Scientific Paper Writing

B.D. Jimenez

Department of Biological Sciences

Mindanao State University-Iligan Institute of Technology

Iligan City

 

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 essay. Challenge yourself to stay within 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.

1. 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.)
   
2. Use scientific citation format in the text instead of footnotes. This format is described below under Literature Cited.
   

1. Use scientific names correctly.
   
   1. Scientific names have a format that is simple and consistent. These names are frequently used in science, business, literature, law, and communications hence, every educated person should know how to write them correctly.
      
   2. 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, man belongs 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).
      
2. Use metric measurements.
   
3. 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...").
   
   1. Use passive voice, for example, you should say, "It was predicted that..."
      
   2. Follow all the standard rules of good English for grammar, subject verb agreement, sentence structure, and use of pronouns.
      

FORMAT

The paper consists of standard sections in a standard order and each has a particular purpose.

Title.

1. Should be specific and reflect the content of the paper.
   

   The following have specific and informative titles:
   

   1. "Enhanced Reproduction of Strawberry Plants under Low Light Conditions"
      
   2. "Effect of Injected Sea Anemone Toxin on Symbiotic Fish Species"
      

The following titles are too vague to be useful.

1. "Photosynthesis" and "Fruit Fly Experiment"
   

1. Should be well spaced and balanced symmetrically about vertical axis.
   
2. Starting with "A study of " or similar phrases usually gives no advantage
   

Abstract

1. This is a brief synopsis of the paper so that the reader can get the point and decide whether to read the entire paper. (200-400 words)
   
2. They are typically included along with titles in bibliographic sources such as the ones you use in on-line searches. It 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.
   
3. It should be very concise and indicate points to be given emphasis in reading the paper.
   

Introduction

1. 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.
   
2. The hypothesis of the study, and specific predictions if relevant, should also be clear. The hypothesis is an educated guess based on previous observations, the validity of which being tested in the experiment.
   

   Example: An experiment on the effect of molecular weight on diffusion rate may be introduced with a discussion of what diffusion is, followed by the hypothesis that heavier molecules diffuse more slowly; with an explanation of how the hypothesis was derived from the experiment using ammonia and hydrochloric acid in a glass tube
   

   1. Should also include citations (See Results and Discussion)
      

Methods (also called Procedure or Materials and Methods)

1. This section describes how the study was done. The primary aim is to make it clear to the reader how the work was done in order to obtain the results. A secondary aim is to allow other investigators to replicate the study or use its methods. (Don't assume that the reader knows what you did, even when "the reader" is your instructor.) 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. The methods used to analyze the data should also be stated, if these were complicated or non-standard (for example, a specialized statistical test).
   
2. Materials are not to be enumerated but incorporated while the procedure is being discussed.
   
3. Write in past passive voice, not in "recipe" style ("The substances were placed on top of the agar").
   

Results and Discussion

1. This is an objective report of what happened and include interpretations of what the data imply.
   
   1. To organize your Results section, decide whether your results be presented in tables or figures. This should guide 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:
      
      1. 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).
      

      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).
         

   2. 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.
      
   3. 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

1. 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.
   
2. 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:
   

   
   
   Figure 1. Effect of daily maximum temperature on flowering date.
   

    
   

   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.
   

3. 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.
   

Summary and Conclusion

This serves as a review of results and discussion, how the results led to the conclusions (answer to hypothesis) and the conditions where such conclusions are valid; it is more detailed than abstract.

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:

• Alphabetize literature citations by first author's last name.
  
• Within a journal citation, give authors, year date, and title of paper, title of journal, volume and pages. Do not use quotation marks around title of paper. Capitalize first word of title and any proper nouns. Do not underline or italicize title of journal.
  
• Within a book citation, give authors, year date, and title of book, publisher, and city. Capitalize first word of book title and any proper nouns. Do not underline or italicize book title.
  

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.

Writing Results and Discussion

I. Writing Results from Data Tables

The first word phrase and sentence is usually the most difficult

2. Data tables provide a good starting point and focus by which students are guided in writing descriptive paragraphs.

3. Usually contain 2 main types of information: the central and most typical value and the variation or spread of data, usually described in scientific terms:

Type of data	Central or typical data	Variation or spread of data
Quantitative data: based upon measurements	Mean-the arithmetic average	Range: the difference between the smallest and largest maximum value
Qualitative	Mode-the most frequently occurring value	Frequency distribution: the number of cases that fall into category

Example of quantitative data:

Table 1. The effect of various concentration of chemical X on the height of tomato

Descriptive Information	Concentration of Chemicals
Concentrations	0%	10%	20%	30%
Mean	15.3cm	18.1cm	10.50cm	6.0cm
Range	7.0cm	63.0 cm	63.0cm	4.0cm
Minimum	12.0cm	14.0 cm	8.0 cm	4.0 cm
Maximum	19.0 cm	2 cm 0.0	14.0 cm	8.0 cm
Number	10plants	10plants	10plants	10plants

Identify independent variable, dependent variable and control

Steps for writing paragraphs of quantitative data:

1. Write a topic sentence stating the independent variable, dependent variable and a reference to tables and graphs:
   
   1. The effect of various concentrations of chemical X on the height of tomato plants is summarized in Table A.
      
   2. Table A shows the effect of various amounts of Chem x con the growth of tomato plants
      
2. Write one or more sentences to compare the means of typical values of the group.
   
   1. The mean height of plants grown at 10% chemical x (18.1) was higher than the control (15.3). At higher concentrations of chem. X, mean plant height was reduced 10.5cm at 20%.
      
3. Write a sentence describing the range and variation in the groups
   
   1. The ranges in plat height were greater in the control and in 10% X groups than in group's receiving 20% and 30%.
      
4. Write a sentence stating whether the data did or did not support the hypothesis.
   
   1. The data partially supported the hypothesis that [plant growth would decrease as concentration pf x increased.
      
   2. Below 10%, x little growth differences were observed however at higher concentrations growth was severely retarded.
      

The same process can be used to write paragraph on qualitative data

Descriptive Information	Concentration of Chemicals
Concentrations	0%	10%	20%	30%
Mode	Green	green	Yellow green	yellow
Frequency Distribution	G:8	G:10	G:2	G:0
	YG:2	YG:0	YG:5	YG:0
	B:0	B:0	B:0	B:6
Number	10plants	10plants	10plants	10plants

Steps in Writing paragraph for qualitative data

1. Write a topic sentence stating the IV, DV and location of table.
   

   a) The effect of various concentrations of Chem X on tomato plant leaves depicted in table
   

2. Write a topic sentence or sentences comparing the modes of the group.
   
3. Green leaves were typically found on both control and 10% plants
   
4. At higher concentrations, leaf color deteriorated, with yellow green leaves characterizing 20% x plants and brown leaves
   

1. Write a sentence or sentences describing the variation of frequency distributions of the groups
   
   1. Little variation in leaf color occurred in the control and 10% x plants.
      
   2. At 20% x, substantial variation existed with 2 green 5, yellow green and 3 yellow plants.
      
2. Write a sentence stating whether the data did or did not support the hypothesis.
   
   1. The findings o leaf color support the hypothesis that higher concentrations of chemical x will seriously impede growth.
      

Writing Conclusion

1. What was the purpose of the experiment? What was the hypothesis?
   
   1. The purpose of this experiment is to investigate the effect of various concentrations of chemical x on the growth of tomato plants.
      
2. What were the major findings?
   
   1. At successive higher concentrations of chemical x the main height of the tomato plants decreased and leaf color deteriorated
      
3. Was the research hypothesis supported/not supported?
   
   1. In general, the research data supported the hypothesis.
      
4. How did your findings compare with that of other researchers? What possible explanations can you offer for your findings?
   
   1. However, Crook and Bolton report that concentrations of 10% x were harmful to radish plants.
      
   2. Differences in findings could result from the different species or differ from the different plant species
      
5. What recommendation do you have for further study or for improving the experiment?
   
   1. Additional studies could be conducted to determine the chemical x within the 0-to 20% range on both types f plants and with different type of plants and with different types of administration