repeat steps 1
and 2.
Data Table1: Observations of Simple Activities
Activity
Using Thumb
Without Using Thumb
Write name
Tie shoelace
Remove and replace watch
“check” = easily completed
“0” = done with difficulty
Work Space:
Part B:
1. Look at the illustrations in Figure 1 of the hands of some primates. Write your
observations as to the type of thumb, palms, and fingers in Data Table 2. Then describe
some possible adaptations suited for each type of hand.
2. Examine the illustrations of the skulls in Figure 2. Note the relative sizes of the jaw and
the degree each one juts forward away from the face. Record your observations in Data
Table 3.
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3. Note the relative sizes of the skulls in Figure 2. Measure the length and width of the
rectangle in millimeters and calculate the area (A = L x W).
4. Examine the illustrations of skeletons in Figure 3. The primates are shown from the front
and the side. Write your observations in Data Table 4.
Data Table 2: Observation of Primate Hands
Primate
Unique Feature
Tarsier
Large pads
Baboon
Orangutan
Gorilla
Human
Data Table 3: Comparison of Primate Skulls
Feature
Skull A
Size of Jaw
Largest
Angle of Jaw
Large, greater than 90
Calculated Area: for
brain (A=LxW)
Possible Adaptation
To climb on tree trunks
Skull B
Skull C
Data Table 4: Comparison of Primate Skeletons (choose from words in italics)
Feature
Skeleton A
Skeleton B
Vertebral Column (spine)
-curved/ straight
Shape of Pelvis
-bowl shaped/narrow
Relative length of arms to legs
-arms shorter than legs
- arms equal to legs
Bipedal (uses two feet to
walk) or
Quadriped (uses arms and
legs to walk)
Position of Skull
- over spine/not over spine
Applying Your Knowledge:
1. Explain the advantage of having a thumb.
2. Place the three primate skulls in order from the smallest jaw to the largest. Explain how
you can infer the identity of the primate with the largest jaw.
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3. Make a statement comparing the size of the brain (area) and jaws for the three primate
skulls. Explain how you think this fits into the evolutionary scheme of primates.
Summary: Write a three paragraph summary using our standard format (what you were doing in
this activity and why, what you found out by doing this activity, and how this information relates
to your life).
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