Untitled Essay Research Paper BODYINTRODUCTION TO EVOLUTION

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Untitled Essay, Research Paper BODYINTRODUCTION TO EVOLUTION What is Evolution? Evolution is the process by which all living thingshave developed from primitive organisms through changes occurring overbillions of years, a process that includes all animals and plants. Exactly howevolution occurs is still a matter of debate, but there are many differenttheories and that it occurs is a scientific fact. Biologists agree that all livingthings come through a long history of changes shaped by physical andchemical processes that are still taking place. It is possible that all organismscan be traced back to the origin of Life from one celled organims.The most direct proof of evolution is the science of Paleontology, orthe study of life in the past through fossil remains or

impressions, usually inrock. Changes occur in living organisms that serve to increase theiradaptability, for survival and reproduction, in changing environments.Evolution apparently has no built-in direction purpose. A given kind oforganism may evolve only when it occurs in a variety of forms differing inhereditary traits, that are passed from parent to offspring. By chance, somevarieties prove to be ill adapted to their current environment and thusdisappear, whereas others prove to be adaptive, and their numbers increase.The elimination of the unfit, or the "survival of the fittest," is known asNatural Selection because it is nature that discards or favors aarticular being. Evolution takes place only when natural selection operates on apopulation of organisms

containing diverse inheritable forms. HISTORY Pierre Louis Moreau de Maupertuis (1698-1759) was the first topropose a general theory of evolution. He said that hereditary material,consisting of particles, was transmitted from parents to offspring. His opinionof the part played by natural selection had little influence on other naturalists. Until the mid-19th century, naturalists believed that each species wascreated separately, either through a supreme being or through spontaneousgeneration the concept that organisms arose fully developed from soil or water. Thework of the Swedish naturalist Carolus Linnaeus in advancing the classifying ofbiological organisms focused attention on the close similarity between certainspecies. Speculation began as to the existence of a sort of blood

relationshipbetween these species. These questions coupled with the emerging sciences ofgeology and paleontology gave rise to hypotheses that the life-forms of the dayevolved from earlier forms through a process of change. Extremely important wasthe realization that different layers of rock represented different time periods andthat each layer had a distinctive set of fossils of life-forms that had lived in the past. Lamarckism Jean Baptiste Lamarck was one of several theorists who proposed anevolutionary theory based on the "use and disuse" of organs. Lamarck stated thatan individual acquires traits during its lifetime and that such traits are in some wayput into the hereditary material and passed to the next generation. Thiswas an attempt to explain how a species

could change gradually over time.According to Lamarck, giraffes, for example, have long necks because for manygenerations individual giraffes stretched to reach the uppermost leaves of trees, ineach generation the giraffes added some length to their necks, and they passed thison to their offspring. New organs arise from new needs and develop inthe extent that they are used, disuse of organs leads totheir disappearance. Later, the science of Genetics disproved Lamarck’s theory, itwas found that acquired traits cannot be inherited. Malthus Thomas Robert Malthus, an English clergyman, through his work An Essayon the Principle of Population, had a great influence in directing naturalists towarda theory of natural selection. Malthus proposed that environmental factors such asfamine