Friday, April 29, 2005

CONTINUATION: Ever Wonder Why Creationists and Biologists don't see eye-to-eye?

` In the article 'bird evolution flies out the window' by Jonathan Sarfati, there is also a link on the word Archaeopteryx, which I'll comment on next.

` Before reading this, it is very important to know one thing - that the people at Creation (typical of creationists) seem to assume that (scientifically?) there are somehow 'classes' of organisms discrete from one another, in between which there is a barrier that would be difficult or impossible to evolve across.
` Because this is not true, terms like 'Class' can't be used much in science anymore because you can't work with them in practice.
` Science, as you should know, is not about thought experiments - which are therefore favored more by pseudoscience - as its very nature insists that you make things work in the real world.

` The seven nesting 'steps' of Linnaeus (e.g. Class, Order, Family) are not enough to contain most categories of life, as there are known to be too many (though categories still fit inside other categories just the same). In reality, there are thousands of known 'steps' all throughout various sections of 'family trees', since too many known species lie 'in between' the former seven.
` Instead of adding more and more steps with the prefixes supra-, super-, sub-, and infra-, scientists have grown weary of this and simply call them all 'taxons' or 'clades.' The only Linnaean terms that are of any great value anymore are 'Genus' and 'Species'.

` I should note that birds have (for at least a century) been considered one of many clades of reptiles, even back when they formally used 'classes'. The 'bird class' was simply integrated into the 'reptile class'. If the thought of this gives you a headache, I think I've gotten my point across.

` Anyway, the link goes to this interview article with a retired anatomist by the name of Dr Menton;

Bird evolution flies out the window, by Carl Weiland

Weiland; "Of course, evolutionists have long argued that feathers evolved from reptile scales and are thus fundamentally the same structure - very similar."

Dr Menton; "Yes - so I became interested in comparing them myself. I had a laboratory technician at the time who had a 'pet' boa constrictor, so I took a look at some of its scales from shed skin. I was amused that they were, of course, not even the slightest bit similar to feathers... The only similarity is that they are both made of the protein keratin - like hair, nails and our skin."

` Wow, what a scientific observation! For one thing, his point is rather similar to saying that a dolphin's flipper must not be a forelimb because it doesn't look like an impala's front leg, even though both are made of the same bones and muscles.
` For another thing, the kind of scales that snakes have are not thought to have evolved into feathers anyway, but he probably would have said the same thing about any old scale.

` The key to understanding almost any type of evolution lies in modification! One thing you have to study to determine that feathers and certain scales are the same thing is their development. In my DatD series, you will see that the type of scales that extinct dinosaurs had, which are found on birds' feet, can be simply and easily coaxed to develop into more or less normal feathers. It's a very strange, long story.

` Ed. note: after this Creation magazine article was written, we came across evidence that even this similarity may not be as great as supposed. Feather proteins (f-keratins) are biochemically different from skin and scale proteins (a-keratins). An evolutionary feather expert, Alan Brush, concludes;
` 'At the morphological level feathers are traditionally considered homologous with reptilian scales. However, in development, morphogenesis, gene structure, protein shape and sequence, and filament formation and structure, feathers are different.' A.H. Brush, 'On the origin of feathers', Journal of Evolutionary Biology 9: 131-142, 1996.'

` Not only is that not a secret, but that was completely taken out of context! Another very common creationist trick!! Now, see, if you've read my DatD series, you'd already know that reptillian scales (also called reticulae), which birds have on the very bottoms of their feet, really are that different than feathers.
` However, scutes, which are scales that crocodiles and birds also have, are chemically about the same, and are known to trace their roots from the same part of the DNA as feathers.
` Developmentally, they are similar, and it is the scutes and scutellae which can develop into feathers through simple genetic manipulation.
` Of course, dinosaurs are also known for having scutes and scutellae, including the Maniraptora, which is one of the 'steps' that birds are contained in.

` Back to the article - they're mulling over whether people back at the 1984 International Archaeopteryx Conference thought that Archaeopteryx was a bird or a coelurosaur. I admit I know nothing about this convention itself, but I still find something wrong here - Dr Menton says that most scientists there thought it was a bird, and not many thought it was a dinosaur.
` Bird or dinosaur?
` Once, birds were only thought to be reptiles of some sort, but no one was really sure which sort. Archaeopteryx wasn't thought to be either a bird or a reptile. The question posed at the conference would have been 'Is Archaeopteryx a dinosaur that was a bird or a dinosaur that was not a bird?'
` Honestly, since Archaeopteryx actually had more in common with the dromaeosaurs than it did modern birds, this was a very tricky question.

` Today, birds are now agreed to be coelurosaurs as well as maniraptors, just as Velociraptor was. Birds have a few specialized characteristics of their own group, for example, a certain type of tooth structure the others didn't have, or a certain type of wishbone, or subtle differences in various bones. Some of these subtle differences could affect the flexibility of the skull, which is a subject Menton mentions shortly.
` If you didn't know, dinosaurs had rather flexible skulls, capable of something called metakinesis, which is where various parts of the skull can move independently of other parts. Birds (and some dinosaurs) are capable of what is called prokinesis, which is where the entire top jaw can move up and down.
` It is now thought that Archaeopteryx could move its top jaw up and down, though probably only slightly. Basically, most of the differences between primitive birds and, say, the dromaeosaurs, are actually quite subtle when you think about it.
` Anyway, it should be by clear now that birds are pretty much unanimously thought to be warm-blooded, dinosaurian reptiles of the maniraptor clade, just like Velociraptors are. So when Menton says;

` If, of course, it's a true bird, it is not the half-way, half-reptile, half-bird like we've often heard.

` ...that has nothing to do with 'what scientists think' - or even tell people. In fact, Archaeopteryx is not technically classified as a 'true bird' and is not thought to have evolved into either 'true birds' or enantiornith birds, which are now exinct.
` Anyway, so he's saying;

` The general consensus now is that the brain is essentially that of a flying bird, with a large cerebellum and visual cortex. Also, in most vertebrates, including reptiles, the mandible (lower jaw) moves, but in birds (including Archaeopteryx) so does the maxilla (upper jaw).

` Right. Its brain - though smaller than the brains of other birds - is specialized for flying, though still, dromaeosaurs and troodontids - the most birdlike dinosaurs - had somewhat similar and relatively large brains - and similar skulls, which were capable of moving in somewhat different ways.
` Anyway, so Weiland says;

` Evolutionists point out that it does have some characteristics which are found in other classes, such as reptiles.

` Here we go again - evolutionists may point out that birds are actually reptiles, therefore they do not think that birds are a different 'class' from reptiles! 'Class' is a concept that has had its uses, but today, the work of scientists is too complex to use it.

` Menton; "This is true, but then it's true of almost any vertebrate skeleton. There are also design similarities between reptiles, mammals and living birds too. Birds have a distinctive, specialized skeleton because, as one distinguished evolutionist who is also an ornithologist once said, 'Birds are formed to fly.' So was Archaeopteryx.

` And so are bats! Not all birds can fly, anyway. Kiwis and ostriches evolved from birds that did, and one could say that these animals are 'built like animals that are descended from birds formed to fly.' (Also, many of the features that were previously thought to be essential for bird flight, such as the wide range of motion in the arms and the air-sac-filled bones, are also found in theropod dinosaurs!)
` In other words, Dr. Menton's above statement is just a bunch of fluff that explains nothing, typical of such creationists. Menton next says;

` Archaeopteryx was not the only fossil bird to have had grasping teeth. Some fossil birds had teeth, some didn't. But how can teeth prove a relationship to reptiles, when many reptiles don't have teeth? Crocodiles are really the only group of reptiles that consistently have well-developed teeth. And of course even some mammals do and some don't.

` I think I'm headed into a fluff-storm! He's acting as if scientists are trying to say that always having fully-developed teeth is a defining characteristic of reptiles. It's not - just as always having fully-developed legs is not.
` What scientists do think is that since primitive birds have teeth, then their ancestors must have been toothed reptiles. Since dromaeosaurs and troodontids have similar teeth, as well as just about everything else in common with primitive birds (except for well-developed flight), then there must be a genetic connection between them and primitive birds.
` In fact, when a bird's newer genetics are suppressed, it results in a bird with teeth or a tail similar to that of the earliest birds. This must mean that modern birds must have evolved from primitive birds. (Oh no!)

` Anyway, Menton's statement basically consists of an attempt to undermine scientific findings and steer the reader away from the point by making it sound as if scientists think Archaeopteryx descended from 'reptiles-in-general.' (I've also heard creationists outright say this!)

` Weiland; Some evolutionists have claimed that Archaeopteryx was just a dinosaur plus feathers, in effect. Others have suggested that it's just a hoax - a dinosaur fossil plus chicken feather imprints.
` Menton; Yes they have - Sir Fred Hoyle, for example.

` Yes, these people just love mentioning the names of scientists. In this case, I happen to know offhand that Fred Hoyle was more of an astronomer and sci-fi writer than anything. Though he is renowned, I'm not entirely impressed with him. I read his 1980's pseudoscience book The Intelligent Universe several years ago. Since, back then, I didn't know that science is not immune to sometimes being used as a guise for non-scientific or anti-scientific ideas, I actually took it seriously.
` He was even worse at biological hypotheses; In 1985, he said that the bones of Archaeopteryx were those of a Compsognathus, a primitive coelurosaur (which it closely resembles and has been confused for in the past), but with feathers carved on it. Funny - there are no chisel-marks, only microscopic details of bird feathers!
` Also, the specimens are lined up exactly on both slabs with minute cracks in the limestone - which is definitely something people in the 1800s didn't even know about because you need an electron microscope to see them.
` Because of these cracks, which go all the way through the feathers and bones and everything, lining up in the exact same places, forging an Archaeopteryx would be impossible to do, even today.
` On top of this, in 1988, Hoyle then decided Archaeopteryx wasn't even a dinosaur at all but a pterosaur, which is a whole 'nother ballgame, to say the least. One can conclude from even this incident alone that he clearly didn't know what he was talking about.

` ...Anyway, I was just pointing that out - Menton does not agree with Hoyle, either. I think he probably mentioned his well-respected name just to make the consideration sound reasonable, as many creationists also think it's a fake. Back to the article;

` The feathers are not just simply applied to the surface of the bird. Where they are attached to bone by ligaments, we see tiny 'bumps'. So in Archaeopteryx, the primary and secondary with feathers are attached to the 'hand' and ulna, respectively. And the feathers on the tail are actually minutely attached to each of the 20 vertebrae. There are also a lot of small feathers on the legs and body of this bird, and there is compelling evidence that the head was covered with feathers, too. However, when you see pictures of Archaeopteryx or its imaginary ancestors, it's quite common for artists to show a scaly head.

` Scaly head? I don't remember seeing any pictures like that. Then again, he's probably referring to popular artists, which creationists commonly confuse with scientific artists. Also Archaeopteryx has 22 vertebrae, not 20, and I'm not sure about some of the other stuff.

` Weiland; Do the feet of Archaeopteryx support the view that it was a dinosaur that ran along the ground?
` Menton; No. Archaeopteryx, along with all the perching birds, has what is called a grasping hallux, or hind toe, pointing backwards, Rearward-facing toes may be found in some of the dinosaurs but not a true grasping hallux with curved claws for perching.

` Yes this is true - Archaeopteryx's hallux seems to have been opposable, if a little high up to be the most suitable. And then he starts talking about how hair and feather follicles have nothing to do with scales and more to do with each other. I don't really know enough to make an intelligent-enough answer here, but I can tell you that the way he's talking about it is much too simplistic to really be saying anything important.

` For now I can say that, since feathers are apparently common in smaller theropods, it would make sense that the simplest type of feathers - down-like structures - were the first to evolve, and later feathers with rachides evolved as 'guard hairs' perhaps. From all the evidence that exists, this makes sense.
` As far as why they evolved, it seems to be because dinosaurs had a body temperature to maintain, so to prevent themselves from having to stay in warmer areas, and to conserve energy and therefore fuel intake, they could retain heat with their feathers. The creationists will tell you that the evolutionists think differently, though:

` Weiland; How do evolutionists believe birds evolved flight?
` Menton; There are really two theories - you can't test either, of course.

` Typical downplay, 'you can't test'... which specifically means you can test everything relevant, but you can't watch it actually happen because that is the normal nature of history. That's what you get when you're faced with the task of reconstructing history of any type, though, not just biological.
` The current theory is that small maniraptors similar to dromaeosaurs and Archaeopteryx most likely used their feathers to glide through the trees. But what does Menton say?

` The arboreal theory says that they started up in the trees, and flew down, and so scales are viewed as having grown longer and longer somehow to promote gliding.

` Uh... like I said... no. He's just making it sound silly. Allow me;

` When animals fall from trees, they instinctively spread out. Feathers which stick out even a little would have been a boon for a small dinosaur trying not to fall on the ground. Ones without sufficient control in falling would probably be killed if not careful - so the individuals with the best brains, reflexes, and 'parachuting' ability would survive.
` Also important is the fact that a tree-dwelling animal uses up a lot of energy running down one tree and scrambling up the next. Such animals would risk dying, so individuals who could avoid that the most often would be more likely to survive.
` Probably these reasons are enough to explain why so many gliding species exists all around the world today - including such animals as snakes, frogs, and ants!
` Evidently, it is an easy thing for a lineage to evolve. Some gliding species known have used the hind legs only, or even the toes and fingers only; ribby extensions of some type are common in lizards and similar reptiles; and mammals such as sugar gliders, feather-tailed gliders, scaly-tailed squirrels, flying squirrels, and flying lemurs use webs of skin and a tail with long fur extending out to either side.

` Now, small, birdlike dinosaurs had flat feathers, right? Those would most likely have an influence on the air if one fell, especially if the animal had long feathers on the arms, as some ground-dinosaurs did. Fast-forwarding: If a small maniraptor at some point had evolved long feathers on the arms for display or gliding and flapped them, the animal could have increased thrust while decreasing drag, though it probably still could not have produced lift. Gliding farther is still a definite advantage.
` Some dromaeosaurs lived in trees, and Microraptor is most notable in that it had also evolved proper wings and flight feathers on the tail, similar to Archaeopteryx's, as well as long flight feathers on the legs. This is probably the result of convergent evolution, as Microraptor probably did not evolve from primitive birds. It seems to have had very weak flight, or at least a very strong gliding ability, but a form of aerial maneuverability nonetheless, so we know that such an animal can evolve at least once.

` Anyway, Menton continues:

` The cursorial theory postulates that the birds really started on the ground and after vigorous hopping and what-have-you managed to eventually fly up.

` In light of new evidence, not as many scientists are much in favor of the ground-up idea, though that sentance is more of a snide remark than a description of what any professionals have thought.

` Each side is quite certain the other side is dead wrong, of course. Evolutionist John Ostrom speculates that feathers evolved from large scales on the forelimbs of dinosaurs and that these long feathers, as they developed, were used to catch insects! Now, while feathers are remarkably strong for their weight, I can't think of any worse treatment than to bang them together to catch insects. Also, they're an incredibly complex structure to use just for this purpose. And they would blow the insect out of the way. Birds couldn't clap their limbs together in front anyway - they just don't have that kind of a shoulder.

` Ooohhh, kay... I'm pretty sure that Ostrom, in the past, actually said something more along the lines of feathered dinosaurs having long arm-feathers to swat down insects as they leaped into the air. (We know that some did have such feathers, though nobody knows why.)
` Of course, if Menton had been critiquing this idea the way serious biologists do, he would have said something more like; 'When the hypothetical creature leapt off the ground, its source of thrust would have also been terminated.' But, no, he simply resorts to ridicule because this is a political stance (as if this is not obvious enough!), not a scientific assessment.

` Weiland; Is there any evidence for either theory?
` Menton; Not the slightest - and the people who take each view make that point.

` Generally the way the real point is made is like this; 'There is evidence for the other side, but it's not good enough' or something like that.
` Also, I wonder what he supposes paleontologists are talking about when they say that there is evidence for their own theories? Does he think they are just pulling it out of their rectums? The truth about it is; not all theories and hypotheses are equal, and one seems to be prevailing.

` There are no examples of living or fossil scales that even remotely resemble a feather. Archaeopteryx has complete feathers like modern birds.

` I should point out that protofeathers look almost just like modern bird feathers, though they are simpler in their fine details.

` Weiland; So how would you sum up your opinion?
` Menton; The theory of the evolution of flight is not about the birds, so much as it's a theory 'for the birds'.

` Ha. Cute. Into the fluff again. While Menton actually said very little in the scientific area of Archaeopteryx, he did say plenty of things that were non-scientific and even anti-scientific.

` Science aside, since these men are obviously Christian, you may ask if I have anything to say from that perspective? Not being Christian myself, however, I would suggest; why don't we just ask Jesus himself?
` Of course! Ha.

` Well, we can't do that directly, but I can infer this message from the bible: 'Genesis was not meant to be taken literally: Its meaning goes far deeper than the bare words!'
` Certain Christian friends of mine have pointed out that in the gospel as accounted by Matthew, Jesus himself was asked why he gives his stories in parables. His answer was that telling crowds of people 'the truth' straight up might be too freaky, outrageous, or mentally overwhelming.
` A parable is something anyone can grasp that gives the person a general idea of what's being said without telling them exactly what is meant. Symbolic stories are also very common in all religions, and I can see why; among other things, something this abstract can actually be considered a higher form of communication.
` It would therefore not be surprising if much older stories like Genesis were actually meant to be the same way - though keep in mind, they have doubtless been garbled through the ages and also translated many times before ending up in English. (You'd have to go back to the original texts to get a better idea.)

` Even so, as my Christian friends have again pointed out, the Judeo-Christian creation story does somewhat resemble what you might see in a science book - Long ago, the earth took shape and the clouds and ocean were separated by the sky. Depending on which translation you go by, the general idea is that plants, sea creatures and birds then had their start, and afterward came a day/era of mammals.
` Humans are one of the later species in the history of the earth, and they are mentioned in Genesis as being the last created. The first humans began to understand things that the other animals do not, winding up clothed in animal skins and separated from the rest of nature.

` If such creationists as Sarfati saw a parallel between this simple, easy-to-tell story, and the general pattern of the way things have been found to develop on earth, then he would probably say that scientific findings in general agree with the symbology of the Bible, and therefore stop trying to ruin the image of scientists.

` But that's just my two cents.

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