Gradualism Versus Punctuationism Essay, Research Paper
Although modern evolutionists are thought to be divided on the issues surrounding evolutionary theory, a close look at the evidence suggests that both the gradualist school of thought and the punctuationist school of thought share many characteristics in common. This is especially true when evaluating their beliefs about the fossil record, disagreement with the theory of saltation, and the misinterpretation of the word ?rapid? in terms of punctuationist theory. Although this may be the case, the two theories do diverge on one important point, the notion of periods of stasis, but when taken as a whole, the evidence suggests that punctuationism is not as radical as it has been hyped up to be.
In terms of evaluating both arguments, it is important to dispel the some common myths about punctuationist theory. First, there appear to be many large gaps in the fossil record (Dawkins, 1986). Both gradualists and punctuationists agree that the only explanation for these apparent gaps, besides the notion that there are gaps in the record, would be creationism. Creationism holds that the reason for the appearance of largely different organisms in the fossil record, without organisms that display intermediate amounts of change is the presence of a divine creator. Neither gradualists nor punctuationists agree with this assumption.
In addition, when comparing the theories of gradualism with punctuationism, it is important to evaluate the theory of saltationism. Although punctuationists have often been confused with saltationists, this is a huge mistake. Saltationism holds that macromutations are the cause of evolutionary change (Dawkins, 1986). This could make sense when viewed in the context of the fossil record. Saltationists would argue that there really are no gaps in the fossil record. The dramatic changes noted in the fossil record would be products of macromutations which are signs of natural selection. This cannot be the case for two distinct reasons. First, large macromutations are considerably maladaptive for an organism. In this sense, the size of a mutation will determine whether the organism will survive and pass on the mutated gene. Larger mutations will be less likely to be selected, because they will produce large behavioral abnormalities in the organism, which will significantly impair the organism in carrying out normal species-typical behaviors for survival. In turn, the organism will probably die before it is able to successfully reproduce. In addition, some mutations that are termed macromutations are not really macromutations at all, but instead small changes in the genetic instructions that produce large changes in the individual.
It has also been argued, that gradualists believe that evolution proceeds in a constant fashion. This is also a myth. Both gradualists and punctuationists believe that evolution proceeds in a somewhat jerky fashion with periods of evolutionary change being mixed with periods of stasis, or no change (Dawkins, 1986). The main point at which the two theories diverge is on the issue of stasis. Although both believe that periods of stasis do in fact occur, punctuationists take this a step further. Punctuationists argue that during periods of stasis, ?There are genetic forces in large populations that actively resist evolutionary change? (Dawkins, 1986) During these periods of stasis, no evolutionary change can occur. Eventually though, after a long period of stasis, the resistant genetic forces are weakened by the forces of evolution, and a brief period of rapid evolutionary change is allowed to occur. It is also important to note, that ?rapid? in terms of evolution is often misinterpreted. Even in terms of punctuationist theory, changes are really not rapid in the general sense of the term. Evolutionary changes are rapid in terms of geological standards, but by normal standards these changes are very gradual. In this sense, punctuationists really are arguing from a gradualist perspective. As Richard Dawkins (1986) put it, punctuationism should be characterized as ??gradualistic, but with long periods of ?stasis? (evolutionary stagnation) punctuating brief episodes of rapid gradual change?..
Therefore, the theories of gradualism and punctuationism share many elements in common with one major issue on which they diverge. First, both agree that there are gaps in the fossil record, and in doing so, they reject the theory of creationism. Second, neither gradualists nor punctuationists agree with the tenets of saltationism, because scientific evidence refutes the major premises of this theory. In addition, both gradualists and punctuationists agree that evolutionary change does not proceed in a constant and smooth fashion. Both theories assert that evolutionary change is followed by a period of stasis, but the punctuationists believe, that this period of stasis is marked by an active resistance against evolutionary change. Thus, theorists of the punctuationist school should quit looking to completely discredit the gradualist school of thought, because they share many premises in common with each other. Instead, the focus should be placed on identifying the strengths and weaknesses of both arguments in terms of the fundamental difference concerning periods of stasis.Reference
Dawkins, R. (1986). The Blind Watchmaker. New York: W. W. Norton.