How did life start? No creationists please

[Anomalocaris]

I don't know. The Ulrey-Miller experiments in the early 50's fired electricity through what they thought was a prebiotic atmosphere and came up with amino acids and stuff.

But a comet/meteor impact would provide an energy boost on steroids compared to lightning.

Miller Urey experiment was interesting but now generally regarded as having taken origin of life research down the wrong path for 50 years. The simple insuperable problem is what they thought was a reasonable approximation of prebiotic atmosphere wasn't, and miller Urey experiment is impossible to duplicate in what is now regarded as what prebiotic atmosphere was really like.

There is also an enormous gap between amino acids and a self contained, self replicating organism. The idea that some massive zaps of energy would cause amino acids to climb up enormously steep thermal dynamic gradient and not fall back down is hard to swallow. There must be some sustained source of chemical and thermal energy, and even more importantly some very long lasting mechanism to contain and concentrate the results of the occasional thermodynamically possible but unlikely reactions for there to be progress. Otherwise the fruit of each rare and unlikely step towards life would dissipate long before circumstances and chance become favorable again for there to be the next step.

Hence the porous rocky accretions around energy and chemical rich Geothermal vents form such excellent candidates for the site of the actually origin of life.

---

Lately it seems that there have been breakthroughs along this line of investigation.

http://www.sciencedaily.com/releases/201...144326.htm


Again, the amount of energy released in an impact is mind-blowing.

Of course this all drives the creatards up a wall but then, what doesn't?

Do we need an external energy source? It seems that a young earth would be an extremely energetic one. Even now under the deeps of the ocean there is constant seismic and volcanic upheaval.

Once the seas had formed it would probably be only a matter of time before the right chemical reaction took place to produce an RNA chain capable of replicating.

As the earth seems to have been about 500 million years old before life started that, I would guess, is all the time needed.

An equally interesting question, of course, is why, about 3.5 billion years later multi-cellular life started in the Cambrian explosion.

Actually that is 2 questions - why did it take 3.5 billion years to happen and what caused it?

1. There are hints that life existed on earth 4.2 billion years ago. So life may have taken less than 300 million years to arise from the accretion of the earth. Since the earth during her first hundred million years and more must have been truly hellish place, and utterly inhospitable to any life, life may have in fact taken far less the 300 million years to arise starting from the first moment when earth's environment first became suitable for giving rise to life.

2. The notion that multicellular life arose with Cambrian explosion is wrong. As matter of fact, there was a diverse pre-Cambrian multicellular fauna called the ediacrean fauna that left a rich fossil legacy. But Before ediacrean fauna there were another 300 million years of clear trace fossil records of complex multicelluar animal life such as worm burrows, crawl marks, etc. More ambigious trace fossils suggests some mobile complex multicellular life may have existed over a billion years ago. All Cambrian explosion really represented was a major change in sea water chemistry that enabled the development and preservation of mineralized body parts, hence extensive preservation of actual body fossils. The fact the Arthropods at the very beginning of Cambrian explosion already possessed the full suite of highly evolved, specialized adaptive features that distinguish different branches of anthropod family tree down the ages to today, shows that not only did some form of complex animals exist before the Cambrian explosion, but specific forms of highly evolved complex animal life clearly distinguishable as belonging to still extent phyla, and directly ancesteral to existing classes and orders of those phyla, must have existed since before the Cambrian "explosion".