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I fail to see how natural selection can build any kind of new functionality.

New functionality in a design requires sacrificing a complex series of meanwhile useless steps before the new functionality works and becomes advantageous.

For example, if I want to upgrade a stationary chair to a wheelchair, there are many intermediate steps that must be done (which are not advantageous) before the added functionality becomes advantageous.

If a human being sits there and tries to intelligently assemble the wheelchair in such a way that it will be advantageous at each step, he will not be able to do it. it just doesn't work like this.

Can someone fill me in as to how this works and whether there have been experiments that demonstrate this, for example, having someone assemble a simple functional design with the limitation that every few step adds advantageous functionality.

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    $\begingroup$ This is a common misconception of natural selection: Not everything which appears needs to be new (there are szenarios in which other organs change) and not every step needs to be advantageous. It is enough if it causes no negative effects. $\endgroup$
    – Chris ♦
    Commented May 21, 2014 at 10:52
  • $\begingroup$ @Chris let's say for example sonar in bat navigation. how many changes are needed in coordination b4 the functionality becomes advantageous? $\endgroup$
    – user813801
    Commented May 21, 2014 at 10:55
  • $\begingroup$ have you ever tried to build a chair like this? it just doesn't work. $\endgroup$
    – user813801
    Commented May 21, 2014 at 10:57
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    $\begingroup$ Evolution by natural selection does not require that every intermediate step produces some kind of useful functionality - you are assuming some kind of cost to fitness imposed by intermediate steps which is great enough for selection to be effective. Evolution via natural selection leads to change because deleterious changes are selected against, and advantageous ones are selected for - however, selection is not the only force affecting evolution and not all changes to traits have fitness consequences (or strong ones at least). $\endgroup$
    – rg255
    Commented May 21, 2014 at 11:27
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    $\begingroup$ There are homo sapiens who can guide themselves with echo location. How can you argue that it's impossible to evolve when we humans already have it, without requiring specialized adaptations? $\endgroup$
    – swbarnes2
    Commented May 21, 2014 at 20:52

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This is fundamentally a teleological argument.

The error is in assuming that the intermediate steps were a precursor to the present functionality. For example, interpreting an 'intermediate' bird wing as a fully functional wing, intended for flight. In fact, there is no prerequisite that present characteristics or functions have evolved from intermediates that were intended FOR that characteristic or function.

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  • $\begingroup$ what you say is correct, but some things are totally useless without a combined and coordinated functionality and they are irreducibly complex. bat sonar for example requires sending out sound waves, a biological transducer, a signal processing etc. before there will be any useful functionality from this. what intermediate steps could possibly be useful here? $\endgroup$
    – user813801
    Commented May 21, 2014 at 20:10
  • $\begingroup$ You CAN get useful functionality from systems before they are in their modern configurations. The structure of the eye, the bombardier beetle; intermediates CAN have uses. How can you hope to prove that every single element of every single complicated system didn't? $\endgroup$
    – swbarnes2
    Commented May 21, 2014 at 20:50
  • $\begingroup$ @swbarnes2 true, but don't you agree that for some systems there is a minimum complexity before they can be of any advantageous functionality. and that minimum is in fact enormously complex. $\endgroup$
    – user813801
    Commented May 22, 2014 at 5:26
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There are so many wrong-headed premises here, one hardly knows where to start.

First of all, natural selection is the process of changing the frequency of alleles in a population, mutation is what creates new ones.

Second, just because you can't think of every intermediate step doesn't mean it's impossible.

Third, you are assuming that natural selection is so uber powerful that every single stop must be beneficial, and there's no evidence that that's the case. Evolution preserves lots of neutral and nearly neutral mutations.

Fourth, you are assuming that each step in some kind of path way can only possibly be used for the pathway it's in today. That's not true either.

If you want somewhere to start in the literature, try some papers by Lenski:

http://www.ncbi.nlm.nih.gov/pubmed/22992527

http://www.ncbi.nlm.nih.gov/pubmed/23918358

If you really want to argue that it's impossible for, say, E.coli to evolve the ability to metabolize citrate, because it's too hard to get from here to there, you need to address the empirical fact that these bacteria did just that.

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  • $\begingroup$ perhaps E.coli had this functionality built in to the dna. I have seen papers which claim the organism has the ability to modify the dna on its own. $\endgroup$
    – user813801
    Commented May 21, 2014 at 20:11
  • $\begingroup$ If the functionality was pre-built, why don't all E.coli have it? Did you read the paper, or even the abstracts? Modify its DNA with intent? I'm sorry, but there is no evidence of that. I don't see what the point of asking questions is if you are going to make up facts to bolster your per-determined conclusions. $\endgroup$
    – swbarnes2
    Commented May 21, 2014 at 20:46
  • $\begingroup$ pre-determined conclusions? I follow the truth wherever it leads me. for E.coli the process of how it evolved this ability has not been proven that it was through random mutations, correct? We just know it has an ability the parent did not have. but it could well be that there is some kind of pre-built mechanism in the E.Coli for making various "intelligent" variations of daughter cells and these variations. $\endgroup$
    – user813801
    Commented May 22, 2014 at 5:46
  • $\begingroup$ regaring the E-coli, I found this which plays it down "but it’s doubtful that Lenski’s E. coli have achieved any more than two mutations, so have not even reached Behe’s edge, let alone progressed on the path to elephants or crocodiles". from creation.com/… any thoughts? thanks for your patience $\endgroup$
    – user813801
    Commented May 22, 2014 at 7:24
  • $\begingroup$ e-coli already had some ability to metabolize citrate $\endgroup$
    – r2d2
    Commented Apr 20, 2015 at 10:56

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