Of carbon-based life on Earth, beginning with the birth of the Solar The following chronology describes important stages in the development On distant planets? Potential guides to the development ofĬarbon-based life on other planets in the Solar System or aroundĬontinuously changing nature and types of lifeĪnd environmental conditions on Earth that reflect Life on land? What can be observed as signs of carbon-based life Temperatures, or in oxygen poor and carbon dioxide or methane richĮnvironments? How long did it take before large plants and animals Or moon forms around a star like our Sun,Ĭan such life survive and flourish in extremely hot and cold Life likely to develop soon after a hospitable inner rocky planet (carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus)Īnd the presence of liquid water, which is often described as “The result hints towards the possibility that oxygenic photosynthesis, the process that have produced all oxygen 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,” he said.Most known Earth-type life depends on six essential elements “This is the first time that anyone has tried to time the evolution of the photosystems,” said Cardona. This means there must have been predecessors, such as early bacteria, that have since evolved to carry out anoxygenic photosynthesis instead. This is also long before cyanobacteria – microbes that were thought to be the first organisms to produce oxygen – existed. 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. 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, Cardona could work out when oxidative photosynthesis first occurred. Oxygenic and anoxygenic photosynthesis both use an enzyme called Photosystem I. 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. Oxygenic photosynthesis uses light energy to split water molecules, releasing oxygen, electrons and protons.Īnoxygenic photosynthesis use compounds like hydrogen sulphide or minerals like iron or arsenic instead of water, and it does not produce oxygen. There are two types of photosynthesis: oxygenic and anoxygenic. Photosynthesis is the process that sustains complex life on earth – all of the oxygen on our planet comes from photosynthesis. “What allowed microbes to escape the cradle where life arose and conquer every corner of this world, more than 3 billion years ago,” he said. “It may have been that the early availability of oxygen was what allowed microbes to diversify and dominate the world for billions of years,” he said. “The process that sustains almost all life on earth today may have been doing so for a lot longer than we think,” said Cardona. 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. The study, published in the journal Heliyon, can help solve the controversy around when organisms started producing oxygen – something that was vital to the evolution of life on earth, said Tanai Cardona, from ICL. Researchers from Imperial College London (ICL) in the UK studied the molecular machines responsible for photosynthesis and found the process may have evolved as long as 3.6 billion years ago. The findings show that cyanobacteria may not have been the earliest oxygen-producing microbes which means oxygen was available for living organisms very close to the origin of life on earth. London: Ancient microbes may have been producing oxygen through photosynthesis as long as 3.6 billion years ago – a billion years earlier than thought, a study has found.
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