YIF: Chapter 11

This chapter is the final chapter in the book Your Inner fish and is appropriately titled "Meaning of it all." In this chapter Shubin first tells us about evolution and how our genetic tree has developed over the past billion years. This is crucial for the rest of the chapter where he will talk about specifics that did not fit in the last 10 chapters. He relates our speech to that of primates and how they evolved together. Then talks briefly about how our fish and tadpole "ancestors" evolved and how we evolved from them and that is how we have hiccups. He explains that how hiccups are beneficial to fish in their breathing, whereas they are neither beneficial nor harmful for us humans. Lastly he talks about how our shark "ancestors" can help us, especially males, relate to getting hernias. The overall basis for these points in this chapter is the biological "law of everything" that states every living thing on the planet has had parents. The most important idea in the section was how we can link ourselves to each other and how all humans are related, no matter where from on earth, because we all evolved from a common point. The part I find intriguing is how we can tract this relationship with others. To do this we use a method similar to cladograms, except it is almost reversed. We look at a family tree of yourself and you can, for the most part, tell where another person that you have meet would fall. This process is much more complex than I gave it credit for, but that is essentially what happens. However this so called "family tree" would have to go back hundreds of generations of you, so it is not practical for the average person to do. This chapter reverts back only to the first Big Idea of biology that states: The process of evolution drives the diversity and unity of life. This is a very evolution heavy chapter and essentially this Big Idea relates to the chapter because Shubin keeps going back to the point that we have all descended from a common ancestor and thus these evolutionary links can be establish between us and other races. An essential question to take from this chapter would be: "How can characteristics from other species tell us more about our own bodies?"

YIF: Chapter 10

The chapter entitled "Ears" or chapter 10 is about the biology of the human ears and relating the middle ear and inner ear to biological ancestors. Shubin is quick to make the remark that the external ear that we humans have, is a trait that is unique to mammals although some amphibians and reptiles do have a somewhat external ear. The man component of the human ear that has been linked to other ancient organisms is the middle ear, composing of the stapes, malleus, and incus. These three ear bones have been linked to gill arches, the stapes in the second gill arch and the malleus and incus in the first gill arch. Through the brilliant minds of Karl Reichert, Ernst Gaupp, and W. K Gregory the link to fish as well as mammal-like reptiles has been discovered, because the three ear bones found in humans is strongly tied to the anatomy of these organisms. Next Shubin writes about the biology of the inner ear, a topic that fascinated me the most. He talked about how the ear works with the brain and the eyes to determine sound, position or acceleration. What was most fascinating was the part of the ear that is the main component in determining these three things. There is a gel like substance in the ear that is touched by hair cells. When one moves or shifts their body, the gel like substance shifts, and tiny rock like objects on top of this gel exaggerate the shift, causing hair cells to detect the movement and ultimately send signals to the brain. This chapter relates the most to Big Idea #3 and Big Idea #4. Big Idea #3 states Living systems store, retrieve, transmit, and respond to information essential to life processes. It is fairly obvious that the three parts of the ear, the inner, middle, and external ear all work to gather in order to obtain knowledge about the position of the person, their current velocity, and hearing sounds. Big Idea #4 states: Biological systems interact, and these systems and their interactions possess complex properties. And like mentioned before, not only does the three parts of the ear work together, but the ear as a whole works with the eye to get the most accurate information of the current environment that one is in. An essential question that can be formulated based on this chapter would be: How do ancient organisms with no ear at all come to evolve to create complex ear systems?

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?"

YIF: Chapter 8

This chapter titled "Making Scents" is, like the chapter suggests, about the nasal passage and smelling. Shubin spend time talking about the evolution of smelling and how this is relevant to the evolution of smelling to animals and even us humans. Shubin makes a remarkable statement that "our sense of smell allows us to discriminate among 5000 to 10,000 odors." It is very fascinating that out of all the molecules in the air we are able to pick out "up to one part per trillion." The connection to evolution is that "3% of our entire genome is Devoted to genes for detecting different odors." You can trace back to the genes for smelling out from the history of animals. This can be seen by looking at which genes are being expressed in fossils that are extinct or in animals that are still alive. What I found most interesting was how we smell. We smell by tiny molecules in the air which will actually attach themselves to neurons in our nasal passages. The complexity of these neurons is incredible. We have thousands of genes that express for the nerve cells that enable us to detect odors. And apparently we lost many of these genes throughout our evolution. According to Yoav Gilad "primates that develop color vision tend to have large numbers of knocked out smell genes." Going with the assumption in this book that we are we, as humans, are ancestors from primates, we can tell that we have lost large numbers of smell genes for our color vision. This chapter relates a lot to big idea one and four. For big idea one the process of evolution for smelling shows the diversity of life. As we saw in this chapter dolphins had blowholes and lampreys had a nostril and we, humans, have external and internal nostrils. As we look throughout our evolutionary history we see that the amount of genes for smelling has been increasing, this attributes to the diversity of life. For this chapter's connection to big idea for we see the molecular system of smelling and how our brain interacts with this. We see that small amounts of molecules enter through our nose and attach themselves to neurons and our Nasal passages. The book goes on about how the brain interprets these neurons and all of which is explained in great detail in this chapter. An essential question that can be made from this chapter would be, "How does an organism gain or lose the ability to smell?"