Prior to this discovery, the oldest microfossils reported were found in Western Australia and were dated at 3.4 billion years old, leading scientists to speculate that life probably started around 3.7 billion years ago.
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An worldwide team of scientists uncovered organisms in rock that dates to at least 3.8 billion years ago and may be as old as 4.3 billion years. In doing so, we found microscopic filaments and tubes of iron, ranging in size from 5-10 microns in diameter, less than half the width of human hair, and up to half a millimetre in length. In a new study, scientists studying 3.77-billion-year-old rocks have found tubelike fossils similar to structures found at hydrothermal vents, which host thriving biological communities.
Researchers have discovered evidence of the earliest life from at least 3,700 million years ago – around 56 times older than the dinosaurs. “Therefore, we expect to find evidence for past life on Mars 4,000 million years ago, or if not, Earth may have been a special exception”. It also found sulfur compounds in different chemical forms, a possible energy source for microbes, making Mars the flawless spot for living organisms to have sprung up. As both Earth and Mars had liquid surfaces at the beginning and then solidifies later, it is now highly likely that there could be some evidence that Mars indeed supported life some 4 billion years ago.
That issue has still not been settled, but it started an ongoing debate on how to define what counts as evidence of life on Mars or anywhere else away from Earth.
“We’re not talking about these complex forms of life on the early Earth, but this is where we think it actually happened”, O’Neil told CTVNews.ca by phone on Wednesday. Hydrothermal vents deep beneath the oceans have always been thought to be where life originated, leading Matthew Dodd and colleagues to search where they did.
For example, they determined that the graphite they discovered alongside the fossils had an isotopic fingerprint consistent with biological processing.
Dodd and co-authors found the filaments and tubes inside centimeter-sized structures called concretions or nodules, as well as other tiny spheroidal structures, called rosettes and granules, all of which they think are the products of putrefaction.
Filaments and tubes are common features in more recent fossils that are attributed to the activity of iron-oxidizing bacteria at seafloor hydrothermal vents.
ResearchGate: What was Earth like 3.7 billion years ago? We also found key minerals that are commonly produced by the decay of biological materials in sediments, such as carbonate and apatite (which contains phosphorus).
The jasper belt in which the fossils were found is thought to have once been an undersea vent.
The researchers collected multiple forms of evidence to back their claim, which strengthens their case, says Christopher House of the Pennsylvania State University, who was not involved in the study. The team studied the tiny fossils using a high tech microscope that let them examine the surrounding chemicals and minerals.
Life on Earth may have originated in the sunless depths of the ocean rather than shallow seas.
UCL said the researchers’ priority is to determine whether the remains from Canada had biological origins.
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Dodd: Based on the morphology of similar microfossils and organisms alive today in hydrothermal vent environments, these organisms were likely iron-metabolising bacteria, which oxidised iron coming out of hydrothermal vents to provide energy for themselves to grow and fix carbon. The remains are at least 3,770 million years old.
