Date of Award
8-2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Biological Sciences
Committee Chair/Advisor
Dr. Richard Blob
Committee Member
Dr. Samantha Price
Committee Member
Dr. Kara Powder
Committee Member
Dr. Alexander Werth
Abstract
Extreme ecological transitions expose organisms to novel selective pressures that can reshape morphology and performance. This dissertation investigates how the transition from land to water has influenced form and material properties in cetaceans (whales, dolphins, and porpoises), a clade that has undergone dramatic morphological and physiological adaptations to a fully aquatic lifestyle. I integrate comparative morphology, material property testing, and phylogenetic analyses, to explore how ecological demands, particularly related to foraging mode and prey detection, have shaped multiple aspects of cetacean morphology and function. Using nanoindentation and microCT, I measured elastic modulus and bone density of the skull and mandible across 26 species of cetaceans and terrestrial artiodactyls. Cetaceans exhibit lower mandible stiffness and density, consistent with hypotheses that the jaw functions as an acoustic window for underwater sound reception and is released from the function of mastication. In addition, a phylogenetic comparative framework, I evaluated how scaling and shape of flukes and flippers influence hydrodynamic performance. Fluke morphology scales differently in mysticetes and odontocetes, suggesting divergent mechanical or ecological constraints, while pectoral flipper shape is linked to foraging strategies as well as phylogeny. These findings underscore trade-offs between stability and maneuverability and highlight how ecological and functional demands have shaped control surface evolution in cetaceans. Overall, this dissertation provides novel insights into how extreme ecological transitions shape the evolution of different aspects of cetacean morphologies.
Recommended Citation
Adams, Danielle S., "Evolutionary Biomechanics in Cetartiodactyla: Impacts of Ecological Shifts on Bone Material Properties and Control Surface Morphology" (2025). All Dissertations. 4036.
https://open.clemson.edu/all_dissertations/4036
Author ORCID Identifier
https://orcid.org/0000-0001-7367-3212