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The
Precambrian era lasted from the formation of the
world 4.6 billion years ago, until 540 million
years ago. This is an enormous stretch of time -
but there are so few fossils from the period that
it is rarely subdivided further. However, we know
that the first life forms to have existed
appeared about 3,600,000,000 years ago and
fossils of bacteria 3,500,000,000 years old have
been found in Australia. Burrows up to
1,000,000,000 years old indicate that more
complex life appeared much later. The first vertebrates probably
evolved towards the end of this period. The
earliest fossils of multicellular organisms are
between 700 and 570 million years old. They were
soft-bodied creatures and included jellyfish and
segmented worms as well as many bizarre and now
extinct forms. A remarkable number of them were
found in 1947 at Ediacara in Southern Australia,
giving them the name "The Ediacara
Fauna".
See also:
how the earth formed
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