The New World blackbirds (Icteridae) are among the best known songbirds, both through exemplar species, such as the Red-winged Blackbird ( Agelaius phoeniceus), and collectively, as a model clade in studies of morphological, ecological, and behavioral trait evolution. Knowledge …
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Nakwai is a fossiliferous region in the Turkana Basin of northwestern Kenya. Until recently the only ages for the Nakwai formation were based on biostratigraphic correlation with Losodok; a late Oligocene site located to the north of Nakwai. The new 40 Ar/39 Ar ages in this stud…
In this dissertation, I combine population genetic and demographic history analyses of autosomal, mitochondrial and Y-chromosome genetic markers with spatially explicit modeling techniques to study the biogeographic mechanisms responsible for shaping patterns of genetic diversit…
Snake-eyed skinks are relatively small lizards of the genera Panaspis and Afroablepharus. Along with closely-related scincid taxa, the allocation of these genera has been constantly rearranged based on morphology, ecology and biogeography. Members of these genera occur primarily…
One of the fundamental questions in biology is the origin of species. Considerable insights into the processes that drive speciation have come from ancient lake systems. In this thesis, I present insights into speciation processes by investigating the species radiations of the a…
The current dissertation project integrates revisionary taxonomy, comparative morphology, molecular phylogenetics and comparative evolutionary analyses to investigate the diversity and evolution of assassin bugs, focusing on the Malagasy Bekilya group (Peiratinae) and the New Wo…
The Nearctic bark beetle genus Scolytus was revised based in part on a molecular phylogeny. Monophyly of the native species was tested using mitochondrial (COI) and nuclear (28S, CAD, ArgK) genes and 43 morphological characters in parsimony and Bayesian phylogenetic analyses. Pa…
This thesis examines the evolution of the straight-tusked elephant (Palaeoloxodon antiquus) in Pleistocene Europe where it was a conspicuous interglacial faunal element from around 780,000 until 30,000 years ago. This study investigates the evolution of P. antiquus through varia…
Sub-Saharan Africa is believed to possess more human genetic diversity than any other region of the world, a likely consequence of it being the probable place of origin of anatomically modern man. Despite its evolutionary importance studies into the distribution of this genetic …
A central goal of evolutionary biology is to understand the genetic and functional mechanisms through which organisms become adapted to their environments. Testing specific hypotheses about effects of historical genetic changes on organismal functions and fitness, however, has b…
In the first chapter I documented diversity of Symbiodinium for two species of giant clam, Tridacna maxima and Tridacna squamosa , across their Indo West Pacific distribution. At 25 localities across the Indo-Pacific from French Polynesia to the Red Sea, I collected small pieces…
Mosasaurs were giant marine squamates that inhabited all of the world’s oceans approximately 93 to 65 Million Years Ago. The subfamily Mosasaurinae is one of the most diverse groups, including the robust-toothed Globidensini and the ichthyosaur-like members of the Plotosaurini (…
Knowledge of early cetacean evolution has grown greatly in recent decades due to the discovery of dozens of species of archaeocetes that bridge the gap between aquatic cetaceans and their terrestrial ancestors. However, many of the details of how this transition occurred have ye…
The tropical, flowering shrubs in the genus Erythroxylum (230 species) are commonly known as coca. For 8,000 years, two Erythroxylum species have been exploited for their production of cocaine. Coca plants remain culturally significant and economically important. Yet, their orig…
Niche differentiation is argued as one of the mechanisms explaining species coexistence. Despite their sessile nature, similar resource needs and traits to acquire and utilize resources closely related plant species coexist. I hypothesized that i) spatial distribution of congene…
The effects of physical activity and dietary calcium on bone development are not fully understood. Forty-nine female, B6 mice were either given access to a running wheel or housed in a limited activity environment and either fed a regular calcium diet (0.95% Ca) or high calcium …
The genus Allium (Amaryllidaceae) is distributed over mid-latitude regions from the dry subtropics to the boreal zone. It includes ca. 850 species total, with 84 species in North America. The greatest species richness is in the Old World, from the Mediterranean Basin to central …
Malaria is a deadly disease that causes nearly one million deaths each year. Understanding the demographic history of the malaria parasite Plasmodium falciparum and the genetic basis of its adaptations to antimalarial treatments and the human immune system is important for devel…
Symbiosis is an intimate association between two or more different species encompassing a spectrum of interactions from parastism, through commenalism to mutualism. Although it was once thought to be rare and unusual, we now understand symbiosis to be remarkably common and it ha…