Life on Earth may have originated much earlier than previously believed

Recent fossil discoveries have prompted scientists to revise their understanding of when life first emerged on Earth. Previously believed to have originated around half a billion years ago, new findings suggest that life may have begun approximately 1.75 billion years ago. This significant adjustment in the timeline is based on the oldest known evidence of oxygenic photosynthetic structures found in fossils dating back 1.75 billion years. These structures indicate early life forms had the capability to convert sunlight, water, and carbon dioxide into energy and oxygen, highlighting the presence of life during that era.

The importance of this discovery lies in its connection to the Great Oxygenation Event, a pivotal period in Earth’s history that dramatically increased atmospheric oxygen and supported the proliferation of diverse life forms. These primitive photosynthetic structures, though basic compared to the complexity of life today, were instrumental in this transformation of the Earth’s atmosphere and oceans.

The groundbreaking study, published in the journal Nature, focuses on fossils from Australia’s McDermott Formation. Emmanuelle Javaux, a co-author from the University of Liège, emphasizes the impact of these structures on the evolution of the Earth’s biosphere, including the development of complex life.

This new insight follows another significant research achievement in November 2023. Scientists managed to recreate a chemical reaction that could have led to the formation of RNA (ribonucleic acid), a key molecule in the development of life. This experiment aimed to mimic the complex prebiotic conditions on early Earth, contributing to our understanding of how self-replicating structures evolved into living organisms. As described by Quoc Phuong Tran, a PhD candidate in Prebiotic Chemistry at UNSW Sydney, this recreated chain of reactions had to be feasible in the chaotic environment of ancient Earth.