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?”