[Home] [Site map] [Updates] [Projects] [Contents; 1. Introduction; 2. Philosophy (1), (2), (3), (4) & (5); 3. Religion (1) & (2); 4. History (1), (2) & (3); 5. Science; 6. Environment (1), (2) & (3); 7. Origin of life (1), (2) & (3); 8. Cell & Molecular (1), (2) & (3); 9. Mechanisms (1), (2) & (3); 10. Fossil Record ; 12. Plants; 14. Man (1) & (2); 15. Social; 16. Conclusion; Notes; Bibliography A-C, D-F, G-I, J-M, N-S, T-Z]
"PROBLEMS OF EVOLUTION": 13. ANIMALS 1. Development 1. Modular `toolkit' 2. Organs 1. Brain 1. Brain arose only once 2. Eye 1. Evolution has no adequate explanation of the origin of the eye 2. Eyes are found in only four(?) phyla 3. Pax-6 master control gene 4. Gradations due to limitations of natural selection 5. Colour vision 3. Ear 3. Insects 1. Butterfly's wing colours 4. Fish 1. Swim-bladder-lung transition 5. Amphibians 1.Fin-leg transition 6. Reptiles 1. Amniotic egg 7. Birds 1. Reptile-bird transition 2. Archaeopteryx 3. Lung 4. Feather 8. Mammals 1. Reptile jawbone-mammal earbone transition 2. Hair 3. Land mammal-whale transition 4. Insectivore-bat transition [top]
"PROBLEMS OF EVOLUTION": 13. ANIMALS 1. Development 1. Modular `toolkit' Notice that the following says that Darwin was (and Darwinism is) inadequate and "Not a single biologist ... ever anticipated that the genes controlling how a tiny fruit fly's body and organs are made also control the making of most animals, including man." Personally, an "ancient tool kit with [a] ... small number of common ingredients" that is sufficient to build all "animals ... [from] repeated, modular parts" sounds like brilliant farsighted design to me, not the work of a `blind watchmaker':"For those who want to enhance their sense of kinship with butterflies, zebras, apes, and even ancient dinosaurs, Sean B. Carroll offers a treasure trove in "Endless Forms Most Beautiful: The New Science of Evo Devo." Evo Devo, evolutionary developmental biology, intertwines Earth's family of animals in a way not done in the past: Its most surprising finding is that all animals, including those with arms, wings, or fins, originated from a small number of primitive "master" genes. Over long spans of time, that "ancient tool kit" of genes evolved animals and created the enormous diversity around us: stripes in zebras, spectacularly colored butterfly wings, and intricate human hands. One ancient gene led to the creation of eyes across the entire animal kingdom, writes Carroll, a genetics professor at the University of Wisconsin-Madison. Evo Devo is the third revolution in the field known as evolutionary biology or how animals were made and evolved. The first revolution came when Charles Darwin published his seminal book on evolution, "The Origin of Species." Darwin explained how, over eons, living organisms became diverse through a process called natural selection, meaning that nature decided which species had best adapted to their environment, and thus would thrive. The second revolution came with the merging of Darwin's theories and the science of genetics. But neither of those approaches revealed how individual animal forms were made or how they evolved. That's where Evo Devo comes in, attempting to explain a process through which a single- celled egg develops into a multibillion-celled animal, and why there are such deep connections among animals. And while this third revolution may seem complex, it's based on the ancient tool kit with the small number of common ingredients. Carroll contends that Evo Devo simply has stunned biologists, reshaping their picture of how evolution works. Not a single biologist, he writes, ever anticipated that the genes controlling how a tiny fruit fly's body and organs are made also control the making of most animals, including man. By studying fossils, Evo Devo shows that animals evolved with a pervasive use of repeated, modular parts. So why are there such great differences in the way a butterfly and a human appear? Carroll goes to great lengths to explain how differences in form arise from changes during evolution in terms of where and when certain genes are used; for instance, the joints in the flippers of a sea turtle versus the paws of a dog. In addition, DNA that regulates or determines when, where, and how many of the parts of a gene are made contributes to the diversity of form we see around us. He says part of learning how animal forms developed correctly is studying animals that are malformed; for example, animals born with six rather than five digits. Carroll's title, "Endless Forms Most Beautiful," was inspired by the ending of Darwin's book: "...whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved." An acknowledged expert in the field, Carroll takes us through the steps of evolution with the inquisitiveness and thought process of a scientist and helps us appreciate evolution and the relationships of all forms of life. His language is simple and rich, and 116 detailed illustrations make the book accessible to novice and scientist alike. For those who'd like to know more, he provides an extensive reading list. Carroll deals briefly with the controversy surrounding how evolution is taught in schools, and he cites statistics showing that, even when it is taught, there is widespread ignorance about the topic. For example, a National Science Board survey found that 52 percent of Americans believed that the earliest humans lived at the same time as the dinosaurs. He also briefly tackles the struggle between teaching evolution and teaching creationism, pointing out that even Darwin added the words "by the Creator" to "The Origin of Species" to appease critics of the concept of evolution. But he believes Evo Devo may help deepen the case for evolution and suggests that theology should evolve or face the possibility of becoming irrelevant. Carroll concludes by saying the stakes for broader adoption of an evolutionary perspective are critical not only to understanding our planet's history but also to its preservation in the future. ..." (Valigra L., "Where do they all come from?: A new theory traces animal forms to an 'ancient tool kit'," Christian Science Monitor April 05, 2005)"The proliferation of wildly varying body plans during the Cambrian, scientists reason, therefore must have something to do with Hox genes. But what? To find out, developmental biologist Sean Carroll's lab on the University of Wisconsin's Madison campus has begun importing tiny velvet worms that inhabit rotting logs in the dry forests of Australia. Blowing bubbles of spittle and waving their fat legs in the air, they look, he marvels, virtually identical to their Cambrian cousin Aysheaia, whose evocative portrait appears in the pages of the Burgess Shale. Soon Carroll hopes to answer a pivotal question: Is the genetic tool kit needed to construct a velvet worm smaller than the one the arthropods use? Already Carroll suspects that the Cambrian explosion was powered by more than a simple expansion in the number of Hox genes. Far more important, he believes, were changes in the vast regulatory networks that link each Hox gene to hundreds of other genes. Think of these genes, suggests Carroll, as the chips that run a computer. The Cambrian explosion, then, may mark not the invention of new hardware, but rather the elaboration of new software that allowed existing genes to perform new tricks. Unusuallooking arthropods, for example, might be cobbled together through variations of the genetic software that codes for legs. `Arthropods,' observes paleoentomologist Jarmila Kukalova-Peck of Canada's Carleton University, `are all legs'-including the `legs' that evolved into jaws, claws and even sex organs. BEYOND DARWINISM Of course, understanding what made the Cambrian explosion possible doesn't address the larger question of what made it happen so fast. Here scientists delicately slide across data-thin ice, suggesting scenarios that are based on intuition rather than solid evidence. One favorite is the so- called empty barrel, or open spaces, hypothesis, which compares the Cambrian organisms to homesteaders on the prairies. The biosphere in which the Cambrian explosion occurred, in other words, was like the American West, a huge tract of vacant property that suddenly opened up for settlement. After the initial land rush subsided, it became more and more difficult for naive newcomers to establish footholds. Predation is another popular explanation. Once multicelled grazers appeared, say paleontologists, it was only a matter of time before multicelled predators evolved to eat them. And, right on cue, the first signs of predation appear in the fossil record exactly at the transition between the Vendian and the Cambrian, in the form Even more speculative are scientists' attempts to address the flip side of the Cambrian mystery: why this evolutionary burst, so stunning in speed and scope, has never been equaled. With just one possible exception-the Bryozoa, whose first traces turn up shortly after the Cambrian-there is no record of new phyla emerging later on, not even in the wake of the mass extinction that occurred 250 million years ago, at the end of the Permian period. Why no new phyla? Some scientists suggest that the evolutionary barrel still contained plenty of organisms that could quickly diversify and fill all available ecological niches. Others, however, believe that in the surviving organisms, the genetic software that controls early development had become too inflexible to create new life- forms after the Permian extinction. The intricate networks of developmental genes were not so rigid as to forbid elaborate tinkering with details; otherwise, marvels like winged flight and the human brain could never have a risen. But very early on, some developmental biologists believe, the linkages between multiple genes made it difficult to change important features without lethal effect. `There must be limits to change,' says Indiana University developmental biologist Rudolf Raff. `After all, we've had these same old body plans for half a billion years.' The more scientists struggle to explain the Cambrian explosion, the more singular it seems. And just as the peculiar behavior of light forced physicists to conclude that Newton's laws were incomplete, so the Cambrian explosion has caused experts to wonder if the twin Darwinian imperatives of genetic variation and natural selection provide an adequate framework for understanding evolution. `What Darwin described in the Origin of Species,' observes Queen's University paleontologist Narbonne, `was the steady background kind of evolution. But there also seems to be a non-Darwinian kind of evolution that functions over extremely short time periods- and that's where all the action is." (Nash J.M., "When Life Exploded", TIME, December 4, 1995, pp.77-78)[top] 2. Organs 1. Brain 1. Brain arose only once"Probed! Mother of all brains," ABC/Discovery News, Jennifer Viegas, 28 September 2005 ... All brains originated from a single common ancestral brain that emerged at least 700 million years ago, according to a recent analysis of brain studies. The finding suggests this mother brain for all creatures with a central nervous system - such as insects, birds, animals and humans - evolved only once before each species underwent its own evolutionary course. "What we see today in humans, insects and all other multicellular animals with a central nervous system are probably just variations of one ancient scheme," says Dr Rudi Loesel, who conducted the analysis published in the journal Arthropod Structure & Development. "What this ancestral brain looked like, we do not know. Its architecture might have been very simple, but the basic genetic mechanisms and the principal chemical setup was already there [before 700 million years ago]," says Loesel ... The researchers don't know what the creature that contained the mother of all brains looked like. Some scientists speculate it could have been a segmented flatworm, while others think it was a more complex creature. Loesel says that he, and others who study brain evolution, can't rely on fossil evidence because neuronal tissue is not preserved over time. Instead, they compare the brain architecture of living species, identify similarities and then try to find common characteristics that would have belonged to the mother brain. "Taking the similarities in brain biology in such distantly related animal groups like insects and mammals into account, the origin of the brain - the common ancestral brain - must have already evolved before the major animal phyla diverged, which was approximately 700 million years ago," he says. ... At around that time, invertebrates and vertebrates each branched off from the tree of life. The emergence of the common brain likely occurred just before this branch-off, says Loesel, because brains and associated characteristics of insects known to exist then and now share key aspects with human and other animal brains. Loesel says evidence for the once-shared brain can be seen in certain neurotransmitters, which function similarly in most brains, and in genes that regulate the circadian clock that controls sleep-wake cycles. The same circadian clock genes in insects have been found in mammals. Professor Walter Gehring ... agrees with Loesel that insects and animals share common characteristics related to the brain, such as eyes. Gehring and his colleagues studied Drosophila fruit flies and found a master control gene that regulates growth and development of eyes in most fly species. A very similar gene is present in other insects, animals and humans. "The observation that mammals and insects, which have evolved separately for more than 500 million years, share the same master control gene for eye morphogenesis [the process of cell differentiation into various tissues and structures] indicates that the genetic control mechanisms of development are much more universal than anticipated," Gehring says. ... [Darwinists used to claim that because the eye arose 40+ times, it showed how powerful the Darwinian mechanism of the natural selection of random mutations was. But then it turned out that the underlying molecular machinery of the eye, the Pax- 6 master gene, arose only once (Dover G.A., "Dear Mr Darwin: Letters on the Evolution of Life and Human Nature," [1999], University of California Press: Berkeley CA, 2000, reprint, p.172) So now it looks like (pun unintended!) that the molecular machinery underlying brains arose only once too. This means that the Darwinian mechanism of the natural selection of random mutations (RM&NS) could not discover eyes and now brains, despite them being highly advantageous, more than once each in the history of life. The obvious conclusion then is that it was not the natural selection of random mutations that discovered them even once! [top]2. Eye 1. Evolution has no adequate explanation of the origin of the eye Evolution has no adequate explanation for the origin of the eye. Evidence of this is that there is no comprehensive evolutionist explanation of the origin of the eye in any peer-reviewed scientific journal or book. Evolutionists either refer to a variation of Darwin's nearly 150-year old explanation (so called) in his Origin of Species (1859) where a graded series of eyes are merely pointed to (Darwin, 1872, pp.167- 170), or a computer model/simulation (that wasn't even that!) by Nilsson & Pelger (Nilsson & Pelger, 1994; Keeton et al, 1996, p.463), or both (Ridley, 1996a, pp.342-343; Strickberger, 2000, pp.33-35), or don't even mention the eye at all (Dobzhansky et al., 1977, Futuyma, 1986; Maynard Smith, 1975; Mayr, 1970)! [top] In order to explain the origin of the eye, evolution would need to explain "the anatomical and cytological complexity that is revealed by modern biology ... The complexity of the retina, of the sheaths ... all the cerebral connections of the organ" (Grasse, 1977, p.105). And also "the molecular structure ... and ... the chemistry of a complex organ capable of multiple adjustments" (Grasse, 1977, p.105). Darwin just assumed the existence of an original "simplest organ which can be called an eye" which "consists of an optic nerve, surrounded by pigment-cells and covered by translucent skin, but without any lens or other refractive body," but then the question then of "How a nerve comes to be sensitive to light," Darwin evaded with it "hardly concerns us more than how lifeitself originated" (Darwin, 1872, p.167). But as Behe points out, the molecular biology and biochemistry of that `simple' light-sensitive spot, is very complex (Behe, 1996, pp.18-21). So what evolution needs to explain is in fact "How a nerve comes to be sensitive to light"! See my comments on the following at the end of CED message #13730:"Natural selection, acting over time, can lead to complex adaptations, but it can do so only if each small change along the way is itself adaptive. While it is easy to assume that this is true in a hypothetical example of character strings, many people have argued that it is unlikely for every one of the changes necessary to assemble a complex organ like the eye to be adaptive. An eye is only useful, it is claimed, once all parts of the complexity are assembled; until then, it is worse than no eye at all. After all, what good is 5% of an eye? Darwin's answer, based on the many adaptations for seeing or sensing light that exist in the natural world, was that 5% of an eye is often better than no eye at all. It is quite possible to imagine that a very large number of small changes-each favored by selection-led cumulatively to the wonderful complexity of the eye. Living mollusks, which display a broad range of light-sensitive organs, provide examples of many of the likely stages in this process (Figure 1.14): 1. Many invertebrates have a simple light-sensitive spot (Figure 1.14a). Photoreceptors of this kind have evolved many times from ordinary epidermal (surface) cells-usually ciliated cells whose biochemical machinery is light-sensitive. Those individuals whose cells are more sensitive to light are favored when information about changes in light intensity are useful. For example, a drop in light intensity may often be an indicator of a predator in the vicinity. ... Figure 1.14 Living gastropod mollusks illustrate all of the intermediate steps between a simple eye cup and a camera- type eye: (a) The eye pit of a limpet, Patella sp.; (b) the eye cup of Beyrich's split shell, Pleurotomaria beyrichi; (c) the pinhole eye of a California abalone, Haliotis sp.; (d) the closed eye of a turban shell, Turbo creniferus; (e) the lens eyes of the spiny dye murex, Murex brandaris; (f) the lens eyes of the Atlantic dog whelk, Nucella lapis. (Lens is shaded in e and f.) 2. By locating the light-sensitive cells in a depression, the organism will get some additional information about the direction of the change in light intensity (Figure 1.14b). The surface of organisms is variable, and those individuals whose photoreceptors are in depressions will be favored by selection in environments where such information is useful. For example, mobile organisms may need better information about what is happening in front of them than do immobile ones. 3. Through a series of small steps, the depression could get deeper, and each step could be favored by selection because better directional information would be available (Figure 1.14c). 4. If the depression got deep enough, it could form images on the light-sensitive tissue, much the way pinhole cameras form images on photographic film (Figure 1.14d). In settings in which detailed images are useful, selection could then favor the elaboration of the neural machinery necessary to interpret the image. 5. The next step is the formation of a transparent cover (Figure 1.14e). This might be favored because it protects the interior of the eye from parasites and mechanical damage. 6. A lens could evolve either through gradual modification of the transparent cover, or through the modification of internal structures within the eye (Figure 1.14f). Notice that evolution produces adaptations like a tinkerer, not an engineer. New organisms are created by small modifications of existing ones, not by starting with a clean slate. Clearly there will be many beneficial adaptations that will not arise because they are blocked at some step along the way when a particular variation is not favored by selection. Darwin's theory explains how complex adaptations can arise through natural processes, but it does not predict that every, or even most, adaptations that could occur, have occurred, or will occur. This is not the best of all possible worlds; it is just one of many possible worlds." (Boyd R. & Silk J.B., "How Humans Evolved," [1997], W.W. Norton & Co: New York NY, Second Edition, 2000, pp.17-18) [top]2. Eyes are found in only four(?) phyla Far from being the inevitable, mechanical, automatic consequence of a `blind watchmaker', "true image-forming eyes" are found in only "four phyla-annelids, mollusks, arthropods, and vertebrates", and "all of them use the same visual pigment", retinal "suggesting that not many alternative pigments are able to play this role." (Raven & Johnson, 1995, p.955). Interestingly, eyes have evolved independently in three [four] different lines of animals- [annelids], mollusks, insects, and vertebrates. These animals have no common evolutionary ancestor equipped with eyes, yet the eyes of each of them have the same compound, retinal, involved in the process of light reception. That retinal is present in each of these types of eyes is the result of some unique fitness of this kind of molecule for the process of light reception" (Solomon, et al., 1993, p.59) [top] 3. Pax-6 master control gene The problem of the origin of the eye has recently become even harder for evolution to explain. Evolutionists used to confidently claim as evidence for the power of random mutations and natural selection that "eyes have evolved no fewer than forty times, and probably more than sixty times, independently in various parts of the animal kingdom," and "In some cases these eyes use radically different principles" (Dawkins, 1996, p.127), including "at least nine distinct design principles ... pinhole eyes, two kinds of camera-lens eyes, curved-reflector ("satellite dish") eyes, and several kinds of compound eyes" (Dawkins, 1995, p.91). But then it was unexpectedly discovered that these "nine distinct design principles" in "these forty-plus independent evolutions" (Dawkins, 1995, p.91), are all `hardwired' into one master gene, pax- 6. Not only can a transplanted pax-6 gene produce a fruit-fly's eye on its wings, legs, and antennae, but also a transplanted mouse pax-6 gene can produce a fruit-fly's eye on a fruit fly's body (Halder, et al., 1988; Bromham, 2002)! In other words, the underlying machinery of the eye, arose just once (Dover, 2000, p.172), in "the common ancestor of all surviving animals, who lived perhaps a billion years ago" (Dawkins, 1996, p.128), yet anticipated the future development of all eyes in all animals, for all time, in all environments: water, land and air! As Berlinksi observes, "No one in possession of these facts can imagine that they support the Darwinian theory. How could the mechanism of random variation and natural selection have produced an instrument capable of anticipating the course of morphological development ... in widely different organisms?" (Berlinski, 1996). That this was totally unexpected by evolutionary theorists, is evident by Dawkins, who calls this discovery a "Remarkable fact ... [that] is almost too startling" (Dawkins, 1996, p.176). [top] 4. Gradations due to limitations of natural selection"To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree. When it was first said that the sun stood still and the world turned round, the common sense of mankind declared the doctrine false; but the old saying of " Vox populi, vox Dei." as every philosopher knows, cannot be trusted in science. Reason tells me, that if numerous gradations from a simple and imperfect eye to one complex and perfect can be shown to exist, each grade being useful to its possessor, as is certainly the case; if, further, the eye ever varies and the variations be inherited, as is likewise certainly the case; and if such variations should be useful to any animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, should not be considered as subversive of the theory." (Darwin C.R., "The Origin of Species by Means of Natural Selection," [1872], Everyman's Library, J.M. Dent & Sons: London, 6th Edition, 1928, reprint, p.167)"A pinhole camera forms a definite image, the smaller the pinhole the sharper (but dimmer) the image, the larger the pinhole the brighter (but fuzzier) the image. The swimming mollusc Nautilus, a rather strange squidlike creature that lives in a shell like the extinct ammonites (see the 'shelled cephalopod' of Figure 5), has a pair of pinhole cameras for eyes. The eye is basically the same shape as ours but there is no lens and the pupil is just a hole that lets the seawater into the hollow interior of the eye. Actually, Nautilus is a bit of a puzzle in its own right. Why, in all the hundreds of millions of years since its ancestors first evolved a pinhole eye, did it never discover the principle of the lens? The advantage of a lens is that it allows the image to be both sharp and bright. What is worrying about Nautilus is that the quality of its retina suggests that it would really benefit, greatly and immediately, from a lens. It is like a hi- fi system with an excellent amplifier fed by a gramophone with a blunt needle. The system is crying out for a particular simple change. In genetic hyperspace, Nautilus appears to be sitting right next door to an obvious and immediate improvement, yet it doesn't take the small step necessary. Why not? Michael Land of Sussex University, our foremost authority on invertebrate eyes, is worried, and so am I. Is it that the necessary mutations cannot arise, given the way Nautilus embryos develop? I don't want to believe it, but I don't have a better explanation." (Dawkins R., "The Blind Watchmaker," [1986], Penguin: London, 1991, reprint, pp.85-86). [top]5. Colour vision Since "Natural selection tends only to make each organic being as perfect as, or slightly more perfect than, the other inhabitants of the same country with which it comes into competition" (Darwin, 1872, p.187), why then is their colour vision?Marsupials not colour-blind after all , ABC, Catriona Purcell ABC ... 28 March 2005 ... Australian marsupials can see in full colour, new research has found, making them the only other mammals apart from primates to do so. A team led by Dr Catherine Arrese ... reports .... They looked at cone cells at the top of the retina and the rear of the animals' eyes and found three distinct cone types that enable full colour vision. Arrese says marsupials, along with other mammals including dogs, cats and horses, were previously thought to have only two types of cone cells which meant they could not detect several colours including ultraviolet, blues or reds. ...The discovery in marsupials is, she says, a step forward in understanding the evolution of colour vision in humans. Humans also have three types of cone cells but they differ to those found in marsupials. "About 45 million years ago humans appear to have lost two types of cone cells found in reptiles but then developed and re-evolved with a third type of cell that is long and medium wavelength sensitive and picks up reds and greens," Aresse says. ...[Presumably this means "About 45 million years ago [the primate line leading to] humans ...". I regard this as a problem for evolution. Why lose a trait that would always be useful in a coloured world and then "re-evolve" it? More likely colour vision always was there latent in the pax 6 master gene that codes for all eyes.] [top] 3. Ear"With all this, of course, went improvements in the brain, most notably the power to compare the times at which signals from one source reach each ear, thus providing a method of estimating the direction in which the source lies. Thus, in the course of evolution, there were six major developments, two of which occurred in the fishes, two in the amphibia and two in mammals. Such, at least, is the account given by people like Willem van Bergeijk, of Bell Telephone Laboratories who is the acknowledged authority. But the eminent morphologist J. W. Torrey is not convinced. 'The evolutionary origin of the inner ear is entirely unknown,' he insists. In contrast with the case of the eye, where undifferentiated cells were specialised into the required forms, here existing structures have been profoundly modified and even shifted to another position in a progressive series of changes which certainly look more like the refinement of a plan than the result of a series of happy accidents. But the insoluble problem is how and why did a balance organ become an organ of hearing? As van Bergeijk pointedly asks: 'What prompts the fish to begin developing a sensory apparatus that will respond to a stimulus about the very existence of which the fish knows nothing?' Van Bergeijk believes that the original balance organ would never have evolved mechanisms for hearing but for the emergence of the swim bladder. The original purpose of this organ is to enable the fish to adjust its density to the density of the ambient water and so control the depth at which it swims. Since the bladder is sensitive to changes in external pressure, it vibrates in harmony with pressure changes in the water. In time these vibrations came to excite the ear. Hearing as distinct from the mere detection of pressure waves, was born. After describing the last part of this process, the adaptation of the bones linking the jaw to the skull into a chain of ossicles linking the eardrum to the inner ear, Ernst Mayr sweepingly remarks: 'Not all the steps in this process are yet entirely apparent, but I think little doubt is left as to the principle involved.' If by 'principle' one means merely progressive remodelling, the statement is a truism. But if 'principle' means that chance selection brought about these elaborate changes, then there must be very great doubt indeed. Like de Beer, Mayr does not seem to appreciate the elementary point that demonstrating the occurrence of a sequence of events does not explain why they happened. But what kind of mutations could bring about the major changes I have described? Could cause a tube to roll up into a helix? Could cause other tubes to form semi-circular canals accurately set at right angles to each other. Could grade sensory hairs according to length? Could cause the convenient deposit of a crystal in the one place it will register gravity? Even more amazingly, some fishes do not trouble to secrete a crystal but incorporate a bit of sand or stone. What kind of mutation could achieve this - when and only when a natural crystal is not formed? The purpose is fulfilled, the means are unimportant. It just doesn't make sense." (Taylor G.R., "The Great Evolution Mystery," Abacus: London, 1983, pp.105-106. My emphasis) Ear's spiral responds to bass: New theory explains why our hearing machinery is coiled up, Nature News, 13 March 2006, Philip Ball Why is our cochlea, the key organ of hearing, curled into a spiral? It has been often thought to be a space-saving measure. But researchers in the United States have shown that the spiral could be vital for increasing our ear's sensitivity to sound, particularly at low frequencies. Daphne Manoussaki of Vanderbilt University in Nashville, Tennessee, and her colleagues believe that the snail-shell curve of the cochlea focuses sound waves at the spiral's outer edge, making it easier for vibration-sensitive cells to detect them. If the researchers are right, then the ear is more sophisticated than we thought. "It would show we need to take a step back from the cell biology and see how the cochlea works as an integrated system", says Karl Grosh of the University of Michigan in Ann Arbor, who studies the ear's structure. The findings also suggest that artificial cochlear implants for the hard of hearing could be improved. Grosh, who is working on such microscopic devices, says that the work will encourage him to think about mimicking the coiled structure, which was thought previously to have no real function. The cochlea is a fluid-filled, coiled tube, about one cubic centimetre in volume, that narrows towards one end. Sitting in the inner ear, it separates the different frequencies of a sound, picking up sound waves from 20 to 20,000 hertz. Different frequencies peak at different positions along the tube: high frequencies near the spiral's broad mouth, and low frequencies further up the tube. The tube also carries nerve cells that fire in response to vibrations in the watery cochlear fluid. The separation of frequencies happens just as effectively in a straight tube, and so until now it hadn't been clear that the cochlea's coiling did anything other than keep it compact. Some designs for an artificial cochlea have represented it as a straight, tapering channel. But Manoussaki and her colleagues have calculated the way that sound waves travel in a cochlear tube with a realistic coiled shape. They find that the wave energy is not evenly distributed throughout the tube, but becomes concentrated along the outer wall, the more so the further up the duct the wave travels. The researchers say this is similar to the way sound in a cylindrical space such as St Paul's cathedral in London, UK, gets concentrated around the walls; known as the 'whispering gallery' effect, it allows a listener at one part of the wall to hear a murmuring speaker on the other side of the cathedral. Turn up the volume The concentration of energy in one part of the tube could help the membrane cells to detect sound, if they are clustered in that region. Thus the cochlea may be more sensitive further up the tube, where lower frequencies are detected. The researchers estimate that this amplification means that sound at the inner tip of the spiral is boosted by 20 decibels relative to sound at the outer face: the difference between the volume of a normal conversation and that of a vacuum cleaner. A boost of 20 decibels would be significant in an artificial cochlea, says Grosh: "we'd love that." He says that it would be relatively easy to make miniaturized channels in the shape of a coil. ... [top]3. Insects 1. Butterfly's wing colours Note the language of intelligent design, for what is supposed to have been cobbled together by a `blind watchmaker':How butterfly wings use living colour, The Independent, 20 November 2005, Steve Connor ... The brilliant colours of a butterfly's wing are generated in the same way as the high-definition pictures of the trendiest plasma-screen TVs, scientists have found. For the past 30 million years, African swallowtail butterflies have used the principles of light-emitting devices to generate the vivid colours of their wings, says Peter Vukusic, a physicist at Exeter University. A new study shows butterflies' wings are coated with an ultra-thin layer of molecules that form microscopic air spaces where fluorescent pigments absorb ultraviolet light and re-emit it as vivid patches of blue and green. The air spaces themselves have complex, multi-layered mirrors at the bottom to force light out through the top surface of the wings. Further analysis, published in the journal Science, has found that the airspaces are arranged in such a precisely uniform manner that the fluorescent light is prevented from leaking out sideways, to make sure the colours are even brighter and clearer. Dr Vukusic said that the butterfly had essentially invented a biological version of the light-emitting diode (LED) millions of years before they were developed by electrical engineers. "It's amazing that butterflies have evolved such sophisticated design features which can so exquisitely manipulate light and colour. Nature's design and engineering is truly inspirational," Dr Vukusic said. The wings of African swallowtails are coated in micro-scales - regular air-pockets within the stiff material that makes up the insect's external skeleton. "The function of the micro-scales is identical to those in the LED; they prevent the fluorescent colour from being trapped inside the structure and from being emitted sideways," Dr Vukusic said. "The scales on the wing also have a specialised mirror underneath, again very similar in design to that in the LED. This mirror upwardly reflects all the fluorescent light that gets emitted down towards it." The result is a very efficient system for the fluorescent emission of light that gives the butterfly significant control of the direction in which the light is emitted, Dr Vukusic said. "The fact that nature and technology have converged on this pretty analogous device is amazing," he said. ... . [top]4. Fish 1. Swim-bladder-lung transition Darwin `explained' swimbladder-lung transition, but was actually lung-swimbladder transition! [top] 5. Amphibians 1. Fin-leg transition The invasion of the land required modifications to almost every system in the vertebrate body (Hickman, Roberts & Larson, 2000, p.311; Colbert & Morales, 1992, p.80; Carroll, 1988, pp.158ff). It is therefore "among the most difficult evolutionary phenomena to explain" (Carroll., 1997, pp.227- 228). The original evolutionary explanation for the transition from a fish's fin to an amphibian's leg, was that it occurred as an adaptation for one line of fish, the crossopterygians (a sub-group of lobe-finned fish), surviving by dragging themselves between freshwater pools that dried up in summer (Romer, 1933, pp.48-49; Romer, 1945, pp.140-141; Stahl, 1985, pp.195-198; Carroll, 1988, p.166; Colbert & Morales, 1992, pp.67-68; Nash 1995, p.68; Zimmer, 1995b, p.120; Zimmer, 1998, pp.35-37; McLeod, 2000, p.28). But in fact the transition from fins to legs actually occurred underwater (Nash 1995, p.68; Daeschler & Shubin, 1997; Monastersky, 1999; Hickman, Roberts & Larson, 2000, p.311), millions of years before legs were needed on land (Zimmer, 1995b, p.120)!"Of particular interest is the internal structure of the paired fins of the early crossopterygian fishes, which are in decided contrast to the paired fins of the dipnoans. In the early crossopterygians there was a single proximal bone in the fin that articulated with the girdle. This is best seen in the pectoral fin, the structure of which is especially well known. Below the single upper fin bone were two bones articulating with it, and beyond these were still other bones radiating toward the distal edges of the fin. Such a scheme of bone arrangement in the fins could very well have formed the starting point for the evolution of the limb bones in land-living animals. There is every reason to believe that the single proximal bone in the paired fins of the crossopterygian fishes is to be equated with the upper bone of the tetrapod or land-living vertebrate limb, namely, the humerus in the front leg and the femur in the hind leg. Likewise, the next two bones of the crossopterygian fin can be homologized with the radius and ulna of the front leg and the tibia and fibula of the hind leg in the land-living vertebrates. Beyond this point homologies are not easy, but it seems probable that the various bones of the wrist and ankle and of the hand and foot evolved from the complex of distal bones seen in the crossopterygian fin. " (Colbert E.H. & Morales M., "Evolution of the Vertebrates: A History of the Backboned Animals Through Time," [1955], John Wiley & Sons: New York NY, Fourth Edition, 1992, Second Printing, p.65)"We are especially interested in the paired fins of rhipidistians ... because they form the basis of the structure of the limbs in amphibians and all higher tetrapods. As in the actinopterygians, the shoulder girdle consists of both dermal and endochondral elements. The dermal bones are a direct continuation of the back of the opercular series and the skull roof. The largest ventrolateral element is the cleithrum, which, as in palaeoniscoids, supports the scapulocoracoid. Large paired clavicles and a small median interclavicle lie ventrally. Dorsally, the cleithrum is succeeded by the anocleithrum, the supracleithrum, and the posttemporal, which is in contact with the extrascapulars. The scapulocoracoid is a small bone in Eusthenopteron and has a triradiate attachment to the cleithrum. We can directly compare elements of both the forelimbs and hind limbs of osteolepiform rhipidistians and primitive amphibians .... In the forelimb, the proximal element is clearly comparable to the tetrapod humerus and articulates with a long bladelike radius and a stout posterior equivalent of the ulna. The ulna in turn articulates with an anterior intermedium and posterior ulnare. The ulnare articulates with two or more distal elements that we may compare with the more distal carpals of amphibians. More distally, there are no large endoskeletal supports for the fin and one must suppose that the metacarpals and phalanges of tetrapods developed as almost, if not entirely, new structures." (Carroll R.L., "Vertebrate Paleontology and Evolution," W.H. Freeman & Co: New York NY, 1988, p.145)"Another difficulty seems to be the first formation of the limbs of the higher animals. The lowest Vertebrata are perfectly limbless; and if, as most Darwinians would probably assume, the primeval vertebrate creature was also apodal, how are the preservation and development of the first rudiments of limbs to be accounted for-such rudiments being, on the hypothesis in question, minute and functionless? In reply to this it has been suggested ... that a mere roughness of the skin might be useful to a swimming animal by holding the water better, that thus minute processes might be selected and preserved, and that, in the same way, these might be gradually increased into limbs. But it is, to say the least, very questionable whether a roughness of the skin, or minute processes, would be useful to a swimming animal; the motion of which they would as much impede as aid, unless they were at once capable of' a suitable and appropriate action, which is against the hypothesis. Again, the change from mere indefinite and accidental processes to two regular pairs of symmetrical limbs, as the result of merely fortuitous favouring variations, is a step the feasibility of which hardly commends itself to the reason, seeing the very different positions assumed by the ventral fins in different fishes. If the above suggestion made in opposition to the views here asserted be true, then the general constancy of position of the limbs of the Vertebrata may be considered as due to the position assumed by the primitive rugosities from which those limbs were generated. Clearly only two pairs of rugosities were so preserved and developed, and all limbs (on this view) are descendants of the same two pairs, as all have so similar a fundamental structure. Yet we find in many fishes the pair of fins, which correspond to the hind-limbs of other animals, placed so far forwards as to be either on the same level with, or actually in front of, the normally anterior pair of limbs; and such fishes are from this circumstance called `thoracic' or `jugular' fishes respectively, as the weaver fishes and the cod. This is a, wonderful contrast to the fixity of position of vertebrate limbs generally. If then such a change can have taken place in the comparatively short time occupied by the evolution of these special fish forms, we must certainly expect that other and far more bizarre structures would (did out some law forbid) have been developed, from other rugosities in the, manifold exigencies of the multitudinous organisms which must (on the Darwinian hypothesis) have been gradually evolved during the enormous period intervening between the first, appearance of vertebrate life and the present day. Yet, with these exceptions, the position of the limbs is constant from the lower fishes up to man, there being always an anterior pectoral pair placed in front of a posterior or pelvic pair when both are present, and in no single instance are there more than these two pairs." (Mivart St.G. J., "On the Genesis of Species," Macmillan & Co: London, Second edition, 1871, pp.43- 45. Emphasis original) [top]6. Reptiles 1. Amniotic egg Evolution has no adequate explanation for the origin of the amniotic egg."There are innumerable examples of complex organs and adaptations which are not led up to by any known or even, in some cases, conceivable series of feasible intermediates. In the case, for example, of the flight feather of a bird, the amniotic egg, the bacterial flagellum, the avian lung, no convincing explanation of how they could have evolved gradually has ever been provided" (Denton, 1998, p.274).7. Birds Evolution has no adequate explanation for the origin of birds. [top] 1. Reptile-bird transition "On this point Geoffroy Saint-Hilaire was not more successful than Lamarck; when discussing the external forces involved in evolutionary transformations ...: `It is evidently not through an insensible change that the lower oviparous animals have given rise to the higher degree of organisation represented by the birds. A possible incident, quite slight as regards its initial extent, but of an immeasurable importance as to its effects (this incident, which I shall not even attempt to characterise, has happened in one of the reptiles), has sufficed for the evolution of all the parts of the body constituting the avian type.' [Saint-Hilaire E.G., "Memoires de l'Academie Royale des Sciences de l'Institut de France", 12, 1833, p.64] Here, I confess, a modern Macromutationist must protest, surely many important and independent changes are required to pass from a reptile to a bird." (Lovtrup, 1987, p.71. Emphasis mine) [top] 2. Archaeopteryx Archaeopteryx's brain and inner ear were, unexpected by evolutionists, already ~147 mya, as advanced as modern flying birds (Ali, 2004a) [top] 3. Lung Evolution has no adequate explanation for the avian lung. [top] 4. Feather Evolution has no adequate explanation for the scale-feather transition. [top] 8. Mammals 1. Reptile jawbone-mammal earbone transition Evolution cannot explain why a line of reptiles, which can hear perfectly well, would start to transform their entire jawbone-earbone structure for the benefit of a future line of mammals. Gould asks: "Embryology and paleontology provide adequate documentation of the `how,' but we would also like more insight into the `why.' In particular, why should such a transition occur-especially since the single-boned stapedial ear seems to function quite adequately (and, at least in some birds, every bit as well as the three- boned mammalian ear)? " (Gould, 1993, p.106) See also "Ancient bone provides evolutionary insight;" ABC, February 11, 2005; "Fossil find tests theory of how ear developed," The Independent, Steve Connor, 11 February 2005; "Early mammals had poorer hearing," ABC, Anna Salleh, 11 February 2005; "Ear-splitting discovery rocks mammal identity,"NATURE News, Roxanne Khamsi, 10 February 2005 & "Homoplasy in the Mammalian Ear," Thomas Martin and Zhe- Xi Luo, Science, Vol 307, 11 February 2005, pp.861-862. [top]"Reptiles, birds, and mammals have additional terrestrial adaptations that distinguish them from amphibians. One of these is the amniotic egg, a shelled, water-retaining egg. The amniotic egg functions as a `self-contained pond' that enables these vertebrates to complete their life cycles on land. Although most mammals don't lay eggs, they retain other key features of the amniotic condition. In recognition of this important evolutionary breakthrough, reptiles, birds, and mammals are collectively called amniotes." (Campbell, Reece & Mitchell, 1999, p.634)"Some specialized amphibians have virtually cut free from the ties of water both for everyday life and for breeding, but they do so with difficulty. The reptiles on the other hand have made the transition, in a major evolutionary jump, to an entirely land-based life. Their bodies and eggs are much more waterproof than those of amphibians, and the embryo completes its development in the egg - no reptile goes through a larval stage. Compared with the amphibians, therefore, reptiles are independent of the environment and have the potential to take up ways of life denied to their amphibian forebears. ... Part of this success is a result of the evolution of the egg, or more precisely its container, from the simple jelly-covered amphibian egg. The reptile egg is called 'cleidoic', meaning 'boxlike', and is the forerunner of the bird egg, although the details of its construction vary between groups. .... The most important features of the reptile egg are the three membranes surrounding the embryo: the amnion, chorion and allantois. These act as a life-support system for the embryo, making it independent of the environment, and are a major adaptation for terrestrial life. Reptiles, birds and mammals are called amniotes, to distinguish them from amphibians and fishes which do not have these membranes. The embryo of a reptile or a bird survives on dry land because these membranes provide a water-filled bath, act as lungs for exchanging oxygen and carbon dioxide with the atmosphere, and form a reservoir for waste products." (Burton, 1987, p.34)"Every textbook of evolution asserts that reptiles evolved from amphibia but none explains how the major distinguishing adaptation of the reptiles, the amniotic egg, came about gradually as a result of a successive accumulation of small changes. The amniotic egg of the reptile is vastly more complex and utterly different to that of an amphibian. There are hardly two eggs in the whole animal kingdom which differ more fundamentally. ... some of the main distinguishing features of the amniotic egg [are] the tough impervious shell, the two membranes, the amnion which encloses a small sac in which the embryo floats, and the allantois in which the waste products formed during the development of the embryo accumulate, and the yolk sac containing the food reserve in the form of the protein albumen. None of these features are found in the egg of any amphibian. The evolution of the amniotic egg is baffling. It was this decisive innovation which permitted for the first time genuinely terrestrial vertebrate life, freeing it from the necessity of embryological development in an aquatic environment. Altogether at least eight quite different innovations were combined to make the amniotic revolution possible: the formation of a tough impervious shell; the formation of the gellatinous egg white (albumen) and the secretion of a special acid to yield its water; the excretion of nitrogenous waste in the form of water insoluble uric acid; the formation of the amniotic cavity in which the embryo floats (This is surrounded by the amniotic membrane which is formed by an outgrowth of mesodermal tissue. Neither the amniotic cavity nor the membrane which surrounds it has any homologue in any amphibian; the formation of the allantois from the future floor of the hind gut as a container for waste products and later to serve the function of a respirator organ; the development of a tooth or caruncle which the developed embryo can utilize to break out of the egg; a quantity of yolk sufficient for the needs of the embryo till hatching; changes in the urogenital system of the female permitting fertilization of the egg before the hardening of the shell. The problem of the origin of the amniotic system is even more enigmatic considering that the basic problem it solves, in freeing reproduction from dependency on a pool of water, has been solved in the amphibia by much less radical means, by merely exploiting the basic amphibian egg. Some amphibian eggs have a tough gelatinous skin which will stand a certain degree of desiccation, others are live bearing. Certain amphibia are therefore quite independent of water for reproduction. The origin of the amniotic egg and the amphibian - reptile transition is just another of the major vertebrate divisions for which clearly worked out evolutionary schemes have never been provided." (Denton, 1985, pp.218-219)"Not that life was easy for the first amphibians. They had gravity to contend with-a factor several times greater on dry land than in the buoying water as well as desiccation, the drying-out action of the air. Nevertheless they flourished. ... These newcomers to the land, however, never succeeded in wholly freeing themselves from the water. Although they learned to rely fully on their lungs, and to amble along the swampy riversides on sturdy legs derived from their ancestral fins, they always returned to the water to lay soft, jelly-coated eggs. Reproduction tied them to the past, and to the water. In the fullness of time, mutation and selection again performed their wonders. Some of the amphibians developed an egg which was encased in a firm, leathery shell and was thus far better protected than the soft eggs of the fish and the other amphibians. This new and better egg was internally fertilized and deposited in some safe place until the young were hatched. With its perfection, the egg-laying animals won their full freedom from the water. A well- protected embryo could develop in its own private pool, the amniotic cavity of the egg, guarded not only from dryness but also from the hazards of the land world outside. The new and freer group which was evolving in this way, from amphibian ancestry, was the reptiles. The oldest fossil eggs ever found come from sediments in Texas dated at about 280 million years ago. When the eggs were laid the reptiles were already well advanced. (Moore, 1964, pp.113-114)"THE LAND EGG or reptilian egg, as it is also called has a very special place in the story of life as it lived on earth. The land egg is one of nature's greatest innovations. It made possible the conquest of the land, first by reptiles and then by birds and mammals. If the land egg had not developed, the land would have remained largely empty except for plants, invertebrate life and amphibians. As we have seen, amphibians are not strictly land animals; they cannot venture far from water, and most must return to the water to lay their soft, jelly-coated eggs. Some time after the first amphibians developed, evolution took a decisive leap forward. The first reptiles invaded the land. ... These first reptiles, which had evolved from the amphibians, were able to do so because they had acquired an egg that could be laid and incubated on land. This land or reptilian egg was much more complicated than the simple amphibian egg. The water cradled and protected the amphibian. The developing amphibian got its oxygen and most of its food from the water, and its waste matter was discharged into the water. A land egg if it was to be successful had to provide everything the water had. Let us look closely at the extraordinary solution-the land or amniotic egg, as biologists often call it. ... Enclosed in the calcareous shell is a rich supply of food-the yolk-which, in a fertilized egg, is connected to the digestive tract of the embryo. ... Enclosing the developing embryo is a large sac, the amnion, which is filled with liquid and protects the embryo from injury and desiccation. The amnion is thus the embryo's own private pond. At the back end of the embryo is a tube and a sac, the allantois, which functions both as a bladder for waste matter and as a lung. Enclosing the amnion is a membrane charged with blood vessels, which takes in oxygen and discharges carbon dioxide through the porous calcareous shell which encloses the egg. Another sac contains egg white (albumen). Enclosing everything inside the shell is yet another membrane, the chorion. ... The shell is porous in a special way-it lets gases in and out but sheds a reasonable amount of water. However, if you submerge a developing egg in water, its embryo will surely drown. Thus, with its own food supply (yolk sac), its private pond (amnion), waste disposal and lung (allantois) and protective shell, the tiny reptile was freed from its dependence on water, and the conquest of the land could be attempted." (Stivens, 1974, pp.168-170)"As happened many times, life rallied; evolution responded to ecological challenges by appropriate adaptions. It even turned disaster into success, driven by the great Permian crisis to accomplish one of its most decisive advances. While seed plants took over the cold, dry swamps left barren by the decimation of sporulating plants, some obscure amphibian suddenly soared into prominence by developing the animal equivalent of the seed: the fluid-filled egg. Instead of delivering fertilized egg cells for development in some body of water-the normal amphibian mode-the female of this key transition species enclosed its fertilized egg cells in a fluid-filled sac, the amnion, within which the embryo could pursue its normal aquatic development. After Claude Bernard's milieu interieur to bathe all cells and tissues, here was a re-created milieu exterieur to shelter the developing embryo. A hard, porous shell protected this substitute marine incubator, while a highly vascularized membrane, the allantois, produced by the embryo and lining the inner face of the shell, served in gas exchanges and waste disposal. Another sac, filled with a richly nutritious yolk, provided the embryo with necessary foodstuffs. Thus, the complete development of the organism up to a stage where it could survive on land took place within the protective, well-stocked, and appropriately renewed environment of the amniotic fluid. True terrestrial reproduction was initiated. The first reptile was born." (de Duve, 1995, p.207)"One of the greatest evolutionary advances-the amniotic egg-occurred among the deuterostomes. This type of egg, exemplified by that of a chicken ... first appeared in reptiles about 255 million years ago. The amniote egg allowed vertebrates to roam on land, far from existing ponds. Whereas amphibians must return to water to breed and to enable their eggs to develop, the amniote egg carries its own water and food supplies. The egg is fertilized internally and contains yolk to nourish the developing embryo. Moreover, it contains two sacs: the amnion, which contains the fluid bathing the embryo, and the allantois, in which waste materials from embryonic metabolism collect. The entire structure is encased in a shell that allows the diffusion of oxygen but is hard enough to protect the embryo from environmental assaults. A similar development of egg casings enabled arthropods to be the first terrestrial invertebrates. Thus, the final crossing of the boundary between water and land occurred with the modification of the earliest stage in development, the egg." (Gilbert, 1994, p.31)."Here, if this were a textbook, I should have to tell you how the amphibians gave rise to the reptiles, but I shall confine my account to a single feature of reptilian innovation, the egg - or rather, since fishes lay eggs of a sort, the amniotic egg without which of course we cannot begin to understand how the birds contrived to emerge. It is one of the wonders of evolution. ... a minor miracle. .... Besides being smooth it is rigid enough to protect its cargo while not being so hard that the chick will be unable to peck its way out. The shell also is pervious to gases, so that the chick can breathe ... Suspended in the middle of the egg is the yolk, supported by threads. You can rotate the shell of the egg twenty times without disturbing the yolk: the threads just wind up. The medium in which the yolk floats, the white or albumen, is remarkable too. ... I am speaking of course of the bird's egg as it exists today. The reptilian egg, as it first emerged, was slightly different. It contained the large yolk which served to nourish the developing embryo. It also contained two sacs, the amnion, filled with liquid and containing the embryo, and the allantois, which receives the waste products produced by the embryo while it is in the egg. It was however very different from the egg of fishes. From the shell, constructed of crystals of hydroxyapatite and waxed over, to the altered chemistry, based on fat rather than protein, the amniote egg was in a different class altogether, a stunning advance on the simple blob of jelly that constituted the egg of frogs and fishes - a saltation if ever there was one." (Taylor, 1983, pp.62-64)."A major difference between modern amphibians and the remaining tetrapods is the occurrence of an amniotic egg in the latter group. The amniotic (or cleidoic) egg is sometimes referred to as the `land egg,' but this is a misnomer. .... Nonetheless, the amniotic egg is a derived character that distinguishes the two major groups of tetrapods amniotes and nonamniotes. The amniotic egg, as we know it, is characteristic of turtles, squamates, crocodilians, birds, monotremes, and in modified form, of therian mammals as well. ... An amniotic egg is a remarkable example of biological engineering (Figure 10-19). The shell, which may be leathery or calcified, provides mechanical protection while allowing movement of respiratory gases and water vapor. The albumin (egg white) gives further protection against mechanical damage and provides a reservoir of water and protein. The large yolk is the energy supply for the developing embryo. .... The significant differences [from the anamniotic eggs of amphibians and fishes] lie in three other extraembryonic membranes the chorion, amnion, and allantois. The chorion and amnion develop from outgrowths of the body wall at the ends of the embryo. These two pouches spread outward and around the embryo until they meet At their junction, the membranes merge and leave an outer membrane, the chorion, which surround the embryo and yolk sac, and an inner membrane the amnion, which surrounds the embryo itself The allantoic membrane develops as an outgrowth of the hind gut posterior to the yolk sac and lie within the chorion. It is a respiratory organ and a storage place for nitrogenous wastes produced by the metabolism of the embryo. The allantois is left behind in the egg when the embryo emerges, and the nitrogenous wastes stored in it do not have to be reprocessed." (Pough, Heiser & McFarland, 1989, pp.363-365)."It is easier to understand the stages by which the reptiles evolved temporal fenestrae and other distinguishing skeletal characters than to imagine the steps that led to the development of the `land egg.' Paleontologists continue to speculate upon the way in which the enclosure of the embryo came about, however, because the matter is central to the broad question of reptilian origins. Study of the eggs laid by living reptiles has provided little insight into the evolution of the extraembryonic structures which gave protoreptiles their first advantage over other tetrapods. Rather than recapitulating the process of its evolution, the `land egg' develops in a specialized manner derived, no doubt, by abbreviation and reordering of an earlier procedure. ... All the extraembryonic membranes in the `land egg' of a modern reptile must complete their formation normally if the embryo is to sustain itself. The yolk sac is of crucial importance, because nutritive materials from the yolk mass can enter the body only by passing through the vessels in its surface. The allantois also cannot fail: it serves as the respiratory organ for the embryo, since blood coursing through it loses carbon dioxide and receives oxygen by diffusion through the adjacent chorion and porous shell. In addition, its central cavity stores nitrogenous wastes produced by the actively metabolizing, embryonic cells. Blood reentering the embryo from the allantoic vessels restores to the body water that has When resorbed from the excreted waste and also adds some that passes into the egg from the environmental air. The exterior of the embryo is kept wet by a liquid that accumulates within the amnion. Unlike pond water, to which it is often compared, the amniotic fluid does not act as an oxygen-bearing medium for the embryo. It is an adaptation for protecting the developing, animal against shock and for preventing it from resting against the membranes in the shell and sticking to them. Despite the difficulty of explaining how the embryo might have been served while the "land egg" was evolving to its present state, Szarski has suggested a series of steps by which the reptilian structure may have arisen." (Stahl, 1985, pp.268-270)[top]"With all this, of course, went improvements in the brain, most notably the power to compare the times at which signals from one source reach each ear, thus providing a method of estimating the direction in which the source lies. Thus, in the course of evolution, there were six major developments, two of which occurred in the fishes, two in the amphibia and two in mammals. Such, at least, is the account given by people like Willem van Bergeijk, of Bell Telephone Laboratories who is the acknowledged authority. But the eminent morphologist J. W. Torrey is not convinced. 'The evolutionary origin of the inner ear is entirely unknown,' he insists. In contrast with the case of the eye, where undifferentiated cells were specialised into the required forms, here existing structures have been profoundly modified and even shifted to another position in a progressive series of changes which certainly look more like the refinement of a plan than the result of a series of happy accidents. But the insoluble problem is how and why did a balance organ become an organ of hearing? As van Bergeijk pointedly asks: 'What prompts the fish to begin developing a sensory apparatus that will respond to a stimulus about the very existence of which the fish knows nothing?' Van Bergeijk believes that the original balance organ would never have evolved mechanisms for hearing but for the emergence of the swim bladder. The original purpose of this organ is to enable the fish to adjust its density to the density of the ambient water and so control the depth at which it swims. Since the bladder is sensitive to changes in external pressure, it vibrates in harmony with pressure changes in the water. In time these vibrations came to excite the ear. Hearing as distinct from the mere detection of pressure waves, was born. After describing the last part of this process, the adaptation of the bones linking the jaw to the skull into a chain of ossicles linking the eardrum to the inner ear, Ernst Mayr sweepingly remarks: 'Not all the steps in this process are yet entirely apparent, but I think little doubt is left as to the principle involved.' If by 'principle' one means merely progressive remodelling, the statement is a truism. But if 'principle' means that chance selection brought about these elaborate changes, then there must be very great doubt indeed. Like de Beer, Mayr does not seem to appreciate the elementary point that demonstrating the occurrence of a sequence of events does not explain why they happened. But what kind of mutations could bring about the major changes I have described? Could cause a tube to roll up into a helix? Could cause other tubes to form semi-circular canals accurately set at right angles to each other. Could grade sensory hairs according to length? Could cause the convenient deposit of a crystal in the one place it will register gravity? Even more amazingly, some fishes do not trouble to secrete a crystal but incorporate a bit of sand or stone. What kind of mutation could achieve this - when and only when a natural crystal is not formed? The purpose is fulfilled, the means are unimportant. It just doesn't make sense." (Taylor G.R., "The Great Evolution Mystery," Abacus: London, 1983, pp.105-106) [top]2. Hair Evolution has no adequate explanation for the origin of mammalian hair:"At this point in our discussion I may challenge the adherents of the strictly Darwinian view, which we are discussing here, to try to explain the evolution of the following features by accumulation and selection of small mutants: hair in mammals, feathers in birds segmentation of arthropods and vertebrates, the transformation of the gill arches in phylogeny including the aortic arches, muscles, nerves, etc.; further, teeth, shells of mollusks, ectoskeletons, compound eyes, blood circulation, alternation of generations, statocysts, ambulacral system of echinoderms, pedicellaria of the same, enidocysts, poison apparatus of snakes, whalebone, and, finally, primary chemical differences like hemoglobin vs. hemocyanin, etc. Corresponding examples from plants could be given." (Goldschmidt R.B., "The Material Basis of Evolution," [1940], Yale University Press: New Haven CT, 1982, reprint, pp.6-7) [top]3. Land mammal-whale transition Evolution has a major problem with the land mammal to whale transition. The creationist zoologist, Douglas Dewar, has summarised the immense changes involved in such a transition:"Let us notice what would be involved in the conversion of a land quadruped into, first a seal-like creature and then into a whale. The land animal would, while on land, have to cease using its hind legs for locomotion and to keep than permanently stretched out backwards on either side of the tail and to drag itself about by using its fore-legs. During its excursions in the water, it must have retained the hind legs in their rigid position and swum by moving them and the tail from side to side. As a result of this act of self denial we must assume that the hind legs eventually be came pinned to the tail by the growth of membrane. Thus the hind part of the body would have become likes that of a seal. Having reached this stage, the creature in anticipation of a time when it will give birth to its young under water, gradually develops apparatus by means of which the milk is forced into the mouth of the young one, and, meanwhile a cap has to be formed round the nipple into which the snout of the young one fits tightly, the epiglottis and laryngeal cartilage become prolonged upwards to form a cone-shaped tube, and the soft palate becomes prolonged downwards so as tightly to embrace this tube, in order that the adult will be able to breathe while taking water into the mouth and the young while taking in milk. These changes must be effected completely before the calf can be born under water. Be it noted that there is no stage intermediate between being born and suckled under water and being born and suckled in the air. At the same time various other anatomical changes have to take place, the most important of which is the complete transformation of the tail region. The hind part of the body must have begun to twist on the fore part, and this twisting must nave continued until the sideways movement of the tail developed into an up-and-down movement. While this twisting went on the hind limbs and pelvis must have diminished in size, until the latter ceased to exist as external limbs in all, and completely disappeared in most, whales." (Dewar D., 1938, pp.23-24)Descriptions by evolutionists give some idea of the enormity of these changes: "Evolution had produced a metamorphosis that Ovid would have loved: it had transformed away their legs, given them flukes on their tail, had put their noses on top of their heads" (Zimmer, 2001, p.136); "The lineage that gave rise to dolphins, whales, and porpoises went through a transformation just as staggering as the one that brought vertebrates on land in the first place" (Zimmer, 1998, p.6). Paleontologists "cannot even reasonably begin to entertain the hypothesis of a long, unrecorded interval of diversification," for whales (Stanley, 1979, p.69). But they had thought that "the extent of the change involved in the transformation of a terrestrial mammal into a completely oceanic one was so great that the process must have begun at least as long ago as the early Paleocene (~60 mya) and possibly even before that time, at the end of the Cretaceous period (~65 mya) (Stahl, 1985, p.486). Then "the oldest specimens [of whales], dating back more than 40 million years, were fundamentally like whales today," with "flippers, and no back legs" (Zimmer, 2001, p.136). However, with the discovery of even earlier whale fossils the time frame for this transition has shrunk to only 10-12 million years (Carroll, 1997, p.336; Zimmer, 1995a), or even less (Wesson, 1991, pp.51-52)! But since such changes to be preserved must be "locked up"' by speciation (Gould & Eldredge 1993), that requires that each major transformation be a new species (or "chronospecies"). Since the average mammal species of that Cenozoic Era typically last a million years, "we have only ten or fifteen chronospecies to align, end-to-end, to form a continuous lineage connecting our primitive little mammal with a ... whale" (Stanley, 1981, p.93). But, "this is clearly preposterous. ... a chain of ten or fifteen of these might move us from one small rodentlike form to a slightly different one, perhaps representing a new genus, but not to a ... whale" (Stanley, 1981, pp.93-94)! Adding to the problem is that large mammals, including whales, are limited in their capacity to change through random mutations and natural selection, factors including: "long generation spans (the time between birth and the ability to give birth)" and "low numbers of progeny produced per adult" (Ross, 1998, pp.51- 52). A recent discovery of a 14 myo baleen whale fossil, Eobalaenoptera harrisoni may create further problems for evolution by suggesting that "almost-modern-looking whales lived considerably further back in time than scientists realized" (ABCNews, 2004a)"I simply thought that the time had come to take the fossil record-the patterns of stability and change a bit more literally than had traditionally been the case. George Simpson had begun the process when he insisted that gaps do not explain away the abrupt appearances of large-scale taxa-meaning, large-scale events of evolutionary change. Simpson was perfectly content to blame the absence of examples of gradual change within and between species on gaps in the record, but found (to his everlasting credit) that the argument could not be stretched to encompass large-scale evolutionary change, such as the derivation of whales or bats from terrestrial mammalian precursors." (Eldredge N., "Reinventing Darwin: The Great Evolutionary Debate," [1995], Phoenix: London, 1996, p.96).http://www.abc.net.au/science/news/stories/s1348668.htm ABC Whale found in desert Reuters ... 19 April 2005 The skeleton of the 18 metre whale was found in the remote Wadi Hitan valley, where hundreds of fossils are being exposed by the wind ... An American palaeontologist says he and a team of Egyptians have found what could be the most complete fossilised skeleton of the 40 million year old whale Basilosaurus isis in Egypt's Western Desert. Professor Philip Gingerich ... excavated the well-preserved skeleton in a desert valley known as Wadi Hitan, or the Valley of the Whales, southwest of Cairo. The first Basilosaurus was discovered in 1905 but no full skeleton has been found until now, the university says. "His feeling is that it's the most complete, the whole skeleton from stem to stern," a university spokesperson says. An enigma of evolution The skeleton, which is 18 metres long, could throw light on why there are so many fossilised remains of whales and other ancient sea animals in Wadi Hitan and possibly how the extinct animal swam, Gingerich says. "Basilosaurus is an enigma of whale evolution because of its unusually long serpentine body," he says. Basilosaurus is one of the primitive whales known as archaeocetes, which evolved from land mammals and later evolved into the two types of modern whale. Basilosaurus resembled a giant sea snake, leading early palaeontologists to conclude it was a reptile ... But it looks like a giant sea snake and the palaeontologists who found the first archaeocetes thought they were reptiles. ... "The research team will use the new skeleton to study how it lived and swam, and possibly to learn why it so abundant in Wadi Hitan," Gingerich says. ... Wadi Hitan is unusually rich in fossil remains from the period, trapped in a sandstone formation that then formed the sea bed. The fossils include five species of whale, three species of sea cow, two crocodiles, several turtles, a sea snake, and large numbers of fossilised sharks and bony fish. ... [It is interesting that Gingerich admits that "Basilosaurus is an enigma of whale evolution because of its unusually long serpentine body."...] [top] 4. Insectivore-bat transition http://news.bbc.co.uk/1/hi/sci/tech/4213495.stm BBC ... 28 January, 2005 ... Bat evolution linked to warming ... A sharp rise in global temperatures about 50 million years ago may have been responsible for the evolution of bats, Science magazine reports. This warming is linked to an explosion in the diversity of other mammals, but little was known about bat evolution. New DNA data traces the origin of four major bat lineages to a brief period in the Eocene epoch when the average global temperature rose by about 7C. ... [The SCIENCE article says that bats "originated in the early Eocene ... 52 to 50 million years ago" (http://www.sciencemag.org/cgi/content/abstract/sci;307/5709/580) and the accompanying commentary article is titled "An Eocene Big Bang for Bats" (http://www.sciencemag.org/cgi/content/summary/sci;307/5709/527), which doesn't sound exactly Darwinian! ]"It is thus likely, to say the least, that major as well as minor changes in evolution have occurred gradually and that the same forces are at work in each case. Nevertheless there is a difference and many of the major changes cannot be considered as simply caused by longer continuation of the more usual sorts of minor changes. For one thing, there is excellent evidence that evolution involving major changes often occurs with unusual rapidity, although, as we have seen, there is no good evidence that it ever occurs instantaneously. The rate of evolution of the insectivore forelimb into the bat wing, to give just one striking example, must have been many times more rapid than any evolution of the bat wing after it had arisen. The whole record attests that the origin of a distinctly new adaptive type normally occurs at a much higher rate than subsequent progressive adaptation and diversification within that type. The rapidity of such shifts from one adaptive level or equilibrium to another has suggested the name `quantum evolution,' under which I have elsewhere discussed this phenomenon at greater length. " (Simpson G.G., "The Meaning of Evolution: A Study of the History of Life and of its Significance for Man," Yale University Press: New Haven CT, 1949, pp.234-235) [top]
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Created: 3 November, 2003. Updated: 7 April, 2006.