How did life on Earth get started?

I know about the 'primordial soup', the procaryotic and eucaryotic cells and ultra violet radiation. anything else? life from other planets ending up here? Or from Mars, etc? By the way, this is NOT a religious question so no rubbish about God creating it.

How did life on Earth get started?
Most people are aware of the main theory about how the Earth formed 4.6 billion years ago. There is also evidence of a major asteroid bombardment on the moon 3.8 to 4 billion years ago. It must have affected the Earth even more and wiped out any life that may have existed. There is evidence of stromatolites 3.5 billion years old. Stromatolites are blue green algae that deposit stone in successive layers. Their oxygen is also thought responsible for precipitating the iron out of the early ocean that is the source of nearly all the worlds iron ore deposits so the evidence is pretty good. That gives a pretty good time frame for when life probably began, sometime after 4 billion years ago.



The stromatolites exist today but they aren't thought to be the first life on Earth. It is likely they evolved photosynthesis building on more primitive systems which used hydrogen sulfide to reduce organic compounds and power their metabolism. How life began before that and evolved into those "primitive" bacteria isn't known exactly because life can incorporate all the hydrocarbons so they essentially erased any previous evidence. They appeared so early that little evidence would be likely for the more primitive life that must have evolved into them.



The first life could have taken up several different strategies but the most efficient ones eventually took over. It is likely they consisted of some sort of self replicating chemicals or system. Very complex molecules could be formed by UV, lighting, pressure, heat, asteroid strikes and time. One of the self replicating systems probably started using RNA in much the same way that modern life uses proteins. There are a few RNA molecules in modern life that retain some enzymes built of RNA. I think it was only natural to expand on that so other molecules were added to the RNA. Amino acids were eventually added and cleaved off to make proteins. Amino acids were used because they fit on the RNA molecules. The RNA then adopted the role of template for new protein molecules. Enzymes evolved that enhanced that role. This allowed evolution a much more efficient system and the number of amino acids expanded until the number used by all life was reached. That gave these lifeforms, more primitive than anything today, all the tools they needed to replace nearly all their chemical systems with proteins or enzymes with a very efficient means of evolution. RNA wasn't stable enough so DNA was eventually used for permanent storage of the RNA template. From that point, there really isn't any great mystery or scientific controversy how life evolved.
Reply:Vegetative life started at the bottom of the ocean, on the edge of underwater "volcanoes", where the cool water mixed with the super-heated geo-thermal vents, causing a primordial slime to begin to grow in the dark, some 3-4 Billion years ago!



One Billion years later, this slime eventually mutated into a creature which had half the properties of a plant, and half the properties of an animal. It could breathe either oxygen or carbon dioxide...



Another Billion years later, the first sea animal came into existence, which exclusively operated on oxygen, while eliminating carbon dioxide...



One Billion years ago, the Sea Sponge was born, and that simple animal, that we use to scrub our backs, and clean our sinks, is the common ancestor of all marine and land animals today!
Reply:In not wanting a religious answer you have eliminated the only logical option. The chances of chemicals and energy making life without intelligent input is next to nothing. If you wanted to know the origin of computers, but did not want to invoke man, you will never find the answer.



I think that it is odd that people will believe a natural explanation, even if it logically absurd. However, they disregard any explanation that involves the supernatural regardless of how logical it is.
Reply:Why is it rubbish to say that God created it!



It is utterly unscientific to rule out one possibility before you start!



To claim that life arose from non-life is a religious position in itself - requiring a great deal of faith, since it contradicts all known scientific principles.
Reply:You shouldn't be so closed-minded...there's no proof that some invisible flying god DIDN'T invent life here. Doesn't matter to me, really, because how life got here doesn't matter. It's not important. What we're doing while we're here, is.



Personally, if I gave it any thought, I'd like to think we're an alien experiment, put here by some master race from another planet, to see how long we exist before eradicating ourselves. Then when they get bored, they'll send a Giant Meteor thisaway to see how we cope with impending doom. That would be cool.
Reply:Oparin and Woese had some theories about how life got started from the "primordial soup" but no one has succeeded so far in "creating life" in the laboratory. It is a mystery and a difficult one.
Reply:No one entirely knows; there are some hypotheses out there, but they haven't yet nailed down the likeliest one.



You might find some info at these links:



http://evolution.berkeley.edu/



http://www.newscientist.com/channel/life...
Reply:ALLAH
Reply:If you call God rubbish, you have no chance of getting to Heaven.
Reply:jesus!

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