DISSERTATION RESEARCH: Morphological consequences of trophic evolution

University Of Tennessee Knoxville, Knoxville TN

Investigators

Abstract

A unifying characteristic of all life forms is the need to acquire resources. Resources relating to food and feeding, also known as trophic resources, have been a leading factor in driving the diversity of life on this planet. One of every three living vertebrate species is an acanthomorph fish, a group of spiny-ray finned fishes that includes cichlids and many reef fishes. Members of this group consume a wide variety of resources, ranging from scraping scales off other fish, filtering plankton from the water, biting off chunks of coral, or actively hunting other vertebrates. How effectively the fish feed on these resources is intimately connected to their physical anatomy, especially how well the fish can maneuver and capture prey. Some anatomical traits are thought to lead to increased speciation or decreased extinction rates (these are known as key innovations) but may limit possible flexibility in diet evolution. This is the key question addressed by this research. In addition, this research compares how communities of different ages are shaped by their trophic ecologies. Acanthomorphs are also common aquarium fish, providing a great opportunity to educate the public about form and function in biology, which this research will do by producing interactive software. Understanding the ecological factors that generate and maintain diversity is a major goal in biological research. Trophic ecology is one such factor and is a major driver of evolution. Acanthomorph fishes provide the perfect system to study trophic evolution as they are extremely speciose and diverse in their trophic ecology and morphology. Specifically, this research investigates how trophic ecology may promote or constrain rates of morphological evolution, how morphological key innovations may constrain or promote rates of diet evolution, and how communities of different ages may have different patterns of trophic evolution that have shaped the respective fish fauna. This research will use comparative phylogenetic methods and, for young radiations, phylogenomics, to elucidate relationships of species and test these hypotheses in a comparative evolutionary framework. This research will provide insight into how diet evolves and the macroevolutionary consequences that trophic ecology has on morphology.