The First Life Forms on Earth - Eoarchean Earth - 3.8 billion years ago, 770...

The First Life Forms on Earth - Eoarchean Earth - 3.8 billion years ago, 770 million years after the formation of the Earth, the first life forms appeared as a unicellular organism. Bacteries and archeobacteries (archaea) began to populate the Earth's surface while the atmosphere was still filled with volcanic gases and probably without oxygen. In this illustration, these micro-organisms came out of the ocean to attach themselves to the rock remains of a caldera, bringing colour to this monochrome landscape. 770 million years after the formation of the Earth - - 3.8 billion years ago - - the first life may have appeared in the form of simple, single - celled organisms. Bacteria and archaea may have even found a way to populate the otherwise sterile and inhospitable surface. The atmosphere would likely have consisted solely of gases vented by volcanoes: carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen, methane, hydrogen, methane, ammonia, and water vapor. In this image, a variety of single - celled organisms have ventured out of the ocean and onto the rocky remains of two volcanic calderas, adding color to an otherwise bleak and monochromatic landscape. While the lack of breathable oxygen would be anathema to complex life forms like ourselves, this primitive atmosphere was a rich source of sustenance for these terrestrial vanguards