Biological Drawings

One important function of laboratory classes in biology is to provide opportunities for you to learn first-hand about form, function and relationships among organisms. To do this you must be able to make and record accurate observations. This is achieved by practice. Throughout your studies in biology, you will be expected to record, in original drawings, the details of organisms or materials you observe in the laboratory.

Study the material carefully before beginning to draw and frequently while making the drawing. Do not copy from books nor from the work of other students, as copying (or plagiarism) defeats the purpose of the laboratory course - actual observation by you. Reference books should be used only as guides for what to look for. Draw only what you see. Previous drawings may be inaccurate, but the specimen is always right! As you draw and label each part, try to know what it is, an what its functions are.

Drawing Magnification

where

e.g., You measure your drawing with a ruler and find that it is 640 mm in length. You are viewing the specimen under medium power, and have calculated the field of view to be 1.6 mm. You then estimate that about 5 of the specimens could fit across the field of view. The drawing magnification would be:

Sketch
External view usually done with the low power objective lens or with a dissecting microscope. A sketch shows no cellular details but is accurate in scale and proportion.

Diagram
When a specimen is viewed using the low or medium power objective lens, a diagram can be drawn. No cellular details are shown. The purpose of the diagram is to show the general arrangement of structures and their relationship to one another. The diagram is accurate in scale and proportion.

Detailed Drawing
A detailed drawing is prepared when a specimen is viewed under the high power objective lens. Accurate cellular details are shown and individual cells or groups of cells can be drawn. The detailed drawing is accurate in scale and proportion.

Arrangement

1. Biological drawings are done using plain, white, unlined paper.
2. Either one or two drawings can be done on a single page, but never more than two. If only one drawing is to appear on the page, it is to be centered in the upper two thirds of the page. The drawing must be large enough to allow for small details to be clearly shown and labeled.
3. The drawing title is placed at the bottom left of the page and the drawing magnification calculation is shown aligned on the right margin and halfway between the bottom of the drawing and the drawing title.
4. If two drawings are to appear on a single page, the page can be divided in half so that the drawings will be one above the other. The placement of the drawing title and drawing magnification should be the same. Take a look at the examples to see how drawings can be arranged on the page.

Labels

1. All structures which you are illustrating should be clearly and accurately labeled. Label lines are to be drawn with a ruler and to the right of the drawing.
2. Lines should be parallel and justified on their right ends such that labels appear neat and tidy. Do not use arrowheads.
3. Label lines should never cross one another. If it is necessary for a label line to bend it should be at an angle of 90^o. Take a look at the examples to see how label lines should be done.

Hints

1. Be sure to draw only what you see. Don't give in to the temptation to draw what you "think" you should have seen. It may seem like it would be easy to look in your text or some other source to see a picture of the specimen and then to draw that, but your teacher will probably recognize what you have done. Your teacher has much more experience using a microscope and will know what can and cannot be seen with the specimens you are viewing. If you add structures to your diagram which you would not be able to see using your microscope, your teacher will catch on pretty quickly.
2. If you can't locate some of the structures you have been asked to find, ask for help from a friend or your teacher. If you still can't find one or more structures, make a note at the bottom of your drawing. For example, "Could not locate nucleolus or vacuole." This way, your teacher will know that you at least tried to find everything you were asked to find. Don't use this as an excuse to not look for the structures you have been asked to find, though.
3. If your specimen is larger than the field of view at the magnification you want to use, just draw what fits in the field. DO NOT draw a circle to represent the edge of the field of view. DO NOT draw a line across the drawing to show where the field of view ended.
4. Shading may be used if it adds to the interpretation. Don't attempt to "color" or "shade " your entire drawing.
5. Granular structures may be indicated using stippling (many small dots made with a sharp pencil).
6. If a large structure has a uniform appearance throughout, the detail can be indicated in a small part of the drawing. Simply note that the rest of the specimen, or area, looked similar.
7. It is not necessary to draw all the cells in a given section of tissue or organism. Indicate the boundaries of each different tissue using lines only. It is acceptable to draw a few cells representative of those found in the tissue.
8. Don't rush. Take your time and produce a good drawing. You do not have to be an artist, but you will not get full marks for sloppy work or drawings that appear to have been done in a hurry.