Biology 100LW--Unit #2: Coherence

To communicate effectively in the scientific community, our essays must be clearly and coherently written. Coherence is the quality of being logically connected. A coherent essay is one in which the parts connect or relate to one another to make a logical whole. Writers often use the metaphor "flow" to refer to the smooth, continuous movement of thought that we mean by the term "coherence."

On page 99, Pechenik uses the flow metaphor as follows: "A strong paragraph--indeed a strong paper--takes the reader smoothly and inevitably from a point upstream to one downstream." To achieve this "flow," Pechenik tells us to "Link your sentences and paragraphs using appropriate transitions so that the reader moves effortlessly and inevitably from one thought to the next, logically and unambiguously." The aim is to "Minimize turbulence" and "choppy rides."

One means of achieving coherence is to organize our paper according to a "structure," format, or plan that sequentially distributes certain information in certain parts of the essay.  Structurally, science articles follow a four-part format: introduction, materials and methods, results, and discussion. The four parts "narrate the story," so to speak, of the authors' research process from beginning to end, from the initial question to the final conclusion. This "narrative spine," a clearly told story, is a principal means of creating coherence.

Each of the four parts contributes to the story. Regarding the results section, Pechenik says, "The observations you've made and the data you've collected most likely contain a story that is crying out for recognition" (158). The narrative develops  cumulatively as well as sequentially. That is, as more information is presented, the story builds, becoming cumulatively more complete as it progresses.

Coherence also means that the parts, in a sense, "speak to" each other. For instance, the introduction establishes the direction of the essay and sometimes anticipates an outcome. The results and discussion sections refer back to the introduction and fulfill (or do not) the expectations set up in the beginning.

Furthermore, scientific research builds on previous research. The present work (which is presented in the article) is based on past work. It also proposes to move beyond what is presently known and add to it in some way. So we can see a kind of dialectic between past and present going on in many science articles. This dialectic occurs in both of the articles that are reproduced in your lab manual, "A Scaleless Snake" by Licht and Bennett, and "Coexistence between People and Elephants by Hoare and Du Toit.

For instance, in the "Snake" paper, the researchers tested an existing assumption that reptilian scales play a role in regulating water loss and heat transfer. The "Elephant" paper develops an extended contrast between the "broader" research of Parker/Graham (the past) and the "finer scale" research of Hoare and Du Toit (the present). The latter repeatedly refers back to the earlier research and differentiates itself from it.

This back and forth contrast between past and present is another structural principle governing the essay and contributing to its overall coherence. It is one of several structural principles that are worth mastering and that you may find useful in organizing the material presented in the Unit#2 in-class exercise or in your lab report.