Paragraph Unity, Coherence, and Development

In each paragraph of an essay, one particular idea or topic is developed and explained. In order to successfully do so, however, it is essential that the paragraph be written in a unified and coherent manner. A unified paragraph must follow the idea mentioned in the topic sentence and must not deviate from it. For a further explanation on topic sentences, see the Write Right on Topic Sentences.

A coherent paragraph has sentences that all logically follow each other; they are not isolated thoughts. Coherence can be achieved in several ways. First, using transitions helps connect ideas from one sentence to the next. For more on transitions, see the Write Right on Transitions. Second, ordering thoughts in numerical sequence helps to direct the reader from one point to the next. Third, structuring each paragraph according to one of the following patterns helps to organize sentences: general to particular; particular to general; whole to parts; question to answer; or effect to cause. 

Remember that a paragraph should have enough sentences so that the main idea of the topic sentence is completely developed. Generalizations should be supported with examples or illustrations. Also, details and descriptions help the reader to understand what you mean. Don't ever assume that the reader can read your mind: be specific enough to develop your ideas thoroughly, but avoid repetition

An effective paragraph might look like this:

     It is commonly recognized that dogs have an extreme antagonism toward cats. This enmity between these two species can be traced back to the time of the early Egyptian dynasties. Archaeologists in recent years have discovered Egyptian texts in which there are detailed accounts of canines brutally mauling felines. Today this type of cruelty between these two domestic pets can be witnessed in regions as close as your own neighborhood. For example, when dogs are walked by their masters (and they happen to catch sight of a stray cat), they will pull with all their strength on their leash until the master is forced to yield; the typical result is that a feline is chased up a tree. The hatred between dogs and cats has lasted for many centuries, so it is unlikely that this conflict will ever end.

This paragraph is effective for the following reasons:

1. The paragraph shows unity. All the sentences effectively relate back to the topic sentence at the beginning of the paragraph. 
2. The paragraph shows coherence. There is a flow of thoughts and ideas among the sentences in this paragraph. There are good transitions employed in the paragraph. The writer also presents her sub-topics in an orderly fashion that the reader can follow easily.
3. The paragraph is developed. The writer gives herself enough space to develop the topic. She gives us at least two reasons to accept her argument and incorporates some examples in order to give those reasons more validity.

Exercises

A. In the following paragraph, there are two sentences that diminish unity. Underline the sentences that detract from the unity, and explain how they do so in the space provided below.

     (1) The deforestation of tropical jungles in the southern hemisphere continues, despite its catastrophic effects. (2) The amount of deforestation that goes on in Central America puts the people who live there in constant peril. (3) Each year, a million acres of vernal woodland are cut down and burned. (4) If this type of destruction continues, the region will be depleted of trees that help keep the carbon dioxide levels down. (5) Scientists in Central America do horrible experiments on animals in the jungles. (6) Also, the eventual destruction of the rain forests will stop any type of tourism in these countries. (7) This would be a great financial disaster for the governments of these tropical nations, since tourism brings in millions of dollars to Latin America. (8) Finally, the jungles of Central America contain very poisonous snakes. 

Key

1. Sentence five detracts from the unity of the paragraph because it does not deal with anything about deforestation. It mentions the jungle, but only as a backdrop to the real subject which is cruelty to animals. 
2. Sentence eight detracts from the unity for the same reason. 

B. In the following paragraph there are two sentences that diminish development. Identify what they are in the spaces provided below.

     (1) Although many people scorn the idea of keeping a pet fish because of its lack of emotional response, there are actually quite a few advantages to keeping such a pet. (2) First of all, a fish will never leave its aquarium. (3) Related to this, the second advantage of having a fish is that it is incapable of doing any bodily damage to the owner. (4) Perhaps fish are not very emotional, but it is wise to first look at the positive aspects of having one before making a final judgment on their worth in the home. 

Key

1. Sentence two introduces the sub-topic well, but no example or further elaboration of the sentence is given. It is necessary to explain exactly how not leaving the aquarium is an advantage for the fish owner.
2. Sentence three also needs further elaboration or examples. One question that the writer should probably address is "What sorts of domesticated animals, in contrast, might do bodily harm to an owner?"