Evolution by Natural Selection
Along other mechanisms of evolution such as genetic drift, mutation and migration, natural selection is a fundamental process that is a direct outcome of the interplay between variation, heredity and differential production. These three parameters can be effectively used to break down the entire process into a simpler and understandable process. For instance, the existence of a population of beetles majorly consisting of the brown ones and a few green ones shows a variation in color traits. By natural selection, the environment is not fully able to support the inferior groups as the green population of the beetles is fed on by beetles leaving their brown counterparts to reproduce and multiply. Due to heredity, the subsequent beetle generations have the brown coloration, thus becoming dominant within the beetle population until all the beetles that make out the population are brown. Darwin’s theory of evolution by natural selection is a relatively recent explanation of evolution, regarding the fact that there had been several revolutionary views and opinions by other scientists. Through natural selection, Charles Darwin brings a new face onto the conundrum of evolution theory that had so far lacked a concrete explanation. It is therefore viewed as a major advance to other prior ideas with regard to how organisms evolved over time.
Natural selection as described by Darwin is a channel for the accumulation and preservation of less- significant, yet functionally advantageous alterations and mutation in the genetic makeup of a population. A functionally advantageous trait for instance camouflage or method of flight developed within a species is inheritable and can be passed on to subsequent generations. Organisms exhibiting limiting and non-advantageous traits, no matter how large their population can be are weeded out of this population through death and outlived by their advantageous counterparts. Therefore, the process of natural selection, comparable to the modern domestic breeding, helps preserve a competitive and advantageous trait enabling the individuals that posses them have a competitive edge and survive in the environment. This change and elimination of organisms possessing inferior traits occurs gradually until the entire population is competitively level and similar in traits. In a macro-evolutionary fashion, it is thought that the process of natural selection can entirely redesign the composition of a species and introduce new species. According to Darwin, this is a process that cannot be observed in non-living organisms which exhibit what he terms as irreducible complexity. On his own account, Darwin notes that natural selection is only possible in the existence of any detectable and inheritable variations. At least for all living organisms, this is a necessary evolutionary mechanism for their advancement. He further concedes that the existence of any complex living organism systems that are not products of variations and modification would render his theory of natural selection resolute and void. (“Darwin’s Theory of Evolution”, 2016)
It is widely understood that Darwin was not the first individual to develop such informed trials at explaining revolution. Starting early in the 18th Century several scientists had made postulates and speculations in an attempt to explain this phenomenon, with most of them ending up as scientific catastrophes. Comte de Buffon is credited for making the first observation about the changes that living organisms undergo over time and attributed these changes to environmental and chance causes. Erasmus Darwin is such an individual who wrote obscure publication titled Zoonomia in an attempt to explain the cause of the million years of evolution on earth. However, not much of these speculations did come to light. Later, Jean-Baptiste Lamarck confidently brought to limelight another failed attempt at explaining evolution. He postulated that living organisms were a product of non living materials through transmutation and later progressed gradually and developed into complex organisms through strife for perfection and adaptation. Significant to this theory’s explanation is the concept of inheritance of characteristics acquired by the organisms in order to adapt to their environment and the theory of use and disuse of various organs within an organism. Lamarck put forward examples such as the elongation of giraffe necks in their subsequent generations in order to adapt to changing feeding circumstances. George Cuvier, a critic of Lamarck’s theory also formulated what he called the catastrophism theory. This theory was based on the consequences of natural catastrophes such as floods and earthquakes wiping out an entire existing population of various organisms. New forms of life migrated and flourished in other areas adapting and developing new traits. Cuvier’s theory was however effectively undone by one uniformitarianism theory that is believed to be the basis of Darwin’s theory of natural selection. This theory developed by Charles Lyell held that the natural forces that happen in the present times were much similar to the past and were crucial in understanding the past. (“Early Theories of Evolution:; Pre-Darwinian Theories”, 2016)
Natural selection as described by Darwin is just one of the driving forces in the process of evolution. According to Gregory Carey in his article, Five Forces behind Human Evolution, natural selection, mutations, genetic drift, culture and a population’s mating structure all contribute to remarkable evolutionary changes in the world today and even before. The key factor to natural selection is reproductive fitness, that is, the ability to bring forth viable and adaptive offspring by a parent generation. Genetic drift on the other hand is as a result of alteration in frequency of alleles within a species or a population over some time, singly as a result of chance. Mutation, another evolution causing factor, is the alteration or error in the process of DNA synthesis, more appropriately copying process. Either somatic or germinal mutations results into remarkable alterations in both genotypes and phenotypes of a population for a particular trait, resulting into gradual evolutionary changes. An example in this case is the color discrimination ability and variation among primates and other animals.
A population’s mating structure greatly influences the variations in a genotype and ultimately thee phenotypes in a similar fashion like breeding habits. Culture on the other hand has influenced human habits and approaches to various lifestyles that can cause gradual evolutionary changes. Feeding and religious affiliations have helped enhance the chances of random mating habits and better adaption ways that may enhance or suppress natural selection.
Due to the advanced knowledge and exposure within the modern world through biology, biochemistry and molecular studies, the concept of evolution is better understood. Modern evolutionary genetics incorporates the concept of genetics and Darwin’s theory of natural selection to give a better understanding of evolutionary changes. To this date various traits directly point to natural selection. Behavior of living organisms, for instance a human being’s capability to learn a new language and mating techniques in animals are subject to natural selection. Human activities have also led to environmental changes and impacted an evolutionary change on people through natural selection. An instance is the rise and fall in the population of dark moths that coincided with industrial changes in England in the nineteenth century. Much however is credited to Darwin for the provision of an advanced and informed opinion on the concept of evolution through natural selection. It is however important to note that natural selection is not entirely a random process as it has been interpreted. Variation in traits in population can be random due to the mutation, however, selection for or against a population exhibiting a particular trait is non-random and definite.
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