The goal of a biological diagram is to represent how different parts of a specimen relate to each other, as opposed to what they actually look like. Drawing diagrams allows biology students to record their observations of a specimen and to refer to the illustration at a later date in order to recall the important features of a specimen, for example in preparation for a test. Beginner-level biology students should familiarize themselves with the correct way of drawing scientific diagrams.

Step 1

Use a pencil and unlined paper when drawing a biological diagram. Position the diagram at the center of the page. Draw only what you actually observe, as opposed to what you think you should be seeing.

Step 2

Use sharp single lines to represent an object. Do not use soft lines characteristic of sketches. Make the illustration large so that various parts of the specimen are easily distinguishable.

Step 3

Represent darker areas of an object with stippling or dots. Do not shade any areas of the diagram.

Step 4

Print when labeling the different parts of the diagram. Do not use the plural form when identifying a single part or object. Draw a straight line from each label to the part or object it describes. Make sure that these lines do not cross or overlap.

Step 5

Keep in mind that the first part of a scientific name, or the genus name, must be capitalized. The second portion, or the species name, begins with a lower case letter--except when used in the diagram title. Underline scientific names.

Step 6

Write the title of the diagram in capital letters and center it. Remember that the title must be concise and accurately explain the subject of the illustration.

Step 7

Draw scale bars indicating the length and width of a specimen. A scale bar is a straight line that represents the relationship between space on your page and the actual space occupied by the specimen.

Step 8

For microscopic specimens, indicate the magnification at which you observed the object through a microscope. Write this information in one of the corners of the page.

Step 9

Use sharp single lines to represent an object. Do not use soft lines characteristic of sketches. Make the illustration large so that various parts of the specimen are easily distinguishable.