Alverno Guide to Writing in Biology

General Information

In general, writing in biology (or any science) is like writing non-fiction in any other discipline. Writing should be clear, concise, precise, and organized logically. Biological writing need not be dry, but avoid flourishes that distract from the purpose of the paper. Use appropriate scientific vocabulary.

There are some special conventions that are followed in biological writing. These conventions should be followed in any formal paper for a course. Your instructor will give you additional guidelines for specific assignments.

Metric Units

The metric system is the universal system of scientific measurement. Always use metric units in your writing. If you are converting your units, don’t artificially inflate the precision of your measurements. If you measured to the nearest inch, report your answer in whole centimeters.

Writing Numbers

Use scientific notation for writing very small or large numbers, and truncate (round) the number to a maximum of four significant digits.  For example, 3,879,562.34 should be written as 3.88 X 106, and 0.00000032456 should be written as 32.46 X 10-8.  To avoid confusion, use a leading zero as a placeholder to the left of the decimal (0.5), but not to the right (do not write 5.0). Leave a space between a value and its units: 5.6 ml. 

Scientific Names

Standard scientific names are used internationally to avoid confusion. The scientific name of an organism includes both the genus and the species. It is always underlined or written in italics. The genus is always capitalized, the species (or trivial) name never is. When you use the name of an organism, either use the scientific name consistently or use it the first time you use the common name.


After you have used the scientific name once, you can use the common name or abbreviate the scientific name (P. contorta, or U. arctos) as long as this won’t cause any confusion. If you know the genus, but not the species, you can use the following form:

Certain organisms require the use of subspecies or identification of their strain. Your instructor will give you additional guidance in the use of these designations.

Scientific Citation Style

Any statement of fact that is not considered general knowledge must be followed by a citation. Citations serve two major functions: Allowing the reader to find the original source of information, and giving credit for the ideas or work of others.

Examples of scientific citations:

Citation sources must be listed at the end of the paper in a References or Literature Cited section. The former lists all works used as references, the second only lists those that were cited. The exact form required by each instructor may differ slightly depending on the discipline, but all must include the author(s), year, title, and journal or book information.

Examples of references:

Michener, G. R. 1984. Age, sex, and species differences in the annual cycles of ground-dwelling sciurids: Implications for sociality. Pp. 81-107, in The biology of ground-dwelling squirrels (J.O. Murie and G.R. Michener, eds.) University of Nebraska Press, Lincoln, 459 pp.

Stapanian, M.A. and C.C. Smith. 1978. A model for scatterhoarding: Coevolution of fox squirrels and black walnuts. Ecology, 59:884-896.

Tizard, I. 1992. Veterinary Immunology: An Introduction. W. B. Saunders Co. Philadelphia. 498 pp.

If you retrieved the article through a database, what you got was an electronic copy of a journal, book, or newspaper article. The reference would look like this:

Hall, M. H. P.; Fagre, D. B. (2003, February). Modeled Climate-Induced Glacier Change in Glacier National Park, 1850-2100, Bioscience, 53, 131-140. Retrieved March 27, 2003 from EBSCOhost database.


Plagiarism is a serious academic offense. Briefly, plagiarism is representing the work of another as one's own. One common form of plagiarism is using the words of another without acknowledging the source of those words. This is plagiarism even if the material has never been published or copyrighted. Even text from the internet, from a fellow student, or from an instructor must be immediately preceded or followed by a citation. The quote must be an exact copy of the original and it must be set in quotation marks or in indented text to distinguish it from your own words. Do not merely change a few words of a quote: representing the slightly altered text as your own is still plagiarism. In general, it is best to avoid using quotes because this prevents you from learning to express ideas in your own words. Representing the ideas of another as your own is also plagiarism. Follow the statement of another’s ideas with a citation.

Selecting Appropriate Reference Materials

Scientists must be able to identify appropriate sources of scientific information. One general rule is that the closer one gets to the source of information, the more reliable the information is. A report written by people who actually gathered the information is a primary source. A review of these original research papers is a secondary source of information. A review of reviews, such as one might find in the popular press, is at best a tertiary source. With each step away from the primary source the likelihood of errors and misinterpretation increases. This is why scientific journal papers cite only primary and secondary sources. Advanced students should use primary literature sources whenever possible. Your instructor may give you specific criteria for determining which sources are acceptable for a given assignment. Articles that do not list references are likely to be unacceptable.

Peer-reviewed journals are the preferred source of scientific information. In peer-reviewed journals, papers have been evaluated by other specialists prior to their publication. The goal of this process is to screen out papers that contain faulty experimental design, misinterpretation of data, or other errors. This process is not a guarantee of infallibility, but it does ensure that other experts in the field felt that the work was deserving of scientific attention. You can identify peer-reviewed journals by looking at any volume for the authoring body and the editorial policy.

For help in finding sources of information, see Research tools for biology.

Internet Sources

Internet sources are generally less reliable and less accurate than print sources. Anyone can publish documents on the internet; there is no quality control. Errors, fraud, and misrepresentation are common on the world wide web. For that reason, only a small fraction of the total number of documents on the internet are suitable for citations in your biology course work. The convenience of searching and freshness of information on the internet outweigh some of these problems. You will have to be a careful consumer of internet information sources if you choose to use them. While your instructor may have specific criteria for acceptability of internet sources, here are some general points to consider:

Internet sources should be cited in the text in the same manner that print sources are cited. In the reference section, list the information as follows:

Stiner, M. C. N. D. Munro, T. A. Surovell, E. Tchernov, and O. Bar-Yosef. January 8, 1999. Paleolithic population growth pulses evidenced by small animal exploitation. Science Online.

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Last update: 8/26/03 by Rebecca Burton, Dept. of Biology, Alverno College