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Writing Guide for the Biological Sciences |
Part One: Types of Writing
A.
Short Answers for Tests (and Homework Questions)
B.
Summary of a Scientific Article
C. The Scientific Paper
Part Two: Practical Tips for Scientific Writing
Part One: Types of Writing
A. Short Answers for Tests (and Homework Questions)
This section of the writing guide is intended to give you a set of tips (that you probably already use) to approach short-answer questions on tests or homework assignments.
The main point to keep in mind is to read the question carefully. You must first understand the question to identify what information is required to answer it.
Questions can be straightforward, asking you to recall information and state it simply. Other questions may require that you interpret data or a figure or draw conclusions from a few statements.
Some questions have multiple parts; make sure that you address every aspect of the question.
Be careful not to read too much into a question. If you try to include too much information, you could get confused and write something that is incorrect. It could also seem as though you do not really understand the question or the information.
Plan your answer before you start. Even if it is not a long essay question, think for a moment about how you want to organize your thoughts. Make notes in the margin to put your points in order.
It is important to focus on using succinct, simple sentences that convey one or two ideas.
Start with general statements that answer the question as directly as possible. Provide appropriate examples to support those statements to show you understand the material. Use examples from class, instead of making up untested examples on the spot.
When you are studying, anticipate some likely short answer or essay questions. By preparing for potential questions, you will be studying the material at a higher level. This will help you understand relationships between the concepts you are learning and help you synthesize the information better, even if the exact questions you envisioned do not appear on the exam.
B. Summary of a Scientific Article
This assignment is generally intended to help you learn to synthesize scientific materials and communicate the main points effectively, using plain language.
Start by making sure you understand the central points of what you read. Explain the article in plain language to someone else and answer questions without referring back to the article, to make sure you have grasped the essence of what you read.
The appropriate writing style for a summary of a scientific article is to use simple sentences that express one or two ideas. An example might be a story featured in the mainstream media that explains a recent scientific finding, bringing out the important aspects concisely and without too much scientific jargon.
Do not "cut and paste" from the article. When students do not really understand what they read, their writing is a jumble of statements nearly straight from the article, with no interpretation or synthesis of the article's findings.
C. The Scientific Paper
A well-written scientific paper explains the scientist's motivation for doing an experiment, the experimental design and execution, and the meaning of the results. Scientific papers are written in a style that is exceedingly clear and concise. Their purpose is to inform an audience of other scientists about an important issue and to document the particular approach they used to investigate that issue.
Please do not think that good English is not critical in science writing. In fact, scientists try to be so concise that their English should be better than that of workers in other disciplines! If English is not your first language, then proofreading by a native-speaker might be helpful. The Writing and Reading Lab in The Learning Center offers free assistance in English as a Second Language.
If you have read scientific papers, you will have noticed
that a standard format is frequently used. This format allows a researcher to
present information clearly and concisely. The information presented will be
useful to any student who wishes to write a scientific paper in the biological
sciences.
General organization
The following sections should be included in your report:
(1) Abstract
(2) Introduction
(3) Methods
(4) Results
(5) Discussion
(6) Literature
Cited
Other sections can be included as necessary. It is important to understand the differences between sections and to put information in the appropriate location. Students frequently begin discussing their results in the Results section or present some of their results in the Discussion section.
Reading scientific papers (such as the articles you will use as your references for the Introduction and Discussion) will give you good ideas and guidance as well. After all, these are peer-reviewed and published scientific papers, and they can serve as useful models for your own writing.
Remember to pay attention to issues of plagiarism, however. One useful way to avoid making errors in this regard is to read a section from your source, then restate in writing what you remember of the main points. You would then cite the source of that information in the text. For excellent guidance on this topic, consult V.E. McMillan's 1997 book, Writing Papers in the Biological Sciences. St. Martin's Press, N.Y. for further advice.
The Scientific Paper: Abstract
An abstract is a shortened version of the paper and should contain all information necessary for the reader to determine:
(1) what the objectives of the study were;
(2) how the study was done;
(3) what results were obtained;
(4) and the significance of the results.
Frequently, readers of a scientific journal will only read
the abstract, choosing to read at length those papers that are most interesting
to them. For this reason, and because abstracts are frequently made available
to scientists by various computer abstracting services, this section should be
written carefully and succinctly to have the greatest impact in as few words as
possible.
Although it appears as the first section in a paper, most scientists write the abstract section last.
The Scientific Paper: Introduction
Why is this study of scientific interest and what is your objective?
This section discusses the results and conclusions of previously published studies, to help explain why the current study is of scientific interest.
The Introduction is organized to move from general information to specific information. This background must be summarized succinctly, but it should not be itemized. Take care not to go too far afield in providing background information; limit the introduction to studies that relate directly to the present study. Emphasize your specific contribution to the topic.
The last sentences of the introduction should be a statement of objectives and a statement of hypotheses. This will be a good transition to the next section, Methods, in which you will explain how you proceeded to meet your objectives and test your hypotheses.
For example, you might write the following:
"Our objective was to determine if the relationship between legumes and nitrogen-fixing bacteria is species-specific. We hypothesized that legumes would grow best when infected by the same Rhizobium species that it occurs with in the field."
How to Cite Sources in the Introduction Section
It is important to cite sources in the introduction section
of your paper as evidence of the claims you are making. There are ways
of citing sources in the text so that the reader can find the full reference in
the literature cited section at the end of the paper, yet the flow of the
reading is not badly interrupted. Below are some examples of how this can be
done:
"Smith (1983) found that N-fixing plants could be infected by several different species of Rhizobium."
"Walnut trees are known to be allelopathic (Smith 1949, Bond et al. 1955, Jones and Green 1963)."
"Although
the presence of Rhizobium normally increases the growth of legumes
(Nguyen 1987), the opposite effect has been observed (Washington 1999)."
Note that articles by one or two authors are always cited in the text using their last names. However, if there are more than two authors, the last name of the 1st author is given followed by the abbreviation et al. which is Latin for "and others".
The second citation (above) shows that it is acceptable, and encouraged, to cite more than one source for a particular statement. This gives the statement more validity in its context and suggests that your research was thorough. Note also that the three sources are ordered by publication date, so that the earliest citation comes first. Make sure you give a full citation in the Literature Cited section for all sources mentioned in the text.
The Scientific Paper: Methods
This section provides all the methodological details necessary for another scientist to duplicate your work.
It should be a narrative of the steps you took in your experiment or study, not a list of instructions such as you might find in a cookbook.
You should assume that the other scientist has the same basic
skills that you have, but does not know the specific details of your
experiment. For example, it is unnecessary to write:
"We
poured N-free fertilizer solution into a graduated cylinder until the bottom of
the meniscus was at the 30 ml line. We poured the fertilizer onto the top of
the soil in a pot and then repeated this procedure 24 times."
Rather, you would assume that the scientist knows how to measure and add liquids to pots and write:
"We
added 30 ml of N-free fertilizer to each of 24 pots."
An important part of writing a scientific paper is deciding what bits of information need to be given in detail. Do not quote or cite your laboratory manual!
In the last paragraph, provide a brief description of statistical tests you used (statistics are methods!). Be sure not to include extraneous information, though, as scientists know all about null hypotheses and when to reject them. See the Results section for more information on statistics.
The Scientific Paper: Results
This section presents the results of the experiment but does not attempt to interpret their meaning. As with the Methods section, the trick to writing a good Results section is knowing what information to include or exclude. You will not present the raw data that you collected, but rather you will summarize the data with text, tables and/or figures. Use the text of the paper to state the results of your study, then refer the reader to a table or figure where they can see the data for themselves. For example you may write:
"Nitrogen
fertilizer significantly increased soy bean total biomass (p=0.05) regardless
of the presence or absence of Rhizobium (Table 1)."
The sentence above is well written because: (i) the result of adding nitrogen is stated concisely, (ii) the word significantly is accompanied by the statistical probability level (p=0.05), (iii) the scientific name Rhizobium is italicized, and (iv) the reader is referred to a table where the data to support the statement can be found. Note that the measurement (total biomass, in this case) is mentioned. You must explicitly state the measure you are using.
Do not include the same data in both a table and a figure. It is best to present the data in a table unless there is visual information that can be gained by using a figure. For example, a figure is useful for reporting a regression analysis (line graph), or comparing the several treatment levels (bar graph with error bars). Each table and figure has several lines of text in the legend (or caption) that explain the information that is being presented; this is, they are made to stand alone. A table's legend appears above it, while the legend for a figure appears below the figure.
If your table includes the results of a statistical analysis, be sure to provide the information necessary for the reader to properly evaluate the analysis (probability levels, degrees of freedom, sample size, etc.).
Additional tips on the Results section:
Tables
The good features of Table 1 are: (i) it is numbered, (ii) the legend explains key details of the experiment, (iii) it is clear that the error term is standard deviation, and (iv) it explains the meaning of unusual abbreviations.
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Table 1. Gas
exchange characteristics of an Orontium aquaticum plant before and after 17 d inside a
flow-through cuvette. Values are means± standard deviations. PPFD=photosynthetically-active
photon flux density. |
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|
|
Experimental Treatment |
|
|
|
Before |
After |
|
Photosynthesis (µmol --2
s-1) |
14.7 ± 0.7 |
11.8 ± 2.4 |
|
PPFD (µmol m-2 s-1) |
641 ± 57 |
531 ± 24 |
|
Ambient [CO2] (Pa) |
38.2 ± 1.5 |
34.1 ± 1.6 |
|
Relative Humidity (%) |
46 ± 15 |
67 ± 5 |
|
Number of Leaves Measured |
3 |
5 |
The Scientific Paper: Discussion
In this section, you are free to explain what the results mean or why they differ from what other workers have found.
You should interpret your results in light of other published results, by adding additional information from sources you cited in the Introduction section as well as by introducing new sources. Make sure you provide accurate citations.
Relate your discussion back to the objectives and questions you raised in the Introduction section. However, do not simply re-state the objectives. Make statements that synthesize all the evidence (including previous work and the current work).
Do not make statements that are too broad: it is unlikely, for example, that through one Rhizobium-legume experiment, you will discover that there is no symbiosis between the two organisms. Limit your conclusions to those that your data can actually support, such as "We did not find a significant effect of Rhizobium inoculate on soybean biomass in this experiment." You can then proceed to speculate on why this occurred and whether you expected this to occur, based on other workers' findings.
Suggest future directions for research, new methods, explanations for deviations from previously published results, etc.
If necessary, note problems with the methods and explain anomalies in the data. Do not simply list the problems but provide thoughtful discussion about the implications of the errors in terms of your conclusions.
How to Cite Sources in the Discussion Section
It is important to cite sources in the discussion section of your paper as evidence of the claims you are making. There are ways of citing sources in the text so that the reader can find the full reference in the literature cited section at the end of the paper, yet the flow of the reading is not badly interrupted. Below are some example of how this can be done:
"Smith (1983) found that N-fixing plants could be infected by several different species of Rhizobium."
"Walnut trees are known to be allelopathic (Smith 1949, Bond et al. 1955, Jones and Green 1963)."
"Although
the presence of Rhizobium normally increases the growth of legumes
(Nguyen 1987), the opposite effect has been observed (Washington 1999)."
Note that articles by one or two authors are always cited in the text using their last names. However, if there are more than two authors, the last name of the 1st author is given followed by the abbreviation et al. which is Latin for "and others".
The second citation (above) shows that it is acceptable, and encouraged, to cite more than one source for a particular statement. This gives the statement more validity in its context and suggests that your research was thorough. Note also that the three sources are ordered by publication date, so that the earliest citation comes first.
Make sure you give a full citation in the Literature
Cited section for all sources mentioned in the text.
The Scientific Paper: Literature Cited
This is the last section of the paper. Here you should provide an alphabetical listing of all the published work you cited in the text of the paper. This does not mean every article you found in your research; only include the works you actually cited in the text of your paper.
A standard format is used both to cite literature in the
text and to list these studies in the Literature Cited section. Consult
McMillan (1988) or a recent issue of Ecology for guidance. Hypothetical
examples of the format used in the journal Ecology are below:
Djorjevic, M., D.W. Gabriel and B.G. Rolfe. 1987. Rhizobium: Refined parasite of legumes. Annual Review of Phytopathology 25: 145-168.
Jones, I. J. and B. J. Green. 1963. Inhibitory agents in walnut trees. Plant Physiology 70:101-152.
MacArthur, R.H. and E.O. Wilson. 1967. The Theory of Island Biogeography. Princeton University Press, Princeton, N.J.
Smith,
E. A. 1949. Allelopathy in walnuts. American Journal of Botany 35:1066-1071.
Here is a dissection of the first entry, in the format for Ecology:
Firstauthor, M., D.W. Secondauthor and B.G. Thirdauthor. Year. Article title with only the first letter capitalized. Journal Article Title with Important Words in Caps volume#(issue# if there is one): firstpage-lastpage.
Notice some of the following details:
- the
list is alphabetized;
- no first or middle names are
listed (the author's first and middle initials are used instead);
- only the first word in the
title of the journal article (except for proper nouns) is capitalized;
- different journals use
different styles for Literature Cited sections.
You should pay careful attention to details of formatting when you write your own Literature Cited section.
For papers published in journals you must provide the date, title, journal name, volume number, and page numbers. For books you need the publication date, title, publisher, and place of publication.
Below you will find a list of some common mistakes found in undergraduate writing. The list has been compiled from professors' and lab instructors' comments and V.E. McMillan's Writing Papers in the Biological Sciences (a highly recommended resource for scientific writing).
PROOFREAD!!! You should check your paper to catch and correct these and other common errors.
Abbreviations: You should avoid abbreviations by writing out the full word (minimum, October, Virginia, first, temperature, with...). Exceptions include common biological terms like ATP and DNA, units of measure (m, g, cm, °C), and mathematical or chemical formulas. Sentences should never begin with an abbreviation or an acronym.
Acronyms: You may wish to introduce an acronym for a term that is repeated often: if your paper deals with soybeans, Glycine max, you may use the full scientific name once and substitute G. max thereafter. If you are writing a paper about tidal freshwater marshes, the first time the terms appear, you can introduce an acronym: "Tidal freshwater marshes (TFM) are important transitional zones in the landscape." Throughout the rest of your paper, you would refer to TFM.
Chemical elements are not proper nouns, so do not capitalize them. Only the first letter of the symbol is a capital letter: nitrogen (N), carbon (C), calcium (Ca).
Contractions: In formal writing, you should never use contractions (didn't, can't, haven't...).
Data: The word "data" is plural, as in "the data were collected on January 21, 2001."
Direct quotes should be avoided, unless you are presenting another author's specific definition or original label. You can usually paraphrase the writing effectively and more concisely, taking care to properly attribute the sources of your statements.
Fluff: It is obvious when students do not understand what they are writing about, and their grades suffer as a result. Read and re-read your references. Consult a textbook or another reference to help you resolve any aspects of the paper you do not understand before you start writing.
Footnotes should not be used. See the Introduction or Discussion section of the scientific paper for instructions on in-text citations.
Run-on sentences: You should review your writing to make sure that each sentence presents one or two clear ideas. This will also help you organize sentences within paragraphs in a logical order.
Scientific names, consisting of genus and species, should be underlined or italicized, with only the genus capitalized: Homo sapiens or Ilex opaca.
Significance: In science, the word "significant" implies the result of a statistical test. It cannot be used to say, "the number of root nodules on red clover plants increased significantly when nitrogen was added," if you did not perform a statistical test to determine significant differences. You should analyze your results to determine whether they are statistically significant and report the test you used, the significance level (p=0.05), calculated statistic (tcalc), and degrees of freedom.
Slang: Do not use slang. Try to use precise, scientific terms where possible (without unnecessary jargon) and avoid colloquialisms and figures of speech: "somewhat" rather than "sort of," "many" or "a great deal" instead of "a lot."
Spell-check: Your word processor's spell-check and/or grammar-check function is not error-free. It cannot tell you when to use "it's" and "its," and it cannot tell you that a particular sentence does not make sense. Give yourself enough time to proofread and correct your paper.
Tenses: When describing methods and results, you should use the past tense. The present tense is appropriate for accepted facts, such as the background information presented in the Introduction. In addition, you may use the present tense when you discuss your results and conclusions. Looking over other scientific papers may help you answer questions you might have on this topic.
Units: All units of measure must be metric or SI (international System).
References and Credits
From the
George Mason University Dept. of Biology Web site
http://classweb.gmu.edu/biologyresources/writingguide/index.htm
References
Johnson Andrews, S.K. 2000. Writing to learn: poster presentations. Writing Center Newsletter 3(1):1-2.
McMillan, V.E. 1997. Writing Papers in the Biological Sciences. Boston: Bedford Books. 197 p.
Megonigal, J.P, L. Rockwood, M.R. Walbridge, and L. Brown. 2000. Studies in Ecology: a Laboratory Manual for Biology 307. Fairfax, VA: George Mason University. 125 p.
Piper and H. Cressey. 2000. General hints on how to write lab reports. Unpublished handout in Animal Behavior course. 4 p.
Credits
This web-based writing guide (A Guide to Writing in the Biological Sciences) was developed for the Biology Department under the auspices of a General Education Funding Award received by Writing Across the Curriculum. The guide was designed by Jennifer Morse (jmorse2@gmu.edu) in the Biology Department, in collaboration with Dr. J. Patrick Megonigal, Dr. Larry Rockwood, Dr. Terry Zawacki, and Dr. Rebecca B. Wright.