Create a Bacterium: an Engaging Semester-Long Assignment

INTRODUCTION

Like many other educators, I have adapted the “Adopt a Bacterium” exercise developed by Dr. Amy Cheng Vollmer (1) for use in my microbiology course. The exercise motivates students to learn actively about their chosen bacteria in a holistic way. They research the physiology, genetics, ecology, and phylogeny of the bacteria, organize the information, and report to the rest of the class what they have learned. Despite the undeniable educational potential of this exercise, it is possible for students to accomplish the tasks using primarily lower-order learning skills such as knowledge (remember), understand (describe, explain), and apply. Building upon the success of the “Adopt a Bacterium,” I developed the “Create a Bacterium” exercise aiming to challenge even more my upper-level undergraduate science majors (2). To create a bacterium, students not only had to search for and organize information, but also to analyze and evaluate information (higher-order learning skills). Most importantly, students were challenged to engage in the highest level of the cognitive domain of Bloom’s revised taxonomy, synthesis or creation(3). The specific objectives of this exercise are for students to:

1. Apply newly acquired knowledge more directly. At the end of each lecture topic, students are asked to reflect upon the lecture contents and to decide how to apply what they have just learned to what they are creating.

2. Research scientific literature more broadly. Because the created bacteria do not exist, students need to gather and evaluate information on several real bacteria in order to synthesize information about the fictional ones.

3. Recall, apply, and expand knowledge gained in previous courses. Even though the created bacteria are fictional, the scientific facts used to construct them cannot be. Students are advised to examine carefully whether there are violations of scientific principles (that they know of) when trying to bring together the story.

4. Bring humor to class. The creation/discovery story section of the exercise is where students’ creativity and sense of humor shine. Upper-level undergraduate science majors are ideal subjects for this exercise because they know enough science to compose a seemingly logical story but not enough to hinder their creativity.

5. Be confident about their learning. Ultimately, with more learning skills involved in this modified exercise, students’ learning experiences will be enhanced and they will become more confident in learning.

PROCEDURE

The exercise had three phases, and different features of the bacterium were created in each. In phase I, each pair of students made up a creation/discovery story, named the bacterium, and determined its structural and physiological features. In Phase II, the students determined the taxonomic, phylogenetic, and genomic features of the bacterium. They also created an operon that corresponds to the bacterium’s unique metabolic trait. In Phase III, the students explored the ecological niche of the creation, its interactions with the environment, and its evolutionary history. The tasks of each phase coincided with lecture topics in order to augment class learning. Four writing assignments, two oral presentations, and two individual conferences with the instructor were required (Fig. 1). To fully engage students, all of the above tasks were spread out evenly throughout the semester. Additionally, at the end of every lecture topic, students were encouraged to apply what they had just learned to their creations.

FIGURE 1.

The sequence of events for the Create a Bacterium exercise.

Conferences. The first conference with each pair of students took place in the third week of the semester. Before this conference, students were responsible for using the decision-making flowchart (Fig. 2) and determining the type of bacterium they were creating. They also composed a creation/discovery story. The instructor helped the students fine-tune their story and provided a list of real bacteria that were relevant to their creation to help jump-start the research process. The second conference took place after students crafted two written reports and gave one brief presentation. The purpose of this conference was to give each pair feedback on scientific accuracy, presentation, and writing, and to provide more information on current research that was relevant to their creation.

FIGURE 2.

Decision-making flowchart to guide students to create bacteria of interest.

Writing assignments. Each writing assignment was limited to two pages (single-spaced, one-inch margins, 12-point font size in Times New Roman), plus figures, tables, and references. In addition to the two writing assignments (one for Phase I research and one for Phase II) and the final report (combining Phases I, II, and III), each pair also wrote a 500-word press release after the final oral presentation in order to learn how to communicate with the general public.

Oral presentations. Each pair of students introduced their bacterium to the rest of the class by sharing the creation/discovery story in mid-semester. The 5–10-minute, informal oral presentations turned out to be unexpectedly humorous. The final 15-minute presentations were more science-centered and formal.

CONCLUSION

Students were initially intimidated and anxious about this exercise. To encourage them to apply their knowledge fully and to be creative, I emphasized repeatedly that the final products only had to be “scientifically accurate” at the college junior/senior level. Furthermore, they could retrieve/rebut their previous claims in the previous phases as they learned more about microbiology. With proper coaching, students became more creative and daring. While most students were pursuing careers in allied health and most of their creations were pathogenic, the evolutionary histories of these fictional bacteria were as diverse as their discovery/creation stories (Table 1).

TABLE 1.

Selected bacteria that students in BIO301 Microbiology in fall 2009 and 2010 created.

Bacterium Created	Main Feature
Calvococcus nonvillus	Environmental bacterium that degrades human hair and is later used in hair-removal products.
Pseudomonas syringae pv. Cocanitis	Plant pathogen that degrades cocaine, which leads to unsatisfactory cocaine products on the streets.
Academicus pneumoniae	Opportunistic human pathogen that causes campus pneumonia outbreaks.
Bacteroides jennycraigus	A member of the normal microbiota that helps people lose weight and is later patented by a weight loss franchise.
Librio charticillus	Opportunistic human pathogen that causes glow-in-the dark pimples.
Steltzner nullus-vinumae	Plant pathogen that turns winemaking grapes to vinegar-making ones.
Bacillus phagoliber	Soil microbe that degrades paper and eats students’ homework.
Clostridium punxsutophilus	Opportunistic human pathogen discovered after a meningitis outbreak occurred after Ground-hog Day.
Thiobacillus infaltiovanillae	A member of the normal colonic microbiota that makes the gas we pass smell like vanilla.
Propionibacteria celerguntherium	A skin bacterium that processes the products of body odor-producing bacteria and is used in organic deodorant products.
Bdellovibrio necrocryptium	It attacks and kills Cryptosporidium in freshwater.
Stapphylococcus garfindium	It can be present in the normal microbiota of cat skin and degrades Fel d 1 proteins on the cat, which makes the cat more hypoallergenic.

The learning objectives of this assignment were met. The results of the confidence level assessment on major microbiology concepts indicated that having the lecture topics in sync with this exercise enhanced learning. The exercise further challenged students to synthesize and create. Students needed first to research several bacteria to gain background knowledge, then process, evaluate, and modify the knowledge before it was applied to their creations. They also had to make sure that their newly formulated knowledge agreed with previously learned scientific principles. One student reported on the assessment form saying, “We can’t forget this actively acquired knowledge even when we try.” This exercise elicited students’ sense of ownership (more so than the “Adopt a Bacterium”) because not only did they choose the bacterium, they created it. The students’ sense of humor and creativity shined in the discovery/creation section of the exercise. In fact, this section was their favorite part, with naming the bacterium being a close second. Some students even consulted Latin professors. The only negative comments from the attitude surveys were that this exercise was more time-consuming and demanding than exercises in other classes and that students did not learn a “real” bacterium. Expanding the discussion to note the similarities between fictional and actual bacteria may help overcome this perceived limitation. While the two 30-minute conferences were time-consuming, students reported that the conferences played a vital role in the learning process.

Although the implementation strategy worked well for this course, it can be modified easily to suit different class needs. The number of writing assignments can be varied, one instructor-student conference may suffice, the press release can be replaced by a 90-second podcast, and the presentations can be given in various forms of performing arts. The creation does not have to be a bacterium; it can be virus or even a microbial community. Finally, students do not have to be the only ones who enjoy the creativity!