The exercises this semester should present you with the opportunity to acquire some factual information about the structure and function of green plants and encourage you to develop useful skills and an attitude of inquiry. Because the subject matter must be limited to an amount reasonable for one semester, the emphasis will be on the biochemistry and development of plants. You are therefore presented with the challenge of relating the material encountered here with that in courses emphasizing structural, ecological, and evolutionary aspects.
Two purposes are served by recording the techniques and results of laboratory observations and experiments. In the first place, the record supplements the memory of the observer. After some time has elapsed, it is difficult to recall how one particular thing looked, how it behaved, or under what particular conditions the observations were made, yet this information is required for evaluation of the results and for correlating those observations with others made at a different time. Secondly, a record is necessary to form a basis for communication among individuals. Thus, a scientist must maintain a complete and accurate record of all his/her experiments and observations.
Laboratory records are of various types: notes on observations; tables of measurements; charts or tracings from special instruments; illustrations such as photographs, drawings or diagrams. The type of record varies with the subject, but all laboratory records should be complete, concise, and accurate.
A few suggestions are given here to help you in making a useful record of your laboratory exercises. Your laboratory record will vary with the exercise. In some cases you may have mostly notes supplemented by a few scattered illustrations. For this it is best to have separate notes and figures, the former providing a logically-arranged and coherent report of the observations with a notation of those aspects which are illustrated. In other cases, the bulk of the record may be numerical tables, instrument output, or diagrams and drawings. The record may be kept in the order described in the exercise, or you may find it advantageous to arrange the drawings in a logical sequence and insert a few sentences between the individual illustrations which will serve to connect the various figures by pointing out the interrelationships between the aspects illustrated. You will thus assemble a single coherent account of the laboratory study.
Illustrations
As illustrations for these laboratory exercises, drawings and outline drawings (diagrams) are recommended. One does not need to be an artist to prepare a useful drawing. A good drawing should show the shape, structure, and relationships of the object. It should stress accuracy rather than aesthetics. The most important prerequisite for successful drawing is to look carefully before you draw. When using microscopes, use higher magnification to get a better look to make a detailed drawing possible. If more than one object is available for study, observe several before selecting one that is most representative to draw. Make your drawings large enough so that details can be shown clearly; use clean, sharp lines and use shading RARELY. In drawings of cells, it is better to show a FEW cells accurately than many cells poorly!
An outline drawing or diagram shows the shape, proportions, and relationships of an object but not its detailed structure. For example, a diagram of the cross section of a stem should show the shape of the section, the position and extent of the various tissues in correct numbers and proportions, but NOT the structure in terms of the individual cells of the tissues. Such diagrams will frequently be a useful type of record in these exercises, because they can be made quickly and easily, and they contain a great deal of information.
Often an outline drawing and a detailed drawing can be combined to an advantage: the former shows the general organization by outlining areas, a small portion can then be selected to show the detailed structure. Drawings and diagrams should be very large and extensively labeled; it may be "obvious" at the time the drawing is made what the various details are, but these will not be so obvious from poor illustrations later when you are trying to prepare an abstract, a presentation, or a laboratory report!
Figures (Graphs)
All figures are to be prepared as described in the departmental style manual (Pechenik, 1987). The figures should be numbered sequentially in the legend. The legend should also give both a title for the figure as well as sufficient information for the observer to understand how the data were obtained. The figure should be produced by the Macintosh computers provided in Goddard 114 or must be drawn neatly with extensive use of a straightedge. Use no color in producing figures; different lines on a single graph may be distinguished by different line widths, dash patterns, or data symbols. All axes must be labeled descriptively, numerically, and in SI units. The spacing of ticks on the axis must follow reasonable standards.
For all but two of the exercises, you will be asked to produce an amplified abstract as a record for grading purposes. This consists of a standard one-paragraph summary abstract (Pechenik, 1987) with attached figures as documentation. The abstract should contain elements from all of the parts of a laboratory report:
The abstract is usually no longer than 15 sentences. It should be typed/computer-printed double-spaced on a single page with at least 3-cm margins all the way around. The type should be 12-point in size. The writing should be clear and concise! No extra verbiage is allowed. The use of active voice will save space ("heat increased the rate" vs "the rate was increased by heat"). Fuzzy thinking generates fuzzy writing, but fuzzy writing does not communicate clear thinking either. Do not use the word "affect" in any form; use such descriptive words as "increase" and "decrease" instead."Effect" is the result of some treatment; it is a noun and should never be used as a verb. Another common error is confusion about "then" and "than"; "then" relates to time sequences--"than" compares two items. In the end, the abstract should be easy to read, should "make sense" to any person with a college science background, and should be mostly informative.
The attached figures should follow the standard guidelines and should be sufficiently descriptive in the legends to be understood easily without supporting text. Each numbered figure and its legend must be presented together on a single sheet.
The completed amplified abstracts are due one-week from the date that the last data are collected. Late abstracts will receive penalties of 10% per day late...so turn these in promptly. Early submissions are encouraged.
For one laboratory exercise, you will make a class presentation instead of an amplified abstract. This oral report will be made during either lecture or laboratory and must be made within one week after all data are collected for the exercise. Late presentations will receive severe (10% per class meeting) penalties. Failure to make a presentation before the last day of classes will result in course failure.
You will select one of the exercises, prepare overhead/computer graphics, and make a five- to ten-minute description of your project, its results, and the conclusions you drew from it. At the end of your presentation you will answer questions posed by the class or the instructor. Organization, logic, and delivery are all critical elements of the evaluation for this presentation. I suggest an organization something like:
Introduction (which exercise? why did you select it?)
Hypothesis Being Tested (what questions were you answering?)
Experiments and Results in Sequence Leading To...
Conclusion on Hypothesis (hypothesis rejected? question answers?)
Avenues for Further Experimentation (what next? doubts?)
Audience Questions
For one laboratory exercise, you will produce a complete laboratory report instead of an amplified abstract or an oral presentation. This report must be typed/computer printed double-spaced (not space-and-a-half) with 3-cm margins all around in 12-point font. It must follow the departmentally-approved style manual in every respect. The following sections are required:
Title (sufficiently descriptive)Subheadings within each section are strongly encouraged! The laboratory report is due on the last day of classes, late reports receive a 10% per day late penalty. Failure to hand in this report before the final exam will result in course failure.
Abstract (all sections below present)
Introduction (intro topic, variables, expectations, purpose of project)
Materials and Methods (detailed enough but no trivial garbage)
Results (figures with legends, but also supporting text!)
Discussion (how do the results fit in with what is known? etc.)
Literature Cited (more than text and manual, use correct form).
Pechenik, J. A. 1987. A short guide to writing about biology. Little, Brown and Company. Boston.
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