An essay can be divided into three main sections: an introduction, several body paragraphs, and a conclusion. The purpose of the body paragraphs is to develop the main ideas outlined in your introduction. Each body paragraph in your essay should contain one main idea that is supported with details and examples from the reading and listening sections. Because you have only a short time to write your essay (45 minutes), you may only need one or two body paragraphs. This means that you will need to focus on two to three main ideas in your essay.
Make sure that the separation between your paragraphs is clear to the reader. Either indent the first sentence of each paragraph or leave a space between each paragraph. It is also helpful to use transitional devices to help readers understand the connection between your paragraphs. Words and phrases like "first," "moreover," "in addition," and "in contrast" will make the flow of your ideas easier to follow. You will learn more about these in the next section, Transitional Devices.
The supporting details in your body paragraphs should draw equally on information from both readings and the lecture. Some of your paragraphs may only draw on information from the lecture or one of the readings, but overall the three sources (Reading 1, Reading 2, and the lecture) should be equally represented among your body paragraphs. Most of the information taken from the readings and lecture should be paraphrased rather than directly quoted in order that you can demonstrate your writing ability.
Each of your paragraphs should have a topic sentence clearly stating the main idea. This will usually be the first sentence. The topic sentence should be followed by several supporting sentences that contain details and examples taken from the readings or the lecture. The concluding sentence should summarize the paragraph and remind the reader of the main idea. It should also help create a smooth transition to the next paragraph. Note that the paragraphs in an essay do not all have to be exactly the same length. Similarly, the number of sentences and sentence lengths may vary between paragraphs as well. As you are writing your body paragraphs, try to make sure they each have these three parts:
Topic Sentence: States the main idea
Supporting Sentences: Provides details and examples from the readings and/or lecture
Concluding Sentence: Summarizes the current paragraph and prepares the reader for the next paragraph
Example Essay
The following essay contains well developed body paragraphs. The introduction and conclusion have been included to show their relation to the body paragraphs.
Prompt: Should the Canadian government use the biological method to control the infestation of Zebra Mussels in the Canadian waterways?
Introduction
Did you know that major Canadian waterways are being quietly destroyed by a foreign invader? The population of the zebra mussel—an imported shellfish with no natural enemies in this country—is increasing rapidly in Canadian waters, causing a variety of environmental and economic problems (Reading 1). There have been a number of possible solutions proposed as a way to control the zebra mussel population (lecture). The Canadian government should use a biological method to control the rapid growth of the zebra mussel population rather than employ a mechanical or chemical solution to this problem.
Commentary: This introduction outlines the problems caused by zebra mussels and clearly states the writer's response to the prompt: he is in favour of using the biological method of pest control. The writer has mentioned his preference for the biological method over two other methods (mechanical and chemical), and by so doing, he prepares the reader for his discussion of these methods in the body paragraphs.
Body Paragraph 1
Reading 1 outlines the extent of the damage caused by zebra mussels. They block industrial equipment likes pipes and tubes. They threaten fisheries by consuming plankton that fish depend on. Their presence grows as they are carried from one body of water to another, attached to birds, animals, and vessels. It is imperative that a solution is found to control these pests without causing harm to the environment. According to the lecture, there are several methods for controlling the infestation of zebra mussels. Some of these methods depend on chemicals, the most potent being chlorine. While chlorine is very efficient at eliminating zebra mussels, it is highly toxic and can kill other living things and cause cancer in humans. There are precautions in place to limit the use of chlorine for pest control. A system of pipes and pumps restrict its use in the Great Lakes, but this method still poses a danger to aquaculture and human health and is not sustainable in the long term.
Commentary: Note that the first sentence both states the source of the information in this paragraph (Reading 1) and introduces the main idea of this paragraph (the threat of an out-of-control zebra mussel population). The paragraph then discusses the problems with the chemical solution previously mentioned in the introduction.
Body Paragraph 2
Another possible solution to the zebra mussel infestation that is discussed in the lecture is mechanical in nature. There have been attempts to prevent zebra mussels blocking industrial pipes and tubes by covering these with screens. Unfortunately, very young zebra mussels are so small that they easily pass through these screens. Some have also tried to sink the pipes to a lower level, as the zebra mussels prefer shallow water. However, many lakes are not deep enough for this solution to work. Also, the cost of adding the additional length of pipes proved to be prohibitive. Clearly, the mechanical approach has not proven to be effective.
Commentary: Here again the writer begins with a strong topic sentence which clearly states the subject of this paragraph: the mechanical solution. The main source of the paragraph's information is also indicated. The supporting sentences that follow contain specific details and examples taken from the lecture. The paragraph ends with a concluding sentence that summarizes the overall message of the paragraph.
Body Paragraph 3
The lecture touches on another, more sustainable, approach to the zebra mussel problem. It may be possible to find a species that can control the zebra mussel population naturally. There are certain types of water birds that would eat the zebra mussels. Unfortunately, there simply are not enough of these birds to do the job. There is also a type of poison from an African plant that will kill zebra mussels, but it is toxic to other water creatures as well. Reading 2 does not explicitly mention the zebra mussel problem, but it does list a variety of cases in which one species was introduced into an environment in order to control another. For example, in 1873, an American insect was used to reduce the expanding population of the grape phylloxera in France. Such cases suggest that further research may result in finding a species that is capable of controlling the zebra mussel problem in Canada.
Commentary: The first and second body paragraphs explained why the writer did not support the chemical and mechanical methods. Here in the third body paragraph, the writer explains why he prefers the biological method and provides details (based on the lecture and Reading 2) to support his view.
Conclusion
Based on what we have learned from the lecture, it is clear that a chemical solution to the zebra mussel problem is not sustainable in the long term without causing harm to humans and other species. The mechanical solutions have also proven to be ineffective. The only sensible approach is to continue to seek a natural solution to this problem that will allow us to reduce our dependence on the toxic chemical method and the costly (and grossly ineffective) mechanical method. We must search the globe for a species—be it a bird, bacteria, or other form of life—that will be an effective predator to control this pest.
Commentary: The conclusion has been included here in order to show how the flow of ideas contained in the body paragraphs is brought together in the final paragraph. The writer has made a persuasive case against the chemical and mechanical methods and in favour of the biological method within the body paragraphs. In the conclusion, he has summarized his argument by synthesizing his ideas regarding the three methods of pest control.
Pair or Group Work
Retrieve an essay that you wrote in one of the previous units. Compare some of your body paragraphs with those of your partner or group members. Are they long enough? Do they include a clear topic sentence? Do they have enough details and examples from the readings and lecture? Did you cite your sources?