Ediacara Fauna

Ediacara fauna, also called Ediacara biota, unique assemblage of soft-bodied organisms preserved worldwide as fossil impressions in sandstone from the Ediacaran Period (approximately 635 million to 541 million years ago)—the final interval of both the Proterozoic Eon (2.5 billion to 541 million years ago) and Precambrian time (4.6 billion to 541 million years ago). Traditionally, these fauna have come to represent an important development in the evolution of life on Earth, because they immediately predate the explosion of life-forms at the beginning of the Cambrian Period 541 million years ago. Some scientists have suggested that the Ediacara fauna, named for the Ediacara Hills of South Australia, in which they were discovered in 1946, were the first metazoans (animals made up of more than one type of cell) that required atmospheric oxygen for their growth. These animals were the precursors of organisms with skeletons, the appearance of which marked the end of Precambrian time and the beginning of the Phanerozoic Eon (541 million years ago to the present). The discovery of the Ediacara fauna demonstrated that a far more complex level of evolution had been achieved during Precambrian time than had been previously thought.