The Scientific Paper:  Introduction

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 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 1^st 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.

See examples of Introduction sections.

The Scientific Paper