A diverse Palaeoproterozoic microbial ecosystem implies early eukaryogenesis
1Early Life Traces and Evolution-Astrobiology R.U., Université de Liège, Liege, Belgium.
Summary
Ancient Australian microfossils reveal complex early eukaryotes, pushing back their origin by over 100 million years. These findings suggest a minimum age for the Last Eukaryotic Common Ancestor (LECA) and hint at early microbial symbiosis.
Area of Science:
- Paleobiology
- Microbiology
- Evolutionary Biology
Background:
- Eukaryogenesis, the origin of complex cells, is a pivotal event in life's evolution.
- Cellular palaeobiology offers insights into ancient microbial life and its evolutionary impact.
- The McDermott Formation (Australia) provides a unique window into early life forms.
Purpose of the Study:
- To investigate the evolutionary history of early eukaryotes.
- To determine the minimum age of uncontested eukaryotic fossils.
- To explore evidence of microbial symbiosis and behavior in ancient ecosystems.
Main Methods:
- Analysis of microfossil assemblages from the 1.78-1.73 Ga McDermott Formation.
- Morphological and comparative analysis of fossil cell structures.
- Reconstruction of ancient environmental conditions and microbial community interactions.
Main Results:
- Discovery of fossil cells with complex cytoskeletons and endomembrane systems, indicating advanced eukaryotic features.
- Evidence for early reproduction by budding, simple multicellularity, and cyst formation.
- Documentation of microbial symbiosis, eukaryovory, and ectosymbiosis within the ancient community.
- Pushing back the minimum age of eukaryotic fossils by over 100 million years.
- Suggesting a minimum age of >1.75 Ga for the Last Eukaryotic Common Ancestor (LECA).
Conclusions:
- The findings support early eukaryogenesis and the origin of complex life forms over 1.75 billion years ago.
- Early eukaryotes exhibited sophisticated life cycles, including reproduction and multicellularity.
- Microbial interactions, including symbiosis and predation, played a significant role in early eukaryotic evolution.
- The study provides crucial fossil evidence consistent with molecular clock estimates for eukaryotic origins.
Keywords:
Palaeoproterozoiccellular palaeobiologycyanobacteriaeukaryogenesisevolutionmicrobial symbiosisorganic-walled microfossilspredationprotistMore Related Videos
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