Why Evolution Is True by Jerry A Coyne - Term Paper Example

Evolution Theory Introduction The existence of living organisms has a number of arguments and discussions, with each trying to explain best the genesis of life. Such contrasting proposals were called theories and, included the Creation theory, Evolution theory and many more. This essay is a reflection of the chapter themes of the book “Why Evolution is true” by Jerry Coyne. The essay shall firstly review every chapter as a demonstration of the scientific concepts of evolution. As a summary, at the end of the essay, other concepts of evolution based on Philosophy, Theology and Sociology shall be briefly reviewed. Lastly, the scientific concept of evolution shall be criticized based on a personal opinion. Chapter One Evolution has been defined as the gradual genetic change that the species usually undergo due to the environmental pressures. The DNA, a vital element of the animal cell, has taken all the living creatures to a single common ancestor. Most animals share the patterns of their DNA. This was before the evolution took place. The evolution eventually took place and the organisms have been biologically and geographically separated from each other. Evolution took place in three different forms. These are: Gradualism, Speciation and the Natural selection. In gradualism, the species take several generations to attain the desired change that will enhance their survival. Thus, evolution takes many years to be fully achieved. Speciation is the process whereby organisms split into different species. It is the evolution of different species that cannot easily interbreed. Natural selection, according to Coyne, is just but a ‘tinkerer’. This means that natural selection does not yield any original perfection in a species but, only improves on what ha s already been established. In this chapter, a number of theories have been brought forward. They included the evolution theory, cell theory, plate tectonic theory and atomic theory. However, the book specifically concentrates on the evolution, which, argues that all living organisms originated from a common ancestor. Chapter Two Chapter Two concentrates on the Fossils as evidence of evolution. Fossils are the remnants of the ancient species that resemble the living animals of today. The fossils have always been there since the beginning of time; even Darwin and Aristotle discussed fossils in their books. Fossil formation takes a few but very lengthy steps. First, there must be remains of either animals or plants. These remains must sink in deep waters for quite a long time. However, the sunken remains must be recovered in good time by the process of sedimentation before they decay. The fossil record has been used to trace the ancestry of the species that live in the current world. Grand Canyon concept is a method categorizing the rocks according to their ages. The Grand Canyon illustrates the ages of the rock layers and their chemical composition. For instance, Red-wall Limestone has been estimated to be almost 335 million years old. This limestone is deep red in color. Trilobites, as the name sounds, were used to mean three lobes. The Trilobites were specific groups of extinct arthropods of the deep seas. The arthropods belonged to a class called the Trilobita. These organisms vividly illustrated how animals can survive for several years in an environment by the help of an appropriate adaptation. The trilobites were diversified into scavengers, predators and filter feeders. This diversification is what enhanced their long period of survival. Another fossil species was the Tiktaalik. This fossil drew the interest of many archeologists since it was only one species and, it represented the transitional form between the amphibians and the fish. Upon the study of the skeletal fossil of theropod dinosaur, it was concluded that the birds were the decedents of the dinosaurs. Chapter Three In this chapter, Jerry Coyne uses scientific concepts in relating a few organs of the human body and other animals to prove that these organisms could had have a common ancestor, since they share similar organs. One of such is the Laryngeal nerve that facilitates speaking and swallowing in human beings. This nerve is also found in other animals like the giraffe. In the giraffe, the laryngeal nerve is about 15 feet, thus, it’s an adaptation that aids the giraffe in feeding. The recurrent laryngeal nerve is an ancestral characteristic of the tetrapods. It is, however, also found in human; an implication of common ancestry. The scientists have also mentioned the imperfect designs in animals. Such of the imperfect designs are the alignment of the urethra and the prostate in the male human. Here, the male urethra runs through the middle of the prostate gland. In this design, when the prostate happens to enlarge, it squeezes the male urethra and causes the urethral constriction. Since the urethra is a urinary tract, urine flow may be restricted, thus, resulting to a painful experience (Sarfat, 2008). The very poor designs of organs have also been seen the in the position and location the female ovaries. Chapter Four This chapter discusses the Biogeographic evidence of evolution. This is the distribution pattern of species on various locations of the earth. Biogeographically, different animals with same form happen to live on different locations on the globe. This happens because of the convergent evolution, where, organisms in the same environment may experience selection pressure and thus, develop same adaptive features yet these organisms do not belong to the same species. They will, therefore, tend to behave in the same manner due to these similar features. The convergent evolution has illustrated three types of evolution. These are: Common ancestry, Speciation and the Natural selection. In this very chapter, Jerry Coyne has also demonstrated how fossil tree can be used to prove the validity of evolution. In this aspect of fossil tree, it was found that fossils dug in a given geographical location usually resemble the organisms that normally live in the very location. This is evidence that these existing animals must have evolved from the fossils. Still on the biogeographic evidence, it was proved that animals on an island usually tend to resemble and share more features with the animals that live on the closest mainland than the animals living far away from the island. This implies that both the island and the mainland species might have undergone the same convergent evolution. Chapter Five The chapter is all about how natural selection and randomness has catalysed the process of evolution. In natural selection, the genes that usually produce better adaptive features become more and more frequent with time. These adaptive genes make the species fit to survive in a given environment. Adaptation by natural selection is always based on three factors. These factors are: Variability, Mutation and Selectivity. The genetic variation in an organism is what determines the long term adaptation of a species. Mutation is the errors that sometimes happen in the gene replication. Such radical changes in the gene are always permanent and irreversible. While natural selection is an ordered variation that only keep the good variants and eliminate the bad ones, Randomness keeps both bad and good variants. Both natural selection and randomness may be as a result of mutation, only that natural selection enables some animals to continue surviving as other die or escape. The species that develops the survival features is said to be fit for survival. The fitness is a process that is normally attained through steps. First, the possessor species must have an average number of offspring. Secondly, the possessor must have a high reproductive output. If a species reproduces a multitude of offspring, it enhances the chances of survival. Such that, whenever there is an outbreak of calamity, all of them do not die; a few live to sire more offspring. Chapter Six In this chapter is a scientific demonstration of how sex drives evolution. Before the sexual reproduction, there has to be a sexual selection. The selection has been categorized into two major types by Coyne. These types are: the direct competition between the males and, the choosiness of the female species. The sexual selection is brought about by the asymmetrical gametes. Here, the male species usually make more but small gametes while the female makes few but large gametes. These two species, therefore, have to evolve so as to successfully mate and reproduce a viable offspring. The scientific approach proposes that the male, for that matter, has to be promiscuous and the female must be coy so as to enhance smooth mating process. However, the females must cleverly discriminate the bad genes against the good male genes. This difference in traits exhibited by the two opposite sexes is called Dimorphism. The dimorphism is caused by the difference in genes. The other explanation of sexual dimorphism put across by the scientific concept is that the selection of a male species is usually driven by biasness in nervous system of the female species. Chapter Seven This chapter is an illustration of the origin of all species of the earth. Species has bee defined as a cluster of organisms that can freely interbreed to produce a viable offspring. According the morphological species concept, members of the same species usually resemble each other more than they do to other different species. Going by the morphological concept, it becomes very easy to spot members of the same species, just from the physical outlook. The morphological concept talks less of the interbreeding and the reproduction of the fertile young ones. Some scientists who underrate this concept stress much on the interbreeding as the key factor to speciation. Organisms that belong to different species, therefore, cannot freely sire a fertile offspring. There are always sexual barriers between organisms of different species. However, the evolution scientists have argued that these barriers were just the by-products of the natural selection that had caused the geographical isolation of the species. Chapter Eight Here is the evolution of the human beings. Jerry Coyne concurs with Darwin, that the human beings have a common ancestry with chimpanzees and other several primates like gorillas and monkeys. The evolution of human being dates back to the early ages of the apes. It is said that the human being and other primates were once tetra pods before they could learn the process of bipedalism. The bipedality came with the advanced species called the homoerectus. The homoerectus were the ape species that could walk uprightly. The apes had to stand uprightly so as to gather food above his head. It is, therefore, said that the major cause of the evolution of man that triggered the bipedality was the adverse drought. Studies have shown that there are several genetic differences between man and the chimpanzees. However, the DNA test has proved that these genetic differences are very minimal in the human population. Human beings are said to be mammals that had the same origin as the rest but with time, successfully evolved to a more advanced form in the past billion years. The human beings have evolved from the homoerectus to homosapiens. The speciation to homosapiens made man the most intelligent among the rest of the species. Chapter Nine This chapter has acted as the concluding remarks of the author, Jerry Coyne. Here, he brings together all his energy to support all the points that had already been put across. Every Darwinian Theory has been vividly described, explained and proven true. All the scientific evidence and theories discussed in the previous chapters seem very convincing. However, there is still controversy with the evolution theory since not every individual has been convinced by the description and explanations of Darwin and Coyne. Personal Journey of Discovery The topic of evolution has been very interesting and disturbing at the same time. Through the topic, I have discovered a few issues related to the genesis of the mankind. I have discovered all living organisms may have one common ancestor at one point in time. This has been clearly explained in the fossil concept and the similar stages of life that the animals usually undergo. In embryology, I could learn that the embryos of most animals usually look similar to that of man at one stage of development. The embryology and the laryngeal nerve system described how man shared similar organs with other mammals. Another discovery made from the topic is that other than the human beings, other animals can as well make choices of mates. The sexual selection concepts describes how male and female birds distinctive dimorphism that enables them to make the right choices of mates, especially the female species. The male birds, just like men, compete for the available females by displaying the best features. Above all the discoveries made from the evolution theory is the advancement of man from a primitive creature to a very intelligent organism of all time. It was amazing to know that man used to walk on four legs like the rest other mammals but, later advanced to rule the world. It very interesting the drought made man to stand upright and walk on his two legs in search of fruits that hanged on trees (Darwin, 1909). Philosophical, theological and sociological reflections Even though Coyne has tried his best by supporting the Darwinian theories and verifying these theories further, there is still controversy of the evolution theory. Philosophical and theological arguments have dabbed the evolution theory as evil. The creationists have insisted that the evolution theory has been based on two world views; the naturalism and the materialism. Naturalism assumes that Science is the only way to explain and understand the whole universe and the processes that happen therein. The creationists think that there are more better and godly concepts of explaining the universe. The world, they think, has relied so much on the misleading science. Materialism, on the other hand, is the concept that the only reality in the world is in the physical matter and that all other things, including life, come from this physical matter. The creationists say that this also a wrong idea held by the scientist. According to the creationists, who solely believe in the creation theory, the whole universe and all living things were created by God. Any other theory, according to this theological reflection, is not plausible at all and is termed as evil (Hull, 1967). The philosophical reflection, in particular, holds the argument that evolution is just a mere theory of life pattern but not an ultimate philosophical scheme about the origin of life. Sociologists, like the philosophers, think that evolution, however valid it may look, can only be used to explain the origin other animals but not the human beings. Personal critique of the Evolution Theory The topic of evolution has considerably attempted to explain the origin of life and the emergence of new species. Most of these explanations are easily understood. However, a few concepts and facts do not seem to add up. Some facts even contradict each other while a few lack clear links. In past years, the evolution concept has put it there have been billions of species in the world. However, the fossil record only gives 0.1% of these species. The evolution theory, through the fossil records, has failed to account for the remaining 99.9% species. This only means that the fossil record used a very small sample size of the overall population to draw its results. Such findings cannot be valid. The morphological concept which, tries to explain the process of speciation concentrates on the physical aspects of the species. This concept ignores the fact that species are not only based on the physical distinct and resemblance but also on the sexual barriers. It, therefore, only used one paradigm to draw a conclusion and that makes it an invalid concept. In the origin and speciation of man, the science of evolution does not clearly state the intermediary species of man and the apes. There seems to be a wide gap between the two species, yet there is lack of explanation. Furthermore, the evolution theory does not explain to us why only human being advanced this far while the rest of the apes remained in their original states. Lastly, throughout the theory, the idea of a common ancestor has been mentioned on several occasions. However, both Darwin and Coyne failed to specify and mentioned that common ancestor. This idea of common ancestry, thus, remains an ambiguity in the science of evolution. More research needs to be done ascertain some disturbing findings of the evolution theory and confirm whether the evolution actually took place. Reference Coyne J. (2009). Why Evolution is true. City of Westminster, London: Penguins. Darwin F. (1909). The Foundation of the Origin of Species. Cambridge: Cambridge University Press. Hull D. (1967). The Metaphysics of Evolution: The British Journal for the History of Science. London Sarfat J. (2008). The Prostate Gland- Is it “badly designed”? City of Westminster, London: Penguins. Read More