I redesigned my Intro Bio course from scratch… here’s how it went
Note: This was originally written on December 14, 2022 and posted here on my personal website.
I just finished my first semester teaching Introductory Biology using a curriculum I designed from scratch. It went surprisingly well! While I will tweak some things in the future, overall, my curriculum aligned well with Vision & Change (2011) and helped students meet my highest priority learning objectives. In this post, I look closely at what worked and what didn’t, and I share my biggest take-aways.
What I Liked, Part 1: Designing Course Content Around Core Concepts
When I designed the course from scratch, I took a Backward Design approach and I started by determining the core concepts that the course should cover. Based on the course description, I designed the curriculum around these 3 core concepts from Vision & Change:
· Evolution
· Information Storage & Flow
· Energy Storage & Flow
Here is a visual diagram that shows how I designed the course around these core concepts:
I used case studies as stories around which I taught the “traditional content” of a biology course. For example, I introduced transcription/translation and protein structure as a way to understand how bacteria can be resistant to antibiotics (using this spectacular Superbugs poster from Protein Data Bank as a jumping off point). Having explored the role of the central dogma in bacteria, we did it again, this time as a way of understanding cystic fibrosis (bringing in membrane transport and osmosis/diffusion). We also discussed natural selection as it relates to antibiotic resistance, then we discussed natural selection again in Unit 2 as it relates to selective pressures on human populations from malaria (sickle cell anemia) and milk consumption (lactase persistence).
I really, really liked how this format meant we discussed core ideas in biology multiple times in different contexts – I could tell by their responses on written and oral assessments that students had developed a much better understanding of the Central Dogma and Natural Selection than in any previous semester. That’s a win in my book.
What I Liked, Part 2: Built-In Time for Review
Each unit ended with an Essay Exam that had 4 high-Bloom’s-level questions. Here is an example question from Essay Exam 1:
1. A small proportion of the human population has a variant of the CCR5 gene that makes them resistant to HIV. The HIV-resistant CCR5 gene variant has a 32-base pair deletion, so it is called CCR5-delta32.
a. The 32-base pair deletion occurs at DNA base 585 (out of 1059 DNA bases in the full-length gene). Predict the impact of this mutation on the protein’s amino acid sequence and the protein’s structure. Explain how the mutation results in the protein structure you predicted. (Note that you do not need to know what this protein does in order to answer this question.)
b. Consider the rare instances in which new CCR5-delta32 mutations arise in the human population. HIV prevalence is substantially higher in Africa than anywhere else in the world. Explain whether new CCR5-delta32 mutations are more likely to occur in individuals living in Africa than individuals living anywhere else in the world. Explain your reasoning.
An “E” answer will:
identify the type of mutation that gave rise to the CCR5-delta32 gene variant, and accurately explain the predicted impact CCR5 protein structure
explain why the mutation results in the predicted impact on CCR5 protein using terms related to translation
use CCR5-delta32 as an example to correctly explain the relationship between the generation of new mutations and environmental selective pressure
Full disclosure – this is actually a question from a Practice Exam, which I assigned as homework several days before the actual Essay Exam. In the lecture period before students took the actual Essay Exam, we spent the entire lecture period reviewing the Practice Exam. I compiled anonymized student responses to the Practice Exam homework, and students worked in teams to use the anonymous student answers to craft their “best answer,” which we discussed as a class. Students consistently reported that spending time completing the Practice Exam and reviewing it in class together substantially helped prepare them for the actual Essay Exam.
Since the course was a T/Th structure, this meant that 3 entire weeks of the semester were devoted to the Essay Exams: 1 lecture period each for students to take the Essay Exam + 1 lecture period for us to discuss the Practice Exam. Furthermore, since students could complete revisions on the Essay Exams, Essay Exam 3 needed to happen before Thanksgiving (to give me time to complete grading and to give them time to complete revisions before the end of the semester), which gave us an entire week after Thanksgiving to review and prepare for the Final Cumulative Exam (lower Bloom’s level questions, mostly multiple choice). Including review for the Essay Exams and for the Final Cumulative Exam, my students spent 2 ½ weeks of review in preparation for assessments.
I really, really liked having so much time for review, because it meant students had time to think about and make sure they understood the concepts, rather than just rushing through content for the sake of “coverage.”
Coda: In previous semesters, I’ve held review sessions outside of class time that functioned in a similar way to these built-in review sessions, but in those instances, only some students could attend. That’s an equity issue! By building review sessions into the course, I ensured that all students had access to the benefits of spending time with me reviewing concepts in preparation for the assessment.
What I Liked, Part 3: Real Data, But Not Too Much
In each Unit, I included a couple real science stories, including real data from research studies. For example, in Unit 1, we discussed data from Salvador Luria and Joshua & Esther Lederberg about whether mutations occur in response to selective pressure, and we discussed this recent Cell paper about a patient who had a recurrent antibiotic-resistant lung infection, which was cleared using phage therapy. On the Essay Exams, I asked questions that asked students to explain how the data from those studies supported the scientific conclusions.
Including real data from scientific research (both historical and contemporary) is a key component of my teaching philosophy! I believe that how we do science should be taught concomitantly with scientific content, at all levels of science education.
I’ve taught using a more data-heavy approach in the past (using the textbook Integrating Concepts in Biology), but in my experience, discussing one or more different experiments every day – especially in the cell & molecular fields, which require understanding complex laboratory techniques – felt like too much “content coverage.” In previous semesters, my students were memorizing which experiments corresponded with which conclusions (at best) or just not understanding the experiments at all (at worst). So this semester, including a few examples of real data allowed me to integrate the scientific process with scientific content in a way that felt like it gave space for students to understand both the content and the experiments.
What I Didn’t Like
Agreeing with the main point of The Tyranny of Content is easy: to give space for active learning and deep thinking, we must let go of the notion that we need to “cover” all the content. However, doing this in practice was hard.
In my redesigned Intro Bio course, I spent an absolute minimum amount of time (or, in some cases, no time) talking about chemical bonding and biomolecular structures, properties of water, enzyme kinetics & enzyme regulation, and cell cycle regulation. I ended up not talking about the eukaryotic endomembrane system, which I regret – next time, I want to fit it in to the section about cystic fibrosis since the connection to the case study is obvious there. I just need to figure out how to make the time for it!
Executing this new course structure took a lot of time. This was due, in large part, to the fact that I did not use a textbook, and I took a semi-flipped active learning approach in the classroom. Students had homework every M/W in preparation for class the next day; for homework, students “consumed” new content using free resources online, including YouTube videos, free online textbooks, HHMI BioInteractive resources, etc – curating this homework was time-consuming. But! I did get a mini-grant from my institution due to my adoption of OER materials, which helped compensate me for some of that extra time. And, the curated resources are ready for the next time I teach BIO111!
In my next post, I’ll talk about grading. This semester I tried some new grading approaches and tweaked grading policies I’ve used before, to good effect.