TEACHING ALL VOLUMES SUBMIT WORK SEARCH TIEE
VOLUME 3: Table of Contents TEACHING ISSUES AND EXPERIMENTS IN ECOLOGY
EXPERIMENTS

Challenges to Anticipate and Solve

Overcoming student statistical misconceptions:

Through evaluation we have discovered that some students develop the misconception that plant community changes are unpredictable due to the randomness of the environment. It is important to explain what predictability means. Given knowledge of the probable changes in the environment, and knowledge of how species may respond to these changes, it is possible to predict changes in the community with some degree of certainty. You can remind students of the example of playing the game without disturbance cards. In that case you can make two predictions: 1) there will only be three species in the community, and 2) all three will be late successional species.

You could also discuss this type of ecological forecasting using the example of weather forecasting — the goal is to predict a statistical likelihood of a particular weather pattern such as will it rain or not. If the most likely event is rain, but it then turns out not to rain, that does not mean that the weather forecasting model was wrong. Many students do not understand this distinction, and this simulation is a good way to teach about statistical thinking.

Another way to address this would be to deliberately stack the decks of Event Cards among groups, if one has a larger class. Give some groups very few disturbance cards and give some groups lots of them, but donít tell them ahead of time. Then, at the end when the among group discussion occurs, educe from them the suggestion that disturbance frequency may have differed to account for why one set of groups led to Early winners and in the other set the Late species won out.

Bringing students back to learning mode after playing:

This seems to be a common challenge when doing fun activities. The transition from game playing to filling out worksheets seems to work well in focusing students on the learning aspects of the game, it will work better if each student fills out their own individual worksheet. You could also use a cycle of guided discussions at this stage. First, have students discuss and write responses within groups, drawing their community diagrams on overheads or on the board. Students could then report their results to the class (2 mins/group). Then, you could lead a class-wide among group discussions to compare results.

Translating from the model system to real systems:

The game overstresses the role of chance in plant community dynamics. Be sure to discuss this with students. In real systems, disturbance regimes tend to have some level of predictability. Fire regimes, for example, can be tied to cycles of precipitation and lightning seasons. Periods of high rainfall, which result in high productivity, are followed by dry periods during which plants dry out and become easier to ignite when lightning strikes.

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Lab Description

Introducing the Lab to Your Students:

This activity has been used as an introduction to succession with little or no introduction to the activity. Simply distribute materials, read the rules with students, and walk them through the first round of playing. At the end of game playing, ask students to fill out worksheets. Distribute discussion questions for students to answer and use these to introduce the main concepts of succession and disturbance dynamics.

Activities in the Lab:

The following comments could be shared with students, as part of their introduction to the lab.

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Questions for Further Thought

There are many ways to discuss the activity. After comparing the results of each groupís game, you could discuss what the movement across the board represents (the farther a character travels, the more individuals it has in the community). You could also talk about what made the different groupís game sequences and outcomes different from each other.

Essentially, the outcome of the game is greatly affected by chance events.

Discussion Questions:

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Assessment of Student Learning Outcomes

See the section on Tools for Assessment in the "Lab Description." In addition to writing opinions on the scenario, you could also have students debate the scenario using evidence they gathered by playing the game.

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Evaluation of the Lab Activity

To evaluate the activity, we have quizzed students before and after the lesson to see if they learned what we hoped they would learn. A total of 39 non-majors were tested (28 in Bio 100 and 11 in Environmental Biology for non-majors) in the spring of 2003. The questions used for the evaluation are listed in Tools for Assessment section of the "Description" of the Experiment. Data was analyzed using pairwise t-tests. On average, studentsí scores improved after participating in the activity from 7.6 out of 20 pts to 12.1 out of 20 pts (See Figure 12). For some questions, the scores improved more than for others (Figure 13). Students seem to learn more about how plants respond to disturbance and each other. They are less certain about applying concepts to real community changes, or predicting outcomes.

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Translating the Activity to Other Institutional Scales

This activity can be used with pre-college and college students in introductory courses as is, without including the extension activities. Extension activities add difficulty and depth and are appropriate for advanced undergraduate students. The main difference in conducting the activity with pre-college students as opposed to college students is in the depth of the post-activity discussion. For middle school students, we generally only discuss what happened during the game and how that relates to some examples of successional processes in local plant communities. We include more ecological concepts for high school and college students in the discussion. So far, we have only conducted the activity with non-science majors, but it could easily be adapted for science majors by adding some of the extension activities.

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