Graduate education follows an apprenticeship model, primarily aimed at preparing students for academia; however, the inclusion of teaching within this apprenticeship is not always clear as faculty, students, and other stakeholders do not agree on the need for instructional training (Golde & Dore, 2001). Despite the variability in training, over half will be graduate teaching assistants (GTAs) at some point in their education. This number increases to 91% for chemistry graduate students. This discrepancy between hiring graduate students as GTAs and inconsistent inclusion of instructional training indicates a misalignment between the needs of graduate students and the support programs offer. In addition to this mismatch, there is a need to improve mentoring and support for graduate students as they navigate their programs (Harshman, 2021). In particular, graduate students spend a large portion of their time at work, yet are not treated as full people as many students cite that they must leave parts of their identities behind in academic spaces (Brown, 2016; Tran, 2011).To better support graduate students, we must first understand how graduate student identities develop. The foci of studies are generally placed either on teaching or research or identity, but not both simultaneously (Baker & Lattuca, 2010; Lane et al., 2018; Zotos et al., 2020). Graduate student identity has also been introduced as a lens for encompassing multiple sub-identities, however teaching identity is not emphasized. Through the collection of interviews from 18 chemistry graduate students and the administration of a modified survey across two institutions, this work expands upon the conceptualization of graduate student identity. Sociocultural and identity theories were employed to understand graduate student identity development. Mixed methods analysis with an emphasis on qualitative theme generation revealed that graduate students’ multiple identities often intersect, with research identity being the primary identity around which other identities develop. This includes teaching, student and personal identities such as socioeconomic status, international status, race, ethnicity, and gender. This works illustrates how multiple graduate student identities can develop and that supporting students as whole people including their personal identities and interests is important for a sense of belonging in the field.

Phylogenetic trees, diagrams depicting hypothesized evolutionary relationships between taxa, are used in a widely across multiple biology subdisciplines. Being able to read these diagrams is therefore a crucial step in achieving expertise in biology. Tree-thinking, however, has been found to be quite difficult, especially given the abstract nature of the diagram and its reference to directly unobservable macroscopic biological phenomena. The biology education literature, therefore, has dedicated some effort into investigating the ways in which tree-thinking might be improved in undergraduates. While these investigations have been fruitful, they have not yet included a systematic examination of expertise in comparison to novices in order to fully characterize the skills and conceptions required for tree- thinking. They also have not yet examined the concept at the root of tree-thinking: relatedness understanding. To remedy these issues, I conducted a study employing expert and novice framing of relatedness understanding. I also draw upon cognitive metaphor and Prototype Theory to inform this study which has not yet been employed by the tree-thinking community. I attempted to characterize the everyday ways individuals categorize and identify organisms and how they might differ by experience. I conducted a series of clinical interviews with 29 individuals: 11 experts and 18 novice undergraduate students. Participants grouped organisms from photos and were asked to explain and draw their reasoning. I analyzed the resultant transcripts and artefacts using Grounded Theory. Three primary components of relatedness understanding were apparent in all participants: structural metaphor, grouping strategy, and grouping criteria. Structural metaphor refers largely to spatial conceptual metaphors describing the arrangement of taxa. Grouping strategy refers to group membership determination while grouping criteria refers to the properties used with strategies to determine group identity. Experts exhibited understandings consistent with novices and partially non-normative, suggesting that some repression of nascent relatedness understandings may be occurring or heuristics may be used in certain conditions. Further investigation of the impact of these understandings on tree-interpretation is necessary as well as whether or not learner generated representations of these understandings can be leveraged into normative interpretation of phylogenetic trees.