Free The Four Forces Of Evolution Essay Example

Evolution is one of the most important theories formulated by Charles Darwin in the year 1859, which affects the views of individuals on the relationship between humans and the natural world. The evolutionary theory explains about the transformation of species. Evolution exploits individual variations that are purposeless by eliminating those that confer no benefit to the organism. According to Darwin, the evolutionary theory accounts for change within the species and the emergence of new species in naturalistic terms. The study of genetics explains about the transmission of traits from parents to the offsprings, which helps to predict the chances of an individual to display phenotypic characteristics . In other words, it helps to understand how the process of evolutions becomes a reason for the diversity of life on earth.
The term species refers to a group of organisms that can breed successfully only within a group. Species range over a territory, which may be large involving different kinds of environments. The subterritories formed by the isolation of species form populations. A population is a group of individuals in which breeding of the species takes place. Variation refers to the different traits of an organism, such as body shape controlled by a series of genes . Physical relationship has a close relationship to climate. Climate has a great impact on human variation as it affects the process of growth and development. The importance of variation is that it protects the species from going extinct or populations from dying out due to changing environmental conditions.
The four forces of evolution that create a pattern for biodiversity are mutation, gene flow, genetic drift and natural selection . These forces of evolution disrupt a population’s tendency towards equilibrium. A gene pool contains all the genetic variants of a particular population. Mutation is the ultimate source of genetic variation in human beings. It introduces new alleles into a population. Changes in DNA cause positive, negative or neutral effects to an organism. Environmental factors, such as heat, radiation and chemicals increase the rate of mutation. Genetic drift refers to the effect of evolutionary processes on the gene pool of a population . The occurrence of events in genetic drift accounts for the presence of human variation since humans lived in smaller populations prior to 10000 years.
Gene flow refers to the transfer of alleles from one gene pool to the other. It depends on the migration of individuals or groups of individuals from one territory to another territory. Geographical factors, such as rivers, and social factors such as intergroup conflict, mating rules and distance of travel affect gene flow . Natural selection accounts for adaptive change in human beings. It is the emergence of traits in a species that provide survival advantages under prevailing environmental conditions. It operates in a stabilized way reinforcing a standard range of traits within a species. Natural selection differs from the concept of design in a way that it works with existing species only . Over time, natural selection leads to the formation of new species.
Isolation is a necessary phenomenon as the absence of isolation leads to the differentiation of populations into distinct species through gene flow . It refers to the separation of species due to mountains, deserts and rivers, or the drifting of continents. The inability of the species to reproduce due to isolation leads to the emergence of distinct species because change in the environment does not necessary occurs simultaneously at both the groups. Speciation results in the formation of new species through the process of cladogenesis or anagenesis . While cladogenesis occurs in a branching fashion, anagenesis occurs when a single population gathers a sufficient amount of new mutations over time to form a new species.

References

Haviland, W., Prins, H., Walrath, D., & McBride, B. (2012). The Essence of Anthropology. Belmont, CA: Cengage Learning.