Biological Drawings

Biological drawings are a fundamental tool in the life sciences, serving as a way to accurately record qualitative observations of biological samples. They are a form of scientific communication that allows for a clear and concise representation of a structure, morphology, and/or anatomical features.

A line drawing is a type of scientific illustration that uses lines to represent the shapes and structures of biological specimens, often cells or tissues. These drawings are simplified representations, typically omitting shading or color to emphasize key features observed under a microscope.

As drawing is a form of scientific communication, accuracy is important.  Draw what is seen; not what "should" be there.  Avoid making idealized drawings.  Do not necessarily draw everything that is seen in the field of view.  Draw only what is asked for. Show only as much as necessary for an understanding of the structure – a small section shown in detail will often suffice.  It is time consuming and unnecessary, for example, to reproduce accurately the entire contents of a microscopic field. 

• When drawing tissues, do not draw individual cells. Show only the distribution of cells in the tissue, using lines to outline the structures and representing the relative proportions of different parts of the tissue. 
• When drawing cells, draw only a few representative cells (not necessarily every single cell in the field of view).​

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Example:  labeled photograph of a cross section of a lilac leaf (Syringa vulgaris) view with a 40x microscope magnification 

Line drawing at the tissue level:

Line drawing at the cell level:

https://www.ocr.org.uk/Images/251799-biology-drawing-skills-handbook.pdf

https://www.ocr.org.uk/Images/251799-biology-drawing-skills-handbook.pdf

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To ensure accuracy and clarity, line drawings should adhere to a specific set of guidelines:

1. Drawing materials: Use a sharp pencil to create clean, fine lines. Avoid using pens or colored pencils unless specifically instructed.  Draw on unlined, white paper. 
2. Drawings should be Large and Centered: The drawing should be large enough to clearly show all the important details; it should be centered on the page and fill at least half of the the available space. 
3. Neatness: The entire drawing, including the labels and title, should be neat and well-organized. There should be almost no erasures or stray marks on the paper. 
4. No Shading: Avoid shading or coloring unless specifically instructed. Use stippling or cross-hatching to represent different densities or textures, but do so sparingly.
5. Use Continuous Lines: Use single, continuous lines to outline structures. Avoid sketching or creating "hairy" lines. 
6. Labeling: Use a ruler to draw straight lines from the labels to the corresponding parts of the drawing. These label lines should not cross each other. Labels should be written horizontally and should be neatly aligned in a column.
7. Include a Title: Every drawing must have a clear and descriptive title that includes the name of the specimen, the view (e.g., cross-section, longitudinal section), and the microscope magnification.  The title should always include the organism name in in correct binomial nomenclature format (italicized or underlined).
8. Proportions and Scale: The drawing should be proportional to the actual specimen. The relative sizes of the different parts should be as accurate as possible.  Include a scale bar line labeled with the actual size of the specimen (do not label a scale bar with the measured length of the line). 
9. Drawing Magnification: The magnification of the drawing should be calculated and included in the title. The drawing magnification is how many times larger the drawing is compared to life size.  ​

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Drawings from samples viewed with a microscope should include two magnifications.  

• Microscope magnification refers to how much a microscope enlarges an object as you view it through the eyepiece. It's a property of the instrument itself and is determined by the lenses used. To calculate the total magnification of a compound microscope, multiply the magnification of the eyepiece by the magnification of the objective lens being used.  

• Drawing magnification is a value that describes how much larger the drawing is compared to the actual specimen. This is a crucial part of a scientific drawing because it allows other people to understand the true size of the organism or cell you have drawn. It is not dependent on the microscope's magnification. To calculate the drawing magnification, you must first measure or estimate the actual size of the specimen. Then measure the size of your drawing and use the formula:

If a drawing is labeled "400x (microscope) / 1000x (drawing)", it means the specimen was viewed at 400x magnification through the microscope and the drawing is 1000 times larger than the actual size of the specimen. ​

For additional information, see the Drawing Skills Handbook or Steps to Success.