Complete 1 page APA formatted article: The Four Forces of Evolution. Four Forces of Evolution Evolution is defined as a process that involves the change of alleles that make up genes in an organism. The process of evolution is well defined by four primary sources. gene flow, gene drift, natural selection as well as mutation. In tandem with this assertion, the paper will provide detailed information on the four forces, and they are involved in the evolution process.

Majority of the biologists believe that the world started as a single unit with a small population of primitive organisms. The environmental conditions however continued to change with time leading to accidental changes in the positioning of gene alleles in some species. This genetic drift then led to the splitting of the small population into more populations with varying species. In connection with this, the variation of species as a result of the genetic drift led to the isolation of species as well as occupation of new environments. This isolation however did not last for long, the exponential growth of the population as a result of reproduction exerted pressure on the minimized resources leading to the populations moving to other areas where they interacted and reproduced with other species. It was a result of this gene flow that other species with varying characteristics emerged leading to the formation of new populations. Survival of the emerged new population depended significantly on the natural selection force that enabled them adapt the new environment. Additionally, natural selection force made the organisms develops important traits as well as pass their variations to the progeny in order to enhance their survival. Thus, natural selection led not only to speciation, but also to the advancement of the genetic makeup of species (Haviland, McBride, Prins and Walrath 44). As time went by, the environmental conditions also continued to change leading to alteration of the pattern of genes in organisms in a process referred to as mutation. Just like natural selection, the random mutation of genes also led to the emergence of new species that made up different populations (Haviland, McBride, Prins and Walrath 42). Since the environmental conditions are prone to continuous changes, it is evident that mutation will remain being the ultimate source of evolutionary changes in organisms.

In conclusion, the process of evolution is well defined by natural selection, gene flow, gene drift, and mutation. However, the continuous environmental changes make mutation the main source of genetic variations between species from different populations.

Work Cited

Haviland, William, McBride Bunny, Prins Harald and Walrath Dana. The Essence of Anthropology. New York: Cengage Learning, 2012.