Tree-thinking

Part 1: Investigating Tree Thinking and Ancestry with Cladograms (Volume 77, No. 3, pages 198-204.  DOI:10.1525/abt.2015.77.3.8):

    Interpreting cladograms is a key skill for biological literacy. In this lesson, students interpret cladograms based on familial relationships and language relationships to build their understanding of tree thinking and to construct a definition of “common ancestor.” These skills can then be applied to a true biological cladogram.

Part 2: Using Evolutionary Data in Developing Phylogenic Trees: A Scaffolded Approach with Authentic Data (Volume 77, No. 4, pages 274-283.  DOI: 10.1525/abt.2015.77.4.7): 

    Analyzing evolutionary relationships requires that students have a thorough understanding of evidence and of how scientists use evidence to develop these relationships. In this lesson sequence, students work in groups to process many different lines of evidence of evolutionary relationships between ungulates, then construct a scientific argument for a particular set of relationships as modeled in a cladogram. Visual and verbal scaffolds are used throughout the lessons to address common misconceptions and points of difficulty for students.

Part 3: Tree-thinking: a response (Vol. 78, No 5, pages. 385–388. DOI: 10.1525/abt.2016.78.5.385):

    We respond to the preceding commentary (Brower, 2016) regarding our “Inquiry & Investigation” articles (Davenport et al., 2015a, b) published recently in this journal. Our two articles describe a pair of activities, informed by biology education literature and national standards documents, whose primary goal is to help teachers assist introductory students in evaluating basic evolutionary datasets. In this short response to Brower’s critique, we acknowledge that our activities, which address the complex field of systematics, contain simplifications and inaccuracies. At the same time, we hold that the activities are grounded in careful pedagogical decisions that allow students in general biology courses to readily understand major features of phylogenetic trees. We also argue that the design of the activities allows students to experience firsthand a vital component of the nature of science: prioritizing data when formulating a claim.