Wednesday, 18 August 2010

Discovery of Sea Sponge Fossils Pushes Back Animal Life on Earth By 90 Million Years

American geologists from Princeton University have discovered tiny sea sponge fossils in rocks that are estimated to be between 640 and 650 million years old.  These ancient sea sponges only measured up to 1 cm across and lived on reefs off the coast of South Australia. These remarkable finds are the earliest fossils of of primitive early animals ever found.

It has been believed for a long time that animal life on earth emerged after the Marinoan glaciation, or 'Snowball Earth', when the whole planet was covered in ice and snow, but these new fossils push the emergence of animal life back before this cataclysmic event. This raises the question of how the reef-dwelling ancient sea sponges managed to survive the evastating period of glaciation.

Now there has been a discovery of ancient sponge fossils that are even older in the Etosha National Park in Namibia.  These tiny sponge fossils have been found in rocks that are estimated to be around 760 million years old, and scientists believe that it proves that sponges are the oldest forms of animal life on the planet.  These very early fossils are shaped like a vase and are no bigger than a speck of dust,and have been examined under electron microscope and x-rayed to find out their secrets. This exciting discovery points to the fact that animal life emerged on Earth at least 100-150 million years earlier than was previously thought, and that our very earliest ancestors were most probably sponges, from which all other animal life evolved.

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