Chapters 8-11

Ch 8 Making Scents
This chapter talked about the olfactory and how it works. It was interesting to learn that humans have lots of genes just for smelling. There is a receptor gene for each chemical type, causing these genes to make up 3 percent of all our genes. I thought it was really interesting that we have 300 genes that are useless, but are still carried in each generation. This shows that mutations and moderations took place in the fewer genes that older creatures had, which got passed down. These useless genes became useless as humans slowly began to rely more on sight than smell.
Ch 9 Vision
It was harder understanding all the information about the eyes. But something that I found interesting was that as the environment creatures lived in changed, from less colors to more colors, it caused a switch in the eyes to color vision. Shubin also talked about the eyeless gene in flies and the Pax 6 genes in mice. The connection of eyes of different creatures made much more sense when he described the experiment involving these genes. The mouse gene was able to produce a fly eye on the fly, which shows that these two genes control the development of eyes.
Ch 10 Ears
Something new I realized is that only mammals have external ears. I was the most interested when reading about the three ear bones and its connections to reptiles and fish. The bone stapes is the same thing as a bone in the jaw of a fish, the hyomandibula. It got smaller and smaller as fish began to walk on land, finally becoming the stapes in human ears. And the malleus and incus were moderated from the jaws of reptiles. I also learned that the neuromast organs in fish are the basically the same things as our inner ears, except they have evolved to serve different functions.
Ch 11 The Meaning of it All
This chapter was super long, but it summarized everything Shubin addressed, and the significance and purpose of all that information. This chapter taught me that every single creature is a moderation of its parents. His reference to the "full bozo" helped me to understand that you can take generations of a family and group them into groups, subgroups, and so on with their modifications. Every connection Shubin made about our ears, eyes, hands, skulls, etc serves to show that groupings of characteristics can be made as you follow along the evolutionary process. And lastly, the reason for the defects in our bodies and our health issues is that our bodies right now were not exactly made for this present time. But, we can study our past to help address the ways we can live healthier.
-Sarah You (: