TEACHING ALL VOLUMES SUBMIT WORK SEARCH TIEE
VOLUME 1: Table of Contents TEACHING ISSUES AND EXPERIMENTS IN ECOLOGY
Issues : Figure Sets

Figure Set 5: Eutrophication and Anoxia

Purpose: To help students construct the series of events linking nutrient loading to coastal waters and anoxic events.
Teaching Approach: "Jigsaw"
Cognitive Skills: (see Bloom's Taxonomy) — knowledge, comprehension, interpretation, application, synthesis, evaluation
Student Assessment: diagram quiz

FACULTY NOTES


      In this jigsaw there are 3 subsets of information. Using a class of 30 as an example, divide the class into 6 subgroups of 5 students. Give 2 groups Figure 5A plus accompanying information (below), 2 groups 5B, and 2 groups 5C. Allow these students enough time to look at their figures and background information individually and then with their team members. The goal is for each student to understand their topic clearly enough so that they can teach it to another student. Then, rearrange the groups so that there are 10 groups with an A, B, and C student in each one. Again, give the second grouping time so that students can explain their figure and questions they may have without feeling rushed. The final question for this group is to use their combined knowledge to explain why nutrient loading into the Florida Bay region results in loss of corals, seagrasses, fish and other organisms. That's what makes it a "jigsaw" - the pieces are reassembled to solve the puzzle.

      This may be a challenging problem for both groupings of your students. You of course are the best judge of how much time they will need. It would be best to do this jigsaw during class time when you are available to help students and when they are all present. If you cannot use up this much time, the first group could meet outside of class and the second in class. When it is not possible for students to meet in person, groupwork via computer is an alternative.

      If your students are unfamiliar with units such as “micro” and “milli, log scales, and moles you should explain this to them ahead of time or in a hand-out reference for the groups. You will also need to explain – or have them reason out - that farming, sewage treatment, and septic systems are common sources of N and P for many water bodies if you anticipate that few students will know this.

     You should explain the units for oxygen and salinity in your next group. In air oxygen concentrations are much higher than in water and we measure air oxygen in units of percent (pph) as opposed to ppm in water. The concentration of oxygen dissolved in water depends on the water temperature and the salinity; as temperature and salinity increase, the amount of oxygen “at saturation” decreases. Saturation is an easy concept to understand; if you place a bucket of water in a room, the water in “Saturated” with oxygen when the flux rate of oxygen in and out of the water are the same.

      The salinity units are even easier. Students probably know from experience that seawater is denser than freshwater because you float more easily in the ocean than in a lake. Seawater is denser because of the salt (mostly NaCl) that is dissolved in it. Again, the units for salinity are parts per thousand. Explain to them that the ocean is about 30 ppt which is the same as 3 percent (parts per hundred).


Student Assessment: Diagram quiz.

      Draw a sketch or diagram demonstrating how nutrient loading leads to anoxic conditions.



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.


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