Deconvolving the early record of eukaryotic evolution

Introduction

The Neoproterozoic Era (1 to 0.54 billion years ago) witnessed some of the most dramatic ecological and evolutionary changes in Earth history, which culminated in the appearance and diversification of animals. After almost 4 billion years of bacterial dominance, it took life on our planet just ~250 million years to go from the proliferation of unicellular eukaryotes to the diversification of animals.

Environmental Perturbations

This sequence of rapid ecological and evolutionary changes is thought to be related to unprecedented environmental perturbations, which occurred during this time interval and are recorded in sedimentary rocks. We know these perturbations did happen, but not their magnitude, duration, or driving mechanisms.

Limitations of Data Interpretation

One of the major limitations of interpreting the data is that each sample represents tens, or even hundreds of years of sedimentation, and contains a mixture of unevenly preserved remains of organisms that lived throughout this time.

Methodological Approaches

This project focuses on new methodological approaches at the interface of organic geochemistry, isotope geochemistry, and palaeontology to deconvolve the mixed signals of ancient rocks.

Stable Carbon Isotope Analysis

• Stable carbon isotope analysis on biomarkers of specific groups of organisms would provide insights about the carbon cycle at their habitat.
• Analysing biomarker composition of the first complex microfossils would allow identifying which organisms they were.
• Position-specific isotopic composition of ancient biomarkers might reveal their biosynthetic pathway and thus identify the first ecologically successful eukaryotes on our planet.

Study Objectives

The study is designed to extract information about the composition and ecology of ancient ecosystems, as well as the history of the carbon cycle throughout the critical time of the rise and diversification of complex life.

Conclusion

It aims to resolve what it takes for a habitable planet to evolve complex life and, in turn, how life on our planet responded to possibly the largest perturbations in the global carbon cycle in Earth history.