FACULTY NOTES

      In "Student Instructions" students are asked to look at 3 different figures from a paper by Strayer et al. (1999). This will take a fair amount of time. An alternative is to show (project) or hand out one or more of the figures and lead a discussion. If you decide to do this, give students time to make sense of the figures on their own first — or with another student (as in "turn-to-your-neighbor").

      The first 2 figures are fairly straightforward. There are dramatic decreases in macro zooplankton and clams after zebra mussel introduction. Chlorophylla values (measurement of phytoplankton biomass) and micro zooplankton also sharply decrease. These data also clearly show the value of long-term data sets; 6 years of measurements prior to introduction gave the researchers much more confidence in their conclusions about zebra mussels.

      The increase in 1996 in suspended solids (Figure 2b) shows that other factors besides zebra mussels can be important in this river and that researchers must attempt to tease these out. This is most clearly seen in Figure 2c; temperature and discharge rate can also influence water clarity and chlorophyll concentrations but the data show no consistent pre and post difference in either temperature or discharge.

      Zebra mussels are not all "bad"; this is an important point for students to understand. Zebra mussels can have a positive effect in very eutrophic water bodies because their filtration rates are so high; mussels remove phytoplankton from the water column, which is much clearer as a result (see http://www.sgnis.org/publicat/cjfas617.htm). They have also been used as indicators of low oxygen and pH.

Student Assessment: Essay Quiz

      What is the main question the researchers were asking in this study?
Why did they get data on suspended solids, river discharge (rate of river flow) and temperature in addition to zebra mussel densities?



EVALUATING AN ISSUE: How do you know whether it is working?

      On-going (also called formative) evaluation of the approaches your are using is critical to the success of student-active teaching. Why try out new ideas if you don't know whether or not they are working? This is a brief overview of formative evaluation. For more information, go to the Formative Evaluation essay in the Teaching Section.

Course Goals:

      Formative evaluation only works if you have clearly described your course goals - because the purpose of the evaluation is to assess whether a particular technique is helping students reach these goals. For instance, most of us have "learn important ecological concepts and information" as a course goal. If I reviewed the nitrogen cycle in a class, for evaluation I might ask students to sketch out a nitrogen cycle for a particular habitat or system. Each student could work alone in class. Alternatively, I might ask students to work in groups of 3 and give each group a different situation (e.g. a pond receiving nitrate from septic systems, an organic agricultural field, an agricultural field receiving synthetic fertilizer). The students could draw their flows on a large sheet of paper (or an overhead transparency) and present this to the rest of the class.

The Minute Paper:

      Minute papers are very useful evaluative tools. If done well they give you good feedback quickly. Minute papers are done at the end of a class. The students are asked to respond anonymously to a short question that you ask. They take a minute or so to write their response in a 3x5 card or a piece of paper. You collect these and learn from common themes. In the next class it is important that you refer to one or two of these points so that students recognize that their input matters to you. The UW - FLAG site (www.wcer.wisc.edu/nise/cl1/flag/) gives a good deal of information about using minute papers including their limitations, how to phrase your question, step-by-step instructions, modifications, and the theory and research behind their use.