Ediacaran constraints on early animal evolution

Animals first appear in the fossil record during the Ediacaran time period (631-541 million years ago), but it takes almost 50 million years for animal evolution to really take off, with a rapid diversification of animal life known as the Cambrian Explosion (~540 Ma). The biology and ecology of Ediacaran organisms are not well resolved because their body-plans are fundamentally different to both life today and elsewhere in the fossil record. Consequently, little is known about how the key evolutionary processes of competition and reproduction operate during the Ediacaran, and so it is not clear what role these factors play in the relatively slow start to animal evolution. The overarching objective of this proposal is to understand the interplay of these processes during the Ediacaran and how they influenced early animal evolution.

Ecological statistics are incredibly valuable for studying Ediacaran palaeontology because entire communities are captured in the fossil record, opening the door for the use of techniques normally only applied to living systems. These multiple "snap-shots" of Ediacaran life exist because thousands of immobile organisms were killed and preserved where they lived. This in-situ preservation means that the positions of the fossils on their rock surface encapsulate their life-history: how they reproduced, interacted with each other and with their environment. My previous work utilised spatial analyses to reconstruct how these key evolutionary processes of reproduction and competition operated in the Ediacaran, finding at least one species was dominantly asexual, producing colonies of clones, and that competition between species was relatively rare.

In this proposal I will investigate the consequences of Ediacaran clonal colonies on early animal evolution by addressing three key questions:

1) Are low Ediacaran competition rates a consequence of the dominance of clonal colonies? I will establish the extent to which Ediacaran communities were dominated by colonies of clones, and whether the inter-connectedness within these clonal colonies could have led to resource sharing, reducing competition. Competition is likely reduced for clonal colonies because if resources can be shared within a colony, there is no benefit to individuals out-competing their neighbouring clone.

2) Are Ediacaran ecosystems fundamentally different to modern ones? The relatively low levels of competition in Ediacaran communities stands in stark contrast to modern deep-sea systems, where competition is pervasive, and most species are thought to compete with each other. By analysing the fine-scale community structure of modern deep-sea communities, and comparing these details to Ediacaran communities, I will establish how the Ediacaran was different to the modern, and work out whether such differences were due to the prevalence of clonal colonies, or merely the result of differing environments.

3) Are Ediacaran evolutionary rates fundamentally slow? Having established the prevalence of clonal colonies and their impact on competition and community structure, I will feed this information into theoretical models of trait evolution and genetic diversification. By comparing how these models differ between the Ediacaran and modern communities, I will investigate the repercussions of any differences on evolutionary rates to establish whether Ediacaran evolutionary rates were reduced because of widespread clonality, thus limiting early animal evolution.

There are three non-academic groups that will benefit from my research, and that I will target in my Pathways to Impact plan.

The Interested Public
Understanding the origins of animals has enormous public interest, but is normally focused on the older Cambrian fossils. Recent work has demonstrated that animal life started in the Ediacaran, and I am working to increase awareness of the existence and importance of Ediacaran fauna through public talks and exhibits at science festivals. I regularly give talks to local groups in Newfoundland, Canada through the continued collaboration with Discovery Aspiring Geopark (see letter of support). In Cambridge I give talks to the general public (e.g. at Pint of Science) as well as local interest groups such as the Friends of the Sedgwick Museum and at the Charnia Research Group, a group comprising of interested people from Natural England and local museums, local land owners and academics interested in Charnwood and Ediacaran palaeobiology.

Educators
In Newfoundland I will host a workshop for primary school and secondary school science teachers, proving the syllabus and materials for a module on Ediacaran palaeontology and how local fossil sites inform our understanding of the evolution of life on Earth. In the UK I will develop an online school resource primarily aimed at Upper Key Stage 2: Evolutionary and inheritance and Key Stage 3: Science as evidence for evolution.

Geo-conservation and tourism
I am collaborating with The Discovery Aspiring Geopark, an organisation applying for UNESCO Geopark status, with their application to get Geopark status for a region of the Bonavista Pennisula, Newfoundland, Canada. This application would help to preserve the local fossil sites as well as increasing tourism, thus helping the local economy. I will also continue to share my laser-scans of fossil surfaces with people interested in monitoring erosion of these key sites.