FACULTY NOTES

      The point of "paired think-aloud" is to give students who are used to either talking/solving problems or listening/being more passive a chance to practice both sets of skills. In their instructions students are asked to first work alone to understand the figure as best they can. Then they pair up and one person is the "solver" and the other the "recorder". The solver explains their understanding of the data and experimental design and also asks any questions they have. The recorder writes down what their partner says and encourages them; the recorder does not express an opinion but simply guides their partner along. The students then switch roles. You will have to allow enough time for the 3 parts of the exercise and tell the students how much time they have both ahead of time and during the exercise.

      Assuming the more dominant or more passive role will be very hard for some students. You should spend some class time explaining why you are using this particular approach and why it is important for all of us to step out of our usual roles sometimes. Make sure that everyone understands the directions for each role.

      In this experiment, Orr et al. (2000) found that fire-ant workers feeding on the bait were attacked by the parasitoid, Pseudacteon solenopsidis, which “hovered less than a cm in front of an ant and maintained its position by flying backwards as the ant fled. To oviposit, the fly turned 180 degrees, darted quickly down and inserted its ovipositor in the foramen behind the ant’s head…. The behavioural distractions caused by the phorids reduce the competitive dominance of S. invicta in Brazil and might also diminish its ability to dominate in its introduced range. Due to their extreme host specificity, phorids are a good candidate for biological control although their affinity for North American ants must first be understood.” Their conclusion about introduction of an insect to control an introduced insect would stimulate good discussion about biological control of the red fire ant.


Discussion questions:

• Orr et al. suggest that introduction of the non-native parasitoid might be a good biological control of red fire ants. How would you determine whether or not this was a good idea from an ecological point of view? What experiments might you conduct?

• Humans have greatly accelerated the rate of red ant movement as a result of the housing boom after World War II. What human activities associated with building houses likely contributed to the rapid invasion of this ant?

• Fire ants live in conical shaped mounds of dirt often about 0.25 m high and 0.5 m across. In what ways might such a mound be helpful to the success of this organism?

Data are from:

Orr, M. R., S. H. Selke, W. W. Benson, and L. E. Gilbert. 1995. Flies suppress fire ants. Nature 373: 292-293.



Student Assessment: Essay

      The website http://www.ceris.purdue.edu/napis/pests/ifa/ shows the spread of fire ants through the U.S. from 1918-2000. What observations can you make about the ant's distribution from these visual representations. 250-300 word essay



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.