One part of scientific work is doing experiments or making observations. Another is the communication of the results of this work to other scientists and to the public. It is often not realised that the way in which scientific work is described and discussed is just as important as the way in which the work is conducted.

Scientific communication takes a variety of forms. There is the formal report, which may be published as a research paper, and the scholarly essay which may be published as a review or monograph.

Scientists also communicate with the general public through articles in newspapers and magazines. Verbal communication is also of considerable importance for the scientist. They may describe their work at conferences and verbal discussions usually follow. Talks on the radio and programmes on television about science are becoming more common.

It is important that you learn to communicate during your time at University and it is best to start early. In first year you will be asked to write laboratory reports and essays and these become increasingly common in second and third year units. Verbal reports of laboratory projects are often expected in second and third year and, again, practice in this form of communication is of great value.

Below you will find instructions for preparing laboratory reports and essays together with an example of a short laboratory report. It would be of benefit to you to read these instructions and to practice writing and speaking this year. Essays and laboratory reports will form the basis for assessment in Biology B & C units.

Experimental Laboratory Reports

Requirements

A laboratory report should state clearly what you did, what results you obtained and your interpretation of the results. It should enable another person to repeat your work in order to check your results.

1. Content

a) Aim or Introduction: Show clearly that you understand the significance of the study. What was your initial hypothesis?

b) Materials and Methods. It may not be necessary to describe standard methods used, such as those given on a laboratory handout; but any departure from the standard methods should be described. When you have devised the methods yourself you should describe them in detail.

c) Results: The raw material (such as lists of individual readings or weighings) need not be included, but must be kept (in your laboratory notebook) in case it is asked for. The main findings should be described in consecutive prose with references to the tables and figures. Do not discuss your results in this section.

d) Discussion.: Discuss critically the significance of your results. Do not hesitate to draw obvious conclusions as well as the less obvious ones. If you do not write them down it will not be clear that you have seen them. It may be useful, after a lengthy discussion, to list your conclusions.

e) Bibliography: If you referto the work of others in your report, this should be acknowledged via citations in the text with complete reference details listed in a bibliography. A description of how to cite references is given in the Essay Section.

2. Style

a) The writer's findings and operations must always be reported in the past tense. The present tense may be used for statements, derived from other sources, that can be made with some confidence: for instance, 'the gestation period of a laboratory mouse, when uncomplicated by concurrent lactation, is about 19 days'. (Note the use of 'about', instead of 'approximately'; the latter merely gives a spurious impression of accuracy.)

b) Tables and figures should be referred to in the text with the minimum of words. For example, 'the wild mice were lighter than the laboratory mice (Table 2, Fig. 3).' Not 'Table 2 gives the average weights of wild mice and also of laboratory mice; and Fig. 3 also gives average weights at various ages.' Also, it is never necessary to write: 'see Fig. 3'.

c) International (Sl) units and correct abbreviations should always be used.

3. Sample Laboratory Report

a) Instructions (not part of report)

3 Day Live Chick Embryo - Heart-Beat Rate

From the incubator take one egg which has been incubated for 3 days. Lay the egg on its side. Cut a circular hole, about 3-4 cm in diameter, in the shell. Be careful not to poke the points of the scissors too deeply into the contents of the egg. Remove the disc of shell and examine the embryo in the egg. Note the way in which the blastodisc has spread over the surface of the yoke.

With a sharp pair of scissors, cut around the embryo, peripheral to the outer blood vessels of the blastodisc. It is important that you do not cut the blood vessels of the developing yolk-sac membrane. Take the plastic ring in a pair of forceps and push it into the yolk underneath the blastodisc. Then by lifting upwards pick the embryo and blastodisc on the plastic ring, with the embryo in the middle of the ring and the blastodisc draped over it, and immediately transfer to a dish of 25C saline. You will be shown how to set up this culture dish in a carolina dish of warm water. Check the temperature of the saline in the culture dish and note the rate at which the heart of the embryo is beating. Stir the contents of both carolina dish and culture dish regularly and take readings of both temperature and heart beat rate at 2 minute intervals. When the temperature in the culture dish has fallen to about 25C increase the temperature by adding hot water to the carolina dish. Maintain the water level in the dish every time you add hot water. Use the 20 ml syringe for this purpose. When the temperature in the culture dish has again reached 25C the experiment is completed. Plot individual results of heart beat rate against temperature and heart beat rate against time after removal of the chick from the egg for your own records. Write a short discussion of the significance of your results.

b) Sample Report

3 Day Old Chick Embryo - Temperature Effects on Heart Rate

Aim:

To investigate the effect of changing incubation temperature on the heart-beat rate of chick embryos at 72 hours of incubation.

Method:

The chick embryo was removed from the egg as described in the schedule and was immediately placed in a pet dish containing 0.9% NaCl at about 25C. The saline was changed until it was no longer cloudy with yolk washed off the embryo. The petri dish was then fixed in a carolina dish containing tap water at 25C (Fig. 1). By adding hot or cold water to the carolina dish, the temperature of the saline in which the embryo was submerged could be altered. As soon as the embryo was established in the incubation system, the heart-beat rate (HBR) and the temperature of the saline were measured. These measurements were repeated for various temperatures; first, as the temperature was gradually lowered and second, as the temperature was gradually increased from the lowest point (25C back to 40C).

Results:

There was a linear relationship between HBR and temperature when class results were averaged (Fig. 2) and individual results, although more varied, indicated a linear relationship in most cases. There was no relationship between HBR and the time elapsed after removal of the embryo from the egg (Fig. 3). The variation in HBR seen in this figure related to the changing temperature of the incubation medium.

Discussion:

The averaged class results show a linear relationship between HBR and temperature (Fig. 2) which indicates that the HBR of the chick is determined by the temperature at which it is maintained. This demonstrates the importance of the hen incubating the egg. The line expressing the relationship between HBR and t intercepts the X axis at 21C which suggests that the heart will cease to beat below this temperature. It was shown to be true by some groups.

The results in Fig. 2 might be criticised on the grounds that the embryos were slowly deteriorating in culture. This is refuted by the observation that HBR is not related to the time elapsed after the embryo's removal from the egg. The HBR of embryos will return to normal for 37C after the temperature of the embryos has fallen to 25C and the HBR to 50 beats/ml, suggesting that HBR is unaffected by one hour in culture. It could be tested by keeping embryos in culture for one hour at 37C and monitoring the HBR.

Conclusion:

Chick embryos will remain alive for at least one hour after removal from the egg and cultured in 0.9% NaCl. During this period, the HBR bears a linear relation to temperature.

Essays

1. An essay should never be merely a summary of findings in a particular field. It should include a critical analysis of concepts or methods. It is usually a good idea to indicate important areas of doubt, controversy or ignorance. Never assume that, because a statement has been printed in a reputable journal, or made by an 'authority', it must be true. Sources (papers in journals, or books) should be up-to-date.

2. Plan the argument of your essay carefully before writing it. Write one or several drafts before the final version. A very simple style, with no unnecessary words, is the most effective.

3. An essay should be divided into sections. Different sections in a long essay (>5000 words) should be indicated by using subheadings. An essay should have an introduction, a body or middle, and a conclusion.

4. In developing your argument you will need to use evidence published by other writers. (The bibliographic citations for these examples are given below.)

a) You may want to direct the reader to a particular piece of work, e.g.

De Bach and Sundby (1963) showed that no two Aphytis species could coexist in laboratory populations.

b) You might agree with, and want to use, another writer's conclusions. Never adopt somebody else's words as your own - this is called plagiarism and is equivalent to stealing. If you want to include a direct quotation, use quotation marks and include a citation of the source including a page number. Always acknowledge the published work, e.g.

A balanced competition seems to exist between Erodium botrys and Bromus mollis in which E. botrys is favoured in poor soils and in drought years, and B. mollis is favoured in better soils when adequate moisture is available (McGowan and Williams 1968).

c) If there are more than two writers of a piece of work you are referring to, use the following format in your essay but refer to them in full in the bibliography.

To keep the discussion clear, Whittaker et al. (1973) have suggested

5. Include line drawings and tables to illustrate your arguments. These should be you own work (modified from the original if necessary),and must include a citation (e.g. after or modified from). Do NOT use photocopies of original published data. The only exception to this use of photocopies is for illustration of animals and plants.

6. The bibliography (list of references) should be a complete citation of references appearing in the text, and should appear at the end of your work. Do not use footnotes to give bibliographic details. The bibliography should contain no entries which are not referred to in the text, and there must be no textual citation which does not appear in the bibliography. References must be given in full; abbreviation of journals must be those in the World List of Periodicals. The following is an example of a bibliography.

Bibliography

De Bach P. and Sundby R.A. (1963) Competitive displacement between ecological homologues. Hilgardia 34: 105-166.

McGowan R.L. and Williams W.A. (1968) Competition for nutrients and light between the annual grassland species Bromus mollis and Erodium botrys. Ecology 49: 981-990.

Schmidt-Nielsen K. (1964) Desert Animals. Clarendon, Oxford. 327 pp.

Strong D.R. Jr (1984). Exorcising the Ghost of Competition Past: Phytophagous Insects. In Ecological Communities: Conceptual Issues and the Evidence. Strong, D.R. Jr, Simberloff, D., Adele, L.G. and Thistle, A.B. eds. Princeton UP, Princeton. 613pp.

Whittaker R.H., Levin S.A. and Root R.B. (1973) Niche, habitat, and ecotype. Amer. Nat. 107: 321-338.

7. Your essay should be typed, double-spaced. (If hand-written it must be written neatly). Write on one side only, with 3 cm margins on left and right, and 2.5 cm top and bottom for comments. (If you do not leave a margin you cannot expect the reader to make comments.) The top page must give the title, your name, and a table of contents if you have used sub-headings. Always keep a full corrected copy.

Meanings of Terms

Discuss: Explore the topic through a clear and consistent development of ideas, using adequate evidence.

Critically: Show that you have evaluated what you have read. (See note 3 below also).

Evidence: Information obtained from experimental or field studies. Go back to the original work (eg. journal article), do not cite citations. Avoid using secondary sources such as encyclopaedias or magazines like New Scientist and Scientific American.

Strategy

1. Most topics can be approached from a variety of viewpoints. Decide how you are going to approach the topic you have chosen.

2. Read with a questioning mind. Do not accept that something is true simply because it is published. Do not expect that there is any single correct answer to complex questions.

3. Evaluate continuously what you are reading - test the opinions and judgments of the writer against the evidence provided, and against the evidence and conclusions of other writers.

4. Select only the points which are directly relevant to your topic and your argument.

5. When developing your written argument, structure the material so that each idea fits reasonably with that which precedes it and that which follows, and so the ideas taken together lead towards your overall conclusion.

6. i) Adopt a style which is appropriate to academic writing in Biology. You will need to read essays or review articles in order to become familiar with such a style.

ii) Use the correct format for quotations and citing of references.

7. Edit your final draft carefully for errors in grammar, spellingand punctuation, and for precision in choice of words and expression of ideas.

8. It is strongly recommended that you learn to use a word processor for assignments. Suitable packages are available in University libraries and colleges.

A useful reference for essay writing is:

Clanchy J. and Ballard B. (1981) Essay Writing for Students Longman Cheshire, Melbourne. 123pp.

Criteria for Assessment

1. Relevance: is the essay clearly focused on the topic? Does it cover all parts of the topic?

2. Quality of Research: is there evidence of a thorough search of relevant literature?

Is there evidence of a critical review of the material read?

What use of the source material is made in the essay? (In particular, have you reconstructed relevant material to meet the particular demands of the topic, or have you duplicated chunks of material from the text?)

3. Coherence: is the essay structurally sound i.e. is there a clear logic in the argument of individual ideas and in the linking of ideas? Is the essay internally consistent?

4. Clarity: (partly a function of 3) is the expression of ideas clear? Is the language precise i.e. does it follow standard patterns in grammar, spelling and function?

5. Conventions and Style: does the essay follow recognised standards of scientific writing eg is the tone objective and rational rather than emotive or rhetorical; does the essay use accepted methods of textual reference, bibliographic format, etc.?

6. Presentation: is the essay legible? Is there evidence of thorough proof-reading? If you have used graphs or diagrams, are they appropriate and clearly labelled?

7. Length: The essay must not exceed the permitted length. If it is more than 10% over the limit, marks will be deducted.