Known also as the Vendian, the Ediacaran was the final stage of Pre-Cambrian time. All life in the Ediacaran was soft-bodied - there were no bones, shells, teeth or other hard parts. As soft bodies don't fossilise very well, remains from this period are rare. The world's first ever burrowing animals evolved in the Ediacaran, though we don't know what they looked like. The only fossils that have been found are of the burrows themselves, not the creatures that made them. This period gets its name from the Ediacara Hills in Australia, where famous fossils of this age were found.
Watch video clips from past programmes (1 clip)
Causes of extinctions
During this period the following extinction level events are thought to have occurred.
Impact events, proposed as causes of mass extinction, are when the planet is struck by a comet or meteor large enough to create a huge shockwave felt around the globe. Widespread dust and debris rain down, disrupting the climate and causing extinction on a global, rather than local, scale.
Types of fossils formed in this period
Normally, only the hard parts of animals and plants - shell, bone, teeth and wood - are preserved as fossils. However, every now and then conditions permit the preservation of soft parts and create treasure houses of information for palaeontologists.
BBC News about Ediacaran period