Your conclusion should tie up the threads of the argument you introduced in your opening paragraph and developed throughout the main body of your essay. The length of your conclusion should be in proportion to the length of your essay, i.e., a paragraph for a supervision essay. A dissertation would obviously warrant a longer conclusion. Ideally, your conclusion is an opportunity to reassert your position in relation to the argument, which is an area which supervisors confirm is often lacking in the average essay. Try not to rush your final paragraph and ensure that you move beyond a simple summary of the points you have made and relate your conclusion directly to the question asked, perhaps by actually using similar wording.

Activity

Compare the conclusions below to the three essays we have been looking at (Discuss the role of chance in evolution), noting the following:

• Can you link each conclusion with its introduction from the previous activity?
• Do any of the writers move beyond summary to hint at their own 'position'
• Which conclusion do you feel closes the topic sentences essay?

Conclusion 1

Even today, the balance of importance between chance in the form of drift versus selection is still debated. However, there would be nothing for the directional process of selection to act upon if it were not for random mutations that produce new alleles. In summary the evolutionary events not driven by selection must have occurred through genetic drift. On the one hand, genetic drift is a random process; on the other natural selection acts upon differences in phenotype that have arisen as a consequence of random genetic mutation. Therefore, chance plays several important roles in the evolution of living organisms.

Conclusion 2

The basis of variation, mutations, and how they affect the phenotype involves chance. Except for extreme cases of genetic drift, how Natural Selection then acts on the population isn’t random. Natural Selection itself is definitely not the ‘Law of Higgledy Piggledy’ as John Herschel so eloquently put it. However chance does have a part to play in evolution. Were we to start all over again, the chances are, everything would not happen the same way

Conclusion 3

Ultimately evolution depends on chance because mutations are random. Mutations create novel genes which are then acted upon by natural selection (non-random) and genetic drift (chance). The relative importance of both is dependent on the size of the population, the frequency of the allele and how constant the environment is. If the environment is stable then natural selection will have little role to play in evolution, instead genetic drift will be the most important factor. Similarly, if the allele is rare, genetic drift has the potential to cause large changes to its frequency. However once the gene is fixed in the population, natural selection will have a greater role in changing its frequency dependent on its fitness (non-random). Natural selection, and thus a non-random process, has the potential to cause greater changes in the allele frequency. This is because it is directional whereas genetic drift causes the frequency to fluctuate. Sexual selection also has the potential to cause large changes in the allele frequency purely due to the chance starting frequencies of alleles.

Now click here to access the supervisor's feedback on each of the three conclusions above.