I find this answer fascinating. How did the original IC system evolve? Dr. Spetner suggests that there is a limit to the mutations of an organism based off "how many essential nucleotides it has in its active genome." [spetner 1998 Not by Chance! pg.81] So if this is the case and the variability of a genome of a mammal is roughly 10 to the 24,082,400 power, which is taken on the assumption that the genome only consists of 1% of its dna being "real" information and the rest carrying no information,
How possible is it that the parts will transpose randomly in the genome to result in even one mutation that could result in an IC system?
You're starting with a false premise - that irreducibly complex structures exist, at all.
Short answer: they don't.
Medium answer: every single feature of every organism that currently exists or that we have ever examined from fossil evidence is a slightly modified version of the same feature on another organism.
Longer answer: Take the eye as an example. IC proponents tend to point out that, if you remove the lens, or cornea, or any other part of the eye, it ceases to be a useful structure. It therefor must be irreducibly complex, and could not have evolved. But this does not match up with the evidence. The eye, as a general structure, has evolved in several completely different, completely separated trees (all of the steps of eye evolution are just that useful). The first step is simply a photoreactive cell - something that can tell light from dark. This is useful - sunlight is a source of energy, so it's useful for an organism to be able to tell when it is sitting in sunlight. There are many examples of these - various bacteria, for example, and plants. The next step towards an eye would be having only a small cluster of photoreactive cells in a recessed portion of the organism's body. It doesn't have to be recessed much to make the simple light/dark detecting cells now able to sense the direction of the light as well as its presence - obviously more useful.
Check out the
Wiki article - rather than me typing the whole chain out, they have a decent description, along with a few examples of specific organisms with eye-precursors.
What is the chance of getting a mutation?
100%. Mutation happens literally
all the time. You, in fact, have as few as 50 and as many as several hundred mutations in your very own genetic code. The imperfect replication process makes mutation an inevitability.
What fraction of the mutations have a selective advantage?
Compared to the sum total of all mutations? Slim. Most mutations confer no selective advantage or disadvantage whatsoever. That's why evolution is only directly observable over multiple generations (not so easy with humans, but easy to observe in bacteria, for example, and some organisms mutate at an incredibly rapid rate, like the HIV virus).
How many replications are there in each step of the chain of cumulative selection?
You mean how many replications are necessary to fully evolve a given feature? False dilemma - each of the precursors to the feature you're targeting is, in itself, a fully evolved feature conferring a selective advantage. Otherwise, the final feature would not evolve. Evolution is not goal-oriented. If a beneficial mutation pops up, it will survive better than the organisms without the mutation. That's it. The "chain," as we're calling it, is a human construct to help us see all of the steps to evolving a given feature, but the implication that all useful structures require multiple steps of replication and mutation to evolve is not reflected by either reality or the theory of evolution.
How many of those steps do their need to be for a new species to form?
Many. You really can't get more precise than that, unfortunately - speciation is most commonly defined as when a descendant population is no longer able to reproduce with its ancestor population, creating two reproductively seperated populations. We have observed this in relatively few generations, but it's dependant on far too many variables to give a more precise answer. See, again, the
Wiki article.
Probably a very small chance of these accumulating especially those that need to result in order to achieve an IC system.
Quite to the contrary - beneficial mutations are
forced to accumulate. The better-adapted organisms are the only ones that survive selective pressure, and are thus the ones that continue to reproduce and mutate. If you have an antibiotic-resistant bacteria, and apply antibiotics to an area, the resistant population will be all that survives. This means the next beneficial mutation, whenever it happens, will HAVE to happen in addition to the resistance mutation, since that population is the only one still living.
And again - there ARE no irreducibly complex systems.
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Or the parts may become co-adapted to perform even better, but become unable to perform the specified function at all without each other.
Sounds like a guess, has anyone ever seen this? Is there any evidence that this has occurred?
Sure. The human eye again, for example. It's an evolved structure, as shown previously, but if you take one in its current form and, say, remove the retina, the eye no longer functions at all.
Irreducible complexity relies on the false premise that
evolved features spring in to being fully formed through mutation - ie, a heart's valves must suddenly appear, alone, before the heart can finish evolving. This isn't the way it works at all. Each individual mutation builds on a long history of previous mutations, each of which were beneficial to the organism. When you're taking baby steps, you'll eventually walk from New York to San Francisco, but none of the individual steps look all that different from the ones immediately before and after the current one.
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This brings up another point: the parts themselves evolve. Behe's parts are usually whole proteins or even larger. A protein is made up of hundreds of smaller parts called amino acids, of which twenty different kinds may be used. Evolution usually changes these one by one
As I understand it, if one amino acid in a chain is altered or mutated we can't really expect the same result in the phenotype as was prior the mutation. Correct me if I am wrong. Please don't bog me down with questions I can't answer, that is what you are for. Unless you can't answer please do not respond or lie. Thanks.
Wow. Let's try to be polite, shall we?
Changing an amino acid changes the protein, which
can make significant changes...sometimes. Sometimes, it doesn't do much, or anything. It depends on the gene, and the features the gene controls. Many features are controlled by multiple genes simultaneously, so a change in one will not necessarily cause a change in expression. Others are controlled by a single gene, and altering a single protein will have an effect.
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If you think about it, each protein that your body makes is made at just the right time, in just the right place and in just the right amount. These details are also coded in your DNA (with timing and quantity susceptible to outside influences) and so are subject to mutation and evolution. For our purposes we can refer to this as deployment of parts. When a protein is deployed out of its usual context, it may be co-opted for a different function.
EVOLUTION TO THE RESCUE! Seriously though it sounds interestingly too precise for random chance to produce. When has a protein been "co-opted for a different function?" I thought enzymes played a part somehow?
It's simple chemistry, TheWay - it's not random at all. Chemical reactions happen in certain, prescribed ways because of the physical properties of the chemicals themselves. While mutation is random, it's random within the set of possible chemical reactions, making it less akin to the moronic "tornado assembling an airplane" metaphor Creationists are fond of, and more like "I have a bunch of different shaped pegs and holes, and some of the pegs are made of gold - by trying the pegs and holes randomly, I'll eventually get some gold pegs on the other side."
As for co-opting for a different purpose: much like the "holes and pegs" metaphor, a protein can have more than one chemical reaction possible (like a small enough peg can fit through a hole of a different shape). A protein produced naturally in an organism for one function can be used by a mutation for another, entirely different purpose. Take a look at the
evolution of the Bombardier Beetle over at Talkorigins (another wonderfully debunked example of supposed "irreducible complexity"). Each of the chemicals and enzymes used by the beetle for it's trademark explosion are used for different purposes elsewhere in the organism, and had completely different uses in its ancestors. As an example, one of the chemicals used in the explosive reaction is used in other insects as a defense mechanism because it tastes bad to predators - the bad-tasting chemical was used for a completely different purpose in the beetle.
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A fourth noteworthy possibility is that brand new parts are created. This typically comes from gene duplication, which is well known in biology. At first the duplicate genes make the same protein, but these genes may evolve to make slightly different proteins that depend on each other.
Is the author talking about copying errors? Or is something else? He sure says "may" many times when speaking of evolution as a process. (just a quick jab to the ribs )
I believe he's referring to a case where a gene is transcribed multiple times in a single copy. So, in the sequence "ABC," the gene "A" is replicated an extra time and the sequence becomes "AABC."
We use "may" when talking about evolutionary processes because there are so many possibilities. Selective pressure, mutation, everything in evolution takes many, many forms. Sexual selection and genetic drift cause changes in allele frequency over time, just as the more direct "kill a big portion of the population and the strongest will survive" does, for example.
Irreducible Complexity is a dead idea. It's been debunked so many times that only the gullible or the uninformed still ascribe to it. Behe keeps writing books because there are still a lot of people who don't understand what evolution really is, and have a preset religious motivation to believe in a designer. Note that Behe never, ever addresses the actual scientific community. He never publishes any papers in scientific journals - all he ever does is try to convince the
general public, who know absolutely nothing about the topic and can be fooled so easily as to be embarrassing to the rest of us. What Behe and others like him say is self consistent, so it "makes sense" to the uneducated. It's unfortunately
not consistent with reality, and that unfortunately takes more education than the average person receives on the subject to understand.
Every time a fundy breaks the laws of thermodynamics, Schroedinger probably kills his cat.
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