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    11 Aug '17 03:01
    If we are to have a natural explanation for the origins of life, what explanation is there other than abiogenesis?
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    11 Aug '17 04:39
    Originally posted by @eladar
    If we are to have a natural explanation for the origins of life, what explanation is there other than abiogenesis?
    Wiki says (https://en.wikipedia.org/wiki/History_of_Earth) :

    (quote)
    Origin of life
    Life timeline

    One of the reasons for interest in the early atmosphere and ocean is that they form the conditions under which life first arose. There are many models, but little consensus, on how life emerged from non-living chemicals; chemical systems that have been created in the laboratory still fall well short of the minimum complexity for a living organism.[70][71]

    The first step in the emergence of life may have been chemical reactions that produced many of the simpler organic compounds, including nucleobases and amino acids, that are the building blocks of life. An experiment in 1953 by Stanley Miller and Harold Urey showed that such molecules could form in an atmosphere of water, methane, ammonia and hydrogen with the aid of sparks to mimic the effect of lightning.[72] Although the atmospheric composition was probably different from the composition used by Miller and Urey, later experiments with more realistic compositions also managed to synthesize organic molecules.[73] Recent computer simulations have even shown that extraterrestrial organic molecules could have formed in the protoplanetary disk before the formation of the Earth.[74]

    The next stage of complexity could have been reached from at least three possible starting points: self-replication, an organism's ability to produce offspring that are very similar to itself; metabolism, its ability to feed and repair itself; and external cell membranes, which allow food to enter and waste products to leave, but exclude unwanted substances.[75]

    Even the simplest members of the three modern domains of life use DNA to record their "recipes" and a complex array of RNA and protein molecules to "read" these instructions and use them for growth, maintenance and self-replication.

    The discovery that a kind of RNA molecule called a ribozyme can catalyze both its own replication and the construction of proteins led to the hypothesis that earlier life-forms were based entirely on RNA.[76] They could have formed an RNA world in which there were individuals but no species, as mutations and horizontal gene transfers would have meant that the offspring in each generation were quite likely to have different genomes from those that their parents started with.[77] RNA would later have been replaced by DNA, which is more stable and therefore can build longer genomes, expanding the range of capabilities a single organism can have.[78] Ribozymes remain as the main components of ribosomes, the "protein factories" of modern cells.[79]

    Although short, self-replicating RNA molecules have been artificially produced in laboratories,[80] doubts have been raised about whether natural non-biological synthesis of RNA is possible.[81][82][83] The earliest ribozymes may have been formed of simpler nucleic acids such as PNA, TNA or GNA, which would have been replaced later by RNA.[84][85] Other pre-RNA replicators have been posited, including crystals[86]:150 and even quantum systems.[87]

    In 2003 it was proposed that porous metal sulfide precipitates would assist RNA synthesis at about 100 °C (212 °F) and ocean-bottom pressures near hydrothermal vents. In this hypothesis, lipid membranes would be the last major cell components to appear and until they did the proto-cells would be confined to the pores.[88]
    Metabolism first: iron–sulfur world
    The replicator in virtually all known life is deoxyribonucleic acid. DNA is far more complex than the original replicator and its replication systems are highly elaborate.
    Main article: iron–sulfur world theory

    Another long-standing hypothesis is that the first life was composed of protein molecules. Amino acids, the building blocks of proteins, are easily synthesized in plausible prebiotic conditions, as are small peptides (polymers of amino acids) that make good catalysts.[89]:295–297 A series of experiments starting in 1997 showed that amino acids and peptides could form in the presence of carbon monoxide and hydrogen sulfide with iron sulfide and nickel sulfide as catalysts. Most of the steps in their assembly required temperatures of about 100 °C (212 °F) and moderate pressures, although one stage required 250 °C (482 °F) and a pressure equivalent to that found under 7 kilometers (4.3 mi) of rock. Hence, self-sustaining synthesis of proteins could have occurred near hydrothermal vents.[90]

    A difficulty with the metabolism-first scenario is finding a way for organisms to evolve. Without the ability to replicate as individuals, aggregates of molecules would have "compositional genomes" (counts of molecular species in the aggregate) as the target of natural selection. However, a recent model shows that such a system is unable to evolve in response to natural selection.[91]
    Membranes first: Lipid world

    It has been suggested that double-walled "bubbles" of lipids like those that form the external membranes of cells may have been an essential first step.[92] Experiments that simulated the conditions of the early Earth have reported the formation of lipids, and these can spontaneously form liposomes, double-walled "bubbles", and then reproduce themselves. Although they are not intrinsically information-carriers as nucleic acids are, they would be subject to natural selection for longevity and reproduction. Nucleic acids such as RNA might then have formed more easily within the liposomes than they would have outside.[93]
    The clay theory
    Main article: Graham Cairns-Smith § Clay Theory

    Some clays, notably montmorillonite, have properties that make them plausible accelerators for the emergence of an RNA world: they grow by self-replication of their crystalline pattern, are subject to an analog of natural selection (as the clay "species" that grows fastest in a particular environment rapidly becomes dominant), and can catalyze the formation of RNA molecules.[94] Although this idea has not become the scientific consensus, it still has active supporters.[95]:150–158[86]
    Cross-section through a liposome

    Research in 2003 reported that montmorillonite could also accelerate the conversion of fatty acids into "bubbles", and that the bubbles could encapsulate RNA attached to the clay. Bubbles can then grow by absorbing additional lipids and dividing. The formation of the earliest cells may have been aided by similar processes.[96]

    A similar hypothesis presents self-replicating iron-rich clays as the progenitors of nucleotides, lipids and amino acids.[97]
    Last universal ancestor
    Main article: Last universal ancestor

    It is believed that of this multiplicity of protocells, only one line survived. Current phylogenetic evidence suggests that the last universal ancestor (LUA) lived during the early Archean eon, perhaps 3.5 Ga or earlier.[98][99] This LUA cell is the ancestor of all life on Earth today. It was probably a prokaryote, possessing a cell membrane and probably ribosomes, but lacking a nucleus or membrane-bound organelles such as mitochondria or chloroplasts. Like all modern cells, it used DNA as its genetic code, RNA for information transfer and protein synthesis, and enzymes to catalyze reactions. Some scientists believe that instead of a single organism being the last universal common ancestor, there were populations of organisms exchanging genes by lateral gene transfer.[98]
    (unquote)

    It's not like we know nothing in the subject.
  3. Joined
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    11 Aug '17 06:45
    Originally posted by @eladar
    If we are to have a natural explanation for the origins of life, what explanation is there other than abiogenesis?
    none.
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    11 Aug '17 06:51
    Originally posted by @fabianfnas
    Wiki says (https://en.wikipedia.org/wiki/History_of_Earth) :

    (quote)
    Origin of life
    Life timeline

    One of the reasons for interest in the early atmosphere and ocean is that they form the conditions under which life first arose. There are many models, but little consensus, on how life emerged from non-living chemicals; chemical systems that have be ...[text shortened]... genes by lateral gene transfer.[98]
    (unquote)

    It's not like we know nothing in the subject.
    So--- basically--- you got nothing.
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    11 Aug '17 07:12
    Originally posted by @freakykbh
    So--- basically--- you got nothing.
    You consider that nothing?
    So pseudo science has a better answer?
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    11 Aug '17 07:22
    Originally posted by @fabianfnas

    So pseudo science has a better answer?
    yes; the first microbes came from fairy poo dumped on the edges of flat Earth.
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    11 Aug '17 07:33
    Originally posted by @humy
    yes; the first microbes came from fairy poo dumped on the edges of flat Earth.
    That's the advantage of the pseudo science methods.
    It doesn't have to do anything but contradict real science.
    The fairy poo theory seems totally correct. If your are a pseudo scientist.
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    11 Aug '17 09:49
    Originally posted by @fabianfnas
    That's the advantage of the pseudo science methods.
    It doesn't have to do anything but contradict real science.
    The fairy poo theory seems totally correct. If your are a pseudo scientist.
    Not sure about pseudo wannabes, but this provides yet another example of the unscientific approach.
    When asked how something came from nothing, "science" responds with an encyclopedia-length dissertation which sounds incredibly impressive... until you realize you've just been told "I don't know" in über technical verbiage.
    They just lack the courtesy of telling you straight forward, and in the interest of remaining the smartest one in the room, they'll use the most technical-sounding words and phrases, none of which could actually be verified, tested or falsified.
    And all of which add up to nothing.

    Kinda funny, really.
    Ask a blinded scientist something about nothing, and he'll give you all kinds of something about nothing.
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    11 Aug '17 10:01
    Originally posted by @humy
    none.
    So you believe life originated by way of abiogenesis?
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    11 Aug '17 10:38
    Originally posted by @freakykbh
    Not sure about pseudo wannabes, but this provides yet another example of the unscientific approach.
    When asked how something came from nothing, "science" responds with an encyclopedia-length dissertation which sounds incredibly impressive... until you realize you've just been told "I don't know" in über technical verbiage.
    They just lack the courtesy of ...[text shortened]... nded scientist something about nothing, and he'll give you all kinds of something about nothing.
    So you would rather give the pseudo scientific kind of answer Goddidit?

    So many times has this question been answered in a scientific way - and you just "Lalala, don't listening" without wanting to learn something non-pseudo scientific?
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    11 Aug '17 11:01
    Originally posted by @fabianfnas
    So you would rather give the pseudo scientific kind of answer Goddidit?

    So many times has this question been answered in a scientific way - and you just "Lalala, don't listening" without wanting to learn something non-pseudo scientific?
    So you believe life came into existence by way of abiogenesis?
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    11 Aug '17 11:05
    Originally posted by @eladar
    So you believe life came into existence by way of abiogenesis?
    Yes, of course.

    As this is the Science Forum, any mythological explanations are invalid, like 'goddidit'.
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    11 Aug '17 11:08
    Originally posted by @fabianfnas
    Yes, of course.

    As this is the Science Forum, any mythological explanations are invalid, like 'goddidit'.
    Have you seen ot happen?

    Is it reproducible?

    Is the belief on abiogenesis falsifiable?
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    11 Aug '17 11:17
    Originally posted by @eladar
    Have you seen ot happen?

    Is it reproducible?

    Is the belief on abiogenesis falsifiable?
    No, I haven't, I'm not an experimentalist.
    If such an experiment shows abiogenesis, of course it's reproducable, or else it wouldn't be science.
    You mean that the experiment would be falsifiable? Explain further.

    If I ask you: "Did atoms exist before it was scientifically proved?"
    Would your answer be: "Yes, of course!"
    Then if I ask you: "Did abiogenesis happen whether or not if we know how it worked in detail?"
    Then the answer would be the same, wouldn't it?

    There are scientific phenomenon that eventually will be explained without any need to bring in supernatural explanations. Atoms was one example. Black matter is another. As is abiogenesis.
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    11 Aug '17 11:22
    Originally posted by @fabianfnas
    No, I haven't, I'm not an experimentalist.
    If such an experiment shows abiogenesis, of course it's reproducable, or else it wouldn't be science.
    You mean that the experiment would be falsifiable? Explain further.

    If I ask you: "Did atoms exist before it was scientifically proved?"
    Would your answer be: "Yes, of course!"
    Then if I ask you: "Did abi ...[text shortened]... in supernatural explanations. Atoms was one example. Black matter is another. As is abiogenesis.
    No one has been able to create the correct conditiins for abiogenesis. It has never been reproduced. No one has ever seen it happen.

    Can anyone falsify the idea of abiogenesis?
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