All ETDs from UAB

Advisory Committee Chair

James B McClintock

Advisory Committee Members

Stephen A Watts

John M Lawrence

Document Type


Date of Award


Degree Name by School

Master of Science (MS) College of Arts and Sciences


Ontogenetic allometric analyses can provide novel insights into aspects of evolution, ecology, and conservation. For example, a recent study found marine fish exhibit hyperallometric scaling of reproductive output in relation to body size. Accordingly, to sustain fish populations the largest size class of fish should be protected. The present study exploits a model sea urchin to explore allometry to evaluate the ontogeny of skeletal defense and feeding efficiency (Aristotle's lantern). Lytechinus variegatus were sampled from St. Joseph Bay, Florida. A range of different sized late juvenile to adult individuals were measured and then dissected into skeletal components. Skeletal defense was evaluated by examining whole-body wet mass versus primary spine density (#), length (mm), breakage-strength (N), and Mg-calcite levels (% - high mg skeletons are harder). Feeding efficiency was inferred from the relationship between whole body wet mass versus whole lantern dry wt and mg-calcite content. Results indicate that between the late juvenile phase (up to 30 mm diameter) to adult phase (above 30 mm diameter) L. variegatus displays nonlinear and isometric scaling between body size and various elements of skeletal defense, and hyperallometric scaling between body size and measures of feeding efficiency. Intriguingly, many components of spine defense against predation displayed a non-significant, body-size independent relationship indicating juveniles have invest heavily in spine defenses at a young age. Lantern mass displayed a strong hyperallometric relationship with test diameter reflecting the potential importance of elevating feeding efficiency with increasing age. In the broadest sense, the present study validates that allometric scaling is valuable as a tool to evaluate aspects of defense and feeding efficiency in marine invertebrates.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.