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ECOLOGY LAB REPORTS

For other biology classes, you have probably written formal lab reports in the style of scientific publications. In this class, you will use a similar but modified format which follows.

TITLE

The title succinctly conveys the subject of the lab report. For example, "The effect of tree density on the vocalization patterns of gray squirrels (Sciurus carolinensis)" includes all the relevant information: the main topic (vocalizations), the organism studied (squirrels), and the experimental variable (tree density).

INTRODUCTION

The introduction of a scientific paper gives background information about the topic of study and explains how the current experiment is related to previous biological research. The introduction explains why the experiment was done. For Ecology labs, this information is included in the lab handout, and you only need to summarize it in the lab report.

Ecologists test a hypothesis by testing specific predictions deduced from the hypothesis. You should include in the introduction your hypothesis and the prediction or predictions you tested.

METHODS

The methods section in a scientific paper describes the procedure of the experiment in enough detail that another researcher could repeat the experiment. In addition to the specifics of field and lab procedures used, the methods section also includes a description of the study site and the statistical analyses employed. Because this information is provided in the Ecology lab handout, you do not need to include a methods section in your lab reports.

RESULTS

The results section consists primarily of appropriate tables and graphs with a short written summarization. The summary describes trends or other noteworthy features in the data but does not include interpretation or explanation. Also incorporate the results of any statistical tests into this section.

Data are presented in either a table or a graph. Use a table when you have only a few values to present. For example, the pH values from six lakes could be presented in a table. Tables must be clearly labeled with a descriptive heading and column titles and are numbered sequentially (Table 1, Table 2, etc.) as they appear in the report. Place tables within the text of the paper rather than on separate pages.

Graphs are the most commonly used format for presenting the results of an experiment. Graphs must be clearly labeled with x-axis and y-axis titles and a descriptive caption. A single graph will fill at least a half page, and that page is placed among the text pages of the results section. Graphs and other figures are numbered sequentially (Fig. 1, Fig. 2, etc.) as they appear in the paper.

The most important consideration in making a graph is your selection of variables to be plotted on the x-axis (horizontal axis) and y-axis (vertical axis). If you are investigating the effect of one variable on another (e.g. the effect of tree age on the level of infestation by caterpillars), the variable having the effect (e.g., tree age) is plotted on the x-axis and the affected variable (e.g., infestation level) on the y-axis. If you measure two variables and neither directly affects the other (e.g., the nitrate level and phosphate level in a number of lakes), the choice of x-variable and y-variable is arbitrary. If you measure one variable over time (e.g., mouse population size each month), time is plotted on the x-axis and the variable on the y-axis.

Two types of graphs are most commonly used for biological data. In scatter plots, the data are represented as points on the graph. Use a scatter plot when the x-variable is continuous and can theoretically have any value (e.g., tree age). Do not draw a line or curve through the points unless it is fitted with an appropriate statistical analysis such as linear regression. Also graph time series as scatter plots but connect the points corresponding to sequential times. In contrast to scatter plots, the data in bar graphs are represented as vertical bars. Use a bar graph when the x-variable is discrete and can have one of only a few values (e.g., one of four species of bees).

DISCUSSION

The discussion is the most important section of a scientific paper and the one in which you interpret your results. In the introduction, you stated your hypothesis, and in this section, you discuss the degree of support for the hypothesis. Be sure to explain the results as thoroughly as possible. Also include the implications of your results for organisms in the real world.

In the discussion, the level of agreement between the conclusions of the present study and earlier work is discussed. You should also include ideas for further research and any practical applications of the experiment. You can include limitations of the experimental techniques and possible sources of error if the potential error is of sufficient magnitude to make your conclusions questionable.

LITERATURE CITED

In a scientific paper, you give credit to other people when you use their ideas or results. Credit must be given for ideas even though direct quotes are rarely used. In other forms of writing, footnotes or endnotes are used to credit sources, but in scientific writing, citations are incorporated into the text. Specifically, the last name(s) of the author(s) and year of publication of the work being cited appear within parentheses. For example: The least weasel is the only predator that can enter rodents’ tunnels in soil, under leaf litter, and beneath snow (Ylönon et al. 2003).

At the end of the paper, give complete references for all works cited in the report. The references are listed alphabetically by the primary authors' last names. Each article reference should include the authors' names, year of publication, title of the article, journal title, volume, and page numbers. Book references should include the authors' names, year of publication, book title, and name and location of the publisher. Use the references from the journal Ecology as a guide for the format for complete references.

FORMAT

Ecology lab reports are opportunities to practice and improve writing skills. Write in complete, grammatically correct sentences and paragraphs; correct spelling and punctuation are expected. Active voice is more readable and usually preferred (e.g., "The mice ate white oak acorns..." instead of "The white oak acorns were eaten by the mice..."). Since you are writing about an experiment that has been conducted, use past tense. Also, the subject and predicate of each sentence must agree (e.g., "The technique was...", "The techniques were...", "These data were...").

Write out long phrases the first time they appear and abbreviate subsequently (e.g., "High pressure liquid chromatography (HPLC) was...", then "We used HPLC..."). Also write out the scientific name of an organism initially and abbreviate thereafter. By convention, genus and species names are always underlined or italicized (e.g., "Eastern chipmunks (Tamias striatus)...", then "Nest construction by T.striatus...").

Lab reports should be word-processed. Double-space the text so editorial comments can be given. Also label each of the sections of the report beginning with the Introduction.

PLAGIARISM

Using others' ideas without giving them credit is plagiarism. This includes ideas from textbooks, lab handouts, etc. It is especially bad to copy phrases or sentences from such sources. Also, simply changing the voice of a sentence (e.g., changing "We used artificial plants to test the effect of spatial patterns of seed placement." to "Artificial plants were used to test the effect of spatial patterns of seed placement.") is not considered sufficient paraphrasing.

Each person will write his/her own lab report. If two students turn in substantially similar lab reports, they will share the grade. For example, if two students turn in similar reports and the grade is 16 out of 20, each student will receive an 8 for the assignment.