YIF: Chapter 9

This chapter called "Vision" is mainly about the biology of the eye and a little history of the eye. There are several fascinating experiments that scientists have done on eyes, but the evolution of the eye was not mentioned much. After all "[e]yes rarely make it into the fossil record." (Shubin 149) First the author talks about the biology of the human eye and talks about the molecules involved in light reception. Later he talks about these molecules being incorporated with tissues. Finally, Shubin went into detail of the genes in multiple eyeless genes, and showed how flies, mice, and humans have similar genes that turn on and off the eye genes. This last part was my favorite part of this chapter. Walter Gehring compared the genes of of flies, mice, and humans that all had a similar eye disorder. He found a similar gene in all three in of these organisms, and tested with the eyeless gene in flies and Pax 6 gene in mice and found that if he put the Pax 6 gene any where on a fly, an extra fly eye grew there. This showed the very close relationship between the eye genes found in these organisms. The only Big Idea in biology that relates to this chapter is Big Idea #3, which is  living systems store, retrieve, transmit, and respond to information essential to life processes. Brains respond to information that the eyes receive from their environment and transmit to the brain. The rods and cones are the main parts of the eye that pick up the light from the environment and the brain picks up these signals from various nerve cells. The brain then interprets the light information from the eye and acts accordingly. An essential question that can be made from this chapter is "How do we put variation to use in understanding how our ability to see developed over time?"