From the Dickinson College Biology Department

This is an appendix to our lab manual for General Biology 111-112. It is intended as a BASIC INTRODUCTION to scientific writing format for beginning students in Biology. For advanced work, and to prepare papers for submission to professional journals, consult the instructor of your individual course.

 

WRITING A SCIENTIFIC PAPER

 

Biologists have a standard format for reporting research results. If you don't read technical scientific journals you may never see this format in use, but being aware of its existence is important because it is a good model of the way biologists organize their thoughts. At several points during the course you may be asked to report your findings in standard scientific format. This guide explains the procedure to use.

Contrary to what many people believe, scientific writing is not fundamentally different from other kinds of formal writing. A superbly-written scientific paper is logical, clear, and makes a cogent point. It is also readable, provocative, and even exciting. A person who is an outstanding writer in other contexts does not lay those skills aside when writing a scientific paper.

The major goal of a scientific paper, however, is to report descriptive or experimental observations that relate to a particular question. Because of this priority, some conventions have evolved that most scientific writers follow. When you first try these you may feel confined and awkward, in somewhat the same way as in writing a first haiku or sonnet. Challenge yourself to stay within the confines of these conventions while still writing as well as you possibly can.
STYLE

*Be brief. Say as much as you need to say to be clear, but after you write check over your text to cut out needless or repetitious phrases.
* Be precise. Use exactly the right term for what you mean, even if this means repeating the term several times in a paragraph. (You may have been taught to vary your expressions and use synonyms, but in scientific writing precision has a higher priority.)
* Use scientific citation format in the text instead of footnotes. This format is described below under literature cited.

* Use scientific names correctly (see box).

* Use metric measurements.

* In biology, "data" is a plural noun (singular is datum). Write "These data are..." rather than "This data is..." The word "species" is used both as singular and plural ("These species are..." and "This species is...").

*Formerly, scientific reporting was usually done in the passive voice, but editors and writers now prefer active voice if it is clearer and more readable.For example,, you should say, "We predicted..." rather than "It was predicted that..."

* Of course, follow all the standard rules of good English for grammar, subject verb agreement, sentence structure, and use of pronouns.

USING SCIENTIFIC NAMES

Scientific names have a format that is simple and consistent. Because these names are frequently used not only in science but also in business, literature, law, and communications, every educated person should know how to write them correctly.

A standard scientific name is written in italics or underlined. It consists of two words. The first is the genus name, which is always capitalized. The second is the species epithet, which is never capitalized. The two words together (not just the second word) make up the species name: for example, we belong to the species Homo sapiens. If you have a genus in mind, but not a particular species, you may use the genus name (Homo) by itself. Once a full scientific name has been used in a section of a paper, the genus name may be abbreviated by its first letter (H. sapiens) if this will not lead to confusion. Names of scientific families, orders, classes, phyla, and kingdoms are capitalized but not italicized or underlined (class Mammalia, kingdom Protista).

FORMAT

The paper itself consists of standard sections in a standard order. Each has a particular purpose.


Title. This should be specific and should reflect the content of the paper. "Enhanced Reproduction of Strawberry Plants Under Low Light Conditions" and "Effect of Injected Sea Anemone Toxin on Symbiotic Fish Species" are specific, informative titles; "Photosynthesis" and "Fruit Fly Experiment" are too vague to be useful.

Abstract. This is a brief synopsis of the paper so that the reader can get the point and decide whether to read the entire paper. Abstracts are typically included along with titles in bibliographic sources such as the ones you use in on-line searches. In about 100 or 200 words, an abstract summarizes the purpose of the study or question investigated, the method used, the major results, and the conclusions drawn from the study. It is good practice to write the abstract last, even though it appears at the beginning.

Introduction. This is actually the "first" section of text, because a reader may skip over the abstract. The introduction section presents the question being addressed in the study and places it in the context of what is already known about the topic. You must make decisions about how much background to give the reader, depending on what you can assume the reader knows. For a report on how light level affects photosynthesis, you don't need to review all the biochemistry of photosynthesis, but you might outline what is known about the light reactions and use this information to predict your result. It should be evident to the reader by the end of the introduction what you were setting out to do, and why it was interesting and timely to do it. The hypothesis of the study, and specific predictions if relevant, should also be clear.

Methods (also called Procedure or Materials and Methods). This section describes how the study was done. The primary aim is to make it clear to the reader how you proceeded in order to get your results. A secondary aim is to allow other investigators to replicate your study or use its methods. (Don't assume that the reader knows what you did, even when "the reader" is your instructor.) Write in past tense, not in "recipe" style ("We glued each fly's thorax to the end of a glass rod," rather than "Glue the fly's thorax to a glass rod.") Report all necessary details, particularly those that could have affected the results. Omit unnecessary details. Often you may have had to do preliminary tests to work out your methods -- to find out how much anesthetic was necessary for flies, for instance. However, in your Methods section, describe only those methods that you actually used to produce the result you are reporting. You should also state the methods you used to analyze your data, if these were complicated or non-standard (for example, a specialized statistical test).

Results. This is an objective report of what happened. It does not include your interpretation of what the data imply (save that for the Discussion). To organize your Results section, first decide how to present the data in tables and figures (see box below). Then write a text that guides the reader through the main points that you want him or her to notice in the tables and figures. In the text of the Results section, don't bog the reader down in detail. State the main points (in past tense) and refer to the relevant table or figure. If statistical tests were done, their findings should be shown in the Results section either in the text or in the tables and figures. Some examples of Results text:

POOR: At 5°C, the larva moved 5 cm in 2 minutes. At 15°C it moved 12 cm. At 25°C it moved 24 cm.
BETTER: The larva moved farther at higher temperatures (Fig. 1).

POOR: The results of the experiment are shown in Table 1.
BETTER: The treated group grew faster and died earlier than the untreated group (Table 1).

RESULTS: TABLES AND FIGURES.

Although occasionally you may need tables and figures in other parts of your paper, most of them will be in the Results section. Each table or figure should be self-explanatory so that it makes sense even if the reader doesn't read the text.

A Table is text and numbers in column-and-row format. Tables are numbered, starting with Table 1, in the order in which they are cited in the text. After the number is a title that describes what the table is about. In general, tables are not as good at conveying a point as are graphical figures; any time you are tempted to produce a table, consider whether a figure would be better.

Examples of tables:

Table 1. Mean weights of newborn kittens according to litter size.

Litter size Mean kitten weight (g)
1 98.2
2 97.6
3 94.2
4 89.2


Table 2.Phenotypes of F2 progeny from a parental cross of purple-seeded, long tassel with white-seeded, short-tassel strains of corn.

Phenotype Number of progeny
Purple-long 87
Purple-short 33
White-long 39
White-short 14


A Figure is any kind of pictorial presentation -- graph, photo, map, sketch, etc. Graphs are the type of figure most commonly used. Think hard about the best way to present your data clearly before drawing final figures. In an x-y graph, the independent variable is plotted on the x (horizontal) axis and the dependent variable on the y (vertical) axis. (The independent variable is one that is manipulated to see what its effect is on the dependent variable; that is, the value of the dependent variable will "depend" on the value of the independent variable.) If there is not a clear dependent variable, either one may go on either axis. Figures are numbered, starting with Figure 1, in the order in which they are cited in the text. After the number is a caption that describes what the figure is about. In addition, the figure must have clearly labeled axes (make sure the scale and units are shown) and a legend, if necessary, to explain the bars or data points.


Examples of figures:
effect of temperature graph
Figure 1. Effect of daily maximum temperature on flowering date.

 

fly phenotype graph

Figure 2. Number of flies of each phenotype in F2 generation. Solid bars are observed number, and striped bars are expected number from Mendelian ratio.

Discussion. This section may serve several functions. First, it lets you assess your result in light of your original hypothesis. Did the data support or refute the hypothesis? Second, it can show how the result fits into current knowledge. You can cite other results or theory and compare other studies' findings with yours. Third, it can attempt to explain unexpected or contradictory results. If unanticipated factors could have affected the results, you can suggest what they were and how further refinements could resolve them. (Do not use this section to say "the experiment didn't work.") Fourth, it may allow you consider the biological implications of your result. Does it explain anything about how organisms live? Does it lead to further predictions? Finally, it can be used to suggest what further studies need to be done. Every Discussion should address the first function (evaluating what the data say about the original hypothesis), but you can use discretion about what else to include in this section. After reading your Discussion, the reader should be able to see clearly the take-home message and the overall value of your study.

Literature cited. If you mention any published work in your paper, it must be listed here. Different scientific journals use slightly different citation formats, but the most commonly used one follows these rules:

Examples of Literature Cited:

Greene, E., L. J. Orsak, and D. W. Whitman. 1987. A tephritid fly mimics the territorial displays of its jumping spider predators. Science 236:310 312.
Merritt, J. F. 1987. Guide to the mammals of Pennsylvania. University of Pittsburgh Press, Pittsburgh.

To cite a literature reference in the text of your paper, include the author and year so that the reader can locate the full reference in the Literature Cited. Put these in parentheses after the relevant portion in the text but before any concluding punctuation. If the author's name is used as part of the text, follow it directly with the year in parentheses.

Examples of text citations:
Some flies appear to mimic their predators to avoid attack (Greene et al. 1987). [the et al. means "and others" and indicates multiple authors.]

Merritt (1987) lists endangered or threatened species of Pennsylvania mammals.

The general authority for writing of scientific papers is the Council of Biology Editors Style Manual, which is revised periodically. If you intend to write biology research reports beyond this course, you should become familiar with this reference.


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