<P> The earliest known life forms on Earth are putative fossilized microorganisms found in hydrothermal vent precipitates . The earliest time that life forms first appeared on Earth is unknown . They may have lived earlier than 3.77 billion years ago , possibly as early as 4.28 billion years ago , not long after the oceans formed 4.41 billion years ago , and not long after the formation of the Earth 4.54 billion years ago . </P>
<P> The earliest known life forms on Earth are putative fossilized microorganisms found in hydrothermal vent precipitates . The earliest time that life forms first appeared on Earth is unknown . They may have lived earlier than 3.77 billion years ago , possibly as early as 4.28 billion years ago , not long after the oceans formed 4.41 billion years ago , and not long after the formation of the Earth 4.54 billion years ago . </P>
the first life forms to appear on earth were
the first life forms to appear on earth were
putative fossilized microorganisms
putative fossilized microorganisms