Ediacaran organisms. Illustration of some of the organisms found in the Earth's oceans during the Ediacaran period (around 635-542 million years ago). These included Dickinsonia (brown, centre), Swartpuntia (pink, upper left), Charnia (blue, lower left), Ernietta (yellow, stalked, upper right), and Tribrachidium (yellow, bottom right). Many of these organisms represent the earliest known complex multicellular life. They were mostly replaced by later bursts of evolution (such as the Cambrian Explosion), and it is difficult to determine the exact nature of the Ediacaran biota.