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Can we create life from scratch?

  1. May 16, 2013 #1
    People have achieved injecting desired genetic code into bacteria. This is a big thing of course but it is far from creating life purely out of chemicals.
    Assuming 'life' to be the ability to interact with the environment for benefit and to reproduce, is it possible, at least theoretically, to assemble the necessary 'life chemicals' and create a living cell?
    And if it is possible, what would it speak about things like intelligence and self-awareness?
    Just trying to know your opinions.
     
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  3. May 16, 2013 #2

    mfb

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    I see no reason why it should be fundamentally impossible.
    It is not possible at the moment, however. Cells are not well enough understood, and too complex to assemble them molecule by molecule with current chemistry.

    I don't think the first fully artificial cell will show those features more than a regular unicellular organism. It would disprove vitalism completely, of course.
     
  4. May 16, 2013 #3

    Simon Bridge

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    In principle... that would have to be a "yes". There is no reason to believe that one cannot start out with all-dead stuff and deliberately build some sort of living organism.

    Scientifically the ability to scratch-build a living organism from non-living components says nothing at all about intelligence or self-awareness. [Could disprove a lot of ideas though.]
     
  5. May 16, 2013 #4
    how does a female's(in most species) womb create it ?
    that's probably a great place to start.
     
  6. May 16, 2013 #5

    Ygggdrasil

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    Depending on how you define life, viruses have been generated from cell-free systems (Cello et al. 2002. Chemical Synthesis of Poliovirus cDNA: Generation of Infectious Virus in the Absence of Natural Template. Science 297: 1016. doi:10.1126/science.1072266).
     
  7. May 16, 2013 #6

    mfb

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    It does not do this. It uses existing living cells to make more living cells. That is easy to reproduce in a lab.
     
  8. May 16, 2013 #7

    Ryan_m_b

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    In principle yes but in practice our knowledge in this field is highly limited so any organism created "from scratch" would likely be cobbled together from parts of other organisms. Synthesising an already in existence genome and planting it into an empty cell is one thing, designing and building an organism not modelled on nature is quite another
     
  9. May 16, 2013 #8

    Simon Bridge

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    Do most species have male and female?
    Do all females have a womb?

    Mammals make more mammals by assembling already living cells in a womb - so maybe not such a good place to start. But if the definition of life does not extend to the zygote, then you are on to something :)

    But this sort of question is commonly asked by creationists and vitalists - "life must come from life", so knowing how a womb makes new life is unlikely to count. Leveraging the mechanisms seen in nature would also likely not count (we learned about them from life) ... making the proposition extremely difficult. Technically everything life we build from non-life comes from us and we are alive and we get bogged down in semantics.

    Our bodies do need to be able to take dead stuff to make living stuff (all those cells in your body came from someplace) - all we really need is a totally artificial food, eat it (wait a bit) and you've made living stuff from stuff that was never alive.

    The starting point for lab-created life would be at the really simple level - viruses and viroids perhaps.
     
  10. May 16, 2013 #9

    Borek

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  11. May 17, 2013 #10
    It is amazing how some molecules are capable of self replication.
     
  12. May 17, 2013 #11

    Simon Bridge

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    The lecture in Borek's post is an example of something that is massively frustrating - here we have someone at the front of his field, so we want to listen to him, lecturing an inherently fascinating subject, so we want to hear about it, but he does it in the most boring way possible! If someone were to deliberately try to make the Origin of Life boring, they would be hard pressed to do better than to deliver in a monotone (peppered with upwards inflections at the end of some statements of fact) with erratic pauses and lots of ums and ers.

    The lecture itself is great.

    The number of times I've hunted and searched for some presentation to nail a topic, only to find the delivery is counter-productive. The really good delivery items are often too pop-sciencey to be much use.

    It's also the number-1 complaint from students isn't it?

    (To be fair - there are bits that are easier to listen to; particularly after the half-way mark when the lecturer warms to his subject. Public speaking is hard and we can't all be Richard Feynman.)
     
  13. May 17, 2013 #12

    Simon Bridge

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    Be that as it may ... has your question been answered? Has your topic been addressed?
    Feedback is important to the sort of replies you get.
     
  14. May 19, 2013 #13
    From the presentation, I feel I can safely take the chemical origin of life now.
    But to think life can exist in totally different forms compared to that we see here on earth seems very radical to me. Sort of hard to imagine it. But I don't know, maybe there are still a lot of fundamental bits like mfb said,, that we don't know about life yet.
    And thank you everybody, I didn't expect such a lot of replies to be honest, though I really hoped there'd be. But maybe the subject itself is a very interesting one and that is to be held for it.
     
  15. May 19, 2013 #14
    Even nature has trouble doing this. EVERY living cell was created by another living cell. None are created "from scratch". Well except once 3.5 billion years ago. But that first cell had an easy life because there was no competition. Nature could not do this again because such a primitive cell could not compete with existing life.

    One way to create life might be to emulate the way if happened on Earth 3.5 billion year ago. The first "life" was just a short strip on RNA that may not have even have had a cell membrane and it likely also folded and acted as it's own enzyme. Proteins and DNA came much later. You can build a lot with just RNA. The Earth was different then, no O2 in the air. You need to recreated the ancint environment and then toss just one carefully crafted RNA segment into that environment. That is how life was created and it may be the only way possible. We don't know.
     
  16. May 20, 2013 #15

    Simon Bridge

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    Probably many many times 3.5-4.5 billion years ago.
    ... and wait for a long long time ;)
     
  17. May 20, 2013 #16
    It makes me think, given enough time, is it possible that anything that can happen, will happen?
    And was it just luck that the right sequence of these molecules started getting together or would it be more accurate to say that over the interval of time presented, it was destined?
     
  18. May 20, 2013 #17

    Borek

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    The way evolution works it is enough that you have something that barely works - if it multiplies and compete for resources, it will get optimized over time. Doesn't mean everything will happen. Once you have something that works slightly better than barely, newcomers - which are still just barely working - won't be able to outcompete it. So you can probably start only once.
     
  19. May 20, 2013 #18

    Ryan_m_b

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    Destined is the wrong way to think about it. More like certain environmental conditions allow for a higher probability of self-replicating molecules forming so over long time periods (as long as the environment doesn't change) it is more likely to happen.
     
  20. May 20, 2013 #19

    Simon Bridge

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    That would be the definition of "enough time" then wouldn't it?
    You don't get to go backwards all that much though so once on a path, events have to continue along it.

    How many times would you have to roll a fair die before it is certain that you will roll at least one six?

    The rest of these terms are vague: what is "luck"? How would you recognize it if you saw it? Destiny?

    In AD&D you have to generate characters by rolling 3 dice and adding the total. But there are gamer tricks to get a higher value while keeping the actual number random ... eg - one rolls 4 dice, reroll the 1s and discard the lowest.
    So, in this example, on the first roll I get 5,5,1,1 ... now the odds have changed - I cannot get less than an 12 for that attribute, because some dice rolled high that time. It could have been different? Was it fate? Was it an accidental sequence of events?

    What is the "right" sequence of molecules? We happen to think that the RNA-DNA etc stuff is important because we are made of it ... but isn't that is just our own arrogance in thinking we are important? Why can't the "right" sequence be the one that leads to alcohol and all the rest is wrong? The only meaning to these events is what we assign to them.

    Perhaps there are other sequences that lead to other kinds of self-replication that can develop the kind of complexity we normally associate with what we please ourselves to call "life"? Just 'cause we have it does not mean it's the only way. There is no way of knowing, yet, and detailed speculation is pointless. The point: lets not get up ourselves eh? The Universe still has a lot to teach us.

    What is clear is that, in this "big" "old" Universe, there is enough room and time for many apparently unlikely things to happen. That's the thing about probability - the odds of an outcome change with the number of opportunities to roll the dice - and how the dice are rolled.
     
  21. May 20, 2013 #20
    So you mean to say that even if the given interval of time is long 'enough', we still cannot be sure that life starts?
    If the universe still has a lot to teach us, that can only further justify my point that anything that can happen will, eventually happen. And although I don't and didn't ever mean to say that 'this kind of life' or we 'humans' are the purpose of it all, which I think you believe I have faith in, if you say life can be something entirely different than what we observe, that argument adds to the 'favourable cases' for the chances of origin of 'life', no?
    Correct me if I got you wrong.
     
  22. May 20, 2013 #21
    this conversation turned out to be more interesting than what i had thought.
    nice.
     
  23. May 20, 2013 #22

    Simon Bridge

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    Please excuse me - I'm not sure we are disagreeing exactly - I hoped to warn you off some unhelpful ways of talking.

    No - I am saying that the word "enough" here is meaningless without some statement of how much time is "enough".

    It does not mean that anything at all can happen or even that all events that are possible are certain to occur sometime, somewhere.

    Some events can exclude other events for instance.
    But it does mean that we can expect events which we intuitively feel are unlikely to have occured - our intuitions about what is likely or unlikely are not very helpful here.

    The unhelpful language here was in referring to the sequence of events as the "right" sequence. It is not clear what this means but it is often used to assign some importance to a particular process above others. Don't use it to argue with Creationists for example.

    The possibility that there could be other processes elsewhere does, indeed, add to the favorable cases for the origin of life - though we'd have to extend our definition of "life" to include those other processes.

    Some people won't want to.
    Can we come up with a definition or test for "life" that does not rely on something anthrocentric?
    How would we recognize it if we saw it. It's tougher than it looks. Not everyone counts viruses for example.

    I don't think life is terribly unlikely on the scale of the Universe ... but you have to remember what the Universe does to numbers with lots of zeros in them.

    I remember someone telling me that their favorite authority, told them that the odds of a star having a planet with intelligent life was one to the number of hydrogen atoms within eight light years of the Sun. He thought that was such long odds it couldn't possibly happen.

    Never mind that the number is totally bogus: you can work it out! (~10^150)
    Then compare it with the number of stars in the observable Universe (~10^1021).

    Those kinds of numbers allow for some pretty long (by intuitive measures) odds to be achievable.
    But it does not mean that anything can happen. We can always find something with really really long odds on the scale of the Universe long. Then there are those things that get ruled out because physical laws turned out a certain way.

    Maybe the laws are more like guidelines - but that's one maybe too many: there are rules about that sort of speculation in these forums... our current understanding is that not just anything can happen.

    Anyway - that's about all the metaphysics I can handle tonight ;)
     
  24. May 20, 2013 #23
    No. I disagree. Once live got started, the next time something very primitive got going, it got eaten very quickly. Those primitive RNA strands with no cell membranes would not stand a chance today even a virus needs a protein shell to survive today.

    OK it might have happened twice, each time in a very different isolated environment but as soon as those environments came in contact the primitive stuff was over run. So if it did happen many times, the ones who where late to the party did not have it so well.

    And no again. if the goal is to create "life" (any kind) from scratch, there is no need to wait, that first RNA you introduce to your artificial environment is "life". It is primitive but if it is self replicating and uses energy and nutrients it's life.

    But if the question is can you build "modern multi cell life" in one step from scratch, I'd have to say no. It has never been done by nature. You have to go one step at a time or start with a living cell and modify it.
     
  25. May 20, 2013 #24

    Borek

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    Early Solar system was a quite dangerous place, with plenty of colliding objects - so it is possible that life had a chance to start several times, being wiped each time. But this is a pure speculation.
     
  26. May 20, 2013 #25
    Our problem is that we only have one example, Earth. With such a small sample our statistical confidence is very low.

    You can't say "will eventually happen" because that assumes the universe will las forever. Not it will decay to entropy in time. The hydrogen that powers stars will be used up and eventually it will become very cold. Yes this ail take a very, very long time but a finite time.


    We can guess about probabilities. It now seems that most stars will have planets. My guess is that "life", meaning something no more complex than prokaryotic cells may be common but technological societies might be so rare that there is only at most one in the galaxy at any given time. We could very well be the only one. Evidence for this is that (1) life sprung up on Earth really fast, just as soon as conditions allowed. (2) intelligent life did NOT evolve as soon as conditions allowed. and (3) even with humans who could make fire and stone tools, they did this for a million years and never got past that level except for just recently.

    So life (prokaryotic cells) happens fast and is likely, but complex life is rare because even on Earth it took billions of years for the first multi-cell life and likely some truly freakish event to create humans.

    Another line of evidence is that in only 1,000 years we will likely have the technology to send a robot probe to another star at say 1% the speed of light. At that rate we will have probed the entire galaxy in "only" 10 million years. If technological societies are common then there should be many who are more than 10 millions years older than us, If so then they should have completely colonized the entire galaxy by now even if 0.01c is the speed limit. Earth would have been "discovered" by them multiple times in recent geological history. Even with a 0.001c speed limit we should expect a completely "filled" galaxy. We don't see this. We are likely the first or only society.
     
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