Theory Of Evolution Essay Research Paper Theory

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Theory Of Evolution Essay, Research Paper Theory of 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 selectionoperates on apopulation of organisms containing

diverse inheritable forms. HISTORY Pierre Louis Moreau de Maupertuis (1698-1759) was the firsttopropose a general theory of evolution. He said that hereditary material,consisting of particles, was transmitted from parents to offspring. Hisopinionof the part played by natural selection had little influence on othernaturalists. Until the mid-19th century, naturalists believed that eachspecies wascreated separately, either through a supreme being or throughspontaneousgeneration the concept that organisms arose fully developed from soil orwater. Thework of the Swedish naturalist Carolus Linnaeus in advancing theclassifying ofbiological organisms focused attention on the close similarity betweencertainspecies. Speculation began as to the existence of a sort of bloodrelationshipbetween

these species. These questions coupled with the emergingsciences ofgeology and paleontology gave rise to hypotheses that the life-forms ofthe dayevolved from earlier forms through a process of change. Extremelyimportant wasthe realization that different layers of rock represented different timeperiods andthat each layer had a distinctive set of fossils of life-forms that hadlived in the past. Lamarckism Jean Baptiste Lamarck was one of several theorists whoproposed anevolutionary theory based on the “use and disuse” of organs. Lamarckstated thatan individual acquires traits during its lifetime and that such traitsare in some wayput into the hereditary material and passed to the next generation. Thiswas an attempt to explain how a species could change gradually

overtime.According to Lamarck, giraffes, for example, have long necks because formanygenerations individual giraffes stretched to reach the uppermost leavesof trees, ineach generation the giraffes added some length to their necks, and theypassed thison to their offspring. New organs arise from new needs and develop in the extent that they are used, disuse of organs leads totheir disappearance. Later, the science of Genetics disprovedLamarck’s theory, itwas found that acquired traits cannot be inherited. Malthus Thomas Robert Malthus, an English clergyman, through hiswork An Essayon the Principle of Population, had a great influence in directingnaturalists towarda theory of natural selection. Malthus proposed that environmentalfactors such asfamine and disease limited population