The Evolution of Birds (Or: What missing link?)

Discussion in 'Biology & Genetics' started by Trippy, Sep 28, 2014.

  1. Trippy ALEA IACTA EST Staff Member

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    I came across this today:
    Birds Evolved From Dinosaurs Gradually, Capped With Diversity Burst

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  3. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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  5. Trippy ALEA IACTA EST Staff Member

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    ...Which, if you bother reading the article, doesn't contradict anything said by the article, which bases its conclusion off more than just the evolution of feathers. By the way, were you aware that Tyranosaurids have been found with feathers?
     
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  7. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    yep. lots of dinosaurs had feathers. it was a good mechanism to keep the body warm. the earliest ones looked like the feathers of baby chicks = i.e fuzz. As those dinosaurs evolved, so did the feathers, becoming elongated with a central spine, allowing for better capture of air around the body, keeping it insulated. Some of those dinosaurs likely became gliding, as those feathers also provided some aerodynamic lift when the airs were extended. Over time, it was advantageous to have one side shorter than the other, providing for a stiffer feather in the wind, allowing for first flight, rather than just gliding.
     
  8. Trippy ALEA IACTA EST Staff Member

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    And, once again we come back to the point that the article isn't just about feathers. You really should read it before commenting further on it.
     
  9. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    well, i've read it, and lots of others over the years.

    here's a good article: http://people.eku.edu/ritchisong/feather_evolution.htm
     
  10. Trippy ALEA IACTA EST Staff Member

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    I'm familiar with the evolution of feathers, and once again you're ignoring the fact that this article is not just about feathers.
     
  11. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Did not read article, but it had better tell how the lungs changed than how feathers developed - every intermediate stage must be viable - that is the problem.

    Birds that fly need high metabolism rate so have higher body temperature and much better lungs than man. Man spends half the time exhaling stale air, and worse has used only a tiny fraction of the O2 it contained - huge pumping "pumping energy" requirement. Birds, however have more complex only one way flow system and hold the fresh air static part of the time, and then slowly flow ONLY completely "fresh air" 100% of the time over the absorbing surfaces in their lungs to absorb their large (when flying) O2 requirements. Birds don't even need to expand and contract their rib cage! - That lets it be both stronger and stiffer with less weight.

    How can a two way flow system evolve to a one way flow system? What is the nature and advantage of a viable intermediate?
    I can find drawings showing how they avoid sending exhaled air back out the same path that is used to inhale, but can't get any to post yet. Here is less than 2 minute video telling all and why: www.youtube.com/watch?v=iigxJXFJF4U

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    There is certainly a great deal of "similarity evidence" other than the respiratory systems suggesting the now accepted POV that birds evolved from dinosaurs, but both having feathers is "small potatoes" compared to the lack of even any imagined viable intermediate respiratory system.

    Also it is quite common for similar structures to independently evolve - this has happen at least a dozen times with "eyes" - pit vipers "see" with stereoscopic vision in the IR to find a warm blooded mouse to eat. The octopus's eyes are quite human like in design, but better design as the retina is in front of all the blood vessels and data collection network of nerves, not behind them. - this transition too has no viable intermediate - hence an other wise IDENTIACAL visual system evolved independently. Often there is one best way to do any task and nature tends to find it, quite closely, so identical structures are to be expected, but do not PROOVE one evolved from the other.

    Mother nature is also often "trapped" by an early choice made. For example the giraffe evolved from creature with hardly any neck. One of the facial nerves connecting from its check to the brain happen to go under bone that became the "collar bone" There was no way that is viable to switch it to go on top of that bone. So now the neural impulses that for example tell the giraffe she bit her cheek go all the way down that long neck and then travel all the way back up it to reach the brain for processing what happened. No human baby that survives will ever get the retina up front of all that structure blocking part of the light. Humans are "trapped" with an inferior to octopus eye design.

    If creation "science" and the Bible are both correct this implies God looks like an octopus as he/she made it with the best eye design. "His own image."
     
    Last edited by a moderator: Sep 28, 2014
  12. Trippy ALEA IACTA EST Staff Member

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    Then why are you commenting on it?
     
  13. exchemist Valued Senior Member

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    Agree with Trippy that your point seems rather obscure.

    However, on the interesting point you raise regarding one-way breathing, a quick check on the web revealed the following, which may shed some light on what intermediate steps there may have been - and how long ago they may have started.

    http://www.newscientist.com/article...y-explain-dinosaurs-triumph.html#.VCg-Fkvlduo
     
  14. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Nice link. BillyT's link gave a good diagrammatic explanation. It appears that that puzzle is solved?

    As to Trippy's comments, I'm not ignoring the fact that the article is not just about feathers. But I believe that the evolution of the feather is fascinating, as so many dinosaurs had them, and they were not for flight, but warmth, display, etc. After the feathers, it then became possible for smaller feathered dinosaurs to glide, then fly and become true birds such as archaeopteryx, which entailed additional modification. The teeth are still present in some birds today, and can be induced to grow in non-toothed birds with suitable hormone application. If one wants to take a strange review, one could review the devolution of the penis in most birds, but the huge size in some others.
     
  15. Aqueous Id flat Earth skeptic Valued Senior Member

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    I just read the press release and the abstract but I was esp. interested in their remark that, upon doing a survey of all the known species in the lineage from dinosaurs to modern birds, they came to realize that the progression in morphology was so gradual that it defies any traditional search for a missing link.
     
  16. Trippy ALEA IACTA EST Staff Member

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    Exactly.
     
  17. exchemist Valued Senior Member

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    One further thought: unless I'm misreading the diagram, all the examples shown are of those branches that are NOT in a line of direct ancestry to modern birds. Why is this? Could a diagram not be put together that shows some fossils that ARE on the direct line, at intermediate points?

    Without this, it strikes me that this diagram could be a bit of a gift to a creationist - or would at least allow him some wiggle room.
     
  18. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Trippy complained that I should not comment on the article that I did not read. I did not. I only told two things:

    (1) The main problem with dinosaur to bird evolution theory is the lack of any advantage to adding parts of the one way air flow design while continuing to keep all the parts of a viable two way air flow system the dinosaurs used. (For any change to be selected for, it must give some advantage, not be an extra developmental cost that would be selected against.)
    Worse: No viable intermediate stage with advantage over the dinosaur's two way flow (in then out by same path for 50% duty cycle) has ever (to my knowledge) been suggested, much less one that gives any advantage.

    (2) There are many cases where "mother nature" has INDEPENDANTLY evolved quite similar structures to do the same job. - Such as gathering information from distant part of the environment by sensing / observing the radiation coming from it. Typically there is an optimum solution to this and to most problems
    and mother nature, given enough time comes close to finding it - Thus very similar structures, for example, a lens* with detectors in a curved 2D "focal plane" are what we find in many totally unrelated creatures.

    Thus, even identical structures are NOT evidence that one evolved from the other. For "vision" more than a dozen "eyes" (image formed on 2D plain of photon detectors) have independently evolved.

    The octopus visual system is identical to that of man, except for tiny details, that makes it better for seeing in dim light in the ocean deep - the retina is BEHIND the network of nerves and blood vessels that block a significant fraction of the light entering a man's eye (and I think, like cats and others that hunt in dim light, behind the octopus retina is a reflecting layer so light that did not activate a photon detector reflects back thru the retina to get a "second chance."
    This slightly decreases the resolution but very significantly increases sensitivity. Man and most other "day creature" have a black layer behind the retina to keep the resolution (no scattered light) as high as possible.

    My two points apply to all articles related to evolution - Are not comments on a specific article. Certainly not restricted to articles about how birds came to exist. They, for example, apply to how fish got legs.

    * Pit vipers and the Chambered Nautilus have no lens - they (and many others I'm sure) just use a "pin-hole" camera approach to image forming.

    I have found several images of the Chambered Nautilus, showing the eye, but now realize I can not post images after the change - tried many times in other posts with

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    and failed every time!
    Anyway the chambered nautilus is one of the most ancient creatures that still lives - a "living fossil" - It never got around to adding a lens.
     
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  19. exchemist Valued Senior Member

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    Re your (1), did you read the article I posted? This suggests that archosaurs already had the beginnings of the "one-way" system, achieved without supplementary air sacs, and that this was passed on to the dinosaurs. So that should give you an inkling of how the evolution may have occurred and also that it may NOT be a difference between dinosaurs and birds, as you seem to be assuming.

    Your point that one cannot assume similar structures evolved from each other is of course true in principle. The wing evolved at least three times independently, for example (insects, birds, mammals). However, when you have creatures with similar features that appear closely related for other reasons, it is still a reasonable working assumption unless there is evidence to the contrary.
     
  20. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Yes I read your link - But want to know what advantage part of a one-way flow respiratory system gave?

    Your second paragraph is refuted by the essentially identical eyes of humans and octopi.
     
  21. wellwisher Banned Banned

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    Evolution is often about superficial changes, which is often all you can get from fossils. But certain transition also needed major changes under the hood, that may not be easy to get from fossils. The air low system of the bird is like the turbo needed to get a performance enhancement, so feathers mean more than decoration. Until you have the power for lift, the feathers are decoration.

    In many ways, fossil evidence is like going into a junk yard, where most of the cars have been pillage of parts, with mostly hollow bodies of the car and trucks remaining. We can sort of infer engines by the mounts. The rear wings on the 1960's Imperial may be misleading, since they were not for go, but only for show. The real go was in the missing engine which you can only infer, with engine fossils lacking in the junk yard.

    This may be why evolution is less obvious in real time. Evolution may be waiting for the changes under the hood to change before there is need to change. We can design a car with fancy trim. But once you add a powerful engine this may cause too much shaking and need to be sheared off to avoid other problems.
     
  22. wellwisher Banned Banned

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    If you look at the evolution of the automobile, it was originally called the horseless carriage. It was a carriage with a motor. But by adding the motor, many design problems appear that were not important to the horse and carriage. The motor is heavy and hot. Now you need to firm up the chassis by adding more steal. You also need to add better brakes and steering because you lost the horse who once helped with braking and steering and had its own GPS. Now you need to carry fuel weight. Before, the horse could refuel from grass on the side of the road. One major change, like the motor, and new stresses appear. Before the engine, there is not much push to alter anything.
     
  23. exchemist Valued Senior Member

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    I assume the advantage for the archosaur and its descendants would be more efficient breathing. The article in fact states: "The researchers who have discovered the system in alligators believe it may have given dinosaurs the competitive edge over the ancestors of mammals following the mass extinction at the end of the Permian period, 250 million years ago." So there, if you had read the article properly, is your answer.

    My second paragraph would be refuted only if humans and octopi "appear closely related for other reasons" than the similarity (you've told us already there are not identical) between human and octopus eyes.

    You do not seem to be very good at reading comprehension. However this is understandable if English is not your native language.
     

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