Guide to laboratory work

Your notebook will become a record of all you have seen and done in the lab.  You should use the worksheets and blank drawing pages to develop your observational skills.  In addition to quick sketches of animal form, you can pose questions, create cartoon diagrams of how things work, make “blow-up” sketches that show details, and record collection information and page numbers for further reading.  Try to create drawings and notes that will be not only interpretable but helpful five or ten years from now.

Drawing as an aid to observation.  You don't need great artistic skills to make useful drawings (see the informative but highly non-artistic drawings done by the late Donald P. Abbott in his book, Observing Marine Invertebrates).  In light of digital photography, it may seem pointless to labor over drawings and seek out details that have been described countless times.  But remember: the process of taking a photograph does not aid your learning like the process of drawing.  Your observations and their representation on paper are part of a learning process that forces you to pay attention to how individual parts relate to one another and how they differ from one organism to the next.  If focused, your brain can see and store more useful information than does taking a detailed and more "accurate" photograph.

Useful tools: pencil; good eraser; colored pencils (but use sparingly); drawing paper; dissection tools.  A sense of scale when looking through a microscope with different size objectives.  A textbook for reference.

Suggestions for what to include in your drawings:

  • Make your sketches large to accommodate parts and labels.  It is often better to do a highly simplified sketch or outline of an animal and then “magnify” details of anatomy in smaller blow-up sketches, especially when parts are repeated.  Don't waste your time drawing the same part over and over again, if you won't learn anything from doing so.

  • Sketch in pencil with a light hand to make erasing easier.  Use color sparingly and only to provide information.

  • Label profusely with relevant information, including the phylum/class/species name, the names of structures, collection information, and page numbers of reference material.

  • Pepper your sketches with little notes and questions about the function of structures, speculations, comparisons to other organisms, habitat and lifestyle descriptions, and results of simple experiments.  Try ultimately to record answers to any questions.

  • Include a size scale wherever possible by using a scale bar or writing down the size of the organism or structure.

  • Draw only what you see, not what a photograph or drawing suggests you should have seen.

Resources.  Use your textbook and other published sources to help understand what you see; in turn, use your laboratory experience as inspiration for further reading.  Refrain from reading more than necessary in lab, but mark passages to read in greater detail later.  Collaborate with peers--show them discoveries, ask them questions, and together seek out answers.  Make use of your instructors as well, but also try to become comfortable with seeking out information from your textbook and other references housed in the lab.  An important part of your training as a scientist is to come to conclusions based on the information available.

Etiquette:  Return material to the place where others expect to find it.  Keep your own space clean, leave common spaces cleaner than you found them, and take good care of the microscopes, which rust easily around salt water.  Reserve the last 5-10 min for cleaning everything you used.  Return everything to the condition and location where you found it at the start of the lab period.

Microscopes.  You will use microscopes often in this lab.  Many invertebrates are, or have parts that are, too small to see well without magnification.  You will use two types, Dissection and Compound microscopes:

   Dissection        Compound

Microscopes are expensive and must last a long time.  Keep these basic rules in mind for most effective use:

1. Carry scopes with two hands.

2. For the best 3D view, focus first through the eyepiece without a manual adjustment and then adjust the other eyepiece focus.

3. Scopes rust easily, so keep them from getting wet, especially with saltwater.

4. Turn the scopes off when not in use (specimens are easily cooked by the light).

5. To clean microscope lenses use only moistened lens paper—ask an instructor for help.

Below is an example of a good scientific drawing. It was done by a former student in the class.

Dorsal view of Nereis virens, with blow-up view of parapodium


Helpful hint: To avoid crushing delicate specimens when you prepare a slide wet-mount, try propping the cover slip up over the specimen by putting a nick of clay on each corner of the cover slip.  Ask your instructor for help.


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