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Temperature Effects On The Development Of The Axial Skeleton And Body Shape In Astyanax Mexicanus (Teleostei: Characidae), Joseph David Forberg

College of Science and Health Theses and Dissertations

Humans are causing large-scale changes in environmental conditions across the planet including in temperature. Changes in the environmental conditions can lead to phenotypic changes in ectotherms that affect adaptively important traits like body shape and the axial skeleton. Previous studies have shown that temperature changes during development significantly affects body shape and vertebral number in the Mexican tetra Astyanax mexicanus. How these changes arise early in development is not clear. In this study, I examine how changes in developmental temperature affect body shape in larval and juvenile fish, the order of ossification of elements of the axial skeleton, the size …

Phylogenomics And Population History Of Cichlid And Live-Bearing Fish Species In Lowland Neotropical Rivers, Konrad Taube

College of Science and Health Theses and Dissertations

Within Middle America, cichlids and poeciliids account for more than half of the fish biodiversity. This richness in fish fauna highlights the complexity of Middle American biogeography: no other continental area on earth contains within its range the unparalleled abundance of secondary freshwater fish species (fish that can tolerate both saltwater and freshwater). Research into the biogeography of widely distributed Middle American freshwater fish is essential to understanding this unique region.

Three species of freshwater fishes (Belonesox belizanus – Pike killifish, Vieja maculicauda – Black belt cichlid, and Gambusia nicaraguensis – Nicaraguan mosquitofish) are widely distributed across rivers on …

Comparative Brain Anatomy Of Lamniform Sharks (Elasmobranchii: Lamniformes) And Its Implications To Function, Behavioral Ecology, And Evolution, Francesco Guzzo

College of Science and Health Theses and Dissertations

Understanding the diversity of brain morphology is important to understand the evolution of cognitive ability and how ecology and phylogeny have influenced the variation in brain complexity. I examined the morphological variation of the brain in the shark order Lamniformes based on museum specimens and literature. Where I illustrate a wide range of morphological diversity in lamniform brains, my study shows that there is a strong positive correlation between brain size and body size that sharks with a larger brain tend to have a more foliated cerebellum, but that the body weight over brain weight did not correlate with cerebellar …

Body Forms In Sharks (Chondrichthyes: Elasmobranchii), And Their Functional, Ecological, And Evolutionary Implications, Phillip C. Sternes

College of Science and Health Theses and Dissertations

Sharks are among the oldest vertebrate lineages in which their success has been attributed to their diversity in body shape and locomotor design. In this study, I investigated the diversity of body forms in extant sharks using landmark-based geometric morphometric analyses on lateral view illustrations of nearly all the known (ca. 470) extant sharks in a published guidebook. I ran three different analyses: the ‘full body,' ‘precaudal body,’ and ‘caudal fin' analyses. My study suggests that there are two basic body forms in sharks. The two major body forms are characterized as a ‘shallow-bodied’ form (Group A) and ‘deep-bodied’ form …

Phylogeography Of The Neotropical Fish Genus Rhoadsia (Teleostei: Characidae) In Ecuador, Roberto Valentino Cucalón Tamayo

College of Science and Health Theses and Dissertations

Western Ecuador is considered a biodiversity hotspot. Nevertheless, studies of population genetic structure and variation are rare, especially in aquatic species. The genus Rhoadsia is an endemic freshwater fish in this region with two recognized species, Rhoadsia minor and R. altipinna. Little is known about the evolutionary relationships of their populations, and due to morphological similarities, their validity as distinct species has been questioned. The present study uses a phylogeographic approach to examine the evolutionary history of the genus and the validity of the two described species. Furthermore, I investigated the possible geographical origin of the genus based on patterns …

Genetic And Morphological Diversity Along Altitudinal Gradients In The Genus Rhoadsia (Teleostei: Characidae: Rhoadsiinae), Grace Malato

College of Science and Health Theses and Dissertations

The Neotropics have the highest fish species diversity of any area in the world, with some experts estimating that as many as 4000 species of fishes are present in freshwater ecosystems. Elevational gradients are partially responsible for this diversity due to the rapidly changing ecological conditions associated with changes in altitude in rivers. One area where elevational gradients are particularly important is Western Ecuador; this region forms part of a biodiversity hotspot extending south from Panama along the western side of the Andes. Fish species diversity is relatively low because of the small size of most of the river drainages …

Tectonic Shift: A Scientific Account Of My Young Adulthood, Rosalyn Lederman

College of Liberal Arts & Social Sciences Theses and Dissertations

Tectonic Shift evolved from my desire to examine the role that science has played in my life: as a student, a Jewish American, a friend, a daughter, a writer. My personal search for an understanding of the world around me is what ties together the pieces in Tectonic Shift. In these pages I explore everything from my views on creative nonfiction to my burgeoning fossil collection, all in the context of my larger quest to understand myself and my place in the world.

The question I set out to answer in the following pages—how have my ADHD diagnosis and my …