Did life on Earth begin on land or in water? Ancient rocks are helping to piece together the origins of life
Redrawing the geological timeline of Earth’s first billion years is casting new light on whether life emerged on land or in the oceans.
The geological record gets increasingly spotty the further back in time you go There are no rocks preserved from Earth’s first 500 million years and few from the next aeon, the Archean, which ran from 4 billion to 2.5 billion years ago newscientist.com/article/dn2836
Nevertheless there’s confirmed evidence of microorganisms from 3.5 billion years ago preserved in rocks at Pilbara in Australia
Rocks from South Africa also suggest evidence of microbes on land from 3.2 billion years ago
Still, this leaves a gap of at least a billion years from when Earth formed In theory, life could have originated in a primordial ocean over 4 billion years ago. But it’s also possible that land formed much earlier than 3.5 billion years ago and that life started there
So did life first emerge on land or in water? Emerging geological evidence is helping to piece together a better picture of our planet’s infancy Discover more about the origins of life on Earth, in @m_c_marshal’s feature: newscientist.com/article/mg2553
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