Evolution -Them-To Us

Evolution

The origins of mankind is an extremely controversial issue within today's society. Scientists have a host of different theories pertaining to man's inhabitance of earth. Many disagreements arise between scientists who have different beliefs pertaining to where and how mankind arose. One such argument is the conflict involving the theory of evolution versus the theory of creation. After extensive scientific research, it is apparent that the theory of evolution is correct. Evolution is the theory that life arose by natural processes at an early stage of the earth's history and that complex organisms developed from simpler organisms by a process of slow change. It is the idea that new species rise from older species after thousands of years of gradual chemical, environmental, and genetic change. Evolution can be described as the complex processes by which living organisms originated on earth and have been diversified and modified through sustained changes in form and function "Evolution". Scientists, looking for an explanation to the origin of man and other organisms created this evolutionism theory, which also presented answers to the many asked questions dealing with similarities between species. Unlike the theory of creation, which states that the complexity of life and different species can only be explained in terms of a supernatural creator or god who placed life on earth, the theory of evolution has a plethora of evidence proving it to be true "Creation". There are several different types of observations that support the theory of organic evolution as an explanation for the similarities and the differences among species. One such observation is in the geologic record. The geologic record is the rock scheme found within the earth's outer crust. By means of radioactive dating, the ages of rocks in many places on earth have been determined. It is a timetable of the earth's geologic history. This combined with the fossil record, another observation supporting the evolutionary hypothesis, has produced an apparent sequence of life forms from most simple to most complex during the history of the planet. Fossils are any remains or traces of a once-living organism, which are formed by preservation, petrifaction, or sedimentation. Organisms can be preserved and protected against decay by being trapped in amber, tar, or frozen in ice. The hard parts of an organism, such as shells or bones, can be preserved when the flesh of an organism has decayed away. In other cases, materials of a dead organism may be gradually washed away and replaced by minerals from the water causing the organism to petrify, or harden. Imprints, molds, or casts left by an organism after it is enclosed in sedimentary rock and decomposed are also fossils, as well as footprints and tracks. The fossil record is the timetable of fossils found in within the earth's geologic record. Since the upper layers of sedimentary rocks are assumed to have been laid down over lower layers, the upper layers are younger than those deeper into the earth. Therefore, fossils found within the upper layers are also younger than those found within the lower layers. This combination of geologic and fossil records shows the progression of species as time also progressed. In reiterating the definition of evolution, we are reminded that gradual changes in one life form's anatomy, cytology, embryology, or biochemistry could cause a new species to originate. Similarities in these categories link species together and are therefore studied to support evolutionism. In comparing anatomy, the structures of different organisms often show unexpected similarities. Cell organelles, such as cell membranes, ribosomes, and other structures found within cells, are also similar in organisms of all kinds, showing that comparative cytology can also shows signs of evolution. When comparing the embryos of different organisms, comparative embryology, similarities can be seen in early stages of embryos that are completely different at maturity. Finally, comparative biochemistry, which is the comparing of biochemical compounds, such as amino acids, can also show similarities in species, reinforcing the idea of evolution. As curiosity rose throughout much of the world, scientists began to question the existence of organisms and why some are so alike in so many ways and so diverse as well. Several theories have been proposed in the past to account for the diversity and similarity of species. One scientist by the name of Lamarck proposed that changes in species occurred basically as the result of a striving of organisms for improvement. One main point of this theory was use and disuse. New organs appear in a species as a result of a need for them, and they increase in size or effectiveness through repeated use. Organs not needed decrease in size or strength because of disuse. A second idea included in his theory was the transmission of acquired characteristics. This means that a trait acquired during the lifetime of an organism, including improvements of existing traits, can be transmitted to its offspring. Later in scientific history, it was Charles Darwin who came up with the most convincing theories of adaptation and development. In 1859, he published The Origin of Species, introducing the theory that species evolve from others, including man's development from apes. Darwin proposed that evolution occurred as the result of natural selection. Natural selection is the process by which environmental effects lead to varying degrees of reproductive success among individuals of a population of organisms with different characteristics and traits. It is the idea that organisms with favorable variations are better able to survive and reproduce than organisms not well adapted "Natural Selection". Overproduction is a main idea of Darwin's theory. He believes that more offspring are produced than can survive, because of limitations in living space and food supply. He also believes in competition, where individuals of each generation compete for available food and opportunities to mate and reproduce. A third idea of Darwin's evolution theory is variation, meaning some individuals are better fitted to survive than others, because of variations in characteristics. Survival of the fittest was how he explained the fact that individuals better fitted to survive are more likely to live longer and reproduce. Darwin's idea of transmission of favorable characteristics modified the earlier idea presented by Lamarck. Charles believed offspring of the fittest individuals would inherit only the favorable variations that enabled their parents to survive and reproduce. Explaining this idea, Charles Darwin stated, "Beneficial variations of all kinds will thus, either occasionally or habitually, have been preserved, and injurious ones eliminated"

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