Presentation on theme: "The Challenge of Experiments Dr. Gard W. Otis Department of Environmental Biology."— Presentation transcript:
The Challenge of Experiments Dr. Gard W. Otis Department of Environmental Biology
My Rules as an Instructor: Treat students as individuals Make content interesting: students will learn! Treat students with respect Give meaningful assignments Present clear expectations (reduce student stress) Be fair in all dealings with students (discussions, marking, deadlines) Help students achieve their goals (leaning, employment, personal growth, etc.) Provide detailed and timely feedback Treat everyone equally (students call me“Gard”
Behaviour of Insects (ENVB*4040) “Investigation of the behaviour of insects within an ecological and evolutionary framework. Topics range from basic behavioural principles to the complex behaviour exhibited by social insects.” Course Assignments (in ~1999) ► Behavioural observation assignment (30 Qs) ► Term Paper ► Midterm Exam ► Final Exam
Based on old but effective exercise used in field courses Students observe nature (i.e., insects) and write down unfiltered questions about what they see Great way for students to observe behaviour and ask about what they are seeing, BUT the assignment went nowhere. Decision: to use the “30 Qs exercise” for students to develop ideas for mini-experiments they could conduct during one semester (~8 weeks) in place of a term paper. Behavioural observation assignment (aka 30 Questions)
Student-designed Experiments (2001) Pluses: Student observations led directly to experiments; good continuity from 30 Qs assignment Students were able to follow their personal interests Minuses Limited student expertise shallow hypotheses Limited time constrained experimental design Small groups required excessive time for repetitions Need to maintain insect cultures (timely, expensive)
Instructor-designed Experiments (2002-04) Pluses: Hypotheses were more complex, leading to studies that are potentially publishable (real science!) Experiment complemented lecture material on mimicry Multiple groups (~10) provided repetition. Minuses Time constrained experimental design (i.e., Feb. break) No role for 30 Qs assignment in the experiment Students not able to follow their personal interests
2002: Learning by Assassin Bug Predators of Unpalatable Aposematic Insects The Predator: Platymeris bigutatta, large African assassin bug (Toronto Zoo) The Prey: Oncopeltus fasciatus, the milkweed bug (commercial sunflower- feeding strain)
Oncopeltus fasciatus: Perfect Mimicry!!! Unpalatable: consumed milkweed seeds (+toxins) throughout development: aposematic colouration Palatable: consumed sunflower seeds (no toxins) throughout development: perfect “Batesian” mimic
Experiment: Do insect predators: (1) learn to avoid unpalatable prey? (2) intrinsically avoid aposematic prey? Unpalatable (milkweed)Palatable (sunflower) Aposematic Cryptic Aposematic Cryptic Assasin bugs were given one prey type for 6 days, then other type of same palatability, different colour
Organization of Experiment Students worked in groups of 3-4 First six Friday discussions: discuss literature on mimicry and learning in insects; worked out experimental design Half of one lecture and time in others devoted to finalizing the experimental design Learning trials started immediately after Reading Week Upon completion of study, students sent me their data and the TA and I performed statistical analyses. Students only had ~2 weeks to write up the experiment in manuscript format; very rushed at the end.
Results of Experiment with Assassin Bugs Feeding duration (violent rejection of unpalatable prey): Unpalatable prey, ~2 sec; palatable prey, ~ 19.4 min! Milkweed toxins are effective in deterring predation. Number of prey captured: 1-2 unpalatable prey; many palatable prey (avg. 3.8) Assasin bug predators learn to avoid unpalatable prey! Time to attack: greater for aposematic prey than for cryptic prey! Evidence for innate response to aposematic prey!!!
Student feedback on experiment Unable to contact all students (biased subset of students) 7/18 of those contacted went on to MSc/PhD programs Two to four years have transpired since students conducted the experiments: sufficient time to put their educational experiences into perspective. Survey: “Rate the class experience as an experience to learn about insect behaviour:” 4.4/5.0 Survey: “Rate the experiment as an experience to learn about the process of scientific enquiry: 4.5/5.0
If you took the course again, would you prefer to do an experiment again or write a term paper? 15/15 in favour of experiment!!! What did students think of the experiment? “The experiment was a great change from the rest of my biology courses, where ‘lab’ usually meant examining dead things or doing computer modeling. Having the opportunity to actually go through the process of scientific enquiry (and not just learn how to) was extremely beneficial.” S.L.
What did students think of the experiment? “Until the project that we did in Insect Behaviour, every hands-on experiment that I had done in university was merely a replication of an experiment done many years prior, the results of which were already common knowledge in science. This was the first time that the end result was actually unknown to us and it was exciting to think that our undergraduate class may actually contribute something new to science. It was also a really valuable experience to go through the scientific process from the very beginning, brainstorming with each other about the best methods and materials to use in order to best test our hypothesis.” J.M.
What did students think of the experiment? “Few courses offer true learning experiences. Most seem to limit their scope to class papers. While (hopefully) interesting and useful, they are more a test of how good students are at utilizing library resources and regurgitating them into new and unique text. Your theory of bug-bug defense strategies was a unique one which opened our eyes to the actual world of scientific discovery, where the final result is a huge question mark and not something that can simply be looked up ahead of time. I had my first opportunity to really get into the nitty-gritty of organizing and implementing a novel study. It’s pathetic that undergraduate students aren’t faced with more material like this.” K.K.
What did students think of the experiment? “The only drawback I recall had to do with the issues of integrating the ideas of a large group. As I recall, there were a lot of good ideas as to how to run the experiment but when we tried to mesh them together, it produced a design that was not as neat as it could have been.” K.A. “Normally I would dissuade anyone from doing a group assignment. I’ve had nothing but problems dealing with fellow students. Luckily I had a fantastic group for this experiment and for once, the entire class seemed revved up.” K.K.
What did students think of the experiment? “I can’t remember most of my term papers, but I do remember the entire process of our assassin bug learning experiment. From hashing out all the details in seminars, meeting with my group, and watching the assassin bugs toss the milkweed bugs across the plastic containers! C. T. “What better way to teach future scientists about the methods than to throw them through it once, with all of the uncertainty, errors, time constraints, budget constraints and general adversity that faces real experimentation. D.C.
What did students think of the experiment? “Years later, I marvel at how your course influenced my life long learning objectives. Every time there’s a BBC nature special or an interesting insect news story or a client find unwanted pests in the greenhouse, I find myself pondering questions as if back in class worrying about my assassin bugs! R.G.
Final Thoughts…… The class experiment allowed students to understand science and behaviour better than through traditional lectures or laboratories. The semester is short (12 weeks), requiring a high level of organization. The commitment to teaching and student learning must be very high, because to be effective the experiment requires intensive instructor input. I had dropped the experiment in favour of term papers (less time intensive), but comments from former students show that I should reinstate it!!!
Thanks to…… All students in Insect Behaviour, 2001-2004, who suffered through my learning phase about how to conduct an effective group experiment. Students who provided feedback: Kevin AbbottAmanda BickertonDave Cheung Dave DeSoerKyla ErcitRichard Goetze Sheila GoodfellowJody KocsisKara Kristjanson Seabrooke LeckieJen McCarterElizabeth Novak Kathryn PeimanBen Spears-RoachSupriya Tandan Carolyn ThickettCarrie WoodsgGeoff Gilbert
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