Fish and Humans: Homologus Structure

Over the past few centuries, humans have been questioning and debating over what makes evolution true. In Jerry Coyne’s work, Why Evolution is True, he noted two kinds of evidence from Darwin’s theory of evolution. The first evidence includes the six testable predictions of evolution: evolution, gradualism, speciation, common-ancestry, natural selection, and nonselective mechanisms of evolutionary change. The second evidence that Coyne noted in his work is the retrodiction. In Coyne’s work, Why Evolution is True, a retrodiction is the facts and data that are not necessarily predicted by the theory of evolution but it makes sense only in the light of the theory of evolution. Retrodiction uses present theories to explain events that happens in the past. Since evolution is a slow process, theories could not be tested. Therefore, we explain the existence of vestigial structures and how humans share a common ancestor with fish through the theory of evolution. Throughout the text, examples of retrodiction are the imperfect adaptation of a panda’s thumb and gill slits in the beginning stages of a human embryo. Common ancestry is proven by the existence of fossils and these evidences proves that evolution is true.

All animals with limbs have a common design. If a batwing were to be formed from a person’s hand, make the fingers extremely long; a horse elongates the middle fingers and reduce and lose the outer ones; frogs elongate the bones of the leg and fuse several of them together. All in all, despite radical changes in what limbs do and what they look like, this underlying blueprint is always present.

Chapter 2, Getting a Grip, talks about the connections between the human and other creatures’ limbs. It also talks about Shubin’s fossil, Tiktaalik, and the unique specialized limbs it had.

All primates have a common ancestor, from millions of years ago. Go further back, and you will find a common ancestor for all mammals. Then a common ancestor for all vertebrates, then animals, then all life on earth. How closely two organisms are related can be deduced by looking for homologous structures, structures that look similar and have a similar function. This proves that the organisms descended from a common ancestor. Station 1 contained multiple vertebrate skeletons. They all had homologous structures, including a vertebral column and a rib cage. This shows that all vertebrates are related and come from a common ancestor with a

Primates have four distinct tooth types, which include incisors, canines, premolars, and molars (Larsen, 2008). Dental formulas have been developed by anthropologists with

It is emphasized greatly because that is how we understand ourselves, our past, present and even the future. Through evolution we have discovered when the first organisms came around and how modifications led to the first fish to migrate to land about 375 million years ago, our ancestral fish Tiktaalik, and how that led to mammals and eventually humans. Not only has evolution turned us into the beings we are today but helped to explain some of the diseases that plague humans today. From the ability to store fat that has led to obesity today due to sedentary lifestyles, to the hiccups we endure thanks to tadpoles and fish. Accordingly, with the theory that organisms keep evolving, humans might give way to even more complex life. Evolution is an excellent explanation to the standard limb theory of Sir Richard Owen to show that most species follow a similar pattern of limbs and evolution is the best theory we have to explain the vast similarities we have. Many of the experiments throughout the book showed that we looked similar but are also chemically alike. The Hedgehog gene in every animal makes for mirrored limbs and further solidifies the evolution theory. The experiments were all carried out in the hope of finding why we are who we are and many have explained this because evolution is an essential matter to learn and grow

DNA contains the information that builds our bodies from a single fertilized egg. Cellular diversity gives rise to our tissues and organs, with distinct shapes and functions. Yet, all cells in our body contain exactly the same DNA. The resolution to this apparent paradox lies in the fact that different pieces of DNA are turned on in every cell, and these pieces are called genes. When a gene is turned on, It makes a protein that affects what the cell looks like and how it behaves. Our bodies are a composition of individual genes turning on and off inside each cell during our development. We use this information about gene “switches” to compare the activity of different genes, with the end goal of assessing what kinds of changes are involved in the origin of new organs. For limbs, we catalogue the genetic differences between fins and mammalian limbs. Then, we study the function of these genes in embryos and do experiments to manipulate genes, mutate specimens, and observe the responses to these changes. Each gene has a distinctive sequence, and using molecular tools, researches can scan another species’ DNA for identical sequences. It turns out that the DNA “recipe” to build upper arms, forearms, wrists, and digits is identical in every creature that has

The book Your Inner Fish by Neil Shubin is a journey into 3.5-billion-year history of the human body. The book is an entertaining and useful novel that demonstrates the evolution of some of our major structures through time. By analyzing fossils and DNA, the author shows us that our hands truly resemble fish fins, our head is organized like that of a long-extinct jawless fish, and that major parts of our genome look and function like those of worms and bacteria. The book takes us on a remarkable expedition in which it will show us our inner fish, reptile and

3. When Shubin says this he refers to the chronology of the inter epidermis organisms. Teeth were the first structures to form out of the skin. Without the groundbreaking efforts of the tooth, hair scales and breasts would not have been able to form because they evolved from teeth.

One of the most astonishing things on earth is the human body. They consist of many organs that work together to maintain the person alive. The humans body composition is complex, but what was the origin? How did we become who we are today? These are the questions that intrigued me, and allowed me to understand how the human body evolved over the years. By the examination of our ancestors, and our body we will understand how we look today.

While I was reading Your Inner Fish, I went through a journey that changed my viewpoint on the topic of evolution. Before reading this book, I did not believe in evolution. I thought that is was just another thing that I was being taught to believe and that it didn’t actually have any solid evidence behind it. I figured that there could never be evidence solid enough to convince me that we were related to fish in any way, shape, or form. Your Inner Fish changed my opinion by showing me that there is actual fact to back up the theory. In chapter 5, it explains about the Sonic Hedgehog gene, and how it is in every living creature including humans, and how it forms our digits, and how it is in skates as well.

To demonstrate, the evidence for evolution with embryology, Jerry Coyne uses branchial arches, and the newly discovered phenomena called lanugo. To begin with, by comparing the embryos of fish with that of a human, scientist, have discovered how similar the embryos start out, but overtime their developmental process change to their specific species. In the fish, gills are developed, and in the human part of the head and middle ear. In a word, the discovery of that humans are covered with hair during conception, gives scientist better understanding of humans during their embryonic stage of life, because it proves the connection to our apelike ancestors. Final example used by Jerry Coyne, for embryology evolution is the grasping reflex by babies,

Offspring differ somewhat from their parents and from one another. Instructions for development are passed from parents to offspring in thousands of discrete genes, each of which is now known to be a segment of a molecule of DNA. This essay will explore some of the reasons behind how and why these differences in appearance arise, from the base sequence of DNA through to the observed phenotype.

Humans spent thousands of dollars going to the dentists so we can keep using our teeth healthy and be able to chew on food that we eat every day. Teeth are earliest development and the lead to many other features. They were first seen in eel like vertebrate, the Conodonts that had armor teeth like structure that were made from the interaction of two skin layers. Also found in the ancient fish called Ostracoderms (Shubin, p.77). Its head were composed of tiny bone shield that were made from the teeth like structures. Teeth were developed to process food. The development of teeth was composed of two layers of the tissue in the skin. The protein in the outer layer of the skin produce enamel and the inner layer produces the dentine and the pulp inside the tooth (Shubin, p.78). The process of two

Humans have existed on Earth for approximately 3.4 million years. The oldest known human ancestor is "Lucy," an Australopithecus. Over this extensive period of time, humans have evolved significantly. Homo Sapiens have grown from 3 to almost 6 feet (average), lost most of the body hair, became leaner and adapted to walking. Humans have come a long way, from Australopithecus to Homo sapiens, from living in trees to living in cities. Slowly, through hundreds of thousands of years, we mutated over and over again, natural selection ensuring that no destructive mutations continue. From the slow evolution, four distinctive species emerged and died out, each giving way to its ' descendant: Homo Habilis, Homo Erectus, Homo Sapiens Neanderthalesis, and Homo sapiens Sapiens.