Introducing Evolution and Adaptation, and Setting Class Expectations, with Anolis sp.
The first weeks of class can be the most challenging as we work to promote curiosity and set the tone for our students. At the same time, students are trying to make sense of the course, subject matter, and instructor. Over the years, I have found that I can accomplish my goals, and help students become quickly comfortable with both me and the subject matter, by setting them immediately to work in scientific inquiry.
In my undergraduate mixed majors/nonmajors ecology course at Northwestern Connecticut Community College, HHMI BioInteractive’s short film Origin of Species: Lizards in an Evolutionary Tree, and its related resources, provides students with a powerful real-world introduction to the processes of science, as well as to adaptation and evolution. These materials are a core part of my 80-minute lecture section throughout the semester, along with others from BioInteractive.
In this article, I focus more deeply on student exploration of Caribbean Anolis populations through interactive, hands-on classroom activities. Students not only use universal observation, questioning, prediction, and hypothesis-generation skills, but also take part in group discussions on evolutionary trade-offs, phylogenetic relationships, and accuracy/precision in measurement. They are also able to fully investigate “what-if” scenarios through simulated measurements of anoles from the field.
I approach the activities below as interrupted case studies, allowing both small-group work time and whole-group time for Q&A and delivery of new information. My time is spent as a facilitator: moving and listening to groups as they work while checking in with clarifying questions. The bulk of student work is formative with real-time feedback for lower-stakes exploration of ideas. The summative assessments require long-form responses and extrapolation of concepts (which is also practiced).
I use a flipped model, so traditional “First Day” materials are moved online to familiarize students with our course management system. I assure students that active learning does not necessarily mean “easy learning” and that I do not underestimate what they are capable of. My expectations of them are high, and I want to instill this ethic from the first day. But I also want my students to enjoy their process, so we do brief no-stakes icebreakers to get to know their group-mates before starting group work. This generally involves rotating, paired questions that are inconsequential (e.g., what is your favorite season and why?) but allow students to relax and open up without divulging anything personal.
This combination of a mini-icebreaker with immediate group work is enough to mentally jolt students into noticing differences between my course and other first-day classes that they have drifted through (including my own from the past). Traditionally, my first-day classes would never have involved discussion and no students dared ask questions, even if I asked for them. Since I changed to my new format, students become engaged from day one; they talk to each other and me (usually about class concepts!), they feel comfortable asking questions and for help, and there are very few issues from items covered in the syllabus.
After introductions, my students begin their inquiry in lecture with the resource “Using DNA to Explore Lizard Phylogeny,” a tabletop exercise in observation, questioning, and hypothesis generation on anoles (which also corresponds to Module 1 in the Lizard Evolution Virtual Lab). This first activity is purely exploratory; students observe and group the various anoles. I have found that laminating one set per table of the color-printed cards saves resources. Students are given only the first two pages from the “Student Handout” during this session.
After students have discussed their groupings and explained their reasoning, we watch the first segment of the film Lizards in an Evolutionary Tree (0:00–9:50) (see the film’s activity page for “Educator Materials”). I also add in a very short geography lesson, as most of my students are not familiar with the Caribbean. Once students can identify the ecomorphs and the four islands of geographic importance, they revisit their groupings, make any desired changes, and begin generating a hypothesis around the activity prompt: “Develop a hypothesis about why similar ecomorph classes can be found on many of the different islands in the Caribbean.”
Before we adjourn, each group checks the scientifically accurate grouping of the ecomorphs and reports out their hypothesis. I then reframe or elaborate their hypothesis if needed, modeling good hypothesis formatting. Moving into our first lab, we then watch the film Great Transitions: The Origin of Tetrapods and model with another exercise involving Tiktaalik using a tabletop modification of BioInteractive’s Exploring Transitional Fossils Click & Learn.
Between the first and second class lecture, students complete the “Creating Phylogenetic Trees from DNA Sequences” Click & Learn. This gives them the necessary content knowledge for Day 2 on DNA and species relationships. They also read materials on deep ecological time, adaptation, and evolution. These assignments reinforce our flipped classroom practice.
We review students’ hypotheses from the previous class, briefly review their readings, and reexamine the geography of the Caribbean. After watching the second portion of the film (9:51–14:02), students begin work on Anolis phylogeny (pages 3–5 of the “Student Handout” they started on Day 1) to answer the hypothesis they previously generated (corresponding to Module 2 in the Lizard Evolution Virtual Lab). As a note, coloring a phylogenetic tree is a great active learning strategy and works for learners of all ages, as noted in the “Educator Materials.” Students appreciate the opportunity to see their hypotheses tested graphically. Between the tactile nature of the process, physically seeing the color differences, and possibly feeling a little like they are getting away with something, most nontraditional students become especially engaged when the crayons come out! I find a tackle box of crayons/markers is usually helpful to have on hand.
At this point in the activity, it is critical to have a large class discussion about what they have discovered. These activities are a baseline of understanding for many basic terms and concepts of the course; it is essential that any misconceptions are caught early. After this conversation, we finish watching the film (14:03–17:44), connecting adaptation and evolution to diversity and speciation.
I devote this class to Module 3 in the Lizard Evolution Virtual Lab. In this module, we focus on accuracy and precision of data, rapid evolutionary change, and ecological experimentation. Since the module is self-guided, students perform their inquiry in small groups. They take turns measuring hindlimb lengths of two Anolis, and relative anatomy of eight others, at two different sites.
The samples come from the study discussed in the film, and I emphasize quality control through real-time peer feedback. The Virtual Lab also alerts students if they are significantly off in their measurements, prompting repeated measurements. Groups use simple statistical analyses, graph data, and compare their measurements to the field scientists’. Module 3 concludes by guiding them through multiple choice questions about their process and findings.
Notes and Extensions
The “Teaching Evolution Using Lizards and Tetrapods” resources playlist summarizes how I use the resources above. For Days 1 and 2, students do not need devices. The film can be shown through the teachers’ station. For Module 3 in the Lizard Evolution Virtual Lab, however, students need computers with internet access or tablets with the corresponding app installed. To save class time, students could complete their measurements in Module 3 at home, saving data to a Google account through the interface shown below.
We do revisit our anoles as a touchpoint throughout the semester with other resources accompanying the main film, which students enjoy since they have come to know the lizards. Module 4 in the Lizard Evolution Virtual Lab covers sexual selection and speciation, and the Scientists at Work film, How Lizards Find Their Way Home, is on anole territorialism, both of which are used in our behavior unit. There are also two anole resources that lead into discussions on top-down control in ecosystems: the “Selection by Predation” activity and the “Effects of Predation on the Niche of Lizards” Data Point. By the end of the semester, students are well-versed in the topics at hand through the case of Anolis in the Caribbean: evolution, adaptation, natural selection, etc. In addition, these types of activities include analyzing data, the process of science at several scales, and linking concepts, as well as many “soft skills” such as group work, time-on-task, cooperative learning, and computer literacy.
This, in turn, makes all other areas of the course run more smoothly, especially in field labs, as students understand the similar expectations I have for those class times. Students make deep social connections due to their communal active learning experiences. While they often consider my course a challenge, they also find that they have, indeed, learned a great deal and are further prepared to tackle the next level of biology or other areas of study. They not only learn more about the natural world and how it operates at the larger scales, but also about themselves and their own abilities in a college-level ecology course.
Tara Jo (TJ) Holmberg is Professor of Environmental Science and Biology at Northwestern Connecticut Community College, a small rural institution. She is completing her 18th year of teaching and mentoring in higher ed and is ABD in environmental studies. TJ spends her downtime with her two dogs in her natively landscaped backyard.
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