UC Santa Cruz

Stable social organization in a wide variety of organisms has been linked to kinship, which can minimize conflict due to the indirect fitness benefits from cooperating with relatives. In birds, kin selection has been mostly studied in the context of reproduction or in species that are social year round. Many birds however are migratory and the role of kinship in the winter societies of these species is virtually unexplored. A previous study detected striking social complexity and stability in wintering populations of migratory golden-crowned sparrows (Zonotrichia atricapilla)--individuals repeatedly form close associations with the same social partners, including across multiple winters.

In chapter one I test the possibility that kinship might be involved in these close and stable social affiliations. I examine the relationship between kinship and social structure for two of the consecutive wintering seasons from the previous study. I found no evidence that social structure was influenced by kinship--relatedness between most pairs of individuals was at most that of first cousins (and mostly far lower) and Mantel tests revealed no relationship between kinship and pairwise interaction frequency. Kinship also failed to predict social structure in more fine-grained analyses, including analyses of each sex separately (in the event that sex-biased migration might limit kin selection to one sex) and separate analyses for each social community. The complex winter societies of golden-crowned sparrows appear to be based on cooperative benefits unrelated to kin selection. Although the complex social structure detected in wintering golden-crowned sparrows is not predicted by kinship, genetic variation may play a role in variation of winter social traits.

In chapter two, I investigate the genetic causes of variation in fitness-related traits in a winter population of golden-crowned sparrows. Individuals show great variation in morphological and behavioral traits that may play a role in winter dominance and ultimately survival. I found that individuals that were more heterozygous--based on internal relatedness measures reflecting individual genetic variation--were more socially dominant, had larger gold crown patches (which predict social dominance in some contexts) and had stronger social connections within their social networks.

Although the underlying mechanism driving the HFCs detected in this study is unknown, the detection of moderate correlations between an individual's heterozygosity level and social dominance, winter plumage, and sociality is interesting. Theses traits connect in important ways to winter social behavior, suggesting that these HFC analyses detected true relationships. It is therefore feasible that more heterozygous individuals are more socially dominant because they may be, for example, better foragers and have energy to expend on aggressive behaviors. Another reasonable explanation for the relationship between heterozygosity and social dominance could be that more socially dominant birds could be older; heterozygosity might be linked to longevity. Although a physiological mechanism is unknown in sparrows, it is possible that plumage may reflect the general quality (e.g., better immune function) of the individual. As with social dominance, "core" individuals of a community (i.e., individuals that are more likely to be found flocking with other birds of their community) may also be older or higher quality individuals. "Core" individuals interact and have contact with others in the community and may therefore be at higher risk of encountering disease, parasite, and pathogens. If this measure of heterozygosity reflects immune function heterozygosity, then more heterozygous individuals may be more likely to be "core" individuals.

The recent focus on preparing students to pursue careers in science, technology, engineering, and mathematics (STEM) fields have resulted in educational researchers investigating how best to support this goal. Government and private funding has been directed to STEM internship programs (particularly at the undergraduate level). These internship programs are designed to provide workplace opportunities as well as provide support from the program to acquire skills needed by students to transition from school to the workforce. Most of this support has been developed (by internship programs and researchers) in the sciences. Engineers are in high demand and universities and internship programs are tasked with preparing more engineering students to be professional engineers. Our development of the Solution Articulation Framework (SAF), supports learners' (interns) acquisition of argumentation skills in engineering; engaging in argumentative practices promotes content knowledge and communication skills in many disciplines but has not been explored deeply in the engineering education literature. We focused our attention on improving learners' engineering argumentation practices with a particular emphasis on articulation of engineering solutions.

In chapter three, I identify a critical component (functional requirements) to effectively articulating a proposed engineering solution and offer an operational definition along with suggestions for implementing these ideas in engineering education. My findings were immediately used to revise our SAF and warrants further research on other components of the SAF. The research in this chapter advances the emerging research field in engineering education by highlighting the importance and difficulties associated with teaching argumentation skills in engineering.