nubben Posted May 22, 2018 Share Posted May 22, 2018 I was wondering when scientist figured out when oxygen took a place in evolution. When did they know that oxygen was a byproduct before it was essential for life. At what time did they figure out that oxygen came later? 1 Link to comment Share on other sites More sharing options...
CharonY Posted May 22, 2018 Share Posted May 22, 2018 I am not sure I understand your main question. In fact, it seems that you are asking several, slightly related ones. Do you mean to ask when (historically) folks realized that Earth used to be anoxic? That is unrelated to evolution per se, as I would assume that the initial evidence was gathered from geological records and the timing of the origin is still subject to research. Another related discovery would be photosynthesis and, presumably, the role of cyanobacteria. Since the hypothesis was formed by a confluence of different discoveries, I am not sure whether one could pinpoint a specific time. Link to comment Share on other sites More sharing options...
nubben Posted May 22, 2018 Author Share Posted May 22, 2018 I am sorry for the bad question. What i am asking is when did biological experts first understand, when oxygen came after life. Eg when did the scietific communtiy come to a conclusion that life predated oxygen. I've just started to get into scientific questions so im not that good a writing the questions to get to the point of my thoughts. Link to comment Share on other sites More sharing options...
CharonY Posted May 22, 2018 Share Posted May 22, 2018 Well, there are several points when it became obvious as such, I am not sure there is a specific when. Considering that the timelines are still under investigation and the fact that the early hypotheses were formed due to a confluence of different findings, ranging from geological records, discovery of fossilized traces of cyanobacteria, to radiodating experiments etc. All these data together show a timeline that puts life prior to the oxygenation event on Earth as well as providing evidence of the biological origin. In addition, microbial discovery of tons of microbes living under anoxic conditions, further showed mechanisms on how early life may have looked like. If I had to guess, I would say that by the 50s at the latest it was probably widely accepted. But really, this is more a science history question rather than a science question. AFAIK it is just something that got accepted but did not have a specific publication associated with it that would give it a specific date (such as the publication of GR, for example). Part of it is also because many aspects are still speculative (due to the nature of the question) although it has a lot of supporting evidence. In that regard it is different from theoretical work, which has e.g. a strong basis in mathematics but sometimes lacks empirical evidence. Link to comment Share on other sites More sharing options...
studiot Posted May 22, 2018 Share Posted May 22, 2018 Read this book, Professor Beerling presents a genuine geological history of the Earth's atmosphere. https://www.amazon.co.uk/Emerald-Planet-changed-history-Landmark/dp/0199548145 Link to comment Share on other sites More sharing options...
mistermack Posted June 4, 2018 Share Posted June 4, 2018 On 5/22/2018 at 8:55 PM, nubben said: I was wondering when scientist figured out when oxygen took a place in evolution. When did they know that oxygen was a byproduct before it was essential for life. At what time did they figure out that oxygen came later? Free oxygen in the atmosphere or dissolved in water isn't essential for life. It's essential for some forms of life, but not others. Oxygen is highly reactive, so without being constantly replaced, there wouldn't be any oxygen in the air. It would react with materials in the environment and form stable compounds (oxides). Life involving photosynthesis is the only source of free oxygen in the air, so there's no way that oxygen in the air could come before life. Since we know that some forms of life can exist without oxygen, it's obvious that life came before oxygen. You can have life without oxygen, but not oxygen without life. 1 Link to comment Share on other sites More sharing options...
studiot Posted June 4, 2018 Share Posted June 4, 2018 4 minutes ago, mistermack said: Free oxygen in the atmosphere or dissolved in water isn't essential for life. It's essential for some forms of life, but not others. Oxygen is highly reactive, so without being constantly replaced, there wouldn't be any oxygen in the air. It would react with materials in the environment and form stable compounds (oxides). Life involving photosynthesis is the only source of free oxygen in the air, so there's no way that oxygen in the air could come before life. Since we know that some forms of life can exist without oxygen, it's obvious that life came before oxygen. You can have life without oxygen, but not oxygen without life. If you haven't come across stomatolites look here. https://en.wikipedia.org/wiki/Stromatolite Link to comment Share on other sites More sharing options...
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