Your Inner Fish By Neil Shubin Analysis

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In the book, Your Inner Fish, by Neil Shubin he presents the notion of evolution and how we can trace parts that make up the human body back to jellyfish, worms, and even fish. The book not only discusses how we arose to be what we are today, but also the implications our ancestors had on our current body plan. In this essay, I will demonstrate that I have digested the entirety of Shubin’s book by convincing you (dear reader) that everything in our bodies is based on simple changes to already existing systems. To make this case, I will use the evidence of limb development in a vast array of organisms, the four arches found in the embryological stage of development, the structures inside our noses, and how our ears have come about all due to modifications. There is common plan for all limbs: one bone, followed by two bones, then a bunch of little bones, and finally digits. This array of bones is seen in many species including, but not restricted to bats, whales, and lizards. But how do these limbs develop and why do they all look similar? Shubin explains it by conveying that there are certain genetic switches that help assemble who we are. When scientists went looking for this genetic switch in limbs, they found a couple tissue areas in the limbs that allow this body plan to occur. “A strip of tissue at the extreme end of the limb bud is essential for all limb development…This patch of tissue was named the zone of polarizing activity (ZPA).” ZPA allows humans to have opposable thumbs and pinkies. In other organisms, it differentiates the “thumb” side from the “pinky” side. Scientists then wanted to discover the molecule that allowed this changen in the ZPA, the answer is Sonic hedgehog. Shubin points out that every limbed animal h... ... middle of paper ... ...resting thing is that we also share the gene Pax 2 which is active in the ear region and initiates a chain reaction of gene activity leading to the development of the inner ear. This common gene shows evidence of a common history and how our bodies are made up of many modifications. Neil Shubin’s book is very informative on how our inner fish is real and definitely present in our bodies today. I have given supporting evidence on how our bodies are based on simple changes (relatively) to already existing systems. This is seen even today when scientists study organisms with a simpler body plan than us to understand medical conditions and mutations in the human body. We were created from variations and modifications to become what we are today and this an astounding thing. Our body plan was possible due to simpler organisms and this gave way to the life we know today.

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