Human Biology

http://www.ck12.org Chapter 1. Human Biology

FIGURE 1.86

With color vision, you can tell which cher-

ries in this picture are ripe, because cher-

ries turn red as they ripen.

Summary

• Vision depends on the eyes detecting light and forming images, and then the brain must make sense of the
  images.


• Humans can see in three dimensions and color.

Practice

Use the resource below to answer the questions that follow.

• Evolution of Color Visionat http://www.youtube.com/watch?v=P1V_bJhvoAE (10:08)

MEDIA

Click image to the left for more content.

1. What are the three classes of cone cells in the human eye? How are they involved in color vision?


2. How does the vision of frogs and fish compare to humans? How does the vision of chickens compare to
   humans?


3. What is one theory why some mammals have only two types of cones? How does recent information of the
   platypus relate to this theory? Think carefully and answer as completely as you can.

Review

1. What is vision?


2. Why were depth perception and color vision important for early primates?