Earth's earliest mobile organisms 'lived 2.1 billion years ago'

Scientists have discovered in 2.1-billion-year-old black shale from a quarry in Gabon the earliest evidence of a revolutionary development in the history of life on Earth, the ability of organisms to move from one place to another on their own.

The researchers on Monday described exquisitely preserved fossils of small tubular structures created when unknown organisms moved through soft mud in search of food in a calm and shallow marine ecosystem. The fossils dated back to a time when Earth was oxygen-rich and boasted conditions conducive to simple cellular life evolving more complexity, Reuters reports, citing the research team.

Life emerged in Earth’s seas as single-celled bacterial organisms perhaps 4 billion years ago, but the earliest life forms lacked the ability to move independently, called motility. The Gabon fossils are roughly 1.5 billion years older than the previous earliest evidence of motility and appearance of animal life.

The Gabonese shale deposits have been a treasure trove, also containing fossils of the oldest-known multicellular organisms.