The oxygen in the Earth's atmosphere is essential for complex life, which uses it as a vigorous breath to create viability.
The oxygen level drastically raised the climate for about 2.4 billion years, but why it happened, it's been discussed. Some researchers believe that 2.4 billion years ago, when initially created creatures called blueberries, which could have oxygen-containing (oxygen) photosynthesis.
Other scientists believe that blueberries evolved already 2.4 billion years ago, but something prevented the accumulation of oxygen in the air.
Oxidised photosynthesis appeared at least one billion years before the development of blueberries in a new study by the London Imperial College. Their results indicate that oxygen synthesis could have developed in the very early Earth's 4.5 billion years history.
According to scientists, the discovery could change ideas about how and when complex life developed on Earth, and as much as possible, that it could develop on other planets.
Lead author Dr. Tanai Kardona of the Imperial Department of Life Sciences said: "We know the blueberries are very old, but we do not know exactly how old they are. If blue bacteria are 2.5 billion years old, for example, that would mean that oxygen photosynthesis could begin already before 3.5 billion years, which suggests that it could take billions of years for a process such as oxygen photosynthesis to begin after the start of life. "
During the study, the researchers studied the development of two major proteins involved in oxygen synthesis.
During the first phase of photosynthesis, lightning strings use light energy to split water in protons, electrons and oxygen using a protein set called PhotoSystem II.
Photosystem II consists of two proteins called D1 and D2. Initially, both proteins were equivalent, but despite the fact that they are essentially the same as the structures, at present, their fundamental genetic findings are different.
This shows that D1 and D2 have evolved independently – they simply produce 30 per cent of their genetic sequences in pollen and plants. Indeed, even in their original form, D1 and D2 would have been able to capture photosynthesis of oxygen, thus figuring out to what extent they could not be distinguished before it was discovered when this power was originally created.
To find out how much time difference between D1 and D2 is 100% identical and equal to 30% among blue-green algae and plants, the team determined how fast the protein changes – their evolutionary velocity. Using strong statistical methods and known events in the development of photosynthesis, they found that D2 and D2 proteins Fotosystem II developed very slowly – even slower than some of the oldest proteins in biology, which are considered to be early life.
From this, they calculated that the time between the identical D1 and D2 proteins and 30% similar versions of blueberries and plants is at least a billion years and may be greater than that.
Dr. Cardona said: "Oxygen photosynthesis and blueberries usually appear to be the same. So, to find out when oxygen was first produced, researchers were trying to find when the blue-green algae first developed."
"Our study suggests that oxygen photosynthesis probably started long before the emergence of the youngest predecessor of the cyanobacter, which is consistent with current geological data that suggests oxygen oxygen was accumulated three billion years ago."
Scientists are now trying to reinstate what the background system looked like before D1 and D2 evolved first. Using the known variation in the genetic code of the photosystem in all species living today, they try to combine the genetic code of the predecessor photographic system.
They have published their story in the journal Geobiology.