NSFGEO-NERC: Ancient life in moving fluids: elucidating the emergence of animal ecosystems

Lead Research Organisation: Natural History Museum
Department Name: Earth Sciences

Abstract

The emergence of animal ecosystems during the late Ediacaran (~571-539 million years ago) was a pivotal episode in the evolutionary history of life. However, most of these Ediacaran organisms disappeared immediately before the Cambrian, in what may represent the first mass extinction of complex life. There are thus two key questions that will provide fundamental insights into the origins of modern ecosystems: 1) where do Ediacaran organisms fit in the tree of life? And, 2) what drove their extinction prior to the onset of the Cambrian? We will address these questions by combining new data collected during fieldwork with computer simulations performed on both individual organisms and whole communities. This project will improve knowledge of the early evolution of complex ecosystems, while at the same time pioneering the development of a rigorous new approach for examining how marine organisms evolved in response to moving fluids. We will work together with local school teachers to produce learning modules focused on 3-D modelling and fluid dynamics, suitable for communicating key evolutionary principals to students (16-18 years old) in the UK and USA.

Publications

10 25 50
 
Description The emergence of animals during the late Ediacaran (~571-539 million years ago) was a pivotal episode in the evolutionary history of life. Reconstructing the ecology of Ediacaran organisms is thus crucial for establishing their role in Earth's first animal ecosystems. However, many aspects of Ediacaran ecology are uncertain, hampering efforts to decipher the origins of modern marine ecosystems. To address this, we constructed 3-D digital models of >25 Ediacaran taxa, which were used in computer simulations of fluid flow. The results are shedding new light on the ecology of Ediacaran organisms. We have found evidence for a diversity and abundance of late Ediacaran suspension feeders, suggesting an energy link between pelagic and benthic realms (a key part of modern ecosystems) was established over 550 million years ago. In addition, we have developed a novel hypothesis for the palaeobiology of Ediacaran rangeomorphs, inferring that fronds were adaptations for gas exchange, rather than feeding. We are currently extending our work from simulations of individual taxa to multi-species communities, and this will allow us to uncover how flow patterns changed with the evolving composition of Ediacaran communities through time.
Exploitation Route All the data arising from our work, including 3D models and CFD simulation files, have been (and will continue to be) made freely available alongside publications. These data are thus available for other scientists to use as part of their own research. They could also be used by educators to teach topics such as the evolution of life and digital modelling techniques.
Sectors Education,Environment,Culture, Heritage, Museums and Collections

 
Description They were used in an online lecture on "Uncovering the Origin of Animals" that I delivered as part of the NHM's public short course on "Life Through Time: Six Moments in Evolution". A total of 42 people were registered for the short course in 2023 and were thus able to access a recording of the lecture.
First Year Of Impact 2023
Sector Education,Culture, Heritage, Museums and Collections
Impact Types Cultural,Societal

 
Title The life and times of Pteridinium simplex 
Description Pteridinium simplex is an iconic erniettomorph taxon best known from late Ediacaran successions in South Australia, Russia, and Namibia. Despite nearly 100 years of study, there remain fundamental questions surrounding the paleobiology and -ecology of this organism, including it's life position relative the sediment-water interface, and how it fed and functioned within benthic communities. Here, we combine a re-description of specimens housed at the Senckenberg Forschungsinstitut und Naturmuseum Frankfurt with field observations of fossiliferous surfaces to constrain the life habit of Pteridinium and gain insights into the character of benthic ecosystems shortly before the beginning of the Cambrian. We present paleontological and sedimentological evidence suggesting that Pteridinium was semi-infaunal and lived gregariously in aggregated communities, preferentially adopting an orientation with the long-axis perpendicular to the prevailing current direction. Using computational fluid dynamics simulations, we demonstrate that this life habit could plausibly have led to suspended food particles settling within the organism's central cavity. This supports interpretation of Pteridinium as a macroscopic suspension feeder that functioned similarly to the coeval erniettomorph Ernietta, emblematic of a broader paleoecological shift towards benthic suspension feeding strategies over the course of the latest Ediacaran. Lastly, we discuss how this new reconstruction of Pteridinium informs on its potential relationships with extant animal groups, and state a case for reconstructing Pteridinium as a colonial metazoan. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Impact Provided digital models that will be used in planned future community-scale CFD simulations. 
URL http://datadryad.org/stash/dataset/doi:10.5061/dryad.0rxwdbs1g