YIF: Chapter 7

            In this chapter of Your Inner Fish, the author does a lot of explaining about the history and organisms with different types of bodies, organs, and the way they make their bodies. The author explained about the collagens and other molecular chemicals that are found in bodies organisms, and how even some primitive organisms, like sponge, have these. The author did not say too much about this and its evolutionary connection with humans, but he did write about how the in the timeline of the Earth that there weren’t bodied organisms until about 1 billion years ago. He said that when bodied organisms started to appear on the Earth that the life that Earth had was forever changed. This explains why humans and animals of all kinds are bodies, which was the point of the entire chapter. My favorite part of the chapter was the short story about the evolutionary experiment that was performed by Martin Boraas. In this experiment he let single cell alga organisms thrive in a controlled environment. After 1000 generations, he let a single celled creature with a flagellum into the environment where it thrived off eating the other organisms. After less than 200 generations the alga organisms evolved into an eight celled ball where each of the cells could get light to photosynthesize, and where it wouldn’t get eaten by the predator. This is my favorite part because it describes an experiment that shows that evolution of an organism is very possible and it supports the author’s belief of evolution. The Big Ideas of biology that are connected to some ideas that are present in this chapter are:  living systems store, retrieve, transmit and respond to information essential to life processes, biological systems utilize free energy and molecular building blocks to grow, to reproduce and to maintain dynamic homeostasis, and the process of evolution drives the diversity and unity of life. The first Big Idea has connection to this chapter, and it is that when the author was talking about the timeline of the bodied organisms he mentioned that the organisms might have become bodied in response to predators eating them, also that the sponges respond to the outside environment with the information around them. The second Big Idea’s connection to this chapter is that the single celled biological systems utilized the energy from oxygen and the sun to become bodied and then the homeostasis of the prey was stabilized. Lastly the third Big Idea’s connection to this chapter is that all bodied organisms are diverse but at the same time united by the fact that they are multicellular and certain cells have certain roles, and also that all the bodied organisms are bodied due to the change in the way of life and body-building. An essential question that can be made from this chapter would be, “How (chemically) does one cell evolve to become an organism with two trillion cells?”

YIF: Chapter 6

            This Chapter does a lot of explaining of evolution in terms of embryos yet again. But instead of the connection between humans and other animals being gill arches it is about the body plan of the embryo in the very early stages of development. Karl Ernst von Baer did experiments with the embryos of chickens and other animals and noticed some very strong similarities. And his ultimate conclusion was this: “Every animal organ originated in one of [the] three [germ] layers. Significantly, the three layers formed the same structures in every species.” This discovery is found in humans as well, the three layers being the ectoderm, mesoderm, and endoderm. This shows that von Baer’s conclusion of the evolution is relevant to human evolution because since most animals have it, then it is likely that we descended from the same ancestors. When the book was talking about the human embryo stages of development was my favorite part of the chapter. I loved how it talked about the early timeline of the fetus in the mother’s body and how childbirth is such a wonderful thing. It was also very fascinating to know and understand what the fetus looks like before it has any distinguishing features. I think the most interesting part of this section of the chapter would be when the author talked about the three germ layers, the mesoderm, endoderm, and ectoderm and how they will all develop into separate organs, like the mesoderm into the body cavity and other organs and the endoderm into the digestive tract and other organs. The Big Idea that has connections to this chapter of the book is the process of evolution drives the diversity and unity of life, because the author lectures about the genetics and embryonic similarities between species so that he can convey that they are unified and also diversified. This is one specific example that was used in this chapter but there are many more connections that can be found as well. An essential question that can be made from this chapter would be “What can similarities in genetics cause to be similar between two creatures?”

YIF: Chapter 5

            This chapter was in some ways irrelevant to evolution. It took a little while for the author to tie what he was saying into the evolution of human. What he was mainly talking about was the head of mammals, fish, worms, and humans. What was special and what he said that they all have in common, yes even the headless worms, was that they all had something called the four gill arches. Each of the four categories of animals that I listed not long ago all have these arches and they look similar to each other when each of these animals is an embryo. It is when they develop further along into the stages of their embryo that they separate and look different from each other and each of the gills forms into something different. The author didn’t relate the four gill arches to the evolution of humans until he mentioned that the essence of our heads goes back to worms, such as the Amphioxus, who didn’t even have heads, and this is because these worms have the same gill arches, but when they develop they form separate organs that humans do and it is believed that these headless worms are part of the origin of the arches that we have. The most interesting part of this chapter was when the author said that “we can manipulate the identity of the gill arches almost at will, by changing of the gills inside.” (Shubin 94). This fascinated me more so than other parts of this chapter because it kind of reminded me of the ZPAs that we heard about a few chapters ago, in that we can manipulate the genes to change the embryo when it fully develops. In the book the author used the example of manipulating the gill arches of frogs by turning off some of the genes in the gill arches. The outcome of this was that the frog ended up with two jaws. That is simply interesting, however this does have much to do with evolution, and it only deals with the biology of embryos. This chapter has connections with two Big Ideas in biology, one being biological systems interacts, and these systems and their interactions possess complex properties, and the process of evolution drives the diversity and unity of life. The first idea makes a connection with this chapter because of the insane complexity of the four gill arches and how they develop into something so specialized and they interact with each other to make the organism better functioning. The second Big Idea makes a connection with this chapter because of the idea that the headless worms that existed millions of years ago share the same gill arches that several different animals, ranging from sharks to humans, have the same arches, but they develop into organs with different functions. This idea means that the diversity of the mammals can be unified by using the perspective of this one evolutionary aspect.

YIF: Chapter 4

            This chapter encompasses the evolution of animals by taking the perspective of teeth. The evolution starts at conodonts, then, ostracoderms, all the way up to humans. Teeth are a powerful window into an animal’s lifestyle, especially their diet. Also the author talks about teeth and how they are preserved well and why, which is because teeth contain something called hydroxypatite. This is why teeth are more preserved than other bones and tissue. The evolution history of humans can be explained by something as small as teeth because of the type of teeth, their size, and their alignment. For example our mammalian way of precise chewing, emerges in the fossil record from around the world that ranges from around 225 million to 195 million years ago. My favorite part of the chapter was the largest portion of the chapter; it was the story of the author’s first expedition and the first two expeditions that he led with his colleagues. This story was well written and grasping and intriguing, after each page that I read, I wanted to react more because it was intertwined and showed a progression in wisdom and experience. It made it seem realistic and the effort that was put into the expeditions could be easily seen. Also I love how he sets up each expedition is a many story by making a sort of suspense by talking about his failure, what he did to improve and then him getting better, and then finally him finding something special to both him and something that is very relevant to the purpose of the book. The Big Idea of biology that makes a connection to this chapter is the same as all the others, and that is the process of evolution drives the diversity and unit of life. The reason being is that once again this proves that multiple animals that are seemingly different can be classified in the same category as humans due to a common ancient ancestor. One essential question that can be made for this chapter would be, “How can mammal teeth show the relationship between two species?”

YIF: Chapter 3

            This chapter brought embryos and eggs to show some of the biology of evolution that occurred. They did this by mentioning and describing and relating ZPAs, zones of polarization activity, which are essentially a patch of tissue that causes the pinky side to be different than the thumb side. Then the author went on and said that many animals, including humans, have the ZPA. Then scientists were curious so the wanted to see if the adding of another animal’s ZPA would cause to same result of adding the same animal’s ZPA to another ZPA and surprisingly it did. This was probably the part that most interested me as it justified, scientifically, the relationship of animals to each other using genetics. It is so intriguing to see that this was one of the first ways that scientists used to prove that different animals have similar genetic makeup. More specifically the part where they took a mouse’s ZPA and put it near the ZPA of a skate’s and the two reacted as if the two ZPA were from the same animal, which is an example, to what was mentioned above. This shows scientists that the genetic material of humans is similar to the animals that we already have seen similarities to. This just strengthens the fact that humans share a common ancestor to other animals. This is also the idea that can be drawn by relating this chapter to the Big Idea of biology, the process of evolution drives the diversity and unity of life. The overall essential question that can be made based off of this chapter is, “What is the relationship between genetics and evolution?”

YIF: Chapter 2

            This chapter was mainly focused on the origin and evolution of the hand and arm, and where they came about and how they were proven through multiple discoveries. Also, while going through what limbed animals have in common the topic of Owen came up. While the author was mentioning Owen, he talked about the patterns that he saw and how they were accurate and how they are related with all limbed animals. Those patterns would be: all creatures with limbs, have a common design; the differences between creatures lie in differences in the shapes and sizes of the bones and the numbers of blobs, fingers, and toes; and lastly, probably the most important pattern in the chapter, the skeleton of a human arm has one bone in the upper part of the arm, two bones in the forearm, several bones at the wrist, then the series of rods that are the fingers, and this arrangement is similar to all other limbed animals and the differences between different animals is explained in the second pattern. This overview shows scientist that we have similar characteristics to other animals, like frogs, horses, and seal, which show that the evolution of the human body and the evolution of these animals, and animals like them, are similar in many ways, only by looking at the arm. The most interesting part of this chapter was when the author when back to the fish that he discovered, the Tiktaalik, and analyzed it and told us how its fin has the same pattern that Owen described and it had similar bone structures to ours. And what was even more surprising was when he said that this fish had the ability to do pushups! It is simply amazing how a fish that existed so long ago has some human capabilities and that is possible that we could have gotten some of these abilities from this animal! The overall topic from this chapter can answer two Big Ideas of biology, one being the process of evolution drives the diversity and unity of life, and the other being biological systems interact, and these systems and their interactions possess complex properties. The first idea encompasses the obvious, that evolution of animals like Tiktaalik unify the limbed animals and us together. The second idea can be thought of how the interactions that occur in the hand from performing simple maneuvers make the hand have unique and complex properties. All in all, the chapter creates one essential question, “How does evolution of the same animal create separate species?”

YIF: Chapter 1

            This chapter does a great deal in mentioning the author’s, Neil Shubin, experience in fossil hunting and what they do to determine a great location for fossils which are the rocks’ age, sedimentary rocks (the types of rocks most ideal for preserving fossils), exposed rocks at the surface, and lastly serendipity. He explains how he used these four factors in his own expeditions, and he later describes the result of each expedition, how he was able to accomplish it, and what this tells us about the history of the evolution of limbed animals. His second expedition that he mentioned has the most relevance when talking about the Tiktaalik, a fish that he discovered in the Arctic, because this fish is an evolutionary intermediate between fish and primitive land-living animals, it is very important in understanding the evolution of humans. The most important conclusion that can be determined by analyzing this fish is determining how fish transitioned from living in water to living on land, which can be seen by analyzing its fins and head and shoulders and most of the rest of his body. This idea about the Tiktaalik was the most interesting to me because it was such a huge discovery and it involved so much to how reptiles and amphibians transitioned from fish which is just incredible. And what makes this discovery that much more amazing is that scientists predicted this type of fish would have existed and that they also were to give a relatively accurate period of time that this fish would have existed. This chapter makes the largest connection with the Big Idea of biology that is the process of evolution drives the diversity and unity of life. I will use the Tiktaalik again to describe this connection. This connection is that this fish leads people to conclude to the origins of life diverge. Because one can easily see that different land animals have similar body builds, with the same types of bones but in different locations and sizes, it can be determined that they all evolved from the same primitive land animal, and this discovery of the Tiktaalik shows that land animals evolved from fish which raises a lot of questions about the origin of land-animals but also answers a lot. Finally an overall question that can sum up all of the ideas from the first chapter of Your Inner Fish is, “How can fossils of the past help with our present?”