what are the oldest life forms on earth

The oldest life forms on Earth are microorganisms that lived between about 3.7 to 4.28 billion years ago. Fossilized remains of tiny bacteria-like filaments and tubes, found in ancient rocks in Canada, have been dated to around 3.77 to 4.28 billion years old and are considered some of the earliest direct evidence of life. Additionally, stromatolites—layered structures created by mats of cyanobacteria—are fossils dating back about 3.4 billion years and represent some of the earliest known life structures still found today. There is also geochemical evidence, like biologically fractionated carbon isotopes found in ancient minerals in Australia, suggesting life might have arisen as early as 4.1 billion years ago. These earliest life forms were microscopic, single- celled organisms likely inhabiting iron-rich hydrothermal vent environments in the ocean.