The evolutionary biology curriculum detailed below was implemented over a four-week summer university course and was designed
to strengthen aspiring educators’ ecology and evolution knowledge
and their understanding of scientific inquiry. The course was cross-listed in the Department of Curriculum and Instruction and the
Department of Biology and was cotaught by faculty from these departments at a large, public, land-grant research university in the midwestern United States. The university instructors had extensive experience
with the science content and with supporting students as they construct explanations in an MBI environment. Some of the students were
undergraduates majoring in the life sciences with the intention of
becoming science educators, while others were earning their Master
of Science degree and their initial secondary teacher certification.
The students ranged in age from 18 to 35.
As is typical with MBI curriculum and instruction, instructors
work as facilitators with distinct student learning outcomes in mind
with respect to a specific scientific phenomenon. Students are
engaged in modeling the phenomenon of greater species diversity
in the tropics compared with temperate zones ( i.e., the latitudinal
diversity gradient). A general recurring lesson plan throughout this
course consists of instructors providing students with relevant data
and facilitating discussions that allow students to construct meaning
based on the data. Students codevelop and revise models as a community of scientists. As with other constructivist pedagogies, MBI
requires work that students may find frustrating to accomplish, given
the demands of constructing their own understandings; although
this work is an important component of constructivism and scientific
model development, students are not often asked to perform such
challenging work (Hewson et al., 1999; Cakir, 2008). Likewise,
instructors are often not practiced in the type of facilitation that
allows students to struggle with the challenge. Both students and
instructors become more accustomed to such work as they progress
through the multiple lessons in the curriculum that require them to
work in groups on model development and assessment. Students
build and assess models with respect to the criteria of empirical consistency (accounting for all data), conceptual consistency (how realistic the models are), and predictive power (Cartier et al., 2001).
Students engage in argumentation concerning competing models
that meet the criteria for a viable model. Once instructors determine
that the class has collectively arrived at and understood competing
models, students are presented with additional data that require
them to account for new evidence and revise their models to be
more empirically consistent. The data selected for this modeling
activity follow the scientific community’s historical development of
competing models regarding evolutionary phenomena that are still
being explored and debated.
This curriculum assumes a basic college-level understanding of
evolution and genetics, namely natural selection. Students will
also benefit from having some understanding of phylogenetic
trees and experience with tree thinking. For an MBI activity to
strengthen these understandings, see our previous article
(Bouwma-Gearhart & Bouwma, 2015). We have included a Facilitator’s Outline (Appendix A; to view supplements, please see the
online version of the journal) to help instructors plan appropriate
time for the curriculum/unit and each set of activities.
At the start, it is important for the instructor to frame the
curriculum/unit for students, informing them that it will make
use of the scientific practice of modeling. Students may not have
had previous experience with modeling, so it is important to briefly
describe modeling, especially toward helping students understand
the iterative nature of this work, to manage potential student frustration regarding the lack of instantaneous and definitive answers.
To help illustrate this, instructors should also indicate to students
both the authenticity and the complexity of the problem under
study; it is helpful to inform them that explaining the latitudinal
diversity gradient has challenged scientists for decades and remains
of interest in the scientific community.
The “Pre-model”: Students Explain Differences in
Tropical vs. Temperate Climate
Students first view the climatograms in Figure 1 and respond to
the question “What regions on Earth might these climatograms
represent?” They make observations about the seasonal changes,
predict which global areas these graphs might depict, and solidify
the requisite understanding that different climates on Earth are a
compilation of long-term weather factors such as temperature
and precipitation. On the basis of their previous experiences,
postsecondary students label climatogram A as depicting “
tropical” regions and climatogram B as indicative of “temperate”
climates relatively easily.
Figure 1. Climatograms of (A) tropical and (B) temperate regions of Earth, showing climate as measured by precipitation (bar
graph) and temperature (line graph). Reproduced from Kricher (2011).