ByDavid Bressan,
Senior Contributor.
Pairing cutting-edge chemistry with artificial intelligence, a multidisciplinary team of scientists found fresh chemical evidence of Earth’s earliest life — concealed in 3.3-billion-year-old rocks — and molecular evidence that oxygen-producing photosynthesis was occurring over 800 million years earlier than previously documented.
The oldest undisputed signs of life on Earth were found in 3.48-billion-year-old rocks from the Dresser Formation in Western Australia’s Pilbara region, where hot spring deposits preserved what many believe to be cell membranes. But this fossil site is a rare exception, as most of Earth’s earliest life left behind no visible traces.
Until 500 million years ago, Earth was ruled by single-celled organisms and algae, with little tissue and no hard parts to fossilize. If by chance sedimentary rocks preserved faint traces of once living beings, in almost all cases the rocks were repeatedly crushed, heated, and fractured, further blurring or erasing any evidence left behind.
