Lead Supervisor: Emily Mitchell, Zoology
Co-Supervisor: Charlotte Kenchington, Earth Sciences and Jason Head, Zoology
Brief summary:
This project will determine which morphological characters drive the ecological dynamics of some of the first animals.
Importance of the area of research concerned:
Animals first appear in the fossil record during the Ediacaran time period (631-541 million years ago). It is during the Ediacaran that animals evolved some of their most important traits: most obviously large body-size but also tissue-differentiation, mobility, bilateral symmetry and ecosystem engineering (reef-building). The study of Ediacaran organisms is fraught with difficulties, because commonly-used morphological approaches have only limited use due to the unique anatomies of Ediacaran organisms. Fortunately, the preservation of Ediacaran fossils is exceptional, with communities comprised of thousands of sessile organisms preserved where they lived under a layer of volcanic ash. Therefore, the position of the fossil on the rock surface encapsulates their entire life history: how they reproduced and how they interacted with each other and their environment (Mitchell et al. 2015). As such, ecological statistics provides a novel approach for investigating fundamental issues in early animal evolution.
Project summary :
It is currently not clear which biological characters or traits are key to influencing taxon interactions in the Ediacaran. This project will focus on the Ediacaran clade Rangeomorpha, which exhibit a “fractal-like” anatomy unique to the Ediacaran, which maximise their surface areas. Since specimen height and population height distributions do not govern community dynamics, contrary to prior hypotheses (Mitchell and Kenchington 2018) other metrics need to be considered. This project will investigate which morphological traits, such as branching characters, correlate with their ecological dynamics to determine what are the key traits of Ediacaran organisms.
What will the student do?:
The student will use existing casts and laser-scan data to quantify different morphological characters, and determine how population variations of these characters correlations with different population dynamics such as extent and strength of competition (Mitchell & Kenchington 2018). NMDS cluster analyses and multivariate regression analyses will be used to investigate how different organism traits influence community composition and dynamics. Specifically this project will be working to establish whether Ediacaran organisms have a “super-traits” - that is a single trait that explain multiple different behaviours. Extant organisms that also maximise their surface-areas include corals and plants. Many ecological interactions among corals depend on their colony mass per unit area, while many plant ecological traits are correlated with leaf-mass per unit area. Further data collection through fieldwork in Newfoundland, Canada is possible, but not necessary depending on the interests of the student.
References - references should provide further reading about the project:
Mitchell, E. G., Kenchington, C. G., Liu, A. G., Matthews, J. J., & Butterfield, N. J. (2015). Reconstructing the reproductive mode of an Ediacaran macro-organism. Nature, 524(7565), 343.
Mitchell, E. G., & Kenchington, C. G. (2018). The utility of height for the Ediacaran organisms of Mistaken Point. Nature ecology & evolution, 2(8), 1218.
Mitchell, E. G., Harris, S., Kenchington, C. G., Vixseboxse, P., Roberts, L., Clark, C., ... & Wilby, P. R. (2019). The importance of neutral over niche processes in structuring Ediacaran early animal communities. Ecology Letters 22(12) 2028-2038
Applying
You can find out about applying for this project on the Department of Zoology page.
Dr Emily Mitchell