Story Source: Materials provided by Elsevier. Journal Reference : Tanai Cardona. Early Archean origin of heterodimeric Photosystem I. Heliyon , ; 4 3 : e DOI: ScienceDaily, 6 March Photosynthesis originated a billion years earlier than we thought, study shows. Retrieved November 11, from www. Their evolution dramatically changed the Earth allowing oxygen to accumulate into the atmosphere for the first time ScienceDaily shares links with sites in the TrendMD network and earns revenue from third-party advertisers, where indicated.
Print Email Share. Boy or Girl? You Need a Chickadee Brain. Living Well. View all the latest top news in the environmental sciences, or browse the topics below:. Keyword: Search. The finding could change ideas of how and when complex life evolved on Earth, and how likely it is that it could evolve on other planets.
Oxygen in the Earth's atmosphere is necessary for complex forms of life, which use it during aerobic respiration to make energy. The levels of oxygen dramatically rose in the atmosphere around 2. Some scientists think that 2. Other scientist think that cyanobacteria evolved long before 2. Cyanobacteria perform a relatively sophisticated form of oxygenic photosynthesis -- the same type of photosynthesis that all plants do today.
It has therefore been suggested that simpler forms of oxygenic photosynthesis could have existed earlier, before cyanobacteria, leading to low levels of oxygen being available to life.
Now, a research team led by Imperial College London have found that oxygenic photosynthesis arose at least one billion years before cyanobacteria evolved. Their results, published in the journal Geobiology , show that oxygenic photosynthesis could have evolved very early in Earth's 4.
Lead author Dr Tanai Cardona, from the Department of Life Sciences at Imperial, said: "We know cyanobacteria are very ancient, but we don't know exactly how ancient.
If cyanobacteria are, for example, 2. It suggests that it might not take billions of years for a process like oxygenic photosynthesis to start after the origin of life. If oxygenic photosynthesis evolved early, it could mean it is a relatively simple process to evolve.
The probability of complex life emerging in a distant exoplanet may then be quite high. It is difficult for scientists to figure out when the first oxygen-producers evolved using the rock record on Earth. The older the rocks, the rarer they are, and the harder it is to prove conclusively that any fossil microbes found in these ancient rocks used or produced any amount of oxygen.
Instead, the team investigated the evolution of two of the main proteins involved in oxygenic photosynthesis. It's hard to keep oxygen molecules around, despite the fact that it's the third-most abundant element in the universe, forged in the superhot, superdense core of stars.
That's because oxygen wants to react; it can form compounds with nearly every other element on the periodic table. So how did Earth end up with an atmosphere made up of roughly 21 percent of the stuff? The answer is tiny organisms known as cyanobacteria, or blue-green algae. These microbes conduct photosynthesis : using sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen. In fact, all the plants on Earth incorporate symbiotic cyanobacteria known as chloroplasts to do their photosynthesis for them down to this day.
For some untold eons prior to the evolution of these cyanobacteria, during the Archean eon, more primitive microbes lived the real old-fashioned way: anaerobically. These ancient organisms—and their " extremophile " descendants today—thrived in the absence of oxygen, relying on sulfate for their energy needs.
But roughly 2. At roughly the same time and for eons thereafter , oxidized iron began to appear in ancient soils and bands of iron were deposited on the seafloor, a product of reactions with oxygen in the seawater. It took up residence in atmosphere around 2.
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