Photosynthesis originated a billion years earlier than we thought, study shows

March 6, 2018, Elsevier
The crystal structure of Photosystem I (PDB ID: 1JB0). Credit: Elsevier

Ancient microbes may have been producing oxygen through photosynthesis a billion years earlier than we thought, which means oxygen was available for living organisms very close to the origin of life on earth. In a new article in Heliyon, a researcher from Imperial College London studied the molecular machines responsible for photosynthesis and found the process may have evolved as long as 3.6 billion years ago.

The author of the study, Dr. Tanai Cardona, says the research can help to solve the controversy around when organisms started producing oxygen - something that was vital to the evolution of on earth. It also suggests that the microorganisms we previously believed to be the first to produce oxygen - cyanobacteria - evolved later, and that simpler bacteria produced oxygen first.

"My results mean that the process that sustains almost all life on earth today may have been doing so for a lot longer than we think," said Dr. Cardona. "It may have been that the early availability of oxygen was what allowed microbes to diversify and dominate the world for billions of years. What allowed microbes to escape the cradle where life arose and conquer every corner of this world, more than 3 billion years ago."

Photosynthesis is the process that sustains complex life on earth - all of the oxygen on our planet comes from photosynthesis. There are two types of photosynthesis: oxygenic and anoxygenic. Oxygenic photosynthesis uses light energy to split water molecules, releasing oxygen, electrons and protons. Anoxygenic photosynthesis use compounds like hydrogen sulfide or minerals like iron or arsenic instead of water, and it does not produce oxygen.

Previously, scientists believed that anoxygenic evolved long before oxygenic photosynthesis, and that the earth's atmosphere contained no oxygen until about 2.4 to 3 billion years ago. However, the new study suggests that the origin of oxygenic photosynthesis may have been as much as a billion years earlier, which means would have been able to evolve earlier too.

A culture of Synechocystis sp. PCC 6803, a type of unicellular Cyanobacteria. Credit: Elsevier

Dr. Cardona wanted to find out when oxygenic photosynthesis originated. Instead of trying to detect oxygen in ancient rocks, which is what had been done previously, he looked deep inside the that carry out photosynthesis - these are complex enzymes called photosystems. Oxygenic and anoxygenic photosynthesis both use an enzyme called Photosystem I. The core of the enzyme looks different in the two types of photosynthesis, and by studying how long ago the genes evolved to be different, Dr. Cardona could work out when oxidative photosynthesis first occurred.

He found that the differences in the genes may have occurred more than 3.4 billion years ago - long before oxygen was thought to have first been produced on earth. This is also long before cyanobacteria - microbes that were thought to be the first organisms to produce oxygen - existed. This means there must have been predecessors, such as early bacteria, that have since evolved to carry out anoxygenic photosynthesis instead.

"This is the first time that anyone has tried to time the evolution of the photosystems," said Dr. Cardona. "The result hints towards the possibility that oxygenic photosynthesis, the process that have produced all on earth, actually started at a very early stage in the evolutionary history of life - it helps solve one of the big controversies in biology today."

One surprising finding was that the evolution of the photosystem was not linear. Photosystems are known to evolve very slowly - they have done so since cyanobacteria appeared at least 2.4 billion years ago. But when Dr. Cardona used that slow rate of evolution to calculate the origin of , he came up with a date that was older than the itself. This means the photosystem must have evolved much faster at the beginning - something recent research suggests was due to the planet being hotter.

"There is still a lot we don't know about why life is the way it is and how most biological originated," said Dr. Cardona. "Sometimes our best educated guesses don't even come close to representing what really happened so long ago."

Dr. Cardona hopes his findings may also help scientists who are looking for life on other planets answer some of their biggest questions.

Explore further: Photosynthesis more ancient than thought, and most living things could do it

More information: Tanai Cardona, Early Archean origin of heterodimeric Photosystem I, Heliyon (2018). DOI: 10.1016/j.heliyon.2018.e00548

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11 comments

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FredJose
1 / 5 (4) Mar 07, 2018
But when Dr. Cardona used that slow rate of evolution to calculate the origin of photosynthesis, he came up with a date that was older than the earth itself.

...therefore the logical conclusion, no matter how absurd, follows.
"There is still a lot we don't know about why life is the way it is and how most biological process originated," said Dr. Cardona. "Sometimes our best educated guesses don't even come close to representing what really happened so long ago."
Might be best to simply say you have absolutely no clue.

The process of photosynthesis is so irreducibly complex there's no snowball's chance in hell that it could have happened by accident. Besides which it seems to involve a quantum entanglement to transfer the captured energy at room temperature. This is just NOT going to happen by some happy random chemical event. Only Someone with the right knowledge and tools could have set it up. On purpose. ALL life depends on the results produced by it.
IwinUlose
2.6 / 5 (8) Mar 07, 2018
... irreducibly complex...


Flagellum.
forumid001
4.3 / 5 (6) Mar 07, 2018
One of the proudest achievements of humans is that we have found that the complex organs such as human brain or gigantic systems such as the universe could be formed without resorting any supernatural acts.
humy
5 / 5 (6) Mar 07, 2018
Science has shown there isn't such thing in nature as irreducibly complex.
The religious-nut irreducible complexity hypotheses makes a prediction that if you have any one component taken away then the whole will not function.
And yet we observe examples of photosynthesis, flagellum, eyes etc in primitive forms of life that have one or even several less parts than those in more advanced life forms and yet they function just fine thus proving irreducible complexity false.

For example, in the case of flagellum;
http://www.miller...cle.html
TheGhostofOtto1923
5 / 5 (4) Mar 07, 2018
Phred the phact phobe opines;
Might be best to simply say you have absolutely no clue
What can you say about the arrogance of the typical religionist who chooses to ignore evidence that even he must admit his own god left for him to find?

God tempts us in order to test our faith, says phred. God lies to phred in order to find out how much phred trusts him, says us.

Phreds religion conditions him to accept lies as fact and then encourages him to make up his own.

No sin too egregious in defending the faith, eh phred? Including self-deception, perhaps the foulest of all-
jonesdave
3.3 / 5 (7) Mar 07, 2018
Without having read the paper, I wonder how this compares with dating of red beds and Banded Iron Formations? The previous dating of substantial O2 in the atmosphere was, I thought, based on the fact that O2 couldn't build up as long as Fe was taking it up in the oceans, and laying down these beds. It was only after the Fe had been used up by combining with O, that it was possible to build up substantially in the atmosphere.
Nonlin_org
1 / 5 (4) Mar 07, 2018
How do you even "study how long ago the genes evolved to be different"?

These are just bad models with bad assumptions that spit out nonsensical results.
Evolutionary astrology at its worst.
Parsec
5 / 5 (3) Mar 08, 2018
How do you even "study how long ago the genes evolved to be different"?

These are just bad models with bad assumptions that spit out nonsensical results.
Evolutionary astrology at its worst.


You ask a question answered in most rudimentary college genetics classes. Then you posit an answer best described as woefully ignorant. You not doing anything good for your reputation trying to make political and nonsensical responses to scientific articles.
Nonlin_org
1 / 5 (2) Mar 08, 2018
How do you even "study how long ago the genes evolved to be different"?

These are just bad models with bad assumptions that spit out nonsensical results.
Evolutionary astrology at its worst.


You ask a question answered in most rudimentary college genetics classes. Then you posit an answer best described as woefully ignorant. You not doing anything good for your reputation trying to make political and nonsensical responses to scientific articles.

Have you ever built a scientific model? Do you know what it takes to do that?
"Genetic clock" is BS if that's what you refer to. Rudimentary genetics classes are for rudimentary people that believe the evolutionary pseudo-science and are incapable of questioning the nonsense.
TheGhostofOtto1923
5 / 5 (1) Mar 11, 2018
You ask a question answered in most rudimentary college genetics classes. Then you posit an answer best described as woefully ignorant
His question is really an answer. He doesnt want to know how.

That's the way godders think.
Nonlin_org
not rated yet Mar 12, 2018
You ask a question answered in most rudimentary college genetics classes. Then you posit an answer best described as woefully ignorant
His question is really an answer. He doesnt want to know how.

That's the way godders think.

Why don't you wait until you have something to say? Like, I don't know... a valid argument? Something intelligent?

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