| The written
lab reports that follow several of the BIOG 1105-1106 labs are an important
part of the lab portion of the course and can be a big stumbling
block for some students. This page is intended to be a reference
for the student, guiding you around some of the more obvious and
common pitfalls in scientific writing assignments.
Lab Report Format
All lab reports for BIOG 1105-1106 are written in the format of a
scientific paper. All scientific journals (publications like Nature, Science,
and the Journal of the American Medical Association)
require authors to submit papers in a specific format. For the purposes
of
BIOG 1105-1106 you will be expected to submit your papers in the format
specified in Appendix A of the Survival Manual. This format includes
most of the conventions of standard scientific writing.
The Major Sections
Scientific papers typically include the following sections:
- Abstract
- Introduction
- Materials and Methods
- Results
- Discussion
- Literature Cited
- Appendix (or Appendices)
In some of your labs you will submit full papers that will include
all of these sections. Other labs may require only abbreviated reports.
Be sure to pay close attention in lab and when reading the lab guide
so that you know which sections are expected in your report.
Although the sections should appear in the order listed above, this
is not the order in which most papers are written.
Writing Your Paper
Where should I start?
Many authors find that it is easiest to start with the sections
that are unambiguous. This usually means the Materials and Methods
and/or Results section. These are good places to start your paper
because you are only expected to report exactly what you did (in
the case of Materials and Methods) or exactly what your results
were (for Results). There is less need for creativity and critical
thought in these sections than there will be for the Introduction
or Discussion. Another way to think of it is to look at Materials
and Methods and Results as "facts" - you are just reporting
them, laying them out clearly for the reader so that you can use
them
effectively in the "arguments" you will make in the Discussion
section.
If your Materials and Methods section and Results section are
clear and concise then you are on your way to a good paper. Try
to edit these sections to remove any extraneous information and
be sure to leave any interpretation of data or critique of methods
for the Discussion section. Again, the Materials and Methods and
Results sections should simply and plainly present the "facts"
of your experiment. Nothing more, nothing less.
A final thing to keep in mind about the Materials and
Methods section is that your experiment should be reproduceable from the
text in this section. This means that paying attention to detail
is of the utmost importance here. If you use a specific piece of
equipment, tell the reader what brand and model it was, for example
here is a snippet from the Materials and Methods of one of my
recent papers:
"All measurements were made on adult, wild-caught individuals
and were taken directly with digital calipers (Mitutoyo CD6"C).
All digital images were captured with a high-resolution digital
camera (Kodak DC-120)."
By including this kind of information I make sure that if someone
wants to check the validity of my results they can easily replicate
my experiment in every detail.
Also, always be sure to acknowledge the help of others in your
experiment by including mention of any parties you exchanged data
with in your Materials and Methods, for example:
"The dimorphism estimates obtained
for the two extinct species were compared with those of seven
extant canid species and eleven
extant felid species. Most of the raw data for the extant species
are taken from Gittleman and Van Valkenburgh (1997)."
As for the Results section, one important thing
to keep in mind is that the focus of this section should be the
numerical results
as opposed to conclusions you might draw from those results. Another
important, and often overlooked, detail is that the results section
should usually only present summary data like averages and standard
deviations. Raw data should not be presented in the Results section,
it belongs in the Appendix (which should probably be referred to
in the Results section). The idea here is to show the reader what
you found out, not to bury the reader in a mess of data. the whole
point in writing the paper is for you to communicate what you found
to others so that they don't need to find it out for themselves.
If you present all your raw data without any kind of summation
or distillation, the reader may as well do the data analysis herself.
Lastly, try to avoid redundancy in your results. If all the numbers
are presented in a table, you do not need to list each one in the
paragraphs of text in your results section. Instead, use your written
text to highlight a key result or a major trend and then refer
the reader to the tables or figures that accompany the text so
that
she can
see
the
rest
of the data for herself. Here is two examples from my own scientific
writing:
"The group of carnivorous bears differed significantly from the
other three groups in five of the 19 indices (Table 3)."
"The upper
canine teeth of male C. dirus are estimated to have been
about 11-12% larger than those of females, whereas the average
difference between the sexes in the extant canid sample was only
6%."
Ok, I'm done with my Materials and Methods and Results, now
what?
This is a slightly tougher call than the question of where to
start. My inclination is to write the Introduction now, although
a strong case could be made for writing the Discussion next as
well. In any case, those two sections will be written once the
Materials and Methods and Results sections are complete.
The reason why I suggest writing the Introduction before
the Discussion is that ideally these two
sections will have many parallel elements and in writing your
Introduction and framing your questions and
bringing past works into context, you may come up with ideas to
improve and expand your Discussion. Since the Discussion is often
the most difficult section for students to handle, it makes some
sense to write it near the end, trying to tie together threads
from the previous three sections.
Back to the Introduction. Now would be a good time to answer
the question,
What is the Purpose
of the Introduction?
The Introduction section should do
several things. First, it should give the reader an idea of what
is to
come, meaning that at some point it should clearly state what
the working hypothesis of the experiment is, or what the expected
outcomes
are. Having said that, the Introduction should attempt to build
support for the working hypothesis or expectations by referring
to previous research and other kinds of known information. The
clearer the logical connections between your expectations and
supporting
or background information, the better. Don't include everything.
The Introduction has a tendency to balloon up as authors pile
on more and more information to support their hypothesis or put
their
work in context. Save some of the good stuff for the Discussion
and try to stay focused on the experiment you are writing about.
It is OK to assume that the reader has a scientific background.
Don't assume they are an expert at your level, but assume they've
had a good college-level biology course. Besides identifying
your hypothesis and mustering support for it, the Introduction
section should put your experiment in some larger context. This
may be historical - briefly reviewing research that leads up to
the questions your experiment will attempt to answer. It may also
be more general or less linear than that, simply giving enough
background for the reader to understand why one might be interested
in exploring the area your experiment addresses. Maybe there is
some practical application that follows from the outcomes of your
experiment , for example a step towards a cure for a disease or
the solution to a known problem. Bring these sorts of things up
in the Introduction so that your reader cares and is interested
in what is to come.
Here (again) are some snippets from Introductions from my own
writing. I don't claim these are perfect examples of great writing,
but
they
are
examples
nonetheless...
"Previous research has shown that craniodental
morphology can predict aspects of diet in many large carnivorans
(Van Valkenburgh,
1989). However, the few ursids studied have failed to exhibit the
same pattern of ecomorphological relationships as other members
of the order Carnivora (Van Valkenburgh, 1989)."
The section quoted above is intended to frame the problem. It
essentially says that previous research found a relationship between
skull
shape and diet for many carnivores, but that this relationship
didn't seem to hold up when bears were studied - and they weren't
studied much in the past.
The Introduction section of the same paper ends with this
bit that says pretty plainly what the paper will be about and what
the goals (large and small) of the experiment are:
"This study was undertaken to explore possible craniodental adaptations
among ursids to various specialized diets. To do so, I examined
craniodental morphology in all extant ursids. This study forms
part of a larger, ongoing study of ecomorphology and morphological
variation in the Ursidae. My goal is the determination of a set
of osteological predictors of diet and locomotor behaviour that
can be applied to fossil ursids, as well as to bear-like members
of other families, such as the Amphicyonidae. In addition, by sampling
the full taxonomic, geographic, and dietary diversity of extant
bear species, I hope to explain how the family Ursidae fits into
the overall pattern of carnivoran ecomorphology."
Note that I am using active voice a lot, it tends to be more interesting
to read than passive voice (which used to be preferred in scientific
writing), and that I leave some questions open to try to answer
in the Discussion section. Now I can use my Introduction and Results
to walk me through what I'll want to do in the Discussion section.
My Discussion stinks, how can
I make it better?
The question that begins this section may be a bit presumptuous,
but as I mentioned before, the Discussion can be a real challenge
for even experienced writers. It always takes me the longest to
write and you should expect to put a good bit of time into your
discussion - writing, editing, re-writing, proofreading - if you
expect to get full credit for that section. Editing and proofreading
are important for all parts of the paper, but especially so in
the Discussion because so many student papers seem to wander off
track here. The Discussion section should flow logically, almost
mirroring the Results section. Try to move, step-by-step through
the experimental data, analyzing and critically evaluating each
piece. Critical evaluation of the data is really the key to the
Discussion. You don't have to try to invalidate your results, and
there is nothing wrong with making a small jump to a conclusion
so long as you make it clear how string the support for that conclusion
is. Think of it like this - try to come up with all the ways a
rival scientist might attack your experiment. Was it properly controlled?
Was your sample large enough? What are the assumptions you depend
on? How strong is support for them? If you anticipate all these
things and address them in your Discussion, as well as going over
the conclusions that can be drawn from the data and where the data
might lead next, then you'll have a
good Discussion
and probably a good paper.
The last bit mentioned above is also a very important part of
a good Discussion section. Yes, the author should try to critically
evaluate the data, but she should also spend at least as many words
and as much time showing the reader what can be done with the data.
What new questions are raised by the data? What conclusions can
be drawn? Do these conclusions tie into any larger issues? For
example, suppose you study the activity of an enzyme at various
pHs and find that its peak activity is not at pH 7 as you expected.
One question that is immediately raised, if it isn't known already,
is what is the pH of the enzyme's normal environment? Also, what
is the chemical structure of the enzyme? If information is known
about these questions, discuss it. Tell the reader what is known
and how that information matches with your data (or doesn't match).
Can you make an educated guess about its structure based on your
results? If so, go ahead and tell the reader what you think. This
is the whole point of the Discussion, to really dig through, think
about, and discuss your data.
How do Literature Citations work?
One very important aspect of scientific writing hasn't been mentioned
yet - literature citations. Citing the work of others that contributes
to your experiment or your paper is of the utmost importance. Failure
to use proper citations is not only unethical in the sense that
you are passing off someone else's work as your own, but it also
undermines the foundation of scientific communication - the idea
that in sharing what we know openly and honestly we can allow the
state of our collective knowledge to progress much faster than
we could if we all operated in isolation. It is important for the
reader to know where you are getting your information, both so
that he or she can independently evaluate your assumptions and
facts, and so that he or she can be inspired to branch off from
your paper to find out more about a subject or another experiment.
A couple tips about using the literature in your papers...
Don't be afraid to include too many citations. If there is any
ambiguity about where a piece of information is coming from then
you are not citing often enough. It may seem like you have a citation
after nearly every sentence, but it is much better to cite too
frequently than not enough.
Where should citations appear? Most of the citations will be in
your Introduction and Discussion sections. Your Materials and Methods
might also have a few if you refer to a source for an experimental
protocol or point the reader to previous uses of a similar or the
same procedure. Your Results section will not usually have many,
if any, citations -
remember,
you are
just
reporting
what you got. And last, your abstract should not have any citations
at all. The abstract should be able to stand alone and be read
and understood without referring to outside sources.
How should citations look? We require parenthetical citations,
meaning that sentences containing information taken from another
source should end with the names of the authors and year of publication
in parentheses. There are lots of details about how to handle various
citation situations described in Appendix A of your Survival Manual.
In general, use direct references to other authors sparingly. Here
is an example of what I mean:
It is generally preferable to write...
"The sloth bear Ursus melursus is an insectivore,
feeding mainly on termites and ants (Joshi, Garshelis, and Smith,
1997)."
Rather than...
"Joshi, Garshelis, and Smith found in their 1997 paper that the
sloth bear Ursus melursus is an insectivore that feeds
mainly on termites and ants."
Make sure that every item cited in your text appears in your Literature
Cited section and vice versa. Check this over carefully. If your
Literature Cited section says Brown's paper was published in 1997
then your citations shouldn't read (Brown, 1979). Attention to
detail when dealing with citations is critical!
Some sample citations (as they should appear in your Literature
Cited section), see Appendix A of the Survival Manual for more
examples and information:
Books:
Leopold, A. 1949. A Sand County Almanac
and Sketeches Here and There. Oxford University Press, New York.
pp. 23-34.
NOTE, in general you should cite the specific pages of a book
that you used. If there is more than one author, list them in order
as they appear on the book's copyright page. If there is more than
one edition of the book, be sure to note which edition you used.
For example, include "2nd ed." following the title of the book.
Journal Articles:
Sacco, T. and B. Van Valkenburgh. 2004.
Ecomorphological indicators of feeding behaviour in the bears
(Carnivora: Ursidae). J. Zoology.
263:41-54.
List all authors in the order they appear in the article heading.
For our purposes journal titles need not be abbreviated, but it
is OK to do so. A list of title abbreviations is available here.
Lectures:
Sacco, T. 2005. The Tasmanian Devil, Friend or Foe? Lecture presented
in BIOG 1106. Cornell University, Ithaca, NY. February 20th, 2005.
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Writing Lab Reports