Evolution of the threespine stickleback (Gasterosteus aculeatus): a ...

Evolution of the threespine stickleback (Gasterosteus
aculeatus): a test of natural selection in the lab.
Part I- Getting to know all about sticklebacks.
Readings for Discussion:
Foster, S.A. 1997. Courting disaster in cannibal territory. Natural History. Nov. 1990 pp
52-61
Baker, J.A., S.A. Foster, and M.A. Bell. 1995. Armor morphology and reproductive
output in threespine stickleback, Gasterosteus aculeatus. Env. Biol. of Fishes. 44:225-
233.
Objectives:
•To gather background information on the threespine stickleback system.
•To develop a research hypothesis for your project.
•To learn how to write a scientific report.
•To begin to accumulate relevant literature for your report.
Assignment:
Your assignment will be to write a report (Due week of 18 Nov.) in the style of a
scientific manuscript (see below) based upon your chosen project. Additionally, you will
be required to give a short presentation of your report (week of 18 Nov). It is strongly
suggested that you begin writing now.
For next week- write a one-page (or less) typed proposal of your project (details TBA).
The layout of the report-
The paper will be written in the same style as your second paper for the lecture course. If
you do not follow this style, your grade will suffer. Guidelines follow:
Your paper should be 4-6 pages typed and double spaced (excluding literature and/or
figures and tables). Also, do not include a title page. It is unnecessary here and is a waste
of paper. The margins should be 1.5 inches (L&R) and 1 inch (top & bottom) and the
type should be no greater than 12 pt. It must be stapled neatly in the upper left corner.
The paper should consist of the following sections (modified from Dr. Foster's
guidelines).
Title
Not a separate section really, but every paper should have a title that informs the reader
what the paper is about without getting too flowery. Examples of bad titles include,
‘Stickleback,’ ‘Evolution Lab,’ ‘Stickleback Evolution Lab,’ and my least favorite ‘One
fish, two fish, dead fish, blue fish.’ While this last one was clever, it gave no information
whatsoever.

Abstract
A one-paragraph summary of the paper excluding citations. Write this last.
Introduction
Here you set up the issue and review the background logic and literature. If you
are exploring morphological evolution in stickleback (that is, only worrying about this
fish, not other organisms) you might introduce the variety of selective regimes
stickleback encounter (e.g., ecological components) and what is expected to occur to
stickleback shape in those conditions citing the relevant literature. You then would
explain that there exists X possible explanations (alternative hypotheses) and that you
will test one (or all) of those by doing…..(whatever it is that you are doing without going
into detail about the methods).
Methods
This is a clearly written account of what you did (in the past tense). Try to avoid
writing in the first person. That is, instead of saying, "I weighed 30 stickleback each from
4 populations to the nearest .01g" you should say something akin to, "Thirty stickleback
from each of four populations were weighed to the nearest .01g." It should be in enough
detail that others could repeat your procedures. It should be concise though and not filled
with needless detail. For example, even though you will take X number of fish from quart
jars supplied by me, you would not write, "Fish were removed from quart jars and placed
onto paper towels" or "Specimens were supplied by the TA." This is unnecessary detail.
Results
Again, this is a straight-forward account of your results. Here you present the
outcome of your analyses using full sentences and figures/tables without interpretation.
Do not include raw data (these are raw data- not results). Any figures or tables should be
clearly labeled included a description of what the figure/table is summarizing. Don't tell
the reader what you think the data mean. That information is for the next section. See any
research article in the journal Evolution to learn how the Results section should written.
Discussion
In this section you interpret your results in light of your original hypothesis which
was set forth in the Introduction. This should not just be a restatement of your results.
You must synthesize and compare ideas. You can conclude with your evaluation of the
most plausible explanation(s), explaining your interpretation carefully. DO NOT SKIMP
ON THIS SECTION. IF YOU JUST RESTATE WHAT WAS ALREADY STATED,
SHOWING NO EVIDENCE OF THOUGHT AND EFFORT, YOU WILL NOT
RECEIVE FULL CREDIT.
Literature Cited- List all of the literature you cite in the text. All citations should appear
in the text as, for example, "the threespine stickleback is holarctically distributed in
nearshore marine and fresh water habitats (Bell & Foster 1994)." If there is just one

author indicate for example (Foster 1998), if there are more than two, (Baker et al. 1998).
All citations in the literature cited section must have been used in the text in support of a
statement you make. Be certain the paper supports the observation (be accurate in
attribution). Always cite sources of ideas or data (or you are committing plagiarism). In
typing the literature cited section of the paper you should follow the format in the journal
Evolution which you will find in the science library. Look at papers in this journal should
you have questions about how to cite literature properly in the text. You should have no
less than 6 primary sources for this paper.