The ability to move has allowed life to spread to every corner of the planet and it is such a necessity for survival that organisms have come up with many different ways to go about. Researchers thought that locomotion was a fairly recent development, but new evidence suggests that it might have been around 2.1 billion years ago.
The claim, published in the Proceedings of the National Academy of Sciences, is based on traces found in rocks from Gabon. Using a brand-new X-ray technique that is not destructive, the international team of researchers spotted tubular structures up to 6 millimeters (0.2 inches) in diameter and 17 centimeters (6.7 inches) in length. These fossils indicate the existence of a group of single cells that came together to form a motile multicellular organism. The fossils are present in the rock in thin layers and next to them the researchers found fossilized microbial biofilms. The team thinks that these acted as grazing grounds for these primitive multicellular organisms.
This is a significant find. Fossilized evidence had so far indicated evidence of mobility in complex organisms, known as eukaryotes, from roughly 570 million years ago. The fact that locomotion might have already been a thing 1.5 billion years earlier is staggering. This date is also 300 million years earlier than the first known eukaryote, making the research even more intriguing.
“It is plausible that the organisms behind this phenomenon moved in search of nutrients and oxygen that were produced by bacteria mats on the seafloor-water interface,” study co-author Dr Ernest Chi Fru, from Cardiff University, said in a statement. “The results raise a number of fascinating questions about the history of life on Earth, and how and when organisms began to move. Was this a primitive biological innovation, a prelude to more perfected forms of locomotion seen around us today, or was this simply an experiment that was cut short?”
The team also provides an example of a potential modern analogy. Some amoeboid cells can, in times of starvation, get together and move together. This is known as a migratory slug phase. But it is just speculation given that we are not exactly clear what type of organism produced the fossils.
Finding such a rock provides an incredible window into the biosphere of the Paleoproterozoic Era. The rock gives us a glimpse of what life might have had to do to survive in a shallow-marine environment, following the catastrophic and irreversible changes of the Great Oxygenation Event.