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13

So earth is estimated to be around 4.5 billion years old, and life has existed for about 3.4-3.9 billion years of that, around >75% the time. For a little perspective, Homo sapiens have been around for up to ~250,000 years, just 0.00005% of the time earth has existed. In that time the earth has changed massively, early earth was pretty hostile, but that ...


8

Short answer Before the RNA world, mineral surfaces may have facilitated the prebiotic containment and organization of biomolecules. Minerals are believed to have promoted the transition from a dilute chaotic prebiotic “soup” to highly ordered local domains rich in key biomolecules. Background As pointed out by others, the transition from a hereditary DNA ...


3

If you're willing to accept many orders of magnitude and define life as the Last Universal Common Ancestor. For the rest of this answer, life begins 3.5 Gya with cyanobacterial mats and stromatolites and so on. Genetically the LUCA is dated to around this time, which matches the fossil record and everything's great. The LUCA can't have sprung from ...


3

You can do without DNA, you need RNA to make proteins. Living organisms create and maintain a bubble that is very far removed from thermal equilibrium. So, you can speculate that at the origin of life, conditions existed where processes that are far from thermal equilibrium could still occur naturally without the support structures one finds inside living ...


1

Our understanding of how life began on earth has indeed advanced substantially since Haldane, Oparin, Miller, and Urey. To learn about the latest ideas, I can't think of a better place to start than this excellent video series with Nobel Laureate Jack Szostack, who is currently doing some of the leading work on the subject.


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This question has actually been covered (although not to the complete extent of evolutionary history) by Richard Dawkins in his book The Ancestor's Tale. He gives the following estimates of LUCA time and generations: Monkeys and apes: 40MY(3M) Mammals: 180MY(120M) Reptiles: 310MY(170M) Ray finned fish: 440MY(195M) Sharks, hagfish and lampreys: ...



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