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Description
Vertebral osteology varies greatly among snake species. This variation may be related to specialization in microhabitat and prey-capture. Radiographs of eight preserved male specimens were taken in order to analyze the vertebral length and morphology of snakes which exhibit extreme characteristics in microhabitat utilization and prey-capture methods (highly arboreal, effective constrictor). This group includes two representatives each from four major families within Serpentes: Boidae, Pythonidae, Viperidae, and Colubridae. The four boids and pythons are effective constrictors, while the four vipers and colubrids are non-constricting. One specimen of each pair is highly arboreal, while the other is terrestrial. Findings support previous research in that constrictors had larger total numbers of vertebrae than non-constrictors. When average maximum adult length and morphology of axial musculature was taken into consideration, however, flexibility gained by vertebral number alone does not theoretically confer a mechanical advantage during constriction, at least among the specimens examined. All arboreal specimens had tails with a greater number of vertebrae than their con-familial terrestrial counterpart, implicating greater flexibility in the caudal region as an important characteristic for arboreality across taxa. Examination of segments of 10 vertebrae revealed that the greatest vertebral elongation occurred at the midpoint of the thoracic region. Reduction in size and length of tail vertebrae appears to occur independently of thoracic vertebrae. Colubrids, specifically, demonstrated a unique caudal vertebral elongation pattern which could potentially be advantageous for quick locomotion. These results indicate that caudal morphology may be more important in behavioral specialization than previously thought.
ContributorsGuerrero, Anna Clemencia (Author) / Fisher, Rebecca (Thesis director) / DeNardo, Dale (Committee member) / Elliott, Steve (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Scientific researchers have studied microorganisms since the emergence of the single lens microscope in the 17th century. Since then, researchers designed and published many thousands of images to record and share their observations, including hand-drawn diagrams, photomicrographs, and photographs. Images shaped how researchers conceived of microorganisms, their concepts of microorganisms shaped their images, and their images and concepts were shaped by the contexts in which they were working. Over time, the interplay of images and concepts in various research contexts participated in the development of new concepts related to microorganisms, like the “biofilm” concept, or the idea that bacteria exist in nature as complex aggregates attached to surfaces via extracellular polymeric matrices. Many histories of microbiology locate the origin of the biofilm concept in the 1970s, but that date obscures the rich history of research about attached microbial aggregates that occurred throughout the history of microbiology. I discovered how the interplay of images and concepts related to bacteria participated in the development of the biofilm concept by documenting when and why researchers used different visual features to represent changing concepts related to microorganisms. I specifically examined how and why scientists represented evolving concepts related to bacteria during the 17th century (Chapter 1), from the late 17th century to the early 20th century (Chapter 2), and during the first seventy-four years of the 20th century (Chapter 3). I discovered the biofilm concept developed in at least three unique research contexts during the 20th century, and how images reflected and shaped the concept’s development in each case. The narrative and collection of images generated from this work serve as a visual history of the development of scientists’ ideas about the nature of bacteria over 300 years.
ContributorsGuerrero, Anna Clemencia (Author) / Maienschein, Jane (Thesis advisor) / Laubichler, Manfred (Committee member) / Sterner, Beckett (Committee member) / Matlin, Karl (Committee member) / Arizona State University (Publisher)
Created2023