Is Evolution a Gradual Process?

Introduction

The change of biological populations through inherited characteristics and over successive generations is referred to as evolution. Through evolution, there is a rise of diversity in the various biological levels from species, various individual organisms and the molecules like protein and the DNA. Charles Darwin is known to the father of evolution. It is believed that the life in earth underwent evolution from a common ancestor over 3.8 billion years ago. Darwin was the first scientist to propone the evolution theory and he presented his argument on a natural selection basis. In his natural selection, Darwin observes that there are three main facts that characterize evolution. The first fact is that there are more off springs that are always produced and that can survive possibly. The second characteristic of this selection is that the individuals vary in terms of their traits and thus, leading to a difference in terms of survival rate and the rate of reproduction. The last observation of this natural selection is that the different traits in individuals are hereditary and can be passed from one individual to the other. Eventually, when the individuals die, there is a replacement by a progeny of other individuals that are more adapted to survive in the environment. There have been two major divergent views concerning the nature of evolution. These two views have given rise to two major sides, one insisting the evolution is a gradual process while the other disputing this fact and observing that evolution is occurs in a mode of punctuated equilibrium. (Muehlenbein, 2010).

Evolution as a gradual process

Charles Darwin, who is also the father and proponent of the evolution theory, believes that evolution was as a result of a slow and a gradual process. He had a belief that this process took a stepwise mode as opposed to being perfectly smooth. In the support for evolution being a gradual process, Darwin indicated that the species took time to evolve and accumulate small variations. This gradualism was further ascertained by the recording of fossils of the changes that are incrementally small within the various species. However, there was the inability to find a number of the intermediate forms, a development that Darwin and other scientists blamed on the gaps that exist in the records of fossils.

Those in support for gradualism indicate that evolution is a variation and a selection that happened in a more gradual manner. Evolution is termed to be gradual because it is often very hard to notice over a short period of given time. There are small variations that do take place in the organisms that eventually make them be better fit to be in the selected environment more than the initial parent organisms. Moreover, organisms with traits that are more helpful do survive in the environment and those with traits that are less helpful end up dying off. The population is bound to change over a long period of time, with this change being gradual. This school of thought believes that evolution is a gradual process that takes place slowly, constantly and consistently. The proponents of the model of gradual evolution believe that the species that are progenitor are the ones that do give rise to other new species yet there is no mechanisms that specially account that account for the numerous new species or genera that are of higher classification. Notably, there is just the accumulation of the various changes attributed to the alleles which are small and found in the pools of genes. (Hall, 2011)

Charles Lyell and James Hutton’s geological based findings indicated that gradualism basically builds to the fact that the mall changes that are built up over a long time are responsible for the large changes that are seen in individuals and in organisms. This perspective is based on the processes of geology and formed the base for Charles Darwin’s Theory of Evolution. This is the idea that he adapted and therefore came to conclusion that evolution is a process that takes place over a long time span for the ultimate change to be observable. In support of this view by Darwin and other proponents of the fact that evolution is a gradual support is the records obtained from fossils. There are numerous fossils which prove these transitional features and ascertain the fact that there are structural adaptations that species develop in the process of transforming into species that are more adaptable and fit to survive in the naturally selected environment. Gradual evolution has further been supported by the geologic time scale which shows that there has been a change in the species since the time that life was incepted in the Earth. This change has taken place over millions of years.

Evolution is not a gradual process

There has been a school of thought that believes that it is a misconception to term evolution as to be a gradual process. This school of thought is based on the factor that evolution occurs in a punctuated mode. This is the mode whereby there is an increment in the changes more that the time that is seen in discrete intervals. This school of thought holds the view that there is most of the time when there is no virtual change on the organisms, thus, dismissing the fact that evolution takes place gradually. According to those who oppose the gradual evolution, they think that the changes seen as a result of evolution often occur in spurts.

According to this view, evolution occurs in punctuation where there are certain periods when the changes are very little or basically not there while in other periods the changes that occur are huge and more pronounced. These changes are believed to occur usually as a result of mutational processes in the genes. The mutations are believed to occur randomly and not inherited by the off springs from the previous generations but are often passed to the next generation. This argument holds that despite the danger of mutations, they do serve an important function in equilibrium that is punctuated and are vital in the survival of individuals in their environments. The mutations are always very important for the purposes of the survival of the individuals and there is usually a change over a short period of time, creating a difference between those who have these traits or mutations and the individuals who do not have them.

This argument based on evolution by punctuation is based on the fact that there are instances or periods when the changes in individuals occur rapidly over a given time. Later, these changes subside and this is followed by a long time of stability and inactivity in as much as changes are concerned. (Mayr, 199)

The argument against gradual evolution is majorly based on the manner in which the changes occur. The punctuated equilibrium bases its argument on the fact that mutations are responsible for the ultimate large changes that are experienced in organisms. However, those in this thought observe that mutation can be rapid and lead to a change in the organisms but can also be cause by sudden changes in the environment. This may force the species to expedite the changes in order to conform to the new environment which may be harsh in order for the species to survive.

Conclusion

Despite the two varying arguments, there is one thing that both schools of thoughts hold, this is the fact that evolution is a process that is taking place and that it occurs over a long period of time. The only point of dispute is on the mode of the change of structures in the species. Those holding on to gradual evolution insist on the gradual rise in formation of the new species from progenitor species while those for punctuated evolution insist on the fact that there are varied changes at various times. They base their argument on the fact that species experience changes at given periods at rapid speed while in other periods there is less or no change at all. Evolution is actually a gradual change as there cannot be variations in the structural developments of the different species. The changes are often effected at very slow pace and take several years to be observed. Further, this gradual change is always as a result of the off spring species developing traits that are more adapted to their new environment and that are more advanced than those of the parent species. 

References

Hall, B. (2011). Evolution: Principles and Processes. London: Jones & Bartlett Learning. 

Mayr, E. (1997). Evolution and the Diversity of Life: Selected Essays. New York: Harvard University Press, 1997

Muehlenbein, M. (2010). Human Evolutionary Biology. UK: Cambridge University Press.