Teaching Tree Thinking to College Students: It’s Not as Easy as You Think

Abstract

The ability to understand and reason with tree-oflife diagrams (i.e., cladograms), referred to as tree thinking, is an essential skill for biology students. Yet, recent findings indicate that cladograms are cognitively opaque to many college students, leading them to misinterpret the information depicted. The current studies address the impact of prior biological background and instruction in phylogenetics on students' competence at two foundational tree-thinking skills. In study one, college students with stronger (N052) and weaker (N060) backgrounds in biology were asked to (a) identify all the nested clades in two cladograms and (b) evaluate evolutionary relatedness among taxa positioned at different hierarchical levels (two questions) and included in a polytomy (two questions). Stronger-background students were more successful than weaker-background students. In study two, a subset of the stronger-background students (N0 41) who were enrolled in an evolution class subsequently received two days of instruction on phylogenetics. As expected, these students' tree-thinking skills generally improved with instruction. However, although these students did very well at marking the nested clades, fundamental misinterpretations of relative evolutionary relatedness remained. The latter was especially, although not exclusively, the case for taxa included in a polytomy. These results highlight the importance of teaching cladistics, as well as the need to tailor such instruction to the difficulties students have learning key macroevolutionary concepts.

Fostering 21st-Century Evolutionary Reasoning: Teaching Tree Thinking to Introductory Biology Students

“…Students received a version of this cladogram that included color photographs. Adapted with permission of Springer Science+Business Media from Figure 1 in Phillips et al (2012, p. 596). (The modification was to include the original color photograph in the online publication.…”

Undergraduate Students’ Initial Ability in Understanding Phylogenetic Tree

“…Therefore, studying about phylogenetic trees has become an important component in the biology education and an interesting area for biology education research [8]. The ability to understand and make sense of phylogenetic trees (referred to as cladistics thinking/tree thinking) is an important skill for biology students [9]. Unfortunately, students often are not taught how to make sense of evolutionary relationship that is depicted in the diagram.…”

“…Unfortunately, students often are not taught how to make sense of evolutionary relationship that is depicted in the diagram. Students are also not provided with information regarding the underlying theory and process of the phylogenetic tree [9]. Therefore, no wonder many undergraduate students have misconceptions in understanding phylogenetic tree [9][10] and students have difficulty in interpreting, constructing, and comparing among the phylogenetic tree [2][10] [11].…”

“…Students are also not provided with information regarding the underlying theory and process of the phylogenetic tree [9]. Therefore, no wonder many undergraduate students have misconceptions in understanding phylogenetic tree [9][10] and students have difficulty in interpreting, constructing, and comparing among the phylogenetic tree [2][10] [11]. The researcher has an opinion that understanding phylogenetic tree is a complex cognitive task and without proper scaffolding, many students cannot transfer the empirical data into visual structure [12].…”

Plant vs. Animal, Which is the Most Prefer Understanding of Evolution?

“…It is vital that those who undertake a study of biology be able to understand and interpret what information these phylogenies are meant to convey [5]. The ability to understand and reason with tree of life diagrams (i.e., cladograms), referred to as tree thinking, is an essential skill for biology students [6]. Tree thinking is the ability to visualize evolution in tree form and to use tree diagrams to communicate and analyze evolutionary phenomena.…”