The Origin of Novelty

We're so lazy we could be bothered to look at the diagrams and see that there was a difference between the eyes other than size. Whereas you have evidently worked really hard on not noticing that.

Honestly: wasting my time.Good day, sir.

Webbed mustelids, for example. Most mustelids don't have webs. No, I don't imagine that. I imagine that webbed toes could occur by chance in individuals from all species of mustelidae, just as they occasionally occur in humans, but that they were conserved by natural selection in the otters because they were swimming and catching fish for a living, but not in others, like weasels, because they have no use for them, and could be slightly impeded by them.The same with ducks, geese, swans, etc. How could your fellow creationists "see that the only example that I can imagine is a mutation for webbed feet" when (a) I did not actually imagine its known occurrence in humans and (b) they don't know whether or not I can imagine plenty of others. Surely you credit them with some minimal intelligence, at least.But have I got your O.P. wrong? I was replying to this paragraph.... .....in which you observe that mutations must be continuing today, and seem to be asking for examples that could conceivably contribute to future characteristics.Isn't that what you meant?

Darwin actually did a good job of discussing the evidence as it concerns the eye (at least in molluscs):

quote:

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In looking for the gradations by which an organ in any species has been perfected, we ought to look exclusively to its lineal ancestors; but this is scarcely ever possible, and we are forced in each case to look to species of the same group, that is to the collateral descendants from the same original parent-form, in order to see what gradations are possible, and for the chance of some gradations having been transmitted from the earlier stages of descent, in an unaltered or little altered condition. Amongst existing Vertebrata, we find but a small amount of gradation in the structure of the eye, and from fossil species we can learn nothing on this head. In this great class we should probably have to descend far beneath the lowest known fossiliferous stratum to discover the earlier stages, by which the eye has been perfected.

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In the Articulata we can commence a series with an optic nerve merely coated with pigment, and without any other mechanism; and from this low stage, numerous gradations of structure, branching off in two fundamentally different lines, can be shown to exist, until we reach a moderately high stage of perfection. In certain crustaceans, for instance, there is a double cornea, the inner one divided into facets, within each of which there is a lens shaped swelling. In other crustaceans the transparent cones which are coated by pigment, and which properly act only by excluding lateral pencils of light, are convex at their upper ends and must act by convergence; and at their lower ends there seems to be an imperfect vitreous substance. With these facts, here far too briefly and imperfectly given, which show that there is much graduated diversity in the eyes of living crustaceans, and bearing in mind how small the number of living animals is in proportion to those which have become extinct, I can see no very great difficulty (not more than in the case of many other structures) in believing that natural selection has converted the simple apparatus of an optic nerve merely coated with pigment and invested by transparent membrane, into an optical instrument as perfect as is possessed by any member of the great Articulate class.

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Charles Darwin, Origin of Species, Chapter 6
The Origin of Species: Chapter 6

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This hits on two parts. First, a transitional fossil is not necessarily ancestral. This was made plain by Darwin from the very start. A transitional is a fossil or living species that show "gradations having been transmitted from the earlier stages of descent, in an unaltered or little altered condition".And of course we can point to much simpler eyes, such as those found in basal urochordates and planaria.

Why? Mutations can be observed to produce novelty in labs.

I think subbie gave you evidence in post #7 that might help in this conversation:"The website for Encyclopedia Britannica has a very nice graphic showing various stages in the process, including an example of a currently living organism for each stage." (emphasis mine)We see the transitional stages.

That was already done in a previous post [edit: a previous thread actually]. We used melanism in pocket mice because we could trace the adaptation to specific mutations in a specific gene:"We conducted association studies by using markers in candidate pigmentation genes and discovered four mutations in the melanocortin-1-receptor gene, Mc1r, that seem to be responsible for adaptive melanism in one population of lava-dwelling pocket mice."
Just a moment...So we can point to specific mutations that give rise to novel phenotypes.Edited by Taq, : No reason given.

Dog breeds adapted to water are a good example. For example, Newfies have much more webbing between their toes than wolves do. This is because this trait was selected for by breeders who were looking for a dog that is a strong swimmer (Newfies helped with gathering nets and saving those who fell overboard).We also understand the developmental pathways that are involved. We all start with webbed phalanges. During development a process called apoptosis removes the skin between them. For webbed feet, all you need is a mutation that turns off apoptosis during this period of development.

What makes it plausible is that each stage offers an advantage over the previous stage. A depressed pit offers crude directionality. Pinching the opening to a pin point can produce a focused image just like a pinhole camera. Covering the opening protects the sensitive retina. Manipulating that covering offers much better focusing, more light, and a better image.

Hi, Bolder-dash. This is something that boggles my mind, as well. There's also a fish that has a fin that looks like a smaller fish (complete with an eyespot), which it uses as a lure prey: how on Earth did it manage to evolve an eyespot in exactly that location, but not anywhere else on the fish?I don't have a complete answer to this question: each instance likely has a unique explanation. But there are places we can turn for insights. For example, arthropods are fantastic models for this, because there are certain traits and characteristics that are common in the group, but differ in placement on the body:Many insects have a membrane-like patch of exoskeleton called the tympanum, that serves as an ear, but they have them all over the place. Grasshoppers have tympana on their legs, moths have them underneath the wings, mantids have only one tympanum on the underbelly, etc.Many arthropods also develop venoms and silks. Spiders produce silk from spinnerets near the anus, and venom from their chelicerae (fangs); whereas mites produce both silk and venom from the chelicerae; and scorpions produce no silk, but venom from a stinger near the anus. Some insects also produce silk: caterpillars produce silk from spinnerets near their mouthparts; and Embiidina (or "webspinners") produce silk from their forelegs. Some insects produce venom, often in the saliva, but Hymenoptera (wasps, bees and ants) produce them in a modified ovipositor (egg-laying organ). Centipedes modified their first pair of legs into "forcipules," which deliver venom just like spider fangs do.So, from my perspective as a professional entomologist, it doesn't seem unreasonable to propose that characteristics can "pop" up on many different parts of the body. Why this doesn't seem to happen often in vertebrates, I don't know. Forgive me for posting yet another diagram, this one, but it's helpful.In this case, the diagram doesn't show evolution of the eye: it shows development of the eye, i.e., it shows how the eye grows from undifferentiated stem cells during the development of an embryo. Let's focus on the cephalopod eye (on the left).From the diagrams that Subbie posted, you see a diversity of mollusc eyes, and you'll notice that each of them corresponds roughly to a phase in the embryonic development of the cephalopod eye. This suggests that, for molluscs at least, eyes evolved by adding steps to the embryonic development of the eye.Also, it gives some insights into how the various phases develop at all. You mentioned 3 phases specifically: "shallow eye," "deeper eye" and "liquid-filled eye." You describe the "liquid-filled eye" as a "sudden" appearance, but, in actuality, it's not sudden at all. The eye cavity has always been filled with liquid (sea water), it just wasn't closed off from the sea.

I showed you a plausible chain of events. That it is plausible is demonstrated by the fact that we can see an organism that actually displays each step along the way. Rather than resorting to trite insults, perhaps you could explain exactly what it is that you are looking for, if not the steps that it took to get to a novel biological feature.

Hi, Taq. I feel obligated to point out that the "transitional stages," in this case, aren't arranged in a phylogenetic order that is consistent with our evolutionary story.For example, Murex is a marine gastropod, but, in that diagram of the "progressive" stages of mollusc eye evolution, it fits between two cephalopods. So, either the nautilus "pinhole" eye is a secondary development from a lensed eye, or the lens has evolved independently in Murex and octopus.I don't think this really hurts the evolutionary explanation, but the ordered sequence of stages is still an extrapolation from non-homologous data sources. That is, we don't have the direct evidence for all these stages yet.

Not as intellectually lazy as your side that hasn't even digested Darwin's original treatise of exactly this scenario from Origin of the Species. I mean - come on - you've had over 150 years to try and understand the implication of it all.The problem with creationists is that they are flora and fauna ignorant as well as scientifically ignorant in general. You have no idea of the vast array of organisms displaying vast intermediates along 'Mount Improbable' to quote Richard Dawkins.The eye: From flat-worms that can just discern light and direction, to a nautilus which can form a blurred pin-hole camera version - and then through the varying improvements in lens, retina formulation, chromatic pigmentation etc - there is a steady grading all the way from no sight at all to the ultimate (i.e. a bald eagle - or at night - an owl) for visual acuity.There is a steady grading from the bottom to the top. Each species has the eyesight that provides it's 'fitness' within it's gene pool. A flatworm doesn't need the eye of a hawk for example in it's muddy domain. And there has NEVER been a demonstration of any item of irreducible complexity - care to submit your candidates?Even your flagship creationist scientist (Behe) was crushed at the Dover trial - forced to admit that the field of immunology did indeed have numeruous volumes and papers detailing the evolution of the immune system which he said did not exist (creationists have had to resort to trying to use biochemical pathways as irreducible complexity examples as they have lost every case of physiological examples put forward by them).Behe tried to use the flagellar motor as irreducible and was crushed - he was sloppy and didn't realise that this had been well researched and biochemical pathways worked out (the TTSS system - a molecular 'pump system' has very similar structural components to the flagellar motor - and Behe didn't 'see' the connection....sloppy!! And he's the best you've so far wheeled out from your camp!).So, it is foolish to say that there is no gradation between no eyes and superlative eyes when the world is replete with just that. Eyes of every quality description etc you can imagine. Here's a challange - describe to me an eye that nature doesn't have. Bet you can't !!Now here's a bigger challenge. Given that every possible type of eye in every possible type of setting and quality already exists in the current life on Earth, and given that there is NO credible irreducible complexity issue (right down to the biochemical level that we can see) - please provide a mechanism for how gradation of eyes (or any other adaptive feature for that matter) cannot happen.Really! Darwin sorted the problem out for you 150 years ago - he took the trouble to learn botany and zoology, to study intensely and to report accurately - and then he gave you the info so that you too can understand the beautiful way in which it all works. It's so elegant....Why do you still have a problem? Is it that you are still scientifically illiterate? You can do something about that you know.......

I'd guess at positive selection on a chance marking that added to the lure illusion, and negative selection elsewhere when such chance markings occurred in individuals, perhaps because of interference with its camouflage, or the way the opposite sex expects it to appear. If you know its name offhand, we could look for a picture.

My intent was not to furnish an actual pathway from ancient beginnings to current day, but instead to furnish current examples of each of the stages of the evolution of the eye. But the point you made is important to note. Thanks.