### by Jessica Shade, Integrative Biology

#### Teaching Effectiveness Award Essay, 2010

A common problem in introductory classes is the surface-level learning of material and vocabulary. Building a scaffolding to support more advanced topics is imperative, but rote memorization of unlinked information can result in short-term retention of facts for tests rather than the ability to understand and connect concepts. Without a strong web linking theories to application, the scaffolding will crumble, preventing deep-level processing and critical analyses of new ideas.

As a GSI for Bio 1B, UC Berkeley’s introductory biology course, I saw several examples of this disparity between surface learning of principles and working comprehension, especially when students were required to synthesize disparate topics such as mathematics and evolution. The concept of Hardy Weinberg Equilibrium (HWE), for instance, requires students to use allele frequency equations to predict or explain trends in natural populations. Unfortunately, students usually focus solely on the memorization of the mathematical formulae, so the underlying importance of the model is lost.

I first realized that students did not understand the concept of HWE when I found a discrepancy in students’ performance between my different assessment techniques. During quizzes they had no problem calculating allele frequencies and genotype ratios using the Hardy Weinberg equations, but they were unable to interpret those results during small-group discussion evaluations. I was surprised that while they could perform complicated calculations on paper, they were baffled by the simple question, “What does this mean?”

To breach the gap between theory and application, I designed an experiential learning simulation that combined the mathematical principles with a physical example. To contextualize the activity and rouse interest in the topic, I used the students as the study population and asked them to describe several of their traits (such as curly or straight hair, attached or detached earlobes, hair color, etc.) in terms of alleles. We used these allele frequencies as a stepping stone to start connecting the math with real life by calculating the expected allele frequencies of the next generation, following the predictions of HWE. We tested these predictions by creating mock offspring. Each student was randomly assigned a partner to produce hypothetical offspring with by flipping a coin to determine which allele they would pass on to their children. Once each partner pair had produced two offspring, we compared these actual allele frequencies to their expected allele frequencies.

To the surprise of the students the actual allele frequencies were vastly different from their predictions. This led to a barrage of questions from students wondering, Why didn’t the simulation work? When I told them it had worked perfectly, they were even more curious about the seemingly odd results of the exercise. To organize their questions and ideas, I had them brainstorm as pairs about the incongruity of our findings. I then teamed the pairs up into groups of four to collaborate about possible problems and answers. By starting with small pair conversations and expanding to larger groups, the activity required every student to participate in a setting that was less intimidating than a full class discussion. Students were more confident about their ideas after discussing them with their classmates, so they were more likely to participate in our analytical dialogues when the class reconvened.

To evaluate the exercise I listened to and participated in student group discussions and observed students analyses of the exercise outcomes. I also had each group write several questions they had about the topic of HWE. The questions they posed linked concepts from past modules with the current topic, showing that they were thinking critically about HWE.

To wrap up the lesson we discussed our results as a class. By that time, most of the students’ questions had been answered by their peers, and they were able to make connections between their mathematical predictions and the real-world implications, including the limitations of their predictions. I was happy to see students who had previously been confused about the applications of HWE participate confidently in the discussion. This confidence and working comprehension of topics allowed the students to connect personally to the material and become more interested in complex topics, which will enable them to succeed throughout their academic careers.