From: Understanding the tree of life: an overview of tree-reading skill frameworks
Halverson and Friedrichsen (2013) | Novick and Catley (2016) | Skills by other authors | Core idea |
---|---|---|---|
Level 1: no use of representation | Naïve handling | ||
Level 2: superficial use of representation Students base interpretations of phylogenetic trees on superficial features of the representation without connection to the underlying meanings of the phylogenetic relationships illustrated | |||
Level 3: simplified use of representation Interpretations of phylogenetic trees are based on the idea of a main branch, with taxa branching off from a main branch and later branching off from one another | |||
Level 4: symbolic use of representation Students at this level understand the symbolic elements associated with parts of phylogenetic trees; however, they overemphasize nodes when interpreting and comparing phylogenetic representations (often engage in node-counting) | Halverson (2011): reading and understanding | Identifying structures | |
Level 5: conceptual use of representation Phylogenetic trees are viewed as 2-D illustrations of 3-D representations and their branches as being able to rotate around nodes without altering the relationships represented. However, students at this level do not make connections between their interpretations of phylogenetic trees and the evolutionary history represented | Reason about common relationships in the face of changing subsets of taxa. (J) | Halverson (2011): identification and use | Handling apomorphies |
Rotating cladogram branches around their nodes does not change the relationships among the affected taxa, even though the adjacency relations among the taxa do change. (K) | |||
Level 6: scientific use of representation Students are able to scientifically interpret the relationships illustrated within the topology of a phylogenetic tree based on represented common ancestry, monophyletic patterns, and implied apomorphies separating taxa. These students consistently compare phylogenetic representations based on patterns of clades regardless of the style of the representation | Identify a synapomorphy that two or more taxa share due to inheritance from their MRCA. (A) | Meir et al. (2007) Skill A: reading traits from trees Halverson (2011): identification and use | Identifying relationships |
Identify a set of taxa that share a certain character. (B) | |||
Identify the sequential order of appearance of characters on a designated evolutionary path. (H) | |||
Recognize that characters that appear on multiple branches of a cladogram are indicative of convergent evolution. (I) | |||
Evaluate whether a given set of taxa compromise a clade. (C) | Blacquiere and Hoese (2016) Knowledge of most recent common ancestors Halverson (2011): identification and use | Comparing trees | |
Mark all nested clades in a cladogram. (D) | |||
Assess relative evolutionary relatedness when three taxa are resolved (i.e., compromise a three-taxon statement). (E) | |||
Assess relative evolutionary relatedness when three taxa compromise a polytomy (i.e., no two of the taxa share a more recent common ancestor with each other than with the third taxon). (F) | |||
Level 7: expert use of representation This level is reserved for describing experts in the field of systematics and is not applicable for beginning students. These scientists can quickly interpret representations on the underlying phylogenetic meanings that trees represent. At this level, multiple representations are used and generated consistently to solve phylogenetic problems, explain evolutionary phenomena, and make predictions | Use the information depicted in a cladogram to make an inference based on phylogenetic relationship. (G) | Meir et al. (2007) Skill B: deducing ancestral traits Halverson (2011): evidentiary support | Arguing and inferring |