Current Issues in Internal Auditing

This Capstone project examines current internal auditing issues including behavioral factors, electronic data processing auditing, environmental auditing, ethics, fraud, operational auditing, outsourcing, and reporting. Information for the Capstone was gathered from a literature review utilizing the publications Internal Auditor and Internal Auditing. Each article is individually summarized, and each auditing issue is summarized.B.S. (Bachelor of Science

Testing Hypotheses About Evolutionary Change on Single Branches of a Phylogeny Using Evolutionary Contrasts

Interspecific comparisons of phenotypes are used extensively to test hypotheses about the evolutionary forces shaping phenotypic variation, but comparative data analysis is complicated by correlations due to the common ancestry of species. The method of evolutionary contrasts removes such correlations by estimating the amount of character change between pairs of closely related species that has occurred since their most recent common ancestors. The original method allows character change to be estimated only along pairs of branches on a phylogeny, but many hypotheses address change along single branches. In this article the method of evolutionary contrasts is extended to allow character change along a set of single branches on a phylogeny to be estimated, expected variances are presented, and it is shown that these extensions also result in a set of contrasts that are not correlated because of common ancestry. These extensions will allow hypotheses to be tested concerning character change associated with host or habitat shifts, changes in breeding system (e.g., monogamy vs. polygyny, monoecy vs. dioecy), changes in life history (e.g., semelparity vs. iteroparity), and changes in quantitative characters in many other situations in which one is interested in character change along single branches

Trade-Offs, Food Web Structure, and the Coexistence of Habitat Specialists and Generalists

Species differ greatly in the breadth of their environmental distributions. Within the same collection of habitats, some species occur in many habitats, while others are only able to exist in one of a few. Trade-offs in the abilities of species to perform in various ecological interactions are important both to facilitating species coexistence within a habitat and to limiting the distributions of species among habitats. In this article I use a food web model to explore how in the same collection of habitats some species may be limited by trade-offs to occupying only one habitat, while other species may face no trade-off between habitats and therefore be able to generalize in their habitat use. Food web interactions define the available niches within a habitat. Changes in food web structure cause some niches to be lost and replaced by other niches as one moves between habitats. Species occupying these niches will have more limited habitat distributions. However, other niches may be available in the food web structures of multiple habitats, and species occupying these niches will have broad habitat distributions. Understanding the structure of trade-offs within and between communities is fundamental to predicting the types of species with broad or narrow habitat distributions

The Consequences of Changing the Top Predator in a Food Web: A Comparative Experimental Approach

Changing the top predator in a food web often results in dramatic changes in species composition at lower trophic levels; many species are extirpated and replaced by new species in the presence of the new top predator. These shifts in species composition also often result in substantial alterations in the strengths of species interactions. However, some species appear to be little affected by these changes that cause species turnover at other positions in the food web. An example of such a difference in species responses is apparent in the distributions of coenagrionid damselflies (Odonata: Zygoptera) among permanent water bodies with and without fish as top predators. Enallagma species segregate between ponds and lakes that do and do not support fish populations, with each lake type having a characteristic Enallagma assemblage. In contrast, species of Ischnura, the sister genus to Enallagma, are common to both fish and fishless ponds and lakes. Previous research has shown that Enallagma species segregate because they are differentially vulnerable to the top predators in each lake type: dragonflies in fishless lakes and fish in fish lakes. This paper reports the results of a series of laboratory and field experiments quantifying the mortality and growth effects of interactions in the food webs surrounding Enallagma and Ischnura species in both lake types. These results are compared to determine how features of the food web change to force segregation of Enallagma species between the lake types but permit Ischnura species to inhabit both. The results of experiments conducted in a fishless lake show that damselflies are not food limited in this lake type, but that they do strongly compete via interference mechanisms. Interference effects between the genera are symmetrical. Ischnura species have substantially higher growth rates than Enallagma species under all conditions in fishless lakes. Although both Enallagma and Ischnura experience substantial mortality from predation by dragonflies (Anax and Aeshna species, the top predators in fishless lakes), these dragonflies display a significant bias towards feeding on Ischnura. Mortality rates due to dragonfly predation are not density dependent. The results of experiments done in a fish lake indicate that damselflies are food limited and thus compete for resources in fish lakes. Ischnura growth rates are also substantially higher than Enallagma species in the fish-lake system. Dragonfly species that coexist with fish (Basiaeschna and Epitheca species) do not impose significant mortality on coexisting damselflies, but they do compete for resources with the damselflies, and they may also generate feeding interference in the damselflies. Fish impose significantly higher mortality on Ischnura species than on coexisting Enallagma species, and this mortality is negatively density dependent. The coexistence of Enallagma and Ischnura species is fostered in both lake types by trade-offs in their abilities to avoid predators and to utilize resources. Native Enallagma species are better at avoiding coexisting predators in each lake type, but these abilities come at the expense of the ability to utilize resources effectively and to avoid the predator found in the other lake type. In contrast, Ischnura are better at utilizing resources in both lake types, but these abilities come at the expense of effectively avoiding both fish and dragonflies. Understanding the trade-offs faced by species at similar trophic positions within a food web is critical to predicting changes in food webs following major environmental perturbations such as changing the top predator

Linking Local Species Interactions to Rates of Speciation in Communities

Regional species diversity limits the diversity of local communities by defining the pool of species that are available to colonize sites. Biogeographical processes that influence speciation and extinction rates determine the size and composition of this regional species pool. Community ecologists are beginning to recognize the importance of these biogeographical processes in influencing diversity patterns among local communities, but the potential for local interactions to influence biogeographical processes, especially speciation, has been little considered. In this paper I discuss one mechanism by which variation in the strengths of local interactions can influence the potential for population differentiation and thus for influencing speciation rates in the allopatric model of speciation. When more than one selective agent acts on the phenotype, the shape of the overall fitness surface depends critically on the relative strengths of the various selective agents. If one selective agent, which imparts strong selection, acts in all populations of a species, population differentiation via adaptation to local ecological conditions or via differentiation of sexual systems is retarded because the overall fitness surface in all populations strongly resembles the shape of the strongest selective agent. Consequently, the potential for speciation is reduced. Alternatively, if selective agents in various populations impart relatively equitable strengths of selection, the potential for differences in the overall fitness surfaces among populations is enhanced, which will enhance the potential for population differentiation and thus speciation. Analogous results obtain when multiple selective agents impact genetically correlated characters. Because the strength of selection generated by a species interaction should increase with the strength of the interaction, and because fewer species can usually coexist when the strengths of interactions are greater, the number of coexisting species and the potential for speciation in component taxa may covary among communities. This analysis indicates that the relative strengths of interactions can be as important to diversification in communities as the number of niche dimensions along which differentiation can occur