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Thread: Contra evolution arguments?

  1. #1 Contra evolution arguments? 
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    As I know there exist at least two arguments against evolution theory:

    1)Up to date no one scientist was able to create life in laboratory experiments
    from basic chemical components.This is supposed to be a way how life appeared
    on Earth according to evolution theory.Either, I still didn`t read anything about
    computer model of chemical processes which would show principal
    possibility of life self-generation from basic components.

    2)According to evolution theory all kind of living spicies could be traced to some common
    ancestor.Even scpecies with different number of chromosomes.Usually only the same kind
    of spicies which have the same number of chromosomes give normal and fertile offsprings.
    Lets suppose for example that tigers descended from lions.For example lions have 40 chro-
    mosomes and tigers have 41.Then tigers mutated from lions.But there is a questions:
    a)what mutation was able to create entire new chromosome (with many genes in it)???
    b)With whom the fist tiger was supposed to mate with if he was alone in the entire World?
    With lions?But they already had different number of chromosomes and normal fertile offsprings
    are unlikely.
    c)How to avoid genetical degradation because of close relatives interbreading?For example there
    were first couple of tiger and tigress.Their offsprings will be brothers and sisters.Do they suppose
    to mate with each other?And how they will acheive genetical diversity which is important for
    any kind to suvive?Again mutations and mutations?But majority mutations are harmfull.And they
    do not happen very often.How to avoid interbreeding too?


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  3. #2  
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    In regards to point 1. That is not the purview of the theory of evolution at all, but rather it belongs to the concept of Abiogenisis.


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    Tigers and lions both have 38 chromosomes and can produce both sterile and fertile hybrids when zoo keepers interfere with the natural order of things.



    Tigers and lions are not related in the way you suggest. In the language of evolutionary biology, you'd describe them as sharing a common ancestor that lived 3 to 4 million years ago.

    There was never a single tiger that just appeared out of nowhere, all alone without a mate. If there is one thing you do today, make sure it is to relieve yourself of such notions. Such a process of speciation is totally wrong, and contrary to what many claim, is certainly not an argument against the validity of evolutionary theory. It doesn't even begin to make sense, which is why - if you believe such crazy ideas - it can seem to be an effective argument against evolution.

    Imagine the following simplified story as an example of how speciation can actually occur, in this case an example of allopatric speciation. Take an ancestral population of cats, living in a particular region, some 4 million years ago. Now imagine that this species begins to extend its range, to cover a far larger area encompassing more varied terrain types. We might, after a time, end up with two populations of cats, one living in the forests of the plain and another on the high mountain slopes. The two groups may only have limited contact with each other. In time they may become increasingly isolated, say by changes in food supply or changes in geography and ecology. As a result we may end up with two populations that are geographically isolated from one another. We can say that they are genetically isolated too (they do not breed with each other). These two populations are effectively now free to travel upon their own unique evolutionary trajectories becoming increasingly different from each other. Again, in time, they may become unable to breed with each other. A new species has been formed.


    Note here that no one cat magically mutated into another type of cat. What happened was that an ancestral population went through a process of "splitting" (see the family tree diagram below):

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    As a result we may end up with two populations that are geographically isolated from one another. We can say that they are genetically isolated too (they do not breed with each other). These two populations are effectively now free to travel upon their own unique evolutionary trajectories becoming increasingly different from each other. Again, in time, they may become unable to breed with each other. A new species has been formed.
    This explanation doesn`t explain how species with new number of chromosomes could evolve.You still need to have some jump for it.It can`t happen gradually.For example there could be only 40 and 41 number of chromosomes but not 40 and 1/2.
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    A beneficial/neutral mutation in one specimen, add several generations of reproduction, and you get a change in chromosome count.
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    Stanley514,

    As I hinted at before, don't think about individuals, think about populations instead. Someone once said "Nothing in biology makes sense except in the light of evolution". What they should have added was "...and nothing in evolution makes sense except in the light of population genetics". With this view it's not too difficult for our extra chromosome to spread throughout a poplulation to some degree - even if those individuals have reduced fertility. The odd chromsome can then pair up with another from another individual with the same mutation.

    I wouldn't get too caught up on the idea of chromosome number itself as being of much importance in the grand scheme of things. As an argument against evolution I'd describe it as a non-starter. Chromosome number really isn't a problem.
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    All this worry about numbers of chromosones is needless. Evoutionary theory is not dependent on or derived from rarified microbiologic studies. It is based on common "barn yard" observations.
    1) Offspring inherit charateristics from their parents. Like begets like. Duck eggs hatch out ducklings not chickens or turtles.
    2) The above process is not perfect. Offspring are not perfect duplicates of their parents. Freaks happen.
    3) All individuals are not equally hardy or sexually attractive. Some of each generation will fail to pass on their genes to the next generation.
    4) Those individuals who fail to reproduce will not pass on their genes to the next generation. (If your grand father died childless , chances are so will you.)
    5) Disasters happen. Events that kill off large portions of the population, droughts, famines, plagues, etc., happen. Only those who's inhereted characteristics helped them survive the disaster will contribute to the next generation.
    6)individuals will mate with the most attractive individual avilable to them even if he/she is not very attractive. If you can't be with the one you love , love the one you are with. See picture of tiger getting it on with lioness.
    That's pretty much all that you need to prove evolution. And unless you can disprove one of those then Evolution stands.
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    With this view it's not too difficult for our extra chromosome to spread throughout a poplulation to some degree - even if those individuals have reduced fertility. The odd chromsome can then pair up with another from another individual with the same mutation.
    In this case,what is a sense for a nature to bother with different chromosome numbers?Especially,for a scpecies which are not extremelly distant?Species could evolve even without different chromosome numbers.It only make evolution more complicated.And could you imagine random mutation which could create entirely new chromosome with all its genes?
    I guess, a bit more should be told about mutations which according to Darvin is only driving force of evolution.Because natural selection could only fix positive mutations.By the way,what is all the reasons for a mutations to happen?I could imagine only two: radioactivity from isotopes and chemical mutagens.Both those sources should be extremely rare in nature.And even if some animal swallows a mutagen,this mutagen needs to make its way to germ cells instead been just extracted from organism.We take in account that most of healthy organisms produce billions of germ cells per their life,and most of those cells just die.For example a fish or frog could produce billions of berries during their life and most of them die or either most of their offsprins die very young.Then,most of mutations are harmfull and maybe only one per million could be helpfull for a particular species in a particular conditions.If we take all this factors in account then it would take a billion years for any particular species to get a smallest positive mutation.And evolution would be too slow to have any value.Also could you imagine how mutation from radioactive decay,for example,is able to crate some new and valuable proteine?It seems it could only destroy...When radioactive particle such as betta electron hits DNA molecule,do you think it is able to create something?Also,because vast majority of mutations are harmfull,then it is much valid choice for a living cells to aquire some mechanism of protection against of mutations than allow them to happen.And this is not extremely difficult to do.For example cockroaches are known to be extremely resilient to most of kinds of radiation.But species are clamed to be able to evolve quite fast.For example during last few tens of millions of years there evolved immense number of very different mammals.Could you explain it?
    Last edited by Stanley514; February 26th, 2012 at 02:38 PM.
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    Quote Originally Posted by Stanley514 View Post
    In this case,what is a sense for a nature to bother with different chromosome numbers?...
    you seem to imply that nature HAS to make sense - what gave you that idea ?
    as long as the process of reproduction works, however imperfect the copying machine works, there will be modified offspring

    nature may be imperfect + not often make obvious sense, but it always finds a way
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  11. #10  
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    In fact, to further Marnix's point, why bother with chromosomes at all? Prokaryotes get on very well without them.

    In fact, having chromosomes leads to telomere shortening (and so death), increases the probability of "errors" in copying DNA, and leads to disorders such as Down's Syndrome. In evolutionary biology, this makes sense, since this will lead to mutants and so drive evolution. But in a static, unchanging biology?
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    Hi Stanley514,

    Mutations are not as uncommon as you may have been led to believe. UV light is a well-known mutagen, and it is not alone in having this property - check out this list of chemical mutagens (1). Not only this, cells have a certain basal rate of endogenous mutation due to errors in DNA replication (2,3,4). When you take into account all of the mishaps that can occur during meiosis, it becomes more obvious how the mutation rate could be so seemingly high. I agree with you that mutations are more likely to have a neutral or detrimental effect on the resulting phenotype (like tinkering with a finely-tuned piano) however don't forget that evolutionary time scales are large in comparison with our lifespans and compared with the timescales that our brains have evolved to be able to comprehend. So, the propagation of positive mutations is feasible - moreover, once such a mutation has occurred, the penetrance rate in the population may well be high, if it provides a strong selective advantage. Oh, and, organisms have indeed evolved protection mechanisms against mutation e.g. DNA repair mechanisms (5), it's just that these mechanisms sometimes go awry (Nature is not perfect) and this is how mutations are allowed to happen. This is especially if, e.g. in humans, our cells lose their 'guardian of the genome', p53 (6). It can be difficult to get your head around how a single nucleotide change in a gene can produce a positive effect. Here is an example, G80A reduced folate carrier SNP modulates cellular uptake of folate and affords protection against thrombosis via a non homocysteine related mechanism (7).

    Best wishes,

    Tridimity

    Ref.

    1.Mutagen List - List of chemical mutagens
    2. http://www.ncbi.nlm.nih.gov/pubmed/1844244 - Endogenous mutations
    3.
    http://www.nature.com/nature/journal/v380/n6576/pdf/380683a0.pdf - Human minisatellite mutation rate after the Chernobyl accident
    4. The high spontaneous mutation rate: Is it a health - PNAS article, The high spontaneous mutation rate: Is it a health risk?
    5.
    DNA repair - Wikipedia, the free encyclopedia - DNA repair
    6. p53 - Wikipedia, the free encyclopedia - p53
    7. G80A reduced folate carrier SNP modulates cellular uptake of folate and affords protection against thrombosis via a non homocysteine related mechanism 10.1016/j.lfs.2005.02.029 : Life Sciences | ScienceDirect.com - beneficial SNP
    Last edited by tridimity; February 26th, 2012 at 06:19 PM. Reason: References messed up
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  13. #12  
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    Quote Originally Posted by Stanley514 View Post
    As I know there exist at least two arguments against evolution theory:

    1)Up to date no one scientist was able to create life in laboratory experiments
    from basic chemical components.This is supposed to be a way how life appeared
    on Earth according to evolution theory.Either, I still didn`t read anything about
    computer model of chemical processes which would show principal
    possibility of life self-generation from basic components.
    As others have pointed out, this is abiogenesis and is largely irrelevant to evolution. We have a lot of evidence for how various tages of abiogenesis could have occurred: creation of basic biochemical constituents such as amino acids, formation of membranes, sources of energy, etc. We don't have all the bits but there don't seem to any reasons not to think it came about through a natural process of "chemical evolution".

    2)According to evolution theory all kind of living spicies could be traced to some common
    ancestor.Even scpecies with different number of chromosomes.Usually only the same kind
    of spicies which have the same number of chromosomes give normal and fertile offsprings.
    Copies of whole chromosomes or sections of chromosomes can be produced during reproduction. This can be the first step in the creation of a new species. Once you have a copy of the chromosome, one copy can continue to provide the normal functions while the other is able to undergo mutation to generate new functions.

    You might want to look at this page with some examples of speciation: Observed Instances of Speciation
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    Stanley514,

    There's a awfully large amount of misconceptions in your last post. A worrying amount, so let me address a few of these below.

    When biologists speak of mutations being random, they usually mean that they are random with respect to organismal fitness, not that they occur at random. Most changes in DNA sequence are not harmful, but are in fact neutral. Natural selection can fix mutations that are beneficial, harmful or neutral.

    Chemical mutagens and radioactivity are probably only very minor sources of genetic variation at best and couldn't accurately be described as being the only driving force of evolution. Most genetic variation is introduced by other means including a whole variety of processes that could collectively be called recombination. It's also important to realise that much variation arises without any mutation at all (at least not the in the way you imagine mutation). Recombination is a key component of evolutionary change, as is gene flow. Smaller changes in DNA sequence typically arise, not through ingesting some mutagen, but by replication and repair errors.

    New genes don't typically pop into existence due to a mutation. What tends to happen is that genes get duplicated and then one of the duplicates subsequently diverges; this is one of the major patterns of evolution seen in the Metazoa (ie Animals) - the expansion and contraction of gene families (so-called "birth-and-death" evolution). Exon shuffling and the movement of promoters and other control regions is also likely to be important. As an example, consider the fact that humans have around 900 olfactory receptor genes (not all of which are functional now). Evolution didn't have to build all these genes one by one, base by base, using stray beta particles over a period of billions of years. What happens is than an ancestral gene has become duplicated hundreds of times and then each gene has become modified slightly and shuffled around onto different chromosomes. Under such a scenario I hope you can see that the "speed" of evolution is far greater than you might at first suppose.
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    Quote Originally Posted by Stanley514 View Post
    I guess, a bit more should be told about mutations which according to Darvin is only driving force of evolution.Because natural selection could only fix positive mutations.
    Note that the process is not: mutation -> selection -> new feature

    I would say the "driving forces" of evolution are:
    • population diversity, which provides a pool of different attributes to be selected from
    • selection, which determines which variants have some (usually small) benefit for survival and reproduction


    Mutations are one of the ways in which diversity is created. Perhaps the main way for most higher animals. For some species other mechanisms (e.g. gene swapping, hybridization) may be dominant.
    Last edited by Strange; February 27th, 2012 at 06:16 AM.
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    If I am not mistaken, there is some recent speculation that there might be something going on between intestinal bacteria and host DNA as well, which would be very interesting.



    BTW, a great series of posts in his thread. Really makes spending time here worth our while. Thanks guys!
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    As others have pointed out, this is abiogenesis and is largely irrelevant to evolution. We have a lot of evidence for how various tages of abiogenesis could have occurred: creation of basic biochemical constituents such as amino acids, formation of membranes, sources of energy, etc. We don't have all the bits but there don't seem to any reasons not to think it came about through a natural process of "chemical evolution".
    Let`s talk about abiogenesis then.If life could been created in nature from the simplest chemical components then those conditions could be recreated in laboratory.Why they can`t do this yet.Do you have any clue?
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    Quote Originally Posted by Stanley514 View Post
    Let`s talk about abiogenesis then.If life could been created in nature from the simplest chemical components then those conditions could be recreated in laboratory.Why they can`t do this yet.Do you have any clue?
    I assume because it was a very long and complex process involving many steps that we don't yet fully understand. Even when we do understand all the stages involved, it isn't clear that it could be easily replicated in a lab.
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    Quote Originally Posted by Stanley514 View Post
    Let`s talk about abiogenesis then.If life could been created in nature from the simplest chemical components then those conditions could be recreated in laboratory.Why they can`t do this yet.Do you have any clue?
    Just to amplify on Strange's comments. The simplest life today is vey likely more complex than the first life that came into existence on the Earth. The difficulty of the subject was long recognised, so that investigators steered clear of it as a subject appropriate for scientific investigation. Then, some thirty years into the 20th century J.B.S.Haldane in the UK and Alexandr Oparin in Russia independently published brief assessmentsof the topic that placed it on a firm, if restricted scientific basis. Then, a long pause when nothing much happened. Why? Any biologist worth his or her salt was getting to grips with the Modern Synthesis of Evolution that was being put together by Haldane and Sewell Wright and Ernst Mayr and Theodosius Dobzhansky and George Gaylord Simpson and others.

    Then, in 1952 Urey's research student Stanley Miller conducted the famous Miller-Urey experiment in which they tested the ideas of Oparin and Haldane in the lab. What was important about this experiment was not the findings, but the demonstration that the origin of life could be a valid field for laboratory study.

    Since then the sopihistication of laboratory experiments has advanced greatly and computer simulations of possible reaction pathways can be run. But we are still at the stage of trying to figure out details of specific stpes in what may have been the process byw hich life forms. Here is the key point Stanley: no life has yet been created in the laboratory because no researcher is trying to create life in the laboratory. (Please ignore the sensationalist reports in newspapers that researchers are trying to do this. This is down to a combination of reporter ignorance and editorial demands to sell more papers.)

    We have a great deal more work to do before we either postulate a full sequence of events that led to life and then duplicate these in the lab. The latter may never be possible, since the sequence of steps likely took many millions years, if not hundreds of millions of years to occur. We have less than half a centuryof serious investigation of this problem. I think we have come a long way in our understanding, but the good news is we still have a great deal more to learn and understand.
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    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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    I got to number 6 when it said "spontaneously formed..." then stopped reading. I guess thats why it's still called the theory of evolution instead of the Origin of the Species as Darwin had intended.

    btw, nice strawman Strange.
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    Lander_Greys,

    The spontaneous formation (self-assembly) of such structures is an an energetically favourable process. Spontaneous formation plays an important role in the formation of many biological structures - you'd be dead if it didn't. Wash your hands at the kitchen sink and think about the physics and chemistry of what is happening when you do this.
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    Quote Originally Posted by Lander_Greys View Post
    I got to number 6 when it said "spontaneously formed..." then stopped reading.
    knee-jerk reaction ? because i don't see anything offending with the line "Fatty molecules coated the iron-sulphur froth and spontaneously formed cell-like bubbles." ? that's simple chemistry that can be replicated in a lab
    of course if your mind switched off because it saw that line as evidence of spontaneous generation of life, you switched off too soon and read something that wasn't there
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    Quote Originally Posted by Lander_Greys View Post
    I got to number 6 when it said "spontaneously formed..." then stopped reading. I guess thats why it's still called the theory of evolution instead of the Origin of the Species as Darwin had intended.

    btw, nice strawman Strange.
    Take the word "spontaneously" out, if you like; it doesn't change anything.

    And it's not a straw man:
    Quote Originally Posted by Stanley514
    Let`s talk about abiogenesis then.
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    Quote Originally Posted by marnix
    "Fatty molecules coated the iron-sulphur froth and spontaneously formed cell-like bubbles." ?
    There Isn't anything spontaneous about it (I hate the word in general), there will always be a cause to these reactions that are externally caused. I refuse to acknoledge sources that overlook that simply on the grounds that "we don't actually know".

    Quote Originally Posted by marnix
    of course if your mind switched off because it saw that line as evidence of spontaneous generation of life, you switched off too soon and read something that wasn't there
    click on the "cell-like bubbles" link on that page and see what shows up.

    And it's not a straw man
    from the evidence above I'd say abiogenesis is directly linked to evolution under this contex. It's a strawman as it's sort of like a tree cutting off its own roots.
    I've never met a man who was more intelligent then I was. Then again, I've never met one who was as ignorant as me either.
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    Quote Originally Posted by Lander_Greys View Post
    And it's not a straw man
    from the evidence above I'd say abiogenesis is directly linked to evolution under this contex. It's a strawman as it's sort of like a tree cutting off its own roots.
    I'm not quite sure what you mean by "straw man" then.

    As I said, abiogenesis is a form of chemical evolution (including selection process, driven by thermodynamics). Once we have a full theory of abiogenesis, I'm sure it will be subsumed under a more general theory of evolution. But out current theory (theories) of evolution don't include abiogenesis.
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    I'm not quite sure what you mean by "straw man" then
    I'll give you that, my first hearing of the term was actually not a few days ago when I read you using it here in another topic. Perhaps you'll give me a "B" for basic understanding.

    Quote Originally Posted by Strange
    As others have pointed out, this is abiogenesis and is largely irrelevant to evolution.
    Quote Originally Posted by Strange
    ...current theory (theories) of evolution don't include abiogenesis.
    Then why did you give a link to one that did...? A tad confusing no?

    Perhaps this is what threw me off to begin with.
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    Quote Originally Posted by Lander_Greys View Post
    I'm not quite sure what you mean by "straw man" then
    I'll give you that, my first hearing of the term was actually not a few days ago when I read you using it here in another topic. Perhaps you'll give me a "B" for basic understanding.
    OK. So a straw man argument is when someone attacks a different point than the one you are making; for example:

    A: "Evolution is driven by selection on population variation"
    B: "How could a random mutation produce something as perfect as the eye?!" <-- straw man! A wasn't talking about "mutation" or "randomness" (never mind various other fallacies: eyes did not appear de novo, eyes aren't perfect, etc.)

    Quote Originally Posted by Strange
    As others have pointed out, this is abiogenesis and is largely irrelevant to evolution.
    Quote Originally Posted by Strange
    ...current theory (theories) of evolution don't include abiogenesis.
    Then why did you give a link to one that did...? A tad confusing no?
    Because Stanley514 said, "Let`s talk about abiogenesis then."
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    Quote Originally Posted by quote
    OK. So a straw man argument is when someone attacks a different point than the one you are making; for example:

    A: "Evolution is driven by selection on population variation"
    B: "How could a random mutation produce something as perfect as the eye?!" <-- straw man! A wasn't talking about "mutation" or "randomness" (never mind various other fallacies: eyes did not appear de novo, eyes aren't perfect, etc.)
    well I don't feel too bad then, I just misinterpreted your interpretation of Abiogenesis which to me seem more like an original standpoint on the origins of evolution than an alternate theory by itself. Perhaps we should look towards ways of safely advancing them into a simbiosis relationship

    Because Stanley514 said, "Let`s talk about abiogenesis then."
    Then I'll kindly ask that you never post links that are without direct context, especially here when the link itself seems to be more affiliated with the theory of evolution then abiogenesis. Sorry if I didn't catch your implied context.
    Last edited by Lander_Greys; February 27th, 2012 at 05:15 PM.
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    We have a great deal more work to do before we either postulate a full sequence of events that led to life and then duplicate these in the lab. The latter may never be possible, since the sequence of steps likely took many millions years, if not hundreds of millions of years to occur.
    It doesn`t sound convincing to me.According to the vews of modern science chemecal elements and other physical constants were exacly the same few billion years ago as it is now.Therefore those conditions could be easily recreated in lab.
    Defenetly the life that is able to self-organize from the simplest chemical elements should be capable to instant self reproduction.Because this is only way to support life in long term perspective.
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    Therefore those conditions could be easily recreated in lab.
    What conditions would those be, exactly?

    Trying to piece together events that took place 3-4 billion years ago is no trivial task, especially when much of the evidence has been destroyed. For all intents and purposes the earth of such ancient times can be considered as effectively being another planet, very much unlike the earth we know.
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    As I know most of known chemical reactions start instantly under right conditions.
    There is no chemical reactions which would take hundreds of millions years to start
    under right conditions.Chemical elements on Earth were not different 3-4 billion years
    ago from now.The simplest chemecal element that existed on Earth from very beginning
    is very easy to foresee.This is CH4,H2O,NH3,CO and CO2.Therefore mixture of those elements
    should be able to produce self-replicating life.Temperature is also should be easy to predict.
    Defenetly it should be higher than water freazing and lower than boiling point.Somwhere in
    this range for sure.Or you will switch from materialism to mysticism and say that we need some
    ``magic`` component?
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    Quote Originally Posted by Stanley514 View Post
    We have a great deal more work to do before we either postulate a full sequence of events that led to life and then duplicate these in the lab. The latter may never be possible, since the sequence of steps likely took many millions years, if not hundreds of millions of years to occur.
    It doesn`t sound convincing to me.According to the vews of modern science chemecal elements and other physical constants were exacly the same few billion years ago as it is now.Therefore those conditions could be easily recreated in lab.
    Defenetly the life that is able to self-organize from the simplest chemical elements should be capable to instant self reproduction.Because this is only way to support life in long term perspective.
    Perhaps you would be kind enough to describe the condtions that existed 3.5-4 billion years ago and why they are easy to recreate in a controlled setting.
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    Quote Originally Posted by Stanley514 View Post
    It doesn`t sound convincing to me.According to the vews of modern science chemecal elements and other physical constants were exacly the same few billion years ago as it is now.Therefore those conditions could be easily recreated in lab.
    Defenetly the life that is able to self-organize from the simplest chemical elements should be capable to instant self reproduction.Because this is only way to support life in long term perspective.
    It wasn't (can't have been) an instantaneous event. It was a long process requiring the gradual development of the conditions necessary for the next step.
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    Quote Originally Posted by Stanley514 View Post
    As I know most of known chemical reactions start instantly under right conditions.
    I have emphasised your remark, right conditions.

    One of the right conditions required for the emergence of life are a whole suite of complex chemicals and a range of self sustaining, perhaps cyclical chemical reactions. It will take time to build up the complex chemicals and the complex systems that will permit, or ensure that life emerges.

    Presently researchers are looking at what they suspect may have been specific steps in the process. When we have a better understanding of these steps, in detail, and can understand how they may inter-relate then we might consider trying to string them together. However, my suspicion remains that the process is so complex that it will take millions of years to duplicate. This doesn't mean someone will not try to do it, or that the attempt should not be made. It means it is unlikely to be successful.

    Quote Originally Posted by Stanley514 View Post
    The simplest chemecal element that existed on Earth from very beginning
    is very easy to foresee.This is CH4,H2O,NH3,CO and CO2.
    It turns out that this composition is rather unlikely. nitrogen and carbon dioxide were probably the major constituents of the atmosphere. Ammonia and methane were either absent or present in insignificant quantities.
    Quote Originally Posted by Stanley514 View Post
    .Therefore mixture of those elements
    should be able to produce self-replicating life
    No, they shouldn't, because those are probably the wrong compounds. Moreover we have no clearly established way in which prebiotic chemistry proceeded. Amino acids may well have been delivered, along with much of the Earth's water, by impacting comets and asteroids, for example. Or they could have been produced by one or more terrestrial means. These options are all being explored.

    You also make the simplisitc statement that we know what conditions obtained on primeval Earth. I ask you, where on primeval Earth? Around hot springs, in the ocean depths, in tidal shallows, on the surfaces of clay minerals, around black smokers? All very different conditions? Should they be reducing, or oxidising, or neutral? Acid or basic? What specific temperature range is needed for which reaction? Do some steps in the process occur in one environment and rely on chance transport of molecules to another environment? We don't know. Until we know or can make an educated guess then trying to duplicate the process in the laboratory is all but pointless.
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    We don't know. Until we know or can make an educated guess then trying to duplicate the process in the laboratory is all but pointless.
    Why is it so difficult to ``guess``?Currently chemical synthesis is well established science and scientists used to create many complicated organic molecules.They have powerfull supercomputers to calculate millions of possibilities for different chemical reactions.Do you think all thoses scientists are so stupid that they can`t even imagine what is needed for some reactions to occur?I read that such numerous experiments already been carried out.But no entity which is capable to self reproduction was ever created.This is what they have to do at least,not necessarly to recreate conditions which were on Earth exacly.To create an any selfreplicant would be their success.
    Presently abiogenesis has all the features of pseudoscience from modern point of view.It can`t be proved experimentally regarless relatively simple concept.And adherers of this theory can`t even explain why.In this case this theory could be regarded as unproved at best.
    Last edited by Stanley514; February 28th, 2012 at 08:58 AM.
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    Quote Originally Posted by Stanley514 View Post
    Presently abiogenesis has all the features of pseudoscience from modern point of view.
    Nonsense. We understand many of the possible steps very well. Many of these have been confirmed by observation or experiment.

    What features of pseudo-science do you think it has?

    It can`t be proved experimentally regarless relatively simple concept.
    Many of the individual steps have been replicated in lab or natural experiments. Obviously, the whol process cannot be repeated experimentally until we know what the whole process is. Duh.

    And adherers of this theory can`t even explain why.
    See above.

    In this case this theory could be regarded as unproved at best.
    Probably no argument with that. But then again, science rarely, if ever, "proves" things. It works better by disproving things.

    I would ask if you have an alternative but I fear that really will take us into pseudoscience.
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    Quote Originally Posted by Stanley514
    But no entity which is capable to self reproduction was ever created.
    Self-replicating chemical systems are actually fairly easy to create in the lab. Note too that it is by no mean certain that self-replication is even a necessary property of the first "living" entities. Whether replication appeared first or later is very much open for debate.
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    Pseudoscience?

    There are two, and only two options: Either life emerged from a concoction of non-living material all on it's own (abiogenesis) or some infinite being created it.

    Science does not concern itself with non-science/supernatural imaginings, only with those things that exist as part of our universe, things that follow the rules of the universe. So, as a scientific pursuit, life in the universe could only have come about all on its own from non-living matter. To suggest anything else means you are leaving scientific enquiry and moving into philosophy at best.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    Self-replicating chemical systems are actually fairly easy to create in the lab.
    I'm intrigued.Could you give me a link to decription of experimets with such results?
    Note too that it is by no mean certain that self-replication is even a necessary property of the first "living" entities.
    How else a life would be able to maintain itself in a long term perspective without self replication?
    Another only possibility are immortal creatures which could survive in any conditions.But nature have chosen the way we know.
    Even microorganisms which could survive on their own are able to selfreplicate.
    Last edited by Stanley514; August 31st, 2014 at 10:33 AM.
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    Life is metabolism and it is replication. Metabolism may have started first.

    If you are serious about learning more on the topic of self sustaining autocatalytic cycles and don't mind some heavy reading then refer to any of the books by Stuart Kauffman.
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    Stanley, it is likely that the "missing " ingrediant is time. Abiogenisis was a chemical process that involved a planet sized laboratory, running billions of cell sized experiments, varied randomly and culled by natural selection, over a billion or so years. Bob chemist with modest lab funded by a private university will need at least a hundred times as long to replicate the results. So ask again in a hundred billion years.
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    The abiogenesis discussion belongs in it's own thread, not one on evolution.
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    Quote Originally Posted by MeteorWayne
    The abiogenesis discussion belongs in it's own thread, not one on evolution.
    No, not really.
    I've never met a man who was more intelligent then I was. Then again, I've never met one who was as ignorant as me either.
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    Quote Originally Posted by Lander_Greys View Post
    Quote Originally Posted by MeteorWayne
    The abiogenesis discussion belongs in it's own thread, not one on evolution.
    No, not really.
    Well, they are realted issues, but they are also clearly separate. If we got incontrevertible proof that the first life was created by a direct act of God it would not alter in any way at all the theory of evolution. The theory of evolution works equally well with abiogenesis or God providing the first life form from which all others descend. the volution of mammals is related to the evolution of fishes, inasmuch as mammals are ultimately descended form fishes. But if we had a thread discussin mammla evolution there would be little point in debating aspects of fish evolution. It would be irrelevant.
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    Quote Originally Posted by Lander_Greys View Post
    Quote Originally Posted by MeteorWayne
    The abiogenesis discussion belongs in it's own thread, not one on evolution.
    No, not really.
    Yeah really. Evolution does not address how life first formed. only how it has evolved (note the word) since then.
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    ^Abogenesis was addressed in the OP, It's also been intricated into the thread throughout its lifespan. Not to mention it feeds off the theory of evolution to begin with. Obviously it's related.

    Or are we stretching you both too far to talk about two subjects in one thread? Especially when one topic lead to the other.
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    Quote Originally Posted by lander
    ^Abogenesis was addressed in the OP, It's also been intricated into the thread throughout its lifespan
    Darwinian evolution of replicating combinations of minerals, clays, and various chemicals inorgainic and organic both (note - not necessarily self replicating. "Outside loops" are easily incorporated into the theory) is the leading and best established candidate for explaining abiogenesis. It has the great advantage of being capable of explaining such an event, without recourse to remarkable and as yet never observed phenomena or events. But we are very poorly informed in the matter, and so it could not be and isn't nearly as solid and foundational a theory of that as it is of the evolution of living beings. We have no established theory of abiogenesis, at least partly because we don't know how, when, or where it happened.

    But we have very few candidate theories, and even fewer with any support in evidence. So Darwinian evolution seems by far the most reasonable and plausible working hypothesis. Do you have any objection to that?
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    Quote Originally Posted by Lander_Greys View Post
    ^Abogenesis was addressed in the OP, It's also been intricated into the thread throughout its lifespan. Not to mention it feeds off the theory of evolution to begin with. Obviously it's related.
    then the topic is mistitled in the first place, since how life first began on earth is NOT related to evolution.
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    Quote Originally Posted by MeteorWayne
    then the topic is mistitled in the first place, since how life first began on earth is NOT related to evolution.
    It is in this topic... and in the mind of the OP, unless you would rather have us take the Creationist approach which would get us nowhere.

    They're related under the context of curiosity and comparison. Thats all there is to it. There is no need to split up a topic simply because the OP saw something in a different light and you would rather ignore the viewpoint instead of looking through it. If you don't have curiosity and a thirst for knowledge, what is your purpose being here?
    I've never met a man who was more intelligent then I was. Then again, I've never met one who was as ignorant as me either.
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    The problem is the uncertainties regarding the specifics of abiogenesis are used as a supposed reason to discount the scientifically related, but notably separate, subject of the theory of Evolution.
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    Quote Originally Posted by Lander_Greys View Post
    ^Abogenesis was addressed in the OP, It's also been intricated into the thread throughout its lifespan. Not to mention it feeds off the theory of evolution to begin with. Obviously it's related.

    Or are we stretching you both too far to talk about two subjects in one thread? Especially when one topic lead to the other.
    Both topics are huge and as I have pointed out earlier although they are associated they are wholly independent. It is therefore not very tidy or sensible to dicsuss both in the same thread.
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    Darwin derived the idea of "natural selection" from the practice of selective breeding, as old as domestication itself and a product of intelligent discrimination. But is selective breeding a good model, having this property?

    And the truly parsimonious explanation for things which appear to have been designed- is that they are, in fact, designed.
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    Quote Originally Posted by Arthur Angler View Post
    Darwin derived the idea of "natural selection" from the practice of selective breeding, as old as domestication itself and a product of intelligent discrimination.
    Indeed. And, as far as I know, largely because of this, the general principle of evolution was well accepted before Darwin's work. His breakthrough was not in describing evolution, per se, but in coming up with a mechanism and an explanation as to how this could lead to the variety of species we see.

    But is selective breeding a good model, having this property?
    You mean, because it is driven by intelligence rather than natural selection? I'm not sure this is really relevant. In both cases there is selection of particular traits. Just because in case we choose the traits and in the other it is the environment, doesn't really affect the argument.
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    Quote Originally Posted by Stanley514 View Post
    As a result we may end up with two populations that are geographically isolated from one another. We can say that they are genetically isolated too (they do not breed with each other). These two populations are effectively now free to travel upon their own unique evolutionary trajectories becoming increasingly different from each other. Again, in time, they may become unable to breed with each other. A new species has been formed.
    This explanation doesn`t explain how species with new number of chromosomes could evolve.You still need to have some jump for it.It can`t happen gradually.For example there could be only 40 and 41 number of chromosomes but not 40 and 1/2.
    I havent read the whole thing, and dont know if its relevant or not but trisomy 21 exists in humans.

    "majority of mutation are harmful"
    The majority of mutations we are considering to a greater extent and observe because they happen to create a problem may be harmful, but how many mutations have no visible effects and how do you measure them if they are by definition without visible effect? How do we know if the T-cell mutation that prevents aids virus from affecting a certain % of the population exist without testing for this in particular, you cant tell whos got it and who doesnt by looking at them, and its actually beneficial if the person is infected by aids, but they might be more vulnerable to another type of virus (we probably would not know about that mutation if it werent for aids, and if we had learned about it throught a different disease for which its more deadly then would would probably call that same mutation a genetic "defect"). What about the "Balulla Factisimo Redux" mutation that has no known effect, are we going to spend time finding it and figuring out who has it as opposed to a genetic defect that causes people to die? What about blood type, there's several, is one more harmful than another? Do I get a survival of the fittest advantage for having AB+ or will I get selected out because Im B- which girls really consider as a negative in a mate? What Im getting at is that I think harmful mutations probably get more attention than ones without visible effect, and I think the multitude of mutations which have most of the time no blatant effect are probably underestimated.
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    Good point. In fact, most mutations are neutral (CB101: Most mutations harmful?). They contribute to evolution by providing diversity in the population, not by suddenly creating a new species.
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    Quote Originally Posted by stanley
    This explanation doesn`t explain how species with new number of chromosomes could evolve.You still need to have some jump for it.It can`t happen gradually.For example there could be only 40 and 41 number of chromosomes but not 40 and 1/2.
    Sure you can - if a chromosome breaks for some reason, such as during meiosis, but the pieces line up adequately or otherwise survive mitosis, for example (there are a variety of ways that could happen, including piggybacking on an existing chromosome, simply matching across the break, becoming a satellite unmatched piece added to the normally matched chromosomes, etc). Progeny can inherit the break, the incorporation or swap into existing chromosomes, or the piece(s), and end up with a different chromosome number nevertheless reproductive within the species - an unstable situation that will evolve fairly rapidly under even small pressures, such as drift.

    It's also possible for auxiliary duplicates in various number to carry into the progeny of sexual reproduction - trisomy 21 is one of just a few of these that are viable in humans, it's similarly uncommon but far from unknown in animals especially hybrids (mules, say, which have been known to reproduce btw) but in plants and fungi and the like this is very common and very often viable - hundreds of crop and garden plants have been bred in this manner.
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    I've always disliked the strong abiogenesis/evolution split. I don't think they can be separated so easily and suspect that the reason we say the two shall never be mentioned in the same breath is largely a misconception. Note also that there two uses of the word evolution. One is a theory, the other merely a description of origins, formation, development, history - of anything you care to imagine that can be described in such language (Stellar evolution, for example). So, when we speak of the "evolution of life" there are two evolutions we can speak of. I'd argue that both are applicable.

    The journey from simple replicating entities all the way to the last common ancestor of all modern day life is a process fully compatible with the concepts of evolutionary biology. If a replicator-first model (say an RNA world) is favoured, then I suspect also that the origin of that too can be dealt with by the concepts and language of evolutionary biology. Realising this raises an awkward question: what is the purview of abiogenesis exactly? It seems to me your stuck with some rather basic inorganic and organic chemistry of the sort that occurs in a glass beaker. A Miller-Urey stlye experiment would be the logical end of abiogenesis.

    I'm not convinced that abiogenesis can be studied without the use of evolutionary thinking. There must have been population-level effects that are somewhat analogous to selection or drift taking place, no matter how basic the system. If we go from ultra-simple chemicals to barely complex entities that are not even cellular in nature, and obviously beyond, then there must have been processes occurring that involve ancestor-descendant relationships or shifts in the makeup of populations or improvements in what we might call "fitness". All these things can be described by evolutionary theory just fine. I think the two subjects are heavily intertwined and have no clear boundary;

    When I mention this I usually get howled down - sometimes abusively. Oh well..
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    But evolution, means evolution of life after it existed. You can discuss prebiotic (chemical) evolution leading up to first life, but IMHO, that is a different subject.

    Sorry, no abuse available for a coherent post
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    That's one of the more common objections. I'll try and address it below and turn you over to the dark side.

    There are some interesting experiments with self-replicating RNA enzymes, such as those of Gerard Joyce and others (see ref.). In these purely non-living systems we have many of the essential properties of life including the fact they are template-based replicators that compete for resources. They are essentially primitive genetic systems with very simple behaviour, if you like. These populations of replicators evolve in a so-called Darwinian fashion (variation and selection). In other words they are described by, and in, the language of standard evolutionary biology. To design experiments with these systems and to interpret the results you have to think in evolutionary terms at all times.

    Making a distinction between living and non-living systems doesn't seem to be a valid reason to separate abiogenesis completely from evolution. A major portion of the abiogenesis story is undoubtedly an evolutionary tale. There are no rules that forbid us from widening the scope of evolution if it is required. Besides, I don't think it has somehow defined itself into a corner - it's scope is far wider than most would assume at first.

    In summary, it seems to me that it would be next to impossible to approach the origins of life without an evolutionary framework guiding us most of the way. I'm not even convinced the reason we split them so vociferously is nothing more than a anti-creationist defence that has somehow become gospel (maybe I'm going to far with that line of thought, but sometimes I wonder). Evolution is a subject that tends to be taught and discussed in a really odd manner, in that students, laymen and professionals tend to deal with subsets of the theory only. A truly holistic view is almost entirely absent. I think it can justifiably be extended, and it clearly is by some workers, to areas that most would not have considered before. Evolution of chemical systems is still evolution - population dynamics, mutation, selection, competition for resources etc. I think arguing that this is not within the scope of evolution is the far harder position to take.



    Self-Sustained Replication of an RNA Enzyme (2009)
    Tracey A. Lincoln and Gerald F. Joyce
    Science 27 February 2009:
    Vol. 323 no. 5918 pp. 1229-1232
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  61. #60  
    Administrator KALSTER's Avatar
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    In summary, it seems to me that it would be next to impossible to approach the origins of life without an evolutionary framework guiding us most of the way. I'm not even convinced the reason we split them so vociferously is nothing more than a anti-creationist defence that has somehow become gospel (maybe I'm going to far with that line of thought, but sometimes I wonder). Evolution is a subject that tends to be taught and discussed in a really odd manner, in that students, laymen and professionals tend to deal with subsets of the theory only. A truly holistic view is almost entirely absent. I think it can justifiably be extended, and it clearly is by some workers, to areas that most would not have considered before. Evolution of chemical systems is still evolution - population dynamics, mutation, selection, competition for resources etc. I think arguing that this is not within the scope of evolution is the far harder position to take.
    Well said.

    I agree, it is impossible to not include evolutionary thinking into the idea of abiogenesis. We also don't really have a consistent definition of life. To me a virus is also a form of life, while a prion might not be. Others might disagree, but it is obvious that the line between life and non-life is blurred, just as the line between evolution and abiogenesis is blurred.

    The distinct nature of the two disciplines is that abiogenesis means the development of life from non-life (whatever your definition of life might be), while evolution concerns itself with decent with modification. Therefore if you want to talk about where life came from, you are talking about abiogenesis, which might include some evolutionary principles, while evolution itself is the broad term for decent with modification.
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    I'm not even convinced the reason we split them so vociferously is nothing more than a anti-creationist defence that has somehow become gospel
    I think its related to language and the use of (simplistic) labels (words), like black and white, alive and inert, which sort of help communicating but also hinder comprehension of spectrum/gradual/cyclical/circular realities because we end up being somewhat mentally limited by the words we use to describe a reality that is more nuanced, dynamically changing and complex that a typical given simple and single word allows. This is all the more painful when people no longer recognize that the word they are using is a construct and start to think its a reality.
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