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Four Forces of Evolution

Evolution is a change that affects the inheritable characteristics. Such changes affect only the biological populations and occur in successive generations.it is through evolution process that the modern living organisms have resulted. Four forces of evolution are dwelt on in this discussion. The evolution forces mentioned here refers to the factors that collectively contribute to the overall evolutionary process. Evolution is a generational process that occurs over time. The forces discussed here include mutation, genetic drift, natural selection and gene flow.

Mutation as a force of evolution results to gross alteration of genes and geneexpression; they are inheritable changes and occur randomly. Some forms of mutations are beneficial while others are harmful to organisms. Beneficial changes enable organisms to improve life sustaining adaptive skills like those involving reproduction and feeding abilities. Gene mutation is significantly responsible for the emergence of population variation, the variations in population could be within or between populations and are as a result of either environmental or gene influence.

The forces of evolution may lead to two types of evolution namely micro and macro evolution. Varying processes lead to either of the two types. Microevolution refers to the changes that arise within a pool of genes from one given generation to another. It is greatly influenced by all the four forces of evolution. Macroevolution on the other hand studies changes that go beyond species level; it describes the abrupt occurrences that lead to transformation of one biologic system into another; for examplea change of life from water to land. This led to speciation; different species then came into existence. A species refers to the lowest taxonomic grouping or ranking of organisms that can freely interbreed and give rise to new viable offspring

Natural selection is yet another force of evolution. In this case, the individual members of population continue to exist depending on their ability to reproduce and survive in the existing environmental conditions. It is notable that more organisms are produced by the progeny than can live or survive.Here, organisms with traits that offer advantage over the competitors are passed to the new generation. Those that are disadvantageous are rarely or minimally passed.

A third force of evolution in this discussion is the genetic drift. It is a change in the type of genes found in a population. These changes do occur in successive generations. Allele frequency is more prone to sampling error in a smaller population; a larger population is not affected much by genetic drift as the sampling errors finally cancel off. The drift alone is adequate to alter two separate populations that begun with same genetic material into two divergent populations.

The last evolutionary force is gene flow. It involves the mixing of genetic material among populations and or species. If two populations are completely isolated over time and no exchange of genes occur between them, they develop gene incompatibility. It therefore serves to minimize the genetic difference between populations. Organisms entering a population from another one come with a new set of gene pool. When they mate with the population that they join then they form hybrids that carry these genes from species to species.

Isolation mechanism largely takes part in evolution. In this mechanism, there are reproductive characteristics that prevent the given species from fusing. The mechanisms include physiological processes and behaviors related to reproduction. In this case, the species belonging to two different species are prevented from mating and if they mate, no viable offspring results

In conclusion, all the four forces of evolution discussed above work together additively to foster evolution process. It is these forces that have over the years led to development of the various forms of life that exist in the present time. These processes are gradual but constant and give rise to the variations observed between different species. Evolutionary forces mainly occur in ways that enhance species survival but may occasionally be deleterious.