Tables, Graphs & Figures

Creating a TableTables should be arranged so that all the data for a given

sample can be read from left to right.A table heading, or caption, must: - have a brief description of what the table shows - explain what is in the table (this may detail how the particular samples were manipulated) - summarize the basic trend - be a self-contained explanationTables should be clean and logical. Avoid repeating words

across the columns or down the rows - subheadings can provide that information.

Table I. Body mass (g) of birds raised under different intensities of green, blue and red light.

Green Light * Blue Light * Red Light *

Species 100 lux 200 lux 400 lux 100 lux 200 lux 400 lux 100 lux 200 lux 400 lux

Parus major 1.2 2.8 8.4 2.3 3.8 9.6 1.1 2.1 4.5

Parus minor 1.4 2.4 6.3 1.9 3.5 8.5 1.5 2.0 4.0

Parus benicus 1.2 1.9 7.2 2.2 4.2 7.6 2.1 2.3 3.9

Parus imaginus 1.6 2.6 6.9 2.1 4.0 † 1.6 1.8 5.5

* colors defined by wavelength: green: 510 nm; blue: 460 nm; red: 680 nm

† no data available

“Plantago major was found at three out of the five vacant lots sampled (Table 2).” (description of table in results section)

“The seeds neither imbibed water nor germinated following any of the treatments (Table 3).” (description of table in results section)

Figures in Biology• In general there are two types: -histograms -scatterplots (point graphs)• Other types of graphs are less common for biology papers• Each axis must be clearly labeled and units must be noted• Have enough tick marks on both axes at intervals frequent

enough that the reader can estimate the value of each data point.

• The meaning of any symbols must be clearly indicated (may be in the legend below)

Figure Caption

• A figure caption must always accompany a 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

A Good Caption

From the figure caption, the axis labels, and the graph itself, the reader should be able to:

1) determine the question being asked, 2) get a good idea of how the study was done,

and 3) be able to interpret the figure without going

back to the text.

General Points

• If you have more than one graph, keep styles consistent. The symbols should be the same, etc.

• If a simple sentence will convey the meaning of the data and no graph is needed, don't use a graph. Use tables and graphs only if they make your data work for you. If a table or graph fails to help summarize a trend, leave it out.

For Scatterplots• 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 (if

there isn't a linear relationship, you should probably be using a histogram). When there is clearly a direct relationship draw a smooth curve.

• Use error bars to indicate SE/SD about the mean:• SE standard error – Standard deviation divided by square

root of n (sample size) • SD – standard deviation

For Histograms

• 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 over-embellish (e.g., no 3-D, shadowing, and superfluous color)

Other Kinds of Figures

Some may be appropriate for Biology

Figure 3. Mean coefficient of conservatism (c bar) is compared for belt transects in remnant and restored prairies.The red dot indicates the mean value for each plot.

Box and Whisker Plot Explained

A graphical representation of losses of soldiers during

Napoleon’s Russian campaign.

Fig. 2. A commercial restoration plantation in northeastern Costa Rica. In the foreground are plantedindividuals of Acacia mangium, a fast-growing tree species native to Asia and Australia, which tolerates poor soils. A fast-growing native species, Vochysia guatemalensis is also planted here among the A. mangium trees. In the background is a fragment of 25-year-old secondary forest. Euterpe oleracea, an exotic palm species from Brazil that was cultivated in a nearby plantation has colonized the restoration site (upper right quadrant) and is now invading secondary forests in this area. [Photograph by R. L. Chazdon]