Chapter 8, 9, 10, 11

In chapter 8, Shubin talks about the complexity and purpose of our nose. Our sense of smell allows us to discriminate thousands of different odors that can help us survive in life and decipher whether something is pleasant or not. Shubin tells us about what our noses do each time we inhale. When we sniff, we suck in odor molecules which go behind our nose and gets trapped by the mucous lining our nasal passage. In the nasal passage, their are millions of nerve cells that then send signals to our brain. It is fascinating how one can extract DNA from any tissue in your body to learn about the history and functions of it. Although the nose is often taken for granted, humans devote about 3 percent of our genome to odor genes.

In chapter 9, we learn about the importance of vision. The role of the eye is to capture light in a profound way that it can be carried to the brain and processed into an image Our eyes can function in several unique ways, it adjusts automatically in different settings. For example, are eyes are sensitive to a dark room for the first few seconds, but after being in there for awhile, our eyes adjust and we are capable of seeing more clearly what is in front of us. I learned that opsin is an essential protein inside the eye that helps gather light molecules. We use different opsins to see in black, white, or color. The mutations that occur revolving the eye in this chapter portray how humans are very much similar to a fly or mouse through the DNA structures and sequences. The eyeless (Pax 6), controls the development in all living creatures with eyes.

Ch10: Our ears are distinguished through three parts: external, middle, and inner. The external ear is the outer visible part that sticks out of the side of our head, this is wear we differ from sharks. The middle contains little ear bones, many mammals and other creatures acquire this trait as well. The tiny bones inside the human ear is the same as the rod in the upper jar of a fish. The inner ear is a tube that contains gel-filled sacs. It is used for hearing as well as telling us which way our head is tilted and recording the speed at which our head is accelerating or stopping. The entire system in our head that allows us to perceive position is connected to our eye muscles and connections in our brain.

Ch 11: Shubin sums up all his ideas and points and concludes by giving us an overview of the connections between humans and creatures. Shubin states that every living thing evolved from some parental genetic information. This creates the biological mechanism of heredity. All of our ancestors pass down various traits that later generations continue to obtain, for instance, a squeaky nose or floppy feet. It was informative when Shubin explains the causes for diseases that humans have.