Our biology/English course recently dived headlong into the world of dichotomous keys. It’s a relatively simple concept to master, but the idea behind the use of dichotomous keys is lost on students. Students view the simple choice between A and B as normal practice in many classes. But the difference is that in those classes they are often told exactly how to define A and B. A popular video “I Choose C” makes the rounds at teacher’s in-services to demonstrate how the educational system takes the creativity from a student and gives them a tool to solve a task in the classroom–choose C. Not very helpful for the young lady in the video who is being asked to do a task for which she hasn’t been specifically trained. A dichotomous key–on the surface–seems like the same concept. Students must identify one or the other characteristic and move on in order to identify any particular organism.
When our students first begin applying the use of a dichotomous key we begin small–with beans. Even if they don’t quite understand the use, most students can identify a black bean if necessary. When they had to apply a dichotomous key to conifers the task grew more challenging. What we are always amazed by is that the students are often more challenged with having to make a decision from their own knowledge and trust their decision going forward. How does one identify “leathery” in a two dimensional sketch of a conifer branch? The fear of being incorrect in the decision makes some students panic. We always tell our students that they need to make a logical, well-thought out decision and go forward trusting that they have applied the basic tenets they have learned, experienced, and tested. Then trust that their application will lead them to the correct solution. And sometimes, we warn them, they will be wrong. And when they are wrong to evaluate the solution and process and go forward–try something different.
We need our students to graduate with knowledge, but we need more students who are capable of applying knowledge with the understanding that getting the correct solution the first time is a rare occurrence. When at first you don’t succeed, try, try again.