Assignment #4b: Group Project Hypotheses
Due in lab Week 8
Zoology 316 2008
Description
This assignment involves a) formalizing your initial group project idea into hypotheses
using appropriate rationale, and b) devising and articulating an explicit research planincluding experimental design- to test your hypotheses. You may begin tackling these
steps once you have received feedback and the go-ahead on your initial group project
idea from your TA.
Background: More on Defining Hypotheses
By now, you should be comfortable with the idea of formulating a simple research
question, identifying and defining alternative and null hypotheses, and providing
associated rationale for your proposed arguments. But as many of you have realized,
oftentimes multiple alternative hypotheses appear to exist for the relationship between a
set of variables. One famous limnological example is the idea of top-down vs. bottom-up
control of food webs (Carpenter et al. 1985; Pace et al. 1999). Some alternative
hypotheses may be especially difficult to eliminate prior to an experiment if your ideas
are new (in which case, little existing information will exist), although lack of familiarity
with the system or processes of interest also often contributes. Regardless of the cause,
when multiple alternative hypotheses do appear plausible, is it then your task to simply
lock in on one prediction, hope it pans out, and leave yourself to sort out the missing
pieces later if you are wrong? Not at all! Although admittedly this does happen in real
science sometimes, it is risky and inefficient. Part of this is because your experimental
design will dictate how much evidence you will uncover for any potential explanation.
For example, if you elect to solely examine whether phosphorus controls chlorophyll
concentration in Lake Farve du Klein, and find no evidence for that pattern, you will be
left wondering “Well, what DOES control phosphorus?” And just because you have no
evidence for alternative patterns in the above case, you didn’t actually look for them so it
doesn’t mean they don’t exist. Therefore, during hypothesis development, we encourage
you to try and identify counter rationale- that is, rationale that would function as evidence
against your own alternative hypotheses. Hopefully you will find this not only helps in
developing a robust experimental design and increases the chances your experiment will
uncover any natural patterns that exist, but that it will also function as a useful thought
exercise that will save you precious time and help you better understand your topic. You
may even find that carrying out these thought exercises deliberately will help uncover
logical flaws in your initial rationale such that you can eliminate some alternative
hypotheses from contention prior to the experiment, and instead focus on testing for more
likely outcomes. Translation: if multiple alternative hypotheses do appear to exist,
please identify them and play them against each other (“counter-rationale”) in your
written proposals by providing arguments for each alternative.
.
Your Task
Collaborate and articulate your group project idea into a cohesive proposal.
For the first part of the assignment, follow the model of the previous Multi-Lake
Hypothesis assignment by defining sets of alternative hypotheses and relating the
variables you intend to measure, and provide associated rationale. Include counterrationale where appropriate. Like the multi-lake project, we require examining three
different pair-wise relationships between variables, and at least two variables must be
variables for which measurement techniques are covered in this course. Provide graphs
(NOT hand-drawn this time) of potential patterns for each relationship considered. Also
include a detailed description of your experimental design, a list of all needed equipment,
a map of your study area/sites, and identify the appropriate statistical analyses for testing
each of your pair-wise relationships for patterns. You will be graded as follows:
1. Introduction.
a) Provide a few sentences by doing the following:
i. Indicate the variables of interest. (1 pt)
ii. Briefly address the general question: “Why do these variables
matter?” (1 pt)
iii. End this section by stating your project in the form of a
research question. (1 pt)
b) Hypotheses for each pair-wise comparison of variables. (1 pt x 3)
c) Rationale for potential patterns in each pair-wise comparison of
variables. Include refernences to at least two peer-reviewed journal
articles to support your rationale(s). (2 pts x 3).
d) Computer-drawn graphs illustrating the potential patterns for each
pair-wise comparison of variables. (1 pts x 3)
2. Methods
a) A description of your experimental design, including statistical
methods, in 1-2 detailed paragraphs. (3 pts)
b) An equipment list (please literally list in a table, and indicate any
items you will NOT need the TA’s to provide). (1 pt)
c) Map. (1 pt)
3. Composition, organization, and style. Note that this assignment is a written
proposal, NOT an outline. If you merely hit items in this list in order without
incorporating them into a cohesive, written document, you will lose points
here. (5 pts)
total: 25 pts
References
Carpenter, S. R., J. F. Kitchell, and J. R. Hodgson. 1985. Cascading Trophic Interactions
and Lake Productivity. Bioscience 35: 634-639.
Pace, M. L., J. J. Cole, S. R. Carpenter, and J. F. Kitchell. 1999. Trophic cascades
revealed in diverse ecosystems. Trends in Ecology & Evolution 14: 483-488.