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Species richness of virtually all high-level taxonomic groups is strongly statistically related to climatic variables such as temperature and precipitation, and consistently so across space and time. These observations are consistent with a causal link between the number of species that occur in a given region and its climate. Although dozens of hypotheses have been proposed, the main mechanisms underlying this pattern remain largely unresolved. And, few ecological studies have attempted to identify regularities in the individual species distributions that make up the richness–climate relationship. Despite the complexities of species’ biologies, I found that, to a first approximation, species’ probability of occupancy at continental scales were generally well statistically explained by a Gaussian function of temperature and precipitation. This simple model appeared general among species, taxa and regions. However, although individual species’ ranges are strongly statistically related to climate, spatial variations in richness cannot be explained by systematic variations in species’ climatic niches. And, individual species track changes in climatic variables through time much more weakly than species richness tracks these changes, suggesting that richness is at least partly constrained by mechanisms independent of species identities. Moreover, at macro-scales, species richness was also not strongly predictable from the temperature at which clades have originated, from historical variability in climatic variables nor from local short-term extirpation rates. In sum, I rejected several prominent hypotheses aiming to explain richness–climate relationship and found several lines of evidence inconsistent with the common idea that climatic constraints on individual species, by themselves, can explain richness–climate relationship. I propose a mechanism to explain, as a first approximation, the continental biogeography of species distributions that relies on neutral processes of dispersal and local extinctions within species’ broad deterministic thermal tolerances.

An inherent aspect of an audit is the level of task complexity that junior auditors (staff and senior level associates) endure on a daily basis. This complexity directly impacts an auditor’s ability to form an appropriate problem representation, which in turn impacts judgment performance. One of the key components of this process is having sufficient knowledge for purposes of problem representation; without it, the auditor’s problem representation and ultimately judgment performance are negatively impacted. Conversely, audit teams can positively influence the conciseness of problem representation and performance by way of effective task-specific knowledge transfer. Knowledge transfer in the audit field occurs during three distinct phases: when an auditor reviews prior and/or current year workpapers; when an auditor requests help; and/or during the workpaper review process. For purposes of efficiency and increasing (i.e. improving) problem representation, prior to any deleterious effects, it’s critical that the audit profession understand how to maximize the knowledge transfer as soon as possible after the auditor’s initial assignment of the task. Because auditors commonly will immediately refer to audit programs in the current year documentation in the electronic audit file to gain an understanding of the task, maximizing the knowledge transfer within the electronic audit file is critical to increasing auditor judgment performance. I propose utilizing media richness theory to establish an increased media rich transfer of knowledge via the electronic audit file from the audit managers (expert) to junior auditors (novice). Procedure screens within the electronic audit file would likely be categorized as “written, formal” mediums within the media richness theory, because the source of information is impersonal. However, if audit firms can successfully transform the transfer of information within the audit files from being solely formal document screens to also incorporate personal source characteristics, they will successfully increase the information richness, which will allow for a more successful transfer of knowledge and subsequently the ability for the auditor to more effectively form a problem representation.

Anomodonts are a group of non-mammalian synapsids (“mammal-like reptiles”) that represents the dominant herbivores of their time. Their great taxonomic and morphological diversity, unparalleled by any other clade of Permian-Triassic terrestrial tetrapods, is well documented by a cosmopolitan fossil record. In addition, anomodonts survived the most severe extinction event in Earth’s history at the end of the Permian and experienced a second diversification in the Triassic. Thus, they are an ideal clade to investigate macroevolutionary patterns and play an important role in evaluating the impact of the end-Permian extinction on the terrestrial realm. This work combines descriptive, phylogenetic, and quantitative approaches to study evolutionary patterns of anomodonts with special focus on diversity patterns through time. A taxonomic revision of the Late Permian dicynodont genus Emydops reflects the necessity for a solid taxonomic basis for diversity studies. The description of a new species of this genus is combined with a discussion of dental variability and pathology in dicynodont anomodonts. A detailed description of the postcranial anatomy of the basal anomodont Suminia reveals new insights into the early evolution of anomodonts and therapsids in general. Several derived features, in particular in the autopodium, are unique to Suminia and together with a comparative morphometric analysis indicate grasping abilities of this taxon and the earliest evidence for arboreality in the vertebrate fossil record. The cranial anatomy of the Triassic dicynodont Kombuisia is restudied and a phylogenetic evaluation of the survivorship of anomodonts across the Permian-Triassic boundary reveals more surviving lineages than previously recognized. A review of anomodont-bearing tetrapod faunas forms the basis for a faunal similarity analysis that reveals stratigraphic as well as geographic patterns in faunal groupings. The taxonomic diversity of anomodonts reflects three diversifications and subsequent extinctions in the early Middle Permian, the Early Triassic and the mid-late Triassic.

Anomodonts are a group of non-mammalian synapsids (“mammal-like reptiles”) that represents the dominant herbivores of their time. Their great taxonomic and morphological diversity, unparalleled by any other clade of Permian-Triassic terrestrial tetrapods, is well documented by a cosmopolitan fossil record. In addition, anomodonts survived the most severe extinction event in Earth’s history at the end of the Permian and experienced a second diversification in the Triassic. Thus, they are an ideal clade to investigate macroevolutionary patterns and play an important role in evaluating the impact of the end-Permian extinction on the terrestrial realm. This work combines descriptive, phylogenetic, and quantitative approaches to study evolutionary patterns of anomodonts with special focus on diversity patterns through time. A taxonomic revision of the Late Permian dicynodont genus Emydops reflects the necessity for a solid taxonomic basis for diversity studies. The description of a new species of this genus is combined with a discussion of dental variability and pathology in dicynodont anomodonts. A detailed description of the postcranial anatomy of the basal anomodont Suminia reveals new insights into the early evolution of anomodonts and therapsids in general. Several derived features, in particular in the autopodium, are unique to Suminia and together with a comparative morphometric analysis indicate grasping abilities of this taxon and the earliest evidence for arboreality in the vertebrate fossil record. The cranial anatomy of the Triassic dicynodont Kombuisia is restudied and a phylogenetic evaluation of the survivorship of anomodonts across the Permian-Triassic boundary reveals more surviving lineages than previously recognized. A review of anomodont-bearing tetrapod faunas forms the basis for a faunal similarity analysis that reveals stratigraphic as well as geographic patterns in faunal groupings. The taxonomic diversity of anomodonts reflects three diversifications and subsequent extinctions in the early Middle Permian, the Early Triassic and the mid-late Triassic.

Semantic richness is a multidimensional and dynamic construct that can be defined as the amount of semantic information a word possesses. In this thesis, the semantic richness dimensions of number of associates, number of semantic neighbours, and body-object interaction were investigated. Forty-eight young adults were randomly assigned to perform either lexical decision (LDT) or semantic categorization tasks (SCT). The goal of this thesis was to investigate behavioural and electrophysiological differences (using the Event-Related Potential technique) between semantically rich words and semantically impoverished words. Results revealed that the amplitude of the N400 ERP component was smaller for words with high number of associates and high number of semantic neighbours compared to words with low number of associates or low number of semantic neighbours, respectively, but only during LDT. Behavioural results, however, only showed an accuracy and reaction time advantage (during item analyses) for words with many associates. In contrast, N400 amplitudes did not differ for words with high body-object interaction rating when compared to words with low body-object interaction rating in any of the tasks, although a behavioural reaction time advantage was observed in item analyses of the LDT. These results suggest that words with many associates or semantic neighbours may be processed more efficiently and be easier to integrate within the neural semantic network than words with few associates or semantic neighbours. In addition, the N400 effect was seen in the LDT but not in the SCT, suggesting that semantic richness information may be used in a top-down manner in order to fulfill the task requirements using available neural resources in a more efficient manner.

Zoonotic pathogens shared with wild or domesticated animals are the cause of more than 60% of human infectious diseases. These pathogens are responsible for millions of deaths annually and have resulted in costs of over a hundred billion U.S. dollars in the past three decades. Investigating different aspects of zoonotic pathogens can help inform policy decisions on public health, agriculture, and conservation of biodiversity. Because pathogens play essential roles in natural communities, studying the variables that influence pathogen richness is important in determining the biological principles governing biodiversity. Gaining a better understanding of the factors that influence these pathogens can allow for the development of effective and targeted action plans to deal with zoonotic disease outbreaks. The aims of this work were twofold: (1) to review the current literature and identify statistically significant predictors of pathogen richness, and (2) to analyze responses by public health agencies to recent zoonotic outbreaks. This work also discussed current gaps in the literature and suggested future areas of proposed funding and research.

The decline in biodiversity over the last decade has motivated researchers to investigate the relationship between species richness (biodiversity) and ecosystem function. Empirical approaches are becoming more realistic as more factors have been included. Spatial heterogeneity is an example. Heterogeneity is an inherent part of the environment and apparent in all habitat types creating a patchy, mosaic of natural landscape. Researchers have reported the extent of heterogeneity in the landscape, but surprisingly not yet included heterogeneity into biodiversity and ecosystem function (BEF) studies. In recent years, empirical studies of marine systems have enhanced the BEF debate. Depauperate estuarine systems are ideal candidates for establishing model systems. In this study, estuarine microphytobenthos (MPB) were used as a response variable since the relationship between MPB and primary productivity is well-known. This relationship was exploited to employ MPB biomass as a proxy for primary productivity. Benthic chambers were used to assess the effect of macrofauna in single species and multi-species treatments on both ecosystem function and net macrofaunal movement. Heterogeneity was created through enriching sediment ‘patches’ with Enteromorpha intestinalis, providing areas of high and low nutrient. Heterogeneity, macrofaunal biomass, species richness, species diversity and flow were all varied in order to assess combined effects on the functioning of the system. Heterogeneity was found to have a significant influence on ecosystem functioning and on macrofaunal movement, however, patch arrangement did not. MPB biomass was highest in patches containing organic enrichment suggesting that nutrients were obtained locally from the sediment/water interface rather than the water column. There was variation in MPB biomass with macrofaunal species, probably resulting from differences in behavioural traits. It was also evident that flow altered species behaviour, as there was a significant difference between static and flow treatments. This work shows the importance of heterogeneity for BEF relationships.

Animal phyla vary dramatically in species richness (from one species to >1.2 million), but the causes of this variation remain largely unknown. Animals have also evolved striking variation in morphology and ecology, including sessile marine taxa lacking heads, eyes, limbs, and complex organs (e.g., sponges), parasitic worms (e.g., nematodes, platyhelminths), and taxa with eyes, skeletons, limbs, and complex organs that dominate terrestrial ecosystems (arthropods, chordates). Relating this remarkable variation in traits to the diversification and richness of animal phyla is a fundamental yet unresolved problem in biology. Here, we test the impacts of 18 traits (including morphology, ecology, reproduction, and development) on diversification and richness of extant animal phyla. Using phylogenetic multiple regression, the best-fitting model includes five traits that explain approximate to 74% of the variation in diversification rates (dioecy, parasitism, eyes/photoreceptors, a skeleton, nonmarine habitat). However, a model including just three (skeleton, parasitism, habitat) explains nearly as much variation (approximate to 67%). Diversification rates then largely explain richness patterns. Our results also identify many striking traits that have surprisingly little impact on diversification (e.g., head, limbs, and complex circulatory and digestive systems). Overall, our results reveal the key factors that shape large-scale patterns of diversification and richness across >80% of all extant, described species.