Life on Earth 'surged three billion years ago as early animals learned how to use energy from the sun' - Life on Earth suddenly exploded into being around three billion years ago, according to a new study.
Scientists have studied ancient genes to paint a picture of our planet’s earliest inhabitants and believe the first life developed when microbes learned to use oxygen and energy from the sun to live.
Researchers from the Massachusetts Institute of Technology (MIT) studied 1,000 key genes that exist today and worked out how they evolved from the very distant past.
They created a ‘genomic fossil’ telling not only when genes came into being but also which ancient microbes possessed those genes.
Life on Earth suddenly surged as animals learned to how harvest the sun's energy
Their calculations show that around 27 per cent of all existing genes came into being between 3.3 and 2.8 billion years ago.
About 580 million years ago, life on Earth began a rapid period of change called the Cambrian Explosion, with a huge new range of lifeforms.
Fossils help palaeontologists chronicle the evolution of life since then, but drawing a picture of life during the 3 billion years that preceded the Cambrian Period is difficult, because the soft-bodied creatures of that period rarely left fossil imprints.
However, those early life forms did leave behind one abundant microscopic fossil: DNA.
Because all living organisms inherit their genomes from ancestral genomes, computational biologists at MIT reasoned that they could use modern-day genomes to reconstruct the evolution of ancient microbes.
They combined information from the ever-growing genome library with their own mathematical model that takes into account the ways that genes are inherited, swapped and lost over millions of years.
Scientists Eric Alm and Lawrence David have named this period the Archean Expansion.
Because so many of the new genes they identified are related to oxygen, Alm and David first thought that the emergence of oxygen might be responsible for the Archean Expansion.
Oxygen did not exist in the Earth's atmosphere until about 2.5 billion years ago when it began to accumulate, likely killing off vast numbers of anerobic life forms in the Great Oxidation Event.
'The Great Oxidation Event was probably the most catastrophic event in the history of cellular life, but we don't have any biological record of it,' says Alm.
The figure shows the evolution of gene families in ancient genomes across the Tree of Life. The sizes of the little pie charts scale with the number of evolutionary events in lineages, slices indicate event types: gene birth (red), duplication (blue), horizontal gene transfer (green), and loss (yellow). The Archean Expansion period (3.33 to 2.85 billion years ago) is highlighted in green.
Closer inspection, however, showed that oxygen-utilising genes didn't appear until the tail end of the Archean Expansion 2.8 billion years ago, which is more consistent with the date geochemists assign to the Great Oxidation Event.
Alm and David believe they've detected the birth of modern electron transport, the biochemical process responsible for shuttling electrons within cellular membranes.
Electron transport is used to breathe oxygen and by plants and some microbes during photosynthesis when they harvest energy directly from the sun. A form of photosynthesis called oxygenic photosynthesis is believed to be responsible for generating the oxygen associated with the Great Oxidation Event, and is responsible for the oxygen we breathe today.
The evolution of electron transport during the Archean Expansion would have enabled several key stages in the history of life, including photosynthesis and respiration, both of which could lead to much larger amounts of energy being harvested and stored in the biosphere.
'Our results can't say if the development of electron transport directly caused the Archean Expansion,' says David. 'Nonetheless, we can speculate that having access to a much larger energy budget enabled the biosphere to host larger and more complex microbial ecosystems.' ( dailymail.co.uk )
Scientists have studied ancient genes to paint a picture of our planet’s earliest inhabitants and believe the first life developed when microbes learned to use oxygen and energy from the sun to live.
Researchers from the Massachusetts Institute of Technology (MIT) studied 1,000 key genes that exist today and worked out how they evolved from the very distant past.
They created a ‘genomic fossil’ telling not only when genes came into being but also which ancient microbes possessed those genes.
Life on Earth suddenly surged as animals learned to how harvest the sun's energy
Their calculations show that around 27 per cent of all existing genes came into being between 3.3 and 2.8 billion years ago.
About 580 million years ago, life on Earth began a rapid period of change called the Cambrian Explosion, with a huge new range of lifeforms.
Fossils help palaeontologists chronicle the evolution of life since then, but drawing a picture of life during the 3 billion years that preceded the Cambrian Period is difficult, because the soft-bodied creatures of that period rarely left fossil imprints.
However, those early life forms did leave behind one abundant microscopic fossil: DNA.
Because all living organisms inherit their genomes from ancestral genomes, computational biologists at MIT reasoned that they could use modern-day genomes to reconstruct the evolution of ancient microbes.
They combined information from the ever-growing genome library with their own mathematical model that takes into account the ways that genes are inherited, swapped and lost over millions of years.
Scientists Eric Alm and Lawrence David have named this period the Archean Expansion.
Because so many of the new genes they identified are related to oxygen, Alm and David first thought that the emergence of oxygen might be responsible for the Archean Expansion.
Oxygen did not exist in the Earth's atmosphere until about 2.5 billion years ago when it began to accumulate, likely killing off vast numbers of anerobic life forms in the Great Oxidation Event.
'The Great Oxidation Event was probably the most catastrophic event in the history of cellular life, but we don't have any biological record of it,' says Alm.
The figure shows the evolution of gene families in ancient genomes across the Tree of Life. The sizes of the little pie charts scale with the number of evolutionary events in lineages, slices indicate event types: gene birth (red), duplication (blue), horizontal gene transfer (green), and loss (yellow). The Archean Expansion period (3.33 to 2.85 billion years ago) is highlighted in green.
Closer inspection, however, showed that oxygen-utilising genes didn't appear until the tail end of the Archean Expansion 2.8 billion years ago, which is more consistent with the date geochemists assign to the Great Oxidation Event.
Alm and David believe they've detected the birth of modern electron transport, the biochemical process responsible for shuttling electrons within cellular membranes.
Electron transport is used to breathe oxygen and by plants and some microbes during photosynthesis when they harvest energy directly from the sun. A form of photosynthesis called oxygenic photosynthesis is believed to be responsible for generating the oxygen associated with the Great Oxidation Event, and is responsible for the oxygen we breathe today.
The evolution of electron transport during the Archean Expansion would have enabled several key stages in the history of life, including photosynthesis and respiration, both of which could lead to much larger amounts of energy being harvested and stored in the biosphere.
'Our results can't say if the development of electron transport directly caused the Archean Expansion,' says David. 'Nonetheless, we can speculate that having access to a much larger energy budget enabled the biosphere to host larger and more complex microbial ecosystems.' ( dailymail.co.uk )
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