PhD: Life in three dimensions: unravelling the evolution of bilaterian animal locomotion

Background

The transition from the Ediacaran Period to the Cambrian marks a momentous change in the history of life on Earth, marking the dawn of the age of animals. The sudden appearance and explosive diversification of animals is intrinsically linked to the origin of locomotion, in particular burrowing. This seemingly simple innovation marked a significant departure from previous lifestyles among multicellular organisms. Through burrowing, animals fundamentally altered the composition and makeup of the seafloor, oxygenating sediments, and allowing new lifestyles to originate that ultimately set the stage for the next half a billion years of life in the ocean and on land. The event is well documented throughout the geological record, with vertically penetrating burrows recorded as trace fossils. However, important fundamental questions remain regarding how and why this event occurred, including who those first organisms were, and how they moved. The exceptional soft-bodied and shelly fossil records also document another major lifestyle innovation which occurred at the same time: the invasion of the nekton with swimming animals moving carbon and oxygen through the water column. The Cambrian was a critical interval during which animals first began exploring the world in three dimensions.

The Project

This project will investigate locomotion strategies across the animal tree of life and in deep time. Using restudy of key specimens and visits to hosting institutions, and a phylogenetic analysis of extinct and extant animals, the student will reconstruct the ancestral state for locomotory mode at key nodes in the animal tree. This will identify when and how many times key innovations in locomotion took place, providing an evolutionary framework for understanding the record of locomotion encoded in trace fossils. Study of key extinct taxa using X-ray microtomography and other analytical approaches, will allow a better understanding of locomotion in the fossil record, and the student will also have the opportunity to use these reconstructions to understand locomotion using biophysics simulation.