Presentation on theme: "Writing in Biology -. Results Results Section The results section presents your data, nothing more. no background no methods no discussion or comments."— Presentation transcript:
Results Section The results section presents your data, nothing more. no background no methods no discussion or comments When experiments are well done, the results stand as valid -- interpretations of the data may change with time, but the data themselves will not. Draw the reader's attention to the relevant data (major observations and fundamental trends)
Step #1 - Think about your data Pose questions about your data and see if they support your story. Play devil's advocate. These questions will constitute what your results section should explore. Graph your data or put it in a table or figure so that underlying trends can become apparent. This may require trial and error. Use MS Excel to test various statistical relationships your data may suggest.
The Results Text Do NOT simply describe your figures -- point out major trends. In pointing out trends, be specific -- use your data to quantify and establish limits or ranges in the trends. You need to provide the reader with an unambiguous idea of the trend you are presenting. Whenever you make a statement in your results it must be backed by your data. Stay close to your data (often simply citing the figure will do -- sometimes it might be a specific datum point if the statement is highly detailed). Make it clear to your reader what the intention was in doing a particular experiment or a particular manipulation. In order to determine....
More on the Results Text Always present your results in past tense. Thus the writing will refer to what you did. If you write in present tense it implies that the results can be generalized to all such situations: “Bacteria exposed to ethanol failed to grow as much as bacteria not exposed to ethanol…” vs. “Bacteria given exposure to ethanol fail to grow as much as bacteria not given exposure to ethanol…” Write in active voice – “I found…” or “We measured…” are better than “It was found…” or “Measurements were made…”
Graphing In general there are two types: -histograms -scatter plots (point and line graphs) other graphs are not generally appropriate for biology papers Each axis must be clearly labeled and units must be noted The meaning of any symbols must be clearly indicated (may be in the legend below the figure) A figure legend must always accompany a graph - it has a brief title (the title does not appear on your graph) - it explains what is in the graph (this may detail how the particular samples were manipulated) - it summarizes the basic trend - it should be self-contained
Point Graph Preparation Use a computer to generate your graph. By convention, the independent variable is plotted on the x-axis, and the dependent variable is plotted on the y-axis. The axes of the graphs should begin with the number 0. If there's a large break, indicate this with //. Connect the dots when there is a linear relationship. When there is clearly a direct relationship draw a smooth curve. Use error bars to indicate SE/SD or range about the mean.
Histogram Preparation Used when the relationships between samples is nonlinear (e.g., the variable is nominal or ordinal) You should insert error bars and ranges (where ranges are far from SE/SD) Do not overembellish (e.g.,no 3-D, shadowing, or superflu- ous color)
Figure 1. Summer and annual precipitation in cm as recorded at the weather station at Galesburg, Illinois, USA. Mean precipitation is normalized climatic data collected from 1971 to 2000. 2005 was a drought year, 2001 experienced summer drought.
Figure 4. Amylase activity in the incubation medium of samples heat stressed by slow ramp heat shock. Aleurone layers were incubated in the presence of 1 µM GA3 at 25°C for 13 h then either shifted to 2.5°C warmer shaking water baths every 1 h (slow ramp), shifted to 40°C for 3 h (HS) or maintained at 25°C for 3h (+GA). At the end of each ramp interval, the incubation medium was collected and replaced with fresh medium. The samples of incubation medium were assayed for alpha- amylase activity. The experiment was repeated three times. Ramping to 40°C does not inhibit amylase secretion as rapid heat shock to 40°C does.
Table Preparation Tables should be arranged so that all the data for a given sample can be read from left to right. A table heading, like a table legend, must: - have a brief title (the title does not appear in your table) - explain what is in the table (this may detail how the particular samples were manipulated) - summarize the basic trend - be a self-contained explanation Tables should be clean and logical. Avoid repeating words across the columns or down the rows -- subheadings can provide that information. Again do not unnecessarily embellish your table.
Prairie nameType of prairie Species richness Number of alien species Mean conservatism FQI BrownleeRemnant76114.2234.02 Lost MeadowRemnant5023.8926.99 Spring GroveRemnant5493.6924.74 EastRestored63114.2330.51 SouthRestored6994.6536.02 WestRestored6464.2932.69 Table I. A comparison of species richness, number of alien species, mean coefficient of conservatism, and floristic quality index (FQI) calculated based on all the samples collected in each prairie.
Some Particulars... Numbers: - measured items –> use numerals rather than words - always use a zero before the decimal point when the value is less than zero. -very large or small numbers should use scientific notation 0.000005 M is 5X10 M or 5 µM 600,000 m is 6X10 m or 0.6 Mm Use the term significant (as in significant increase or significant difference) ONLY when an appropriate statistical test has been used to demonstrate that this is the case. Data is plural; datum is singular. "The data ARE significant." Never is it the case that, "The data is significant." In the text Table and Figure are capitalized Proper English is mandatory. -6 5
In the discussion you need to consider several points - 1.What did you expect to find and why? 2.How did your results compare with those expected? If you set out to test specific hypotheses, do you data support one hypothesis more than another? 3.How do your findings relate to those of other researchers? 4.How might you explain any unexpected results? 5.How might you test these potential explanations? 6.Based on your results, what question or questions might you logically want to ask next?
Even the simplest questions you ask may not be easy to answer. The results frequently may differ from what you expected. Don’t try to cover up or hide unexpected or unusual results. Any experiment that was conducted properly tells you something, even if that something is not what you initially set out to learn. When you write your discussion, start out narrowly focused on your own results and then gradually broaden the discussion to consider larger implications of your work – how it compares to others and what it means in the grand scheme of things.
In your writing: Be specific – use data where available to quantify Make sure each sentence is informative – (avoid saying something is “interesting” - simply state what is of interest) Avoid using “etc.” – lists should be inclusive or highly representative of the range Do not overly hedge, but also don’t overstate claims –“Our data indicate that there is the potential possibility that some…” –“Our data PROVE that unicorns exist.” Watch basic grammar Whenever possible avoid the passive voice
Discussions and introductions require the stating of facts that require the use of citations Citations are not footnotes Citations are not direct quotes – they give credit for the source of an idea or of factual information When using a source: –Read the information –Close the book or journal –Make notes about the facts you want to cite –Then when writing your paper, work from the notes Closely follow the accepted citation protocol
Literature Citation “Restoration ecology had its genesis in the 1930’s as Midwestern ecologists came to the realization that nearly all the tallgrass prairie in Illinois, Iowa, and Wisconsin had been converted to agricultural or urban land uses (Curtis and Greene 1949; Anonymous from Critical Trends Assessment Project 1994; Smith 1998). While calls for preservation of remaining prairie in Iowa began by 1919 (Smith 1998), the pioneer restoration ecologists of the early 20th century recognized that if extensive areas of tallgrass prairie were going to be part of our future, they would have to begin to restore these historic grasslands.”
Citation style for journal articles: (Westman 1991) Westman, W. E. 1991. Ecological restoration projects: Measuring their performance. The Environmental Professional 13:207-215. (Curtis and Greene 1949) Curtis, J. T. and H. C. Greene. 1949. A study of relic Wisconsin prairies by the species-presence method. Ecology 30:83-92. (Taft et al. 1997) Taft, J. B., G. S. Wilhelm, D. M. Ladd, and L. A. Masters. 1997. Floristic quality assessment for vegetation in Illinois: A method for assessing vegetation integrity. Erigenia 15:3-95.
Citation style for books: entire book (Leopold 1949) Leopold, A. 1949. A Sand County Almanac and Sketches Here and There. Oxford University Press, New York. book chapter (Howell and Jordan 1991) Howell, E. A. and W. R. Jordan III. 1991. Tallgrass prairie restoration in the North American Midwest. Pages 395- 414 in I. F. Spellerberg, F. B. Goldsmith, and M. G. Morris, editors. The Scientific Management of Temperate Communities for Conservation. London: Blackwell Scientific Publications.