SoftRock Forum: Emily Mitchell of the University of Cambridge, UK, Friday, September 24th 2010, 4pm, Grad Lounge ER-4065.
Emily is a Ph.D. student at the University of Cambridge, UK, and is visiting Newfoundland as part of her research project.
Modelling Feeding Strategies of Ediacaran Biota:
The Ediacara biota are the first documented complex, macroscopic organisms on Earth. They have few similarities with modern organisms, making the ecology very difficult to assess. In order to investigate possible feeding strategies, nutrient requirements and autecologies for these organisms, I present an ecological network model for a middle Ediacaran (575-560 Ma) Avalon-type biota.
The model consists of the 12 most dominant Ediacaran species from the Avalon assemblage, microbial mats, planktonic microbes and nutrients. Fossil abundance, body size data and life history data for planktonic microbes was input into Lotka–Volterra type differential equations to describe the ecosystem dynamics. Stability of the ecosystem was derived using eigenvalues of the Jacobian community matrix and analysed in terms of feedback loops.
Osmotrophy, suspension feeding, chemosynthetic and photosynthetic strategies for the 12 Ediacaran species were considered, with each strategy having different life history traits and interspecies interactions.
It was found that the majority of non-microbe biomass must feed osmotrophically, because there is not enough energy in the system to support a large biomass of suspension feeders. Metazoans have never exhibited large scale multicellular osmotrophy, supporting the theory that Ediacaran organisms were not the precursors to modern life.