Using a Combination of Phylogenetic Comparative and Paleobotanical Methods to Elucidate Patterns of Lineage Selection in Rosales (Plantae: Anthophyta)

An increasing focus in evolutionary biology is on the interplay between mesoscale ecological and evolutionary processes such as population demographics, habitat tolerance, and especially geographic distribution, as potential drivers responsible for patterns of diversification and extinction over geologic time. However, few studies to date connect organismal processes such as survival and reproduction through mesoscale patterns to long-term macroevolutionary trends. In my dissertation, I investigate how mechanism of seed dispersal, mediated through geographic range size, influences diversification rates in the Rosales (Plantae: Anthophyta). In my first chapter, I validate the phylogenetic comparative methods that I use in my second and third chapters. Available state speciation and extinction (SSE) models assumptions about evolution known to be false through fossil data. I show, however, that as long as net diversification rates remain positive – a condition likely true for the Rosales – these violations of SSE’s assumptions do not cause significantly biased results. With SSE methods validated, my second chapter reconstructs three associations that appear to increase diversification rate for Rosalean genera: (1) herbaceous habit; (2) a three-way interaction combining animal dispersal, high within-genus species richness, and geographic range on multiple continents; (3) a four-way interaction combining woody habit with the other three characteristics of (2). I suggest that the three- and four-way interactions represent colonization ability and resulting extinction resistance in the face of late Cenozoic climate change; however, there are other possibilities as well that I hope to investigate in future research. My third chapter reconstructs the phylogeographic history of the Rosales using both non-fossil-assisted SSE methods as well as fossil-informed traditional phylogeographic analysis. Ancestral state reconstructions indicate that the Rosaceae diversified in North America while the other Rosalean families diversified elsewhere, possibly in Eurasia. SSE is able to successfully identify groups of genera that were likely to have been ancestrally widespread, but has poorer taxonomic resolution than methods that use fossil data. In conclusion, these chapters together suggest several potential causal links between organismal, mesoscale, and geologic scale processes, but further work will be needed to test the hypotheses that I raise here.

Criminal Case Processing of Sexual Assaults in Alaska

Discretion plays a role in nearly every facet of the American criminal justice system. It is widely regarded as necessary to do justice but is not without criticisms – especially when it leads to unfavorable or disparate treatment. The role of discretion in sexual assault cases has been particularly scrutinized. Since the majority of sexual assaults do not fit stereotypic beliefs about what constitutes a “real rape” and “genuine victim,” criminal justice officials use their discretion to filter these cases out of the justice system. This study explored this issue by examining two stages of the criminal justice process: the police decision to refer cases for prosecution and the prosecutorial decision to accept referred cases. In doing so, it contributes to this body of literature in three ways. First, it included sexual assault cases that involve Alaska Native victims and suspects. Second, it addressed a gap in the theoretical scholarship by examining the downstream nature of police decision-making. And finally, it examined the formal reasons prosecutors give for charge dispositions. This study found a significant amount of attrition of sexual assault cases as they progressed through the criminal justice system. Moreover, a combination of legally relevant and extralegal factors was found to be important, but not consistently across all types of sexual assaults. Among legal factors, the number of victim injuries was the most consistent predictor. Among extralegal factors, cases that involved Alaska Native suspects had significantly higher odds of case referral and case acceptance compared to white suspects. The effect of suspect race was particularly pronounced in cases with a white victim. Additionally, the findings suggest that not only are Native American defendants more likely to have their cases referred by police, but once referred, they are also more likely to have them accepted for prosecution. Contrary to expectations, victim-suspect relationship, specifically non-stranger assaults, increased the odds of police referral compared to stranger cases. However, the opposite appears to be true for the decision to prosecute cases. Once referred, prosecutors were five times more likely to accept sexual assaults perpetrated by strangers. The implications of these findings are also discussed.