Understanding selection in the early animals of the Ediacaran

Objective

One of the most dramatic events in the history of life on Earth was the emergence of animals after over 3 billion years of just microbial life. Yet the anatomy of the earliest animals, first found in the Ediacaran time period 575 million years ago, is significantly different to all life that followed. While we know they were animals, their unique anatomies have hampered our understanding of what drove their evolution. REVEAL will bring together geochemistry, palaeontology and evolutionary biology to create an innovative framework for understanding early animal evolution – specifically 1) What the patterns of early animal evolution were; 2) How selection acted upon these early animals; and 3) Why these adaptations occurred. REVEAL will leverage innovative laser-scanning protocols to fully record the fossils from 575–560 million years ago; coupled with geochemical analyses to capture changes in carbon cycling and ocean oxygenation, this project will fully document the early animal biosphere. This data will be used to determine What the biodiversity and environmental changes were. To determine How selection acted on early animals, REVEAL will capitalise on the in-situ, census preservation of Ediacaran animals to quantify fitness as the mean number of offspring within clonal reproductive clusters and identify the key traits for evolution as the ones that correlate with the best competitive ability. These trait-fitness associations will be used to quantify the type and strength of selection and determine how phenotypes and the adaptive landscape changed over the first 15 million years of animal life. Finally, to determine the most likely causal processes underlying early animal diversification we will test the relative influences of abiotic and biotic variables on traits to understand Why animals diversified during this time. Taken together this project will REVEAL the What, How and Why for early animals, determining the mechanisms and drivers of early animal evolution.