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Full-Text Articles in Earth Sciences
Ontogenetic Niche Shift As A Driver Of Community Structure And Diversity In Non-Avian Dinosaurs, Katlin Schroeder
Ontogenetic Niche Shift As A Driver Of Community Structure And Diversity In Non-Avian Dinosaurs, Katlin Schroeder
Biology ETDs
As some of the most charismatic megafauna to ever walk the earth, the physiology, morphology, growth and evolution of non-avian theropods has been studied exhaustively, yet little is understood about their roles in ecosystems as juveniles. For carnivorous megatheropods, which exceed 1,000kg in mass yet hatched from eggs of limited size, the likelihood of utilizing different prey through ontogeny was high, simply by proxy of the immense difference in size between adults and juveniles. We found these ontogenetic niche shifts, evidenced by significantly different dental microwear in Tyrannosaurids, to have excluded dinosaurian mesocarnivores from Mesozoic communities. The few dinosaurian mesocarnivores …
Niche Dynamics Of The Felid Guild Following The Pleistocene Megafaunal Extinction, Nicholas A. Freymueller
Niche Dynamics Of The Felid Guild Following The Pleistocene Megafaunal Extinction, Nicholas A. Freymueller
Biology ETDs
The loss of large carnivores is fundamentally restructuring modern mammal communities. However, large carnivore removal is not exclusively a modern trend. The Pleistocene Megafaunal Extinction (PME) resulted in a near-eradication of hyper-carnivorous felids such as saber-toothed cats. However, it is unclear if smaller surviving meso-felids began to infill this ecological vacuum post-PME. I apply Ecological Niche Modeling (ENM) to test evaluate whether surviving felids filled in vacant niches post-extinction, and hypothesize that they ought to have shown increased niche-overlap patterns with mega-felids post-extinction. I model species’ fundamental niches using a multi-temporal approach, and develop a novel test to model realized …
Reconstructing Energy Flow Through Modern And Historical Marine Communities: Insights From Amino Acid Isotope Analysis, Emma A. Elliott Smith
Reconstructing Energy Flow Through Modern And Historical Marine Communities: Insights From Amino Acid Isotope Analysis, Emma A. Elliott Smith
Biology ETDs
The fundamental currency of life is energy. Organisms need energy to grow, to survive and to reproduce. Understanding the acquisition of energy by consumers is thus a foundational aspect of biological research. This is especially important in the modern era, as impacts of ongoing anthropogenic effects will be mediated or amplified through food webs. Here, I explore how isotopic analysis of individual amino acids – a technique new to ecological studies – can be used to trace energy flow through animal communities in modern and ancient time periods. In particular, I focus on kelp forest food webs, which are nearshore …