Weird Eyes

By Carl Zimmer | October 21, 2008 12:07 pm

stalk eyed flyEvolution: Education and Outreach is a relatively new journal that helps teachers, students, and scientists teach evolutionary biology. I’ve just contributed a piece to a special issue on the evolution of the eye. I take a look at a couple examples of eyes evolving in weird ways. One example may be familiar to readers of this blog–the flatfish. The other example, illustrated here, is the stalk-eyed fly. The point I try to make in the piece is that these examples are not just a couple exhibits at a freak show. They tell us something important about the forces at work in evolution. Thankfully, the editors have made the journal open-access, so you can go read it for yourself.

CATEGORIZED UNDER: Evolution, Writing Elsewhere

Comments (22)

  1. A just-so story, also called an ad hoc fallacy, is a term used in academic anthropology, biological sciences, and social sciences. It describes an unverifiable and unfalsifiable narrative explanation for a cultural practice or a biological trait or behavior of humans or other animals. The use of the term is an implicit criticism that reminds the hearer of the essentially fictional and unprovable nature of such an explanation.

    Those who have a professional knowledge of the scientific method know that it is not possible to cook up after the fact explanations of just any trait. There are important constraints on scientific explanation. More to the point, every decent scientific explanation has testable predictions about the design of the trait.

    In short, your darwinian “explanations” are just so much horsepookey. There is not a shred of evidence to establish a plausible nexus between natural selection and the emergence of these traits

  2. Tucker

    “In short, your darwinian “explanations” are just so much horsepookey.”

    In what respect, Charlie?

  3. “In what respect, Charlie?”

    There is not one shred of empirical evidence, either observational or experimental, that establishes a plausible nexus between natural selection and the emergence of these highly organized and distinctive traits.

  4. Tucker

    What evidence can you hypothesize would be sufficient to establish this ‘plausible nexus’, and what would you consider as ‘highly organized and distinctive’?

  5. ” What evidence can you hypothesize would be sufficient to establish this ‘plausible nexus’, and what would you consider as ‘highly organized and distinctive’?

    I would have to see highly organized systems emerging from random, accidental occurrences.
    This has never been shown to occur. All highly organized structures, processes and systems,
    whose origins we can clearly establish, are the result of intelligent input.

    Highly organized means all of the parts have functions that not only support the other functions, but ultimately support the overall function of the device. This type of organization is not obtainable without insight, and insight always requires intelligence.

  6. (corrected)

    ” What evidence can you hypothesize would be sufficient to establish this ‘plausible nexus’, and what would you consider as ‘highly organized and distinctive’?”

    I would have to see highly organized systems emerging from random, accidental occurrences.
    This has never been shown to occur. All highly organized structures, processes and systems, whose origins we can clearly establish, are the result of intelligent input.

    Highly organized means all of the parts have functions that not only support the other functions, but ultimately support the overall function of the device. This type of organization is not obtainable without insight, and insight always requires intelligence.

  7. Tucker

    Sorry to be all philosophical here, but it’s important to have an understanding of terminology before I go rooting around for the appropriate papers that may convince you, but to clarify:

    To establish a connection between natural selection and biological complexity, you require empirical evidence supporting a system in which all parts have functions with inter-connected support that works together in support of an ultimate purpose?

    By function it’s safe to say you mean it performs a task, such as metabolizing chemicals, or reproducing, or making hair red, yes? Or were you thinking smaller scale, like codes for protein?

    I only ask ordinarily ‘complexity’ is measured by information content (and the definition of ‘information’ in that field isn’t really what would match our ordinary use of the term, so it can be confusing).

  8. amphiox

    Firstly, Charlie, natural selection is not a random, accidental process. It is highly directional.

    Secondly, there are NO highly organized structures, processes or systems that have EVER been demonstrated to be the result of intelligent input. Intelligence has only ever been observed to be capable of producing MODERATELY organized structures, processes and systems, at a level of complexity like that of a watch, fighter plane, or municipal legal system.

    No known intelligent agency has EVER been demonstrated to be capable of designing a truly HIGHLY organized structure/process/system, at a level of complexity like that of even a relatively simple ecosystem or organism. All known attempts have inevitably collapsed into chaos within a few decades/centuries once a critical threshold of complexity is surpassed, beyond which intentional intelligent design is simply unable to cope.

    The closest intelligence has ever come is with emergent systems like the internet or the stock market, in which individual components may sometimes be deliberately designed, but the whole emerges and evolves over time from the uncontrolled and unguided interactions of multiple component parts. And even these “quasi-designed” systems are nowhere near the level of complexity exhibited by your average ecosystem, or the biochemical networks of even the most basic microbe.

    Spontaneous self-organization, in which natural selection is just one of several known mechanisms, is the only process known that is capable of generating these kinds of systems and maintaining them in an enduring and stable equilibrium (as in lasting thousands to millions of years, as is the case for many ecosystems and lineages of organisms). To date there remains not one shred of evidence that intelligence is capable of any equivalent feat.

  9. “you require empirical evidence supporting a system in which all parts have functions with inter-connected support that works together in support of an ultimate purpose?”

    Yes.

    “By function it’s safe to say you mean it performs a task, such as metabolizing chemicals, or reproducing, or making hair red, yes? Or were you thinking smaller scale, like codes for protein?”

    Not all of your examples show function. Photosynthesis, protein synthesis, metabolism and molecular motors have function as do mitochondria, blood clotting and eyes.

    Complexity is a red herring that has nothing to do with evolution. Highly complex systems can be generated by random processes, but that’s not evolution. Some papers point to computer simulations to support evolutionary theory. Digital simulations and genetic algorithms have absolutely nothing to do with the kind of evolution that is said to occur in natural settings and is likewise useless. What needs to be done is to connect mutation and selection to the emergence of highly organized systems in which numerous structures and processes perform functions that support other structures and processes as well as contribute to the overall function of the organism. Remember that living organisms are biochemical machines with characteristics similar to other machines. A computer, for example has a power supply whose function is to produce various voltages, disk drives for storage, a processor to do calculations, a monitor to produce images, etc. Each of these structures performs specific functions that support other structures and also support the overall functionality of the computer. No one would ever imagine that a computer could have been the result of random, accidental processes or that it could have been designed and built without intelligent input.

  10. Mel

    There really is no point in arguing with Charlie. He is one of those people who just assumes he knows what he is talking about, and can pontificate against the evidence of evolution not being sufficient despite likely never having picked up a scientific journal. He will accept no argument that is contrary to his delusions, and will never be persuaded by any evidence for evolution. No matter what you answer him with, he will move the goal posts and change the standards, always demanding more, and when given more, declaring it still insufficient. After all, if you go by his website, you will see that he is also a Big Bang denier, as well as a supporter of Velikovsky (most famous for his bizarre and evidence-less idea that much of human mythology was related to events caused by Jupiter ejecting a comet that later became Venus as it passed the Earth – no it doesn’t make any sense). It is best not to waste your time with him.

  11. amphiox

    Charlie Wagner, living organisms are NOT “biochemical machines.” No known machine has ever been demonstrated to be capable of self-replication, and self-replication is THE defining characteristic of a living organism. Intelligence is only required for the assembly on non-self replicating systems, like machines. But living organisms are not machines.

    Another hallmark of machines is that they are chimeric. Component parts are assembled from a wide variety of sources, and are reused in unrelated machines. Living organisms never do this. All their component parts can be traced back to inheritance from a common ancestor and modification over time. If a mammal “needs” a wing to fly, it most certainly does not grab a bird wing “off the shelf,” it must redevelop a wing from pre-existing mammalian body parts.

    The discovery of a true chimeric organism would in fact falsify evolution, at least for that particular organism.

  12. “There really is no point in arguing with Charlie. “

    Thanks, Mel….

    http://www.politicsforum.org/images/flame_warriors/flame_77.php

  13. Mel

    Yep, that describes you quite well.

  14. Tucker

    “Complexity is a red herring that has nothing to do with evolution”

    How you plan to have organization without complexity I’m rather confused by.

    OK, so lets just stick with your examples eh?

    “Photosynthesis, protein synthesis, metabolism and molecular motors have function as do mitochondria, blood clotting and eyes.”

    Photosynthesis is a form of metabolism, so we’ll combine those and hit them first.

    Molecular Evidence for the Early Evolution of Photosynthesis: Science 8 September 2000:
    Vol. 289. no. 5485, pp. 1724 – 1730 [ http://www.sou.edu/biology/Courses/Bi332/Xiong.pdf (Direct Download)]

    This study contains a nearly full phylogenetic work up using genetic sequencing for a comparative analysis of the genes necessary for photosynthesis to function.

    Feel free to read what you can of the article (only seven pages) and let us know your thoughts regarding the findings of the relationship between these phyla.

  15. “Feel free to read what you can of the article (only seven pages) and let us know your thoughts regarding the findings of the relationship between these phyla.”

    I have no doubt whatsoever that they are related. They sequenced various bacteria (green sulfur and green non-sulfur) and drew conclusions about the phylogeny from these data. I could not help noticing that they clearly state ” The conflicting trees derived from such studies indicate that extrapolating the evolution of photosynthesis from nonphotosynthesis gene trees may be invalid.”

    I question whether these “”phylogenies” derived from comparative sequencing have any evolutionary significance at all. Evolutionists often confuse “relatedness” with “phylogeny.
    It certainly may be possible that the molecular sequencing data is not saying anything meaningful at all about evolutionary phylogeny and may be the result of some totally
    different, as yet unarticulated biochemical process related to normal genome functions.

    Even if you believe that valid evolutionary phylogenies can be constructed from sequence data (which I don’t!), there is still nothing in this report that supports the notion that random mutation and natural selection had anything to do with it.

    The authors further state “It should be emphasized that there is a conceptual difference
    between the evolution of photosynthesis and the evolution of photosynthetic organisms. The former involves only a limited number of genes for this bioenergetic process, whereas the latter involves the whole genome, the evolution of which is often represented by strictly vertically inherited genes such as the small-subunit rRNA gene.”

    There is one conclusion that I agree with- “Because the Mg-tetrapyrrole biosynthesis genes
    are shown to have largely co-evolved, these genes may have been transferred as an entity
    during early radiation from ancient purple bacteria, which are known to have all of their
    photosynthesis genes present in a tightly linked “photosynthesis gene cluster” (6).
    “Since the prevalence of lateral gene transfer among prokayotic microorganisms has been
    overwhelmingly demonstrated [see reviews in (24)], the gene phylogenies in prokaryotes
    may indicate only the evolution of specific metabolic processes rather than the evolution
    of the whole genome.”

  16. Owlmirror

    Even if you believe that valid evolutionary phylogenies can be constructed from sequence data (which I don’t!),

    Because you have a PhD in genetics that qualifies you to hold an expert opinion on comparative genomics?

  17. “Because you have a PhD in genetics that qualifies you to hold an expert opinion on comparative genomics?”

    I don’t need a Phd.

    Alan Greenspan has a Phd in economics and look what he did to our economy.

  18. Owlmirror

    I don’t need a Phd.

    Alan Greenspan has a Phd in economics and look what he did to our economy.

    As usual, you pack so many fallacies into a few sentences that that alone qualifies you for crackpot status.

    But just out of curiosity, I’ll focus on the anti-intellectualism.

    So you think doctorates are useless? How about education in general? Should we close all of the schools and colleges, just because Charlie says so? Maybe burn all books?

  19. “So you think doctorates are useless? How about education in general? Should we close all of the schools and colleges, just because Charlie says so? Maybe burn all books?”

    That really hurts.

    My first act of political activism was being suspended from High School for reading “Ulysses”.
    I marched with Bertrand Russell as a founding member of SANE.
    My whole life has been a long and passionate fight against ignorance and censorship.

    You certainly don’t know me very well.

    Check out my website at “charliewagner.com” before you make these ignorant remarks.

    My point was that a PhD doesn’t guarantee wisdom.

  20. Owlmirror

    My first act of political activism was being suspended from High School for reading “Ulysses”.
    I marched with Bertrand Russell as a founding member of SANE.
    My whole life has been a long and passionate fight against ignorance and censorship.

    Good for you….

    But while I will concede the point on the issue of the worthy fight against censorship, your current activities do certainly all appear to be arguments from ignorance.

    You certainly don’t know me very well.

    I have seen your arguments all over the web. I know that in the face of actual cosmology, actual physics, actual chemistry, actual biology… you provide nothing. I know that when asked about what actual books on the topics of developmental biology or cellular biology or biochemistry or genetics you have read, you never answer. I know that you’ve had the fallacies in your arguments pointed out over and over again. I know that you never seem to learn.

    I know that I find this disappointing, and saddening, and irritating, and ever so slightly creepy.

    I know that it’s ironic for you to demand that I inform myself about you before making statements about you, while you have not bothered to inform yourself about biology and other sciences before making statements about them.

    My point was that a PhD doesn’t guarantee wisdom.

    Yes, yes, yes, I know. Data is not information, information is not knowledge, knowledge is not intelligence, and intelligence is not wisdom.

    But you can’t have wisdom without intelligence, you can’t have intelligence without knowledge, you can’t have knowledge without information, and you can’t have information without data.

    And you don’t have anything.

    Sheesh.

  21. “And you don’t have anything.

    Sheesh.”

    You didn’t leave me much to work with. ;-)

    I have no intention of rehashing my arguments or defending my credentials.
    It’s all there for you to see.

    So you won’t be disappointed, I offer the following for your divertissement

    On The Value of Theories and Hypotheses

    The only reason for having theories and hypotheses is to guide
    experiment. They have no value on their own as truth.
    The very idea of “selecting” between competing theories is
    ridiculous. It brings us no closer to the truth. The way to
    decide among competing theories is to test them, not decide
    which is probably true based on some theoretical calculations
    or by using some trick, like Occam’s Razor.
    After you collect all of the data, then you can draw
    conclusions as to what is or is not likely. And one theory will
    usually emerge as superior. Truth does not flow from the human
    imagination, it flows from experiment and observation. That’s
    the only thing that has value. Speculation is interesting and
    keeps the mind amused and helps us to design experiment, but it
    serves no purpose in it’s own right.
    Of course, the number of possible hypotheses is infinite.
    The human mind can create an unlimited number of scenarios to
    explain any observed phenomenon. But if that is true, it’s not
    just a minor flaw in scientific reasoning. It becomes quickly
    evident that all possible hypotheses can never be tested.
    This may not seem to be a problem until you consider that if
    this is so, then the results of *any* experiment will never be
    conclusive. The scientific method becomes incapable of proving
    anything, ever.
    But this is not catastrophic because fortunately, science is not
    in the business of proving and disproving things. The business
    of science is saying what is most and least likely. In addition,
    what is sometimes referred to as “scientific truth” is a very
    fleeting phenomenon at best, and is inversely proportional to
    investigative effort. In the past, scientific truths lasted a
    long time, because very few people were looking very much.
    But as time goes on, their lifespan is becoming increasingly
    shorter. Science finds itself today leading mankind, not to a
    single, absolute truth, but to multiple, indeterminate, relative
    ones. Rational science is supposed to eliminate this uncertainty,
    but it does not. In fact, it contributes to the chaos. Look at
    what we deal with on a daily basis. Studies of various kinds are
    reported every day with wildly varying claims. This is good for
    you today, but it was bad for you yesterday. Substance after
    substance is demonized by alleged “scientific studies” that tell
    us things that we know are not true. Sugar is evil, salt will
    kill you, eggs will give you a heart attack, fat is poison,
    blah, blah, blah. Science is not making things clearer its making
    people crazy. So what happens?
    They look for an anchor, something that doesn’t ever change,
    that is constant and supportive. So they turn to God and religion.
    It’s inevitable. I don’t agree with it, but I understand it.

  22. Owlmirror

    I have no intention of rehashing my arguments

    Which are all fallacious.

    or defending my credentials.

    Which are all nonexistent.

    I offer the following for your divertissement

    A diversionary tactic, indeed. Which, I note, serves your own arguments not at all, and is actually in support of evidence-based science – like modern evolutionary biology.

    You still have nothing.

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The Loom

A blog about life, past and future. Written by DISCOVER contributing editor and columnist Carl Zimmer.

About Carl Zimmer

Carl Zimmer writes about science regularly for The New York Times and magazines such as DISCOVER, which also hosts his blog, The LoomHe is the author of 12 books, the most recent of which is Science Ink: Tattoos of the Science Obsessed.

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