Photosynthesis more ancient than thought

[Plazma Inferno!]

Photosynthesis sustains life on Earth today by releasing oxygen into the atmosphere and providing energy for food chains. The rise of oxygen-producing photosynthesis allowed the evolution of complex life forms like animals and land plants around 2.4 billion years ago.
However, a new study by an Imperial researcher suggests that the first type of photosynthesis did not produce oxygen. It was known to have first evolved around 3.5-3.8 billion years ago, but until now, scientists thought that one of the groups of bacteria alive today that still uses this more primate photosynthesis was the first to evolve the ability.
A more ancient bacteria, that probably no longer exists today, was actually the first to evolve the simpler form of photosynthesis, and that this bacteria was an ancestor to most bacteria alive today.
This primitive form of photosynthesis is known as anoxygenic photosynthesis, which uses molecules such as hydrogen, hydrogen sulfide, or iron as fuel -- instead of water.

https://www.sciencedaily.com/releases/2016/03/160315104148.htm

 

[Walter L. Wagner]

Photosynthesis sustains life on Earth today by releasing oxygen into the atmosphere and providing energy for food chains. The rise of oxygen-producing photosynthesis allowed the evolution of complex life forms like animals and land plants around 2.4 billion years ago.
However, a new study by an Imperial researcher suggests that the first type of photosynthesis did not produce oxygen. It was known to have first evolved around 3.5-3.8 billion years ago, but until now, scientists thought that one of the groups of bacteria alive today that still uses this more primate photosynthesis was the first to evolve the ability.
A more ancient bacteria, that probably no longer exists today, was actually the first to evolve the simpler form of photosynthesis, and that this bacteria was an ancestor to most bacteria alive today.
This primitive form of photosynthesis is known as anoxygenic photosynthesis, which uses molecules such as hydrogen, hydrogen sulfide, or iron as fuel -- instead of water.

https://www.sciencedaily.com/releases/2016/03/160315104148.htm

very interesting. i was unaware of this.

not mentioned if 'modern' oxygenic photosynthetic ability derived from this, or arose independently. i suspect it was a variant on this that became dominant. are the modern bacteria, then, descendants of this lineage, but having lost the anoxygenic photosynthsis? i believe that is what the article suggests.

 

[Daecon]

My Chemistry knowledge isn't as good as it used to be when I was in school, what could hydrogen sulfide or iron be converted into as a form of fuel?

 

[timojin]

[QUOTE="Plazma Inferno!,.
This primitive form of photosynthesis is known as anoxygenic photosynthesis, which uses molecules such as hydrogen, hydrogen sulfide, or iron as fuel -- instead of water.

https://www.sciencedaily.com/releases/2016/03/160315104148.htm[/QUOTE]
So what was synthesized and what kind of organism was it , was it organic , must be, . So how did this organism got ribose without plant photosynthesis

 

[exchemist]

My Chemistry knowledge isn't as good as it used to be when I was in school, what could hydrogen sulfide or iron be converted into as a form of fuel?

Yes, good point. I looked this up and found something very simple to explain what happens, called the van Niel equation:

H₂A + CO₂ +hν -> (CH₂O) + H₂O + 2A. In this, (CH₂O) represents a unit of carbohydrate synthesis. A represents some oxidisable species.

If A is O, then you get classical aerobic photosynthesis. But in the case of green sulphur and purple sulphur bacteria, A is S. So these bacteria take hydrogen sulphide and use light to generate the same carbohydrate, releasing elemental sulphur as a byproduct instead of oxygen. A in some cases is apparently nothing at all, i.e. there are bacteria that use hydrogen gas - though where they get it from is another question.

The common feature is carbon dioxide - the "fixing" of this by partial reduction to carbohydrate seems to be the synthetic end product in all cases, if I understand what I have read correctly. But I do not know what the respiration of these bacteria involves, i.e. whether they use carbohydrate as fuel, in combination with oxygen, or just as a building block.

Maybe a biologist can comment.