Ecology Lab Report.

Volo Bog State Natural Area,
collected data on patterns of water chemistry, water depth, and species abundances across three main successional zones at Volo Bog. We are interested in mechanisms driving this succession and maintaining these distinct vegetation zones during succession. The following is a set of guidelines for exploring patterns in the data we collected. Since this is an observational study, questions concerning mechanisms cannot be directly addressed with our data. Therefore, you will need to supplement the story your data tells with a lot of outside research.

Writing Lab Reports

There are two reasons for asking you to write lab reports: (1) to introduce the concepts, methods, and approaches used in ecological studies, and (2) to familiarize the student with the analyses and presentations used in scientific writing. The best way to learn about scientific writing is to do it using the format of a real journal, in this case Ecology. You may even want to look at an issue of Ecology in the library or electronically.

Writing can be difficult. However, following the format used in scientific papers—Title, Abstract, Introduction, Materials & Methods, Results, Discussion, Literature Cited—will help you clearly present the necessary information.

The maximum length for your lab report is 8 pages, not including references, tables, and graphs. Here are some general rules for scientific writing:
• Be concise
• Write in past tense
• Double space lines, use one inch margins, numbered pages and 12 point font.
Abstract

The abstract is a very brief summary. It explains why the research was undertaken, what hypotheses were tested, the methods, results, and major conclusions. Don’t speculate, don’t cite literature, and don’t make the abstract more than one page long.

The abstract is the only part of your paper many people will ever read, so put your best effort into it. Write it last after you are perfectly clear about your results and their significance.

Introduction

Start this section on a new page. The rest of the sections should follow immediately without page breaks until tables and figures.

The introduction sets the context. In it you explain why the research was done. One way to do this is to explain why the problem you are interested in is important, how others have tried to solve it (lots of references!), and how you propose solve it. End the introduction with a paragraph that starts “The purpose of this research was to….” And then state specific goals or hypotheses.

The hypothesis should state a prediction of the results that is as specific as possible based on what you know about the experiment.

Examples:

WRONG: The null hypothesis was the abundance of yellow-legged frogs would not differ between lakes with fish and lakes from which fish were removed.

CORRECT: If predation by fish limits the distribution of yellow-legged frogs, then the removal of fish should lead to an increase in the abundance of yellow-legged frogs relative to control lakes with fish.

You will want to refer to previous research in the introduction and discussion. The trick is to include the citations in your writing so that the flow of your sentences is not interrupted. Here are some examples:

McNab (1992) found that energetics in the air-breathing catfish was…. Bats of the Kibale Forest, Uganda disperse seeds of a variety of species into open fields (Duncan 1994). The restoration of tropical forest has only been studied by a few researchers (Uhl 1989, Nepstad 1990, Smith 1993).

For papers written by two authors, name both: Malcom and Brower (1989). For papers written by more than two authors, indicate the first author, followed by “et al.”: Brower et al. (1993)

Materials and Methods

Here you explain how, when, and where. Describe the study site and procedures, including scientific names of plant and animal species. Describe what you did so that someone else could repeat your work following only your directions (or directions in papers you cite). The materials and methods section should be written in past tense.

Often this section begins with a description of the field site, proceeds to an explanation of how you measured or collected samples, and continues with what you took back to the lab and how you analyzed it there. The section usually ends with an explanation of the statistical methods used, and the reason for their use. Example: “To compare sun and shade leaves, a Mann-Whitney U test was used because leaf masses were not normally distributed.”

Results

In the results section state, what you found without interpretation. Each paragraph should begin with a simple declarative sentence giving one conclusion from your data. Describe trends in your data, point out interesting data, and report the results of statistical tests. Write descriptive and interesting sentences; don’t just list numbers. Note that “data” is a plural word, and that “datum” is singular.

Be sure to refer to all of your figures and tables in this section. When referring to figures, “figure” is abbreviated and capitalized (Fig. 1) except at the start of a sentence (Figure 1). The word “table” is never abbreviated but should be capitalized (Table 1). The results of statistical tests and references to figures and tables are usually placed in parentheses at the ends of sentences.
Here are some examples:

Example 1. The concentration of nitrogen in Rosa multiflora leaves rose 15% along the nitrogen deposition gradient (Figure 1).

Example 2. Galls were more likely to be found in woods containing hazel and/or beech trees (Table 2).

Example 3. The observed ratio of fruit fly phenotypes in the F2 generation was significantly different from the expected 9:3:3:1 ratio (2 = 9.143, d.f. = 3, p<0.025).

Example 4. The feeding rate of group 1 (mean=12 items minute-1, range 8-14 minutes, S.D.=2.1, n=10 trials) was approximately 50% greater than that of group 2 (mean=8 items minute-1; range 3-13 minutes, S.D.=1.75; n=10 trials; paired t-test=2.33, p<0.05).

Discussion

Interpret your results and relate them to previous research in the discussion. This is where the value of having stated specific goals or hypotheses in the introduction should be apparent to you, because often you can organize the discussion by discussing the support for each hypothesis in turn. Did your results support or refute your hypotheses? Note that hypotheses can never be “proven,” but can only be supported or rejected. If you reject your hypothesis, explain why and suggest a new testable hypothesis based on your results and what you know about the biology. If your hypothesis was supported, explain the significance of your results using background information to support your ideas.

End the discussion with a couple of sentences summarizing the key points of your conclusions.

Literature Cited

A minimum of 6 primary scientific references is required. Follow the style presented in the instruction to authors in Ecology. EXACTLY!

Examples:

Brett, M. T., and C. Goldman. 1996. A meta-analysis of the freshwater trophic cascade. Proceedings of the National Academy of Sciences 93:7723-7726.

Campbell, B. D., and J. P. Grime. 1992. An experimental test of plant strategy theory. Ecology 73:15-29.

Cohen, J. 1977. Statistical power Analysis for the Behavioral Sciences. Academic Press, New York.

Dunham, A., and S. J. Beaupre. 1998. Ecological experiments: scale, phenomenology, mechanism, and the illusion of generality. Pages 27-49 in W. J. Resetarits Jr., and J. Bernardo, editors. Experimental Ecology: Issues and Perspectives. Oxford University Press, New York.
Tables and Figures.

Each table and figure should be on a separate page. Be sure to clearly label the units for each axis. Each table or figure should be numbered, and include a brief caption describing it in complete sentences. For tables include the number of observations in the table. For figures, state the number of observations each data point is based on in the legend. Table captions go above, figure captions go under the figure. If you use EXCEL or similar software for generating graphs, don’t unthinkingly accept the default style: chose line thickness and symbols that are easily visible, scale axes to display the data most effectively.

More…

If you want more information there are a number of copies of the following short book on reserve in the Science Library:

Day, R. A. 1979. How to Write and Publish a Scientific Paper. ISI Press, Philadelphia, PA. 160 pp.

 

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