Primordial Circle: The Origins of Life on Earth

Scientists have long wondered about the ORIGIN of life on Earth — how did living things first appear on a rocky, lifeless planet? Scientists have not determined exactly where life began; the early ocean and hydrothermal vents are among the proposed settings, more than 3.5 billion years ago. Early Earth was a wild, stormy world with no oxygen-rich, breathable air and constant volcanic eruptions. Among the oldest widely accepted evidence of life are approximately 3.5-billion-year-old STROMATOLITES (stroh-MAT-uh-lytes) — layered structures formed by ancient microbial communities — found in rocks in Western Australia. These remarkable formations are like a fossil record pressed into stone, giving us our earliest window into the primordial world. Studying them is like reading the first chapter of the longest story ever told.