2 
INTRODUCTION 
while holding the nut in his mouth. After the hole is dug, 
he pushes the nut into the bottom of the hole with his teeth 
and pulls ( the earth over the nut with his feet. These are 
additional uses of his feet and teeth due to their adaptations. 
Figure 2. 
Notice how the thumb and first two fingers hold the pen securely. The 
flat wrist gives a good sliding surface and the muscles are so controlled 
that the letters are uniform in size and shape. The nails of the fingers are 
adaptations and can be used to pick up small objects. The numerous joints 
in the fingers make the hand more serviceable. How many adaptative 
features of the hand can you think of ? 
Did you ever think of your hand as an adaptation? 
When you use a fountain pen in what ways is the hand 
adapted to the use of this instrument? First, you take it 
from your pocket. Then you take the cap from the pen with 
