Evolution (Essay Sample)

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Natural selection is a major mechanism through which populations evolve. Describe three other mechanisms that can lead to evolution
Introduction
Evolution is a gradual change in features of organisms over a long period of time Futuyma, Douglas J., (2005). He change is unidirectional and gradual. It is not reversible. The change is mainly caused by different factors in the organism and influenced by mechanisms in and outside the body. The most dominant mechanism is natural selection where the organism with the best features survives to reach maturity and reproduce pass off their features to the next generation.
Apart from natural selection there are other mechanisms that drive evolution but at a smaller scale. They include: genetic drift, random mating, and mutation. Genetic drift is the increase in certain alleles and decrease in the other alleles due to random chances that occur in a population. This phenomenon happens due to selection error in selecting genes from a population’s gene pool.it may cause up to 100% deletion of alleles responsible for certain characteristics in a population. This mechanism is very evident in small populations.
Mutations are random change in the allele in a genome. It happens as a mistake in the DNA of an organism. If an organism with the mutation survives to maturity, it passes the mutated alleles to the next generation. Most mutations cause adverse effects on the organism and are major cause of death of the organism. Mutations, for this reason are not prominent but if combined with other mechanisms can cause a significant genetic change in a population.
Random mating is process where the organisms mate randomly within the population while non-random mating happens when mates are selected within the population. According to Bennet, et.al, 2002 (97-119) non-random mating is evident in human race. As the culture forms a base for the selection of mates. This results to a population with similar features