How life started on Earth (Fun Fact)

[Kurt_and_Hunter]

You know those old experiments where they zapped an approximation of the early ocean to see if energy from cosmic rays, lightening, geothermal, etc. could create complex organic molucules...

They did create some organic molocules but nothing like life... it really does seem impossible for that "lightening striking a tidal pool" model to lead to much. The odds of lots of interesting things happening in a tidal pool at just the right moment are so long as to barely be odds at all.

In nature, any big organic molecules you get through chance disappear too fast to plausibly run into other complex molecules to have the necessary trillions of happy accidents.

But (this is so cool) our perspective on the question is distorted by the fact that life already exists. We don't think of sea water as likely to spontaneously produce life because it couldn't possibly do so today.

The reason the earth's oceans today are not full of free-floating complex organic molecules is that living things in the water eat them as soon as they show up.

Before bacteria and such existed these happy-accident molecules survived pretty well and the whole ocean was a soup of carbon-based chemical activity.

So the chemical/evolutionary calculating engine we are talking about isn't a tidal pool one afternoon. It is the ocean getting more and more full of complicated molecules for a billion years.

[stevedeshazer]

Silly me. And here I thought God created it all in six days and watched football on Sunday.

:facepalm:

[BrklynLiberal]

6. right...That is the way most of the newest Congress critters will see it.

[Warpy]

1. Primordial ooze

was a pool full of carbon and mineral compounds in a hot and highly charged atmosphere with frequent lightning. Lab experiments in exactly those conditions produced complex amino acids and strings of RNA and DNA within days, not years, surprising the hell out of the researchers who did the experiments some 30 years ago.

There is a school of thought that says life is an artifact of planets, that any planet that isn't hot enough to incinerate proteins will form at least primitive life to exploit its conditions.

To think either that we are alone in the universe or that we're the end point of some evolutionary climb is ridiculous.

[Kurt_and_Hunter]

3. Amino acids, yes. RNA and DNA, no.

DNA could not be spontaneously generated -- it is a very complex product of evolution. Same for RNA.

The earliest genetic-like molecules would have been pretty simple... just barely enough to facilitate replication with some crude ability to retain traits.

Once you get some sort of smart replication method up and running it isn't what we'd call life, but it offers a path to life. It can evolve.

[Odin2005]

10. Once a evolvable system of chemical reactions develops things start happening very fast.

There is evidence of photosynthetic life as early as 3.85 billion years ago, in the form of isotopes in organic material in rocks of Isua, Greenland. Photosynthesis leaves a distinctive signature in the isotope abundances of carbon. In the same way we can tell that methanogenic Archaea evolved at least 2.7 billion years ago. Chemical fossils of steroid compounds (such as cholesterol), indicative of cells with nuclei, appear soon after, indicating that the Neomura (the Archaea-Eucarya group) emerged from bacterial ancestors around 2.8 billion years ago

[denbot]

2. It wasn't one pool.

There was the entire surface of a newly formed planet. This surface was fractured, giving it geometrically greater surface area. Tiny molecules interacting hundreds of trillions of times per cubic meter, per second, spread over the entire planet.

This initial spark/s of life hardly occurred in a tiny little beaker, and at least to me does not suggest a lack of numbers for "happy accidents.

[Odin2005]

9. the planet was pretty much completely ocean then, and much more volcanically active.

The whole early ocean was one giant organics lab. Hydrothermal vents, asteroid and comet impacts, lightning, UV light, tides (the Moon was much closer then and the tides bigger), etc.

[WillyT]

4. Miller–Urey Experiment

Link: http://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment



:hi:

[Kurt_and_Hunter]

5. Which Darwin anticipated. (Scary!!!)

In Dawkin's THE ANCESTOR'S TALE he has little Darwin quotes at the beginning of the chapters and many are down-right scary.

In one footnote Darwin tossed off the idea of electricity and ammonia and such as the sort of thing that maybe somebody ought to experiment with. (About 40 years before Miller–Urey, IIRC)

Scary dude.

[AlecBGreen]

7. they have found complex organic molecules in space

IIRC they have also found some of the simpler amino acids out there too

http://www.space.com/scienceastronomy/060808_st_life_molecules.html


http://4.bp.blogspot.com/_JcxonRkmibQ/THmIDMr0IbI/AAAAAAAACzo/yRikDq8vzwk/s640/HIFI+Spectrum+of+Organic+Molecules+in+the+Orion+Nebula.jpg

[Odin2005]

8. Many suspect that life can arise in only a few million years given the right conditions.

all it takes is the development of ONE system of chemical reactions that develops some kind of rudimentary genentic system within it and thing will snowball rapidly.

[Control-Z]

11. I wonder if Free Republic

has EVER had a thread/discussion like this.

Somehow I don't think so.