B. Introduction

This section provides guidelines on how to construct a solid introduction to a scientific paper including background information, study question, purpose or biological rationale, hypothesis,andgeneral approach. If done well there should be no question in the reader’s mind why and on what basis you have posed a specific hypothesis.

Description of Elements in the Introduction: (Examples to follow)

• Background information: key issues, concepts, terminology, and definitions needed to understand the reason or biological rationale for the experiment, and the logic for the hypothesis and experimental approach. Remember to be concise and only include relevant information given your audience and your experimental design. Background information may go before and/or after your study question. It often includes a summary of findings from previous, relevant studies.

• Study Question: Your study question could be based on an initial observation that served as a starting point to stimulate an investigation into the background literature or it could be based on previous research in the area. In oral presentations, study questions presented right away work well to engage the audience and pique their interest in your work.

• Biological Rationale:
• The biological rationale is the purpose of your experiment. It may help to think about the rationale as an answer to the questions—how is this experiment related to what we know AND how will this experiment add to our knowledge? Defining the rationale is probably the most critical task for a writer. Done well, it will simplify the writing process because it provides the logical framework for your paper. Through the rationale you identify the scope of the study, why it is important, and the implications of your work. Articulating the purpose forces you to identify the main point(s) –the “So What?”- you will address in the Discussion section, the types and sources of evidence, and how you expect to use the evidence to support the points you make. Understanding this will help you organize your thinking and will help the reader follow your logic throughout the paper.
• Defining the rationale may be difficult. Expect to spend time and mental effort on this. You may have to do considerable digging into the scientific literature to define how your experiment fits into what is already known and why it is relevant to pursue. It may take several attempts to write a statement that seems consistent with the experimental design and the data you expect to obtain. Furthermore, be open to the possibility that as you work with and think about your data, you may develop a deeper, more accurate understanding of the experimental system. You may find the original rationale needs to be revised to reflect your new, more sophisticated understanding. As you progress through Biocore and upper level biology courses, your rationale should become more focused and matched with the level of study i.e., cellular, biochemical, or physiological mechanisms that underlie the rationale. Achieving this type of understanding takes effort, but it will lead to better communication of your science.
• Special note on avoiding social justifications: You should not over emphasize the relevance of your experiment and the possible connections to large-scale processes. Be realistic and logical—do not over generalize or make grand predictions that are not sensible given the structure of your experimental system.

(Examples of rationale statements are included in the “Examples of Introductions” below)

• Hypothesis: Your hypothesis is a specific prediction or set of predictions that you will test during your experiment. This statement should include the independent variable (what you manipulate), the dependent variable (what you measure), the organism or system, the direction of your results, and comparison to be made. See the following examples.

  Hypothesis that needs work: We hypothesized that Daphnia magna reared in warm water will have a greater sexual mating response. [The dependent variable “sexual response” has not been defined enough to be able to make this hypothesis testable or falsifiable. In addition, no comparison has been specified— greater sexual mating response as compared to what?]

  Better Hypothesis: We hypothesized that Daphnia magna [study organism] reared in warm water temperatures ranging from 25-28 °C [indep. var] would produce greater [direction] numbers of male offspring and females carrying haploid egg sacs [depend. var] than D. magna reared in cooler water temperatures of 18-22°C.

• Experimental Approach:Briefly give the reader a general sense of the experiment, the type of data it will yield, and the kind of conclusions you expect to obtain from the data. Do not confuse the experimental approach with the experimental protocol. The experimental protocol consists of the detailed step-by-step procedures and techniques used during the experiment that are to be reported in the Methods and Materials section.

Be Concise yet specific: Remember to be concise and only include relevant information given your audience and your experimental design. As you write, keep asking, "Is this necessary information or is this irrelevant detail?" For example, if you are writing a paper claiming that a certain compound is a competitive inhibitor to the enzyme alkaline phosphatase and acts by binding to the active site, you need to explain (briefly) Michaelis-Menton kinetics and the meaning and significance of K m and V max. This explanation is not necessary if you are reporting the dependence of enzyme activity on pH because you do not need to measure K m and V max to get an estimate of enzyme activity. Another example: if you are writing a paper reporting an increase in Daphnia magna heart rate upon exposure to caffeine you need not describe the reproductive cycle of D. magna unless it is germane to your results and discussion. Be specific and concrete, especially when making introductory or summary statements.

See some Example Introductions!

How will introductions be evaluated? The following is part of the rubric we will be using to evaluate your papers.