New evidence emerges on the origins of life

Discussion in 'Biology & Genetics' started by paddoboy, Jun 1, 2015.

  1. spidergoat Liddle' Dick Tater Valued Senior Member

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    There is no time-line problem with Earth-based abiogenesis.
     
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  3. Vegasprof Registered Member

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    7
    Which way does William of Ockham's razor tell us to go? We have to accept one of three difficult possibilities.
    a) Evolution was greatly speeded up.
    b) Transpermia.


    Terrestrial abiogenesis has been the scientific consensus since, well, since people first asked the question thousands of years ago.
    I claim that it still is the scientific consensus, just as it was the scientific consensus that Wegner's continental drift theory was wrong,
    and it was (in Galilleo's time) the scientific consensus that the Sun orbits the Earth, and, in Pasteur's time that maggots just appear
    in rotting meat.

    Are you aware of the fact that Galilleo had no proof that the Earth orbits the Sun, although he desperately wanted it?

    Most scientists who express opinions about this subject agree with you, spidergoat. But I claim that they will be proved wrong.
    The first step of the proof will be the confirmation that life, or the fossilized remains of life, in the Solar system belong to the same "tree of life" as
    living things on the Earth. It will be a long time before transpermia to and from other systems will be confirmed, but it will be.

    By the way, it was a lecture by JW Schopf that turned me from terrestrial abiogenesis to transpermia.
     
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  5. spidergoat Liddle' Dick Tater Valued Senior Member

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    There's just no need for it. The deep oceans or cracks in rock deep underground could have harbored life even when the surface conditions on Earth seemed unfavorable to life as we know it. Did you know that the entirety of the Earth's surface was vaporized after life evolved, and it still survived to repopulate the planet because you can't very easily vaporize rock to a mile down.
     
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  7. wellwisher Banned Banned

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    5,160
    The theory of life beginning elsewhere, only passes the buck. It does conceptually solve how life appears on earth, which makes it a tempting theory. However, it does not explain how that life began. All this does is perpetuate a random approach, with life reaching the earth as an alien jackpot. This theory also adds new questions, such as where is the elsewhere, where the alien life began? Science can't seem to find life friendly places, close, which if they could form life http earth, should be ahead of us now. How did that life get into space, survive a long space journey, survive the solar radiation of the our sun as it approached earth, survive the hot fiery descent through the earth's atmosphere, and the finally survive a violent impact and still come out ticking ready to go to town?

    The Miller experiment showed one can make amino acids, sugars, oils and tars, from simple gases and water subjected to an electric spark. All these materials are favored in a low oxygen atmosphere which is consistent with what science says was the early earth. The early earth was hot, with constant storms, because of the evaporation and condensation of water into and out of the dense atmosphere. This movement of the boiling and steamy water into the atmosphere, cools the steam, so it condenses, and then rains to the earth. This helps cool the earth faster than only radiational cooling of solid surface materials.

    Water has a large heat capacity, such that even if we have the earth bombarded with asteroids, the boiling point of water will buffer the surface water temperature to near 100C; unless the pressure and salt concentration was higher. Most of the precursors materials have higher boiling points than 100C, and will be protected by the water against vaporization and will accumulate. Without significant oxygen to oxidize they last longer.

    One wild card was the moon. If the earth and moon were forming together, and the earth had the lion's share of water, the earth would be cooling faster than the moon, due to the high heat capacity and convection of the water; stream to rain. What would eventually happen is the moon would stay hotter longer, and begin to "relative", radiate IR heat, like a hot spot in the sky, circling the cooler earth, while pulling tidal effects.

    The moon would eventually become a moving hot spot, that circles the cooler earth, acting like a huge moving evaporator that circles the earth. This will add horizontal convection to the earth's atmosphere, between the opposite sides of the earth and moon, with the clouds flowing toward the moving cool zone opposite the moon. This is a more favorable second round of the Miller Experiment, with the precursors flow into the cooler water,then heating, cooling, heating, cooling, as the moon passes and the rain follow.
     
  8. wellwisher Banned Banned

    Messages:
    5,160
    The theory of life beginning elsewhere, only passes the buck. It does conceptually solve how life appears on earth, which makes it a tempting theory. However, it does not explain how that life began. All this does is perpetuate a random approach, with life reaching the earth as an alien jackpot. This theory also adds new questions, such as where is the elsewhere, where the alien life began? Science can't seem to find life friendly places, close, which if they could form life that early for the earth, should be ahead of us now. How did that life get into space, survive a long space journey, survive the solar radiation of the our sun as it approached earth, survive the hot fiery descent through the earth's atmosphere, and the finally survive a violent impact and still come out ticking ready to go to town?

    The Miller experiment showed one can make amino acids, sugars, oils and tars, from simple gases and water subjected to an electric spark. All these materials are favored in a low oxygen atmosphere which is consistent with what science says was the early earth. The early earth was hot, with constant storms, because of the evaporation and condensation of water into and out of the dense atmosphere. This movement of the boiling and steamy water into the atmosphere, cools the steam, so it condenses, and then rains to the earth. This helps cool the earth faster than only radiational cooling of solid surface materials.

    Water has a large heat capacity, such that even if we have the earth bombarded with asteroids, the boiling point of water will buffer the surface water temperature to near 100C; unless the pressure and salt concentration was higher. Most of the precursors materials have higher boiling points than 100C, and will be protected by the water against vaporization and will accumulate. Without significant oxygen to oxidize they last longer.

    One wild card was the moon. If the earth and moon were forming together, and the earth had the lion's share of water, the earth would be cooling faster than the moon, due to the high heat capacity and convection of the water; stream to rain. What would eventually happen is the moon would stay hotter longer, and begin to "relative", radiate IR heat, like a hot spot in the sky, circling the cooler earth, while pulling tidal effects.

    The moon would eventually become a moving hot spot, that circles the cooler earth, acting like a huge moving evaporator that circles the earth. This will add horizontal convection to the earth's atmosphere, between the opposite sides of the earth and moon, with the clouds flowing toward the moving cool zone opposite the moon. This is a more favorable second round of the Miller Experiment, with the precursors flow into the cooler water,then heating, cooling, heating, cooling, as the moon passes and the rain follow.
     
  9. origin Heading towards oblivion Valued Senior Member

    Messages:
    11,389
    That looks like you think there are 2 possibilities not 3.

    Why do you think evolution was speeded up? What does that even mean?
    I guess the third possibility is that abiogenesis occurred on earth. This makes the most sense. Even your 'transpermia' indicates that life arose on a planet. So we have that. If life originated on earth then we do not have to introduce an unlikely event where a violent explosion propels a rock into space without killing any accompanying life and then that life somehow survives in the freezing vacuum of space for some extended period of time and then survive a reentry into the earth's atmosphere.

    Ockham's razor, it seems to me, clearly pointing to an earthbound abiogenesis.


    Actually, I believe abiogenesis is about 150 years old not 1000.

    Those ideas were wrong so abiogenesis must be wrong? That does not logically follow.

    He had some pretty compelling evidence.

    Well that is your claim and belief. I would need very compelling evidence to accept that since it seems like your 'transpermia' idea is rather convoluted and requires not only the difficulty of abiogenesis but the additional highly unlikely mode of transport to earth.
     
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  10. Yazata Valued Senior Member

    Messages:
    5,550
    I think that there is, and outlined the argument in posts #11, 17 and 18.

    The problem is that some of the more extreme estimates for the early date that microbial life appears on the Earth, puts the origin of life increasingly close to the accretion of the Earth from planetesimals, the planetary collision that's hypothesized to have ripped the Moon from the Earth's mass, and the Late Heavy Bombardment of the Earth by thousands of asteroids.

    It's hard to imagine how an exceedingly complex abiogenesis process involving things like naked nucleic acid replicators could have taken place when the Earth's surface might have still been molten rock.

    Bacterial cells are simple compared to the eucaryotic cells that make up our own bodies. But they already have DNA and RNA, genes and gene transcription, energy metabolism and all of the other rudiments of life. Their biochemical complexity suggests that they are likely the results of a long developmental process that came before them.

    It seems to me that there are two ways out of this conundrum.

    One is the panspermia speculation that life isn't native to Earth, that the Earth was contaminated/seeded by extraterrestrial microbes very early in its history, perhaps as early as the Earth's surface could sustain them. This hypothesis has serious problems of its own, namely explaining how the microbes got from wherever they originated to here. (How long could microbial DNA survive intact in space, even sheltered inside a rock?)

    The other is that life is native to Earth, but didn't make its appearance nearly as early as some people currently think it did.

    I'm inclined to think the latter option is more likely, but I don't rule out panspermia entirely. If the early estimates for life's appearance hold up, it becomes increasingly likely.
     
    Last edited: Jun 16, 2015
    Vegasprof likes this.
  11. spidergoat Liddle' Dick Tater Valued Senior Member

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    53,966
    There is evidence for life 3.4 billion years old, after the crust solidified. Even 10 million years or so is a very long time.
     
  12. Vegasprof Registered Member

    Messages:
    7
    Not really.

    Have you ever spent an hour so more perusing Gray's Anatomy? Can you believe that the sophisticated machine that is the human body could have evolved in a mere 10 million years? Knowing how long various other things took to evolve, I certainly do not.

    Have you ever watched the animation film depicting the action of the ribosome? Can you believe that the ribosome could have evolved in a mere 100 million years or so? 200 million even? I certainly do not. You know the parable of the whirlwind in the junkyard. Well, the ribosome is more complex than a 747. Scientists are having trouble imagining how it could have evolved at all. That's why I want to give it a few billion more years.

    Don't forget: LUCA had a ribosome.
     
  13. spidergoat Liddle' Dick Tater Valued Senior Member

    Messages:
    53,966
    You don't know how the first life accomplished inheritance. I guess that's where you're mistaken.
     
  14. paddoboy Valued Senior Member

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    27,534
    http://phys.org/news/2015-06-earth-mars-seeds-life.html

    Could Mars, of all places, be the place to look for early life on Earth?


    It's an intriguing thought and one that astrobiologists take seriously as they consider the conditions during the early days of Solar System when both planets experienced frequent bombardments by asteroids and comets that resulted in debris exchange between one body and the other.

    "We might be able to find evidence of our own origin in the most unlikely place, and this place is Mars," planetary scientist Nathalie Cabrol of the SETI institute said in a TED Talk in April 2015.

    Cabrol studies life in extreme conditions on Earth with the hope that her research might help improve the search for signs of life on the Red Planet.

    "We can go to Mars and try to find traces of our own origin. Mars may hold that secret for us," she said. "This is why Mars is so special to us."



    Read more at: http://phys.org/news/2015-06-earth-mars-seeds-life.html#jCp
     
  15. pluto2 Banned Valued Senior Member

    Messages:
    1,087
    The origin of life will probably always be a mystery.

    The sad truth is that there are things which we have no way of knowing, the origin of life is one of them, the meaning of life is the other.

    Although I'm not an expert, I think that maybe physics can shed light on the origin of life. You know theories like classical electromagnetism, quantum mechanics, special relativity, general relativity, quantum field theory, thermodynamics, statistical mechanics and particle physics.
     
  16. sideshowbob Sorry, wrong number. Valued Senior Member

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    6,585
    What method are you using to measure the speed of evolution?
     
  17. paddoboy Valued Senior Member

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    27,534
    Bleach a possible key to life on earth
    by Staff Writers
    Canberra, Australia (SPX) Jul 24, 2015

    Hydrogen peroxide - commonly used as hair bleach - may have provided the energy source for the development of life on Earth, two applied mathematicians have found. The heat from ancient geothermal vents may have triggered the varying acidity that was vital for early life to form and spread throughout the oceans.

    "The energy in hydrogen peroxide could have powered the living world before cells evolved," said Associate Professor Rowena Ball, from The Australian National University (ANU). The research, published in the Journal of the Royal Society Interface, solves a number of scientific puzzles about early life and how it emerged on Earth.
    more at......
    http://www.spacedaily.com/reports/Bleach_a_possible_key_to_life_on_earth_999.html
     
  18. Daecon Kiwi fruit Valued Senior Member

    Messages:
    3,133
    Two chemists walk in to a bar, one orders H2O, the other orders H2O too. The first one drinks his drink, feels refreshed and leaves. The other drinks his drink, makes some strange gurgling noises, and dies.
     
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  19. iceaura Valued Senior Member

    Messages:
    30,994
    Nobody does. The minimum timespan over which human beings evolved was about 3 billion years.

    A ribosome is not more complicated than a 747. A whirlwind in a junkyard would be the opposite of evolutionary development, not an analogy to it. And we have every reason to believe that early precursors of living beings, once launched, evolved much more rapidly than modern complex organisms - they had an entire completely uninhabited planet of resources and niches to spread into.
     
  20. paddoboy Valued Senior Member

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    27,534
    Origins of life: New model may explain emergence of self-replication on early Earth
    July 28, 2015

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    A schematic drawing of template-assisted ligation, shown in this model to give rise to autocatalytic systems. Credit: Maslov and Tkachenko
    When life on Earth began nearly 4 billion years ago, long before humans, dinosaurs or even the earliest single-celled forms of life roamed, it may have started as a hiccup rather than a roar: small, simple molecular building blocks known as "monomers" coming together into longer "polymer" chains and falling apart in the warm pools of primordial ooze over and over again.



    Read more at: http://phys.org/news/2015-07-life-emergence-self-replication-early-earth.html#jCp
     
  21. timojin Valued Senior Member

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    3,252
    As for me it is easily to believe that some alien ventured in space exploration and landed on earth, and accidentally contaminated earth, in a similar way as we have contaminated Mars with our toys that have landed for exploration
     
  22. Daecon Kiwi fruit Valued Senior Member

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    3,133
    Why do you think that's easy to believe?

    How long do you imagine such a journey would have taken for this alien to get the Earth?
     
  23. timojin Valued Senior Member

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    3,252
    Do we know of other solar systems on our galaxy that might have life ? I understand it have taken several decades for one of early voyagers to reach the outer part of our solar system . Of course you probable will
    tell me it might take several lite hours or years to come from other galaxy. then my assumption might not be valid.
     

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