Anonymous
Anonymous asked in Science & MathematicsBiology · 2 months ago

Can a succession of random mutations build a heart?

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  • 2 months ago
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    No, for two reasons. First, in order for any biological system to work matter must be shaped so that the system components fit interrelated components. Such shaping is impossible for natural processes because the number of unfitting components — those that won't fit interrelated components, exceeds the computational capacity of the whole universe from its birth to its death. The second limit is that, once in existance, the components must be functionally assembled. This cannot happen by natural processes because nature lacks causality for functional assembly. Let's now explain these limits in more detail.

    Whatever biological function we chose, be it: visual and auditory perception, physiological respiration, terrestrial and aerial locomotion, liquid pumping, processing sensory information, RNA splicing, adaptive immunity, sexual reproduction,... we immediately see that the components of the systems that perform them, must fit interrelated components.

    For practical demonstration let's use the mechanical gear system. This system was discovered back in 2013. in the small hopping insect Issus coleoptratus. The insect uses toothed gears on its joints to precisely synchronize the kicks of its hind legs as it jumps forward. Suppose that evolutionary development of this system is underway and all its components (trochantera, femur, coxa, muscles, ...) are in existence except the toothed structures. As with any system, its components must be shaped so that they fit interrelated components. So in order for this system to provide the synchronization and rotation function, evolution must reshape some preexisting structures into toothed structures that will fit both each other and other interrelated components. How is evolution going to do that? Well, there is only one way. By changing the DNA. This is the only possible way for evolution to reshape anything since biological structures are encoded in genes. In reality, toothed structures are the culmination of the interaction of many different genes over many generations of cell division. But, in order to make it as easy as possible for evolution to do the reshaping job, we will be extremely conservative and assume that toothed structures are encoded with only one average eukaryotic gene. Its size is 1,346 bp. So what evolution actually has to do is find the right DNA sequences of that length. The number of such sequences if extremely large since there can be many micro-deformations of toothed structures and their distinct shapes that will all fit each other and interrelated components, and in that way, provide synchronization and rotation function. Lets's call these sequences - the target sequences. However, the number of structures that won't fit each other and interrelated components (unfitting structures) is even larger. Just try to imagine all the possible shapes and sizes of non-gear structures. Now imagine all the micro-deformations of these structures. Now imagine all the micro swaps that produce equal macro structures. Thus, the number of unfitting structures is unimaginably large. Lets's call the DNA sequences that code these unfitting structures - the non-target sequences. So what evolution has to do is find the target sequences in the space of all possible sequences, that is, target and non-target ones. But is evolution capable of doing that? Unfortunately not. This task is physically impossible for evolution even with our extremely conservative assumption. Below we are explaining why.

    Since there are 4 nucleotide bases (A, T, G and C), the number of all possible sequences of length 1,346 is 4^1,346 = 10^810. Even under unrealistic assumption that toothed structures can tolerate 60 percent deformation and still fit each other and interrelated components, we get that the number of target sequences is 4^(1,346*0.6)=10^486. Given that all other sequences (10^810 — 10^486), are non-target ones, we get that only one out of 10^324 sequences is target sequence ((10^810 — 10^486)/10^486). That means that evolution would have to produce 10^324 changes just to find one target sequence. This is physically impossible because the theoretical maximum of changes that the universe can produce from its birth to its heat death, is approximately 10^220 (the number of seconds until the heat death multiplied by the computational capacity of the universe). Even with the absurd assumption that toothed structures can tolerate 80 percent deformation, evolution would have to produce 10^163 changes. And this exceeds the computational capacity of the whole universe from its birth to the present day. So it is physically impossible for evolution to produce even one fitting component, let alone a myriad of them in all the existing or past life forms.

    But let's now ignore the above problem. Let's assume that target sequences are found and that DNA contains all the genes necessary for the gear system to work. Does that mean that we have a working system? Unfortunately not. Having the right genes stored in the DNA is like having the right engine components stored in a warehouse. Just because they exist, that doesn't mean they will spontaneously assemble themselves into a functional engine. No causality for such an assembly exists in nature. Nature is not aware that functionally interrelated components exist and must be assembled together to help the organism to survive. Nor nature has assembly instructions. So, just having the right genes stored in the DNA, that is, those that encode the right shape of toothed structures, won’t make them to spontaneously express themselves at the right place and in the right time. Nor would that make the products of these genes to assemble themselves the right way into the functional whole. Evolution is capable of changing the genes, the same as corrosion, erosion or other natural processes are capable of changing the components of non-living systems. However, these processes are incapable of bringing separate components together into a logical and coherent system that will perform useful work.

    Therefore, the enormous number of unfitting components and the lack of causality for functional assembly, constitute a physical, chemical, and biological obstacles that prevent random mutations to build a heart, or whatever bio-system.

  • 2 months ago

    Yes, absolutely.  A VERY LONG succession of random mutations.  But what you don't realize or accept is that for ever mutation that takes one more microscopic step in that direction, at least a million mutations DON'T go that way.  But they have no advantage and so die out.

  • 2 months ago

    Yes they can when acted on by non-random natural selection.

    That is what those who try to deceive do not tell you. Natural selection, which is what acts on mutations, is the antithesis of random.

  • 2 months ago

    conceivably.  It isn't a huge step for a muscle to take on shapes instead of being a basic sphincter.  Combine sphincter (dilating muscles, a primitive heart) with longitudinal muscles to assist, and some changes to the piping, and you can get to a heart without major difficulties, as surprising as that sounds.  It is not a really complex structure, in an engineering sense.

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  • Cowboy
    Lv 6
    2 months ago

    If you're talking about evolution - or you THINK that you are - you should understand that even if genetic mutations are random, their selection by local environments is not.

    You have no idea what evolution is anbd what it is not.

  • ?
    Lv 7
    2 months ago

    No, certainly not.  However, a succession of random mutations subjected to natural selection has built all the hearts in existence.

  • CRR
    Lv 7
    2 months ago

    Only if there is a succession of steps, each one of which is beneficial compared to the previous one (with perhaps a few neutral ones). This is itself exceeding unlikely. Even if true there is the waiting time problem; how long does it take to make each step?

    When you're flipping a coin you get 50% favourable so a series of steps is feasible, but with mutations the beneficial ones are less than one in a million. Even then some beneficial mutations head off on a dead end path.

    When the problem is examined with realistic incremental steps and waiting times the answer is that a task such as this exhausts the probabilistic resources available.So even if possible in theory it is impossible in practice.

    Behe examined this in "The Edge of Evolution" where he used the natural experiment of resistance to anti-malarial drugs as a case study. Even the accumulation of two neutral mutations to provide a beneficial effect is only just feasible when dealing with bacteria with vast populations and short reproduction times. In animals with hearts the populations are relatively small and reproduction times long so even a two step mutation becomes a vanishingly small possibility.

    Further in Darwin Devolves Behe showed that even most adaptations that are beneficial actually result from mutations that damage the genes. This is confirmed in Lenski's Long term Evolution Experiment.

    Just saying that chance and selection will provide the solution is invoking evolution of the gaps.

    Source(s): To say "a succession of random mutations subjected to natural selection has built all the hearts in existence" is a statement of faith, not evidence.
  • Anonymous
    2 months ago

    As only the ones that give the creature at least as good survival as the previous generation did will likely reproduce, yes!

    Any mutations that decrease chances of survival are self-eliminating so the end result must be improvement and higher functionality.

    It's "chance" in the same way repeatedly tossing a coin is - then eliminating all the failures (tails) from the results.

    The input is pure chance but the end result all heads.

     

  • 2 months ago

    When filtered through non-random selection, sure.

  • 2 months ago

    Yes, but only if you have selection keeping the things that work.

    Body plan genes and improved multicellularity started our ancestors down that path in the "Cambrian Explosion."

    Edit:

    Behe wrote some interesting books, sure.

    So did Erich von Daniken.

    Both of those guys were wrong.  Read 'em for entertainment value only.

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