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Icons of Evolution By Jonathan Wells Regnery Publishing Co., 2000 Introduction Does the scientific community have empirical evidence to support the theory of evolution? Most biological texts answer with a resounding “Yes.” But is this an accurate answer? Steve Badger 2 Introduction Embryologist Jonathan Wells (PhD in cell and developmental biology, University of California, Berkeley) claims that biology textbooks greatly exaggerate and distort the evidence to support a theory of evolution. He claims “Students and the public are being systematically misinformed about the evidence for evolution” by these books. Steve Badger 3 Introduction He uses direct quotes of articles in peer-reviewed scientific journals, written by experts in the field to illustrate these exaggerations, distortions, and outright deceptions. His approach in this book is neither philosophical nor religious, but it is scientific. Steve Badger 4 1. The Miller-Urey Experiment As a graduate student at the University of Chicago in 1953, Stanley Miller and his major professor, Harold Urey, attempted to simulate the earth’s primitive atmospheric conditions in a laboratory apparatus (see illustration). Steve Badger 5 1. The Miller-Urey Experiment They speculated that the primitive atmosphere had little if any oxygen, but had methane (CH4), ammonia (NH3), hydrogen (H2), and water vapor (H2O). Steve Badger 6 1. The Miller-Urey Experiment The mixture was heated, and the vapors passed through an electric spark (simulating lightening), and then cooled and reheated. After a period of time, the soup was analyzed and found to contain amino acids, the building blocks of proteins. Steve Badger 7 r 1. The Miller-Urey Experiment Steve Badger 8 1. The Miller-Urey Experiment This work has been used to support the idea that life could have arisen spontaneously from non-life (we call this spontaneous generation). Steve Badger 9 1. The Miller-Urey Experiment Does the Miller-Urey experiment support spontaneous generation (abiogenesis)? Is this really hard, scientific evidence for spontaneous generation? What is wrong with this experiment? Steve Badger 10 1. The Miller-Urey Experiment 1. The choices of gases to include and exclude were highly speculative—and most researchers in that field today reject them as being unlikely. Some evidence suggests that the primitive earth atmosphere included oxygen. Steve Badger 11 1. The Miller-Urey Experiment 2. Proteins as the first organic molecule is not part of a reasonable spontaneous generation hypothesis. Neither is DNA. Some suggest RNA is the best candidate for the original molecule in spontaneous generation. But we have thought of no mechanism for synthesizing RNA—other than by life forms. Steve Badger 12 1. The Miller-Urey Experiment 3. The amino acids molecules formed in this experiment were a mixture of two forms (they are called D- and L-). Life is composed only of the latter. The presence of the former would mitigate against spontaneous generation. Steve Badger 13 2. Darwin’s Tree of Life A central feature of almost every contemporary theory of evolution is that all life descended from a common ancestor. Darwin called this “the Great Tree of Life.” This “Great Tree of Life” model predicts: Steve Badger 14 2. Darwin’s Tree of Life 1. Phylum-level and class-level differences appeared only after a long history of changes in species. 2. The fossil record will show evidence of speciation occurring through all epochs. 3. The Tree of Life has been used for so long that many people assume it is factual. Steve Badger 15 2. Darwin’s Tree of Life This theory posits that “phylum-level differences could not have appeared right at the start. Yet that is what the fossil record shows.” (35) We call this “sudden” appearance of many phyla the Cambrian explosion, and biologists typically propose three solutions. “So the branching-tree pattern of evolution is inconsistent with major features of the fossil and molecular evidence.” (54) Steve Badger 16 3. Homology in Vertebrate Limbs Structural similarity is called homology Probably the classic examples of homology are vertebrate forelimbs (compare the bat’s wings, the dolphin’s flippers, the dog’s front legs, and the arms and hands of humans) This fact of structural similarity is cited as evidence of common descent (evolution) Steve Badger 17 3. Homology in Vertebrate Limbs If homology is defined as similarity due to common descent, how can it be cited as evidence for common descent? This is circular reasoning. Steve Badger 18 3. Homology in Vertebrate Limbs Scientists have long known that homologous structures are not (necessarily) due to similar genes. (If homologous structures were the result of common descent, they would be due to similar genes.) Steve Badger 19 4. Haeckel’s Embryos Darwin noticed similarities in embryos of different species and concluded that this demonstrates that they descended from a common ancestor—and what that ancestor looked like. He relied on Ernst Haeckel’s drawing of embryos to illustrate his conclusion. Steve Badger 20 4. Haeckel’s Embryos Haeckel’s drawings of embryos of various vertebrates showed them as almost identical in the earliest stages, becoming more dissimilar as they developed. Steve Badger 21 4. Haeckel’s Embryos r Steve Badger 22 23 Steve Badger 4. Haeckel’s Embryos r 4. Haeckel’s Embryos “Ontogeny recapitulates phylogeny,” they said. He used the term “ontogeny” to stand for embryonic development and the term “phylogeny” to stand for the evolutionary history of a species. Steve Badger 24 4. Haeckel’s Embryos “Biologists have known for over a century that Haeckel faked his drawings; vertebrate embryos never look as similar as he made them out to be.” (82) Haeckel’s drawings greatly exaggerated the similarities and the “evidence [was] twisted to fit the theory.” Steve Badger 25 4. Haeckel’s Embryos “When Haeckel’s embryos are viewed side-by-side with actual embryos, there can be no doubt that his drawing were deliberately distorted to fit his theory.” (92) Even arch-evolutionist Stephen Jay Gould reached this conclusion (Natural History March 2000). Steve Badger 26 4. Haeckel’s Embryos In reality: vertebrate embryos start out looking very different, become more similar in appearance midway through development, and then become increasingly dissimilar as they move toward adulthood. Conclusion? “Instead of providing support for Darwin’s theory, the embryological evidence presents it with a paradox.” (99) Steve Badger 27 5. Archaeopteryx—The Missing Link Darwin’s theory postulated the existence of intermediate, transitional links between extant species and the “parent-species.” Since the fossil record was incomplete, none were known when The Origin of the Species was published in 1859. Just a couple of years later, Hermann von Meyer described a fossil that he named Archaeopteryx (ancient wing). Another better specimen was discovered in 1877. Steve Badger 28 5. Archaeopteryx—The Missing Link Archaeopteryx had bird-like feathers and a reptilian jaw and teeth, so it was hailed as the evolutionary link between reptiles and birds. At last (some thought), empirical, unimpeachable evidence for the theory of evolution. Steve Badger 29 5. Archaeopteryx—The Missing Link Evolutionists are divided over the use of Archaeopteryx as a transitional form Probably the majority of evolutionists no longer claim Archaeopteryx as a transitional form Steve Badger 30 6. Peppered Moths Peppered moths have two variations: light and dark (England & USA) The ratio of dark to light moths changed over time In the 1950s, Kettlewell suggested that birds ate the more visible moths Steve Badger 31 6. Peppered Moths The light variety were more abundant, then the dark variety became more common Pollution-darkened tree trunks made the light variety more visible, so birds ate more light ones An example of protective camouflage? Steve Badger 32 6. Peppered Moths Early test seemed to indicate birds ate more light moths in an environment with dark trees They called it “the most striking evolutionary change ever actually witnessed in any organism” (143) We have observed an evolutionary process Steve Badger 33 6. Peppered Moths If this selective advantage was real, the dark moths should have almost completely replaced the light ones over time Since this did not happen, perhaps something besides camouflage and predatory birds was involved Steve Badger 34 6. Peppered Moths Peppered moths don’t naturally rest on tree trunks, but on the underside of smaller, horizontal limbs Many of the photos of peppered moths on tree trunks were staged Textbooks still cite this as evidence of natural selection Steve Badger 35 7. Darwin’s Finches Darwin suggested that the variety of beaks on finches on the Galápagos Islands is often cited as an example of natural selection Jonathan Weiner called it “the most detailed demonstration…of the power of Darwin’s process” (167) Steve Badger 36 7. Darwin’s Finches Steve Badger 37 7. Darwin’s Finches During the 1970s, research discovered that beak size in these finches is related to rainfall and the abundance of the seed crop Finch beak size may fit a natural selection model, but we have no empirical evidence to support that Steve Badger 38 7. Darwin’s Finches Darwinian theory predicts a diverging model (greater numbers of varieties in beak size) Observation finds the opposite—a converging model (fewer numbers of varieties in beak size) Steve Badger 39 8. Four-Winged Fruit Flies Mutations are easily induced in Drosophila melanogaster One such mutant has two pairs of wings rather than one pair Does this support the theory of evolution? Steve Badger 40 8. Four-Winged Fruit Flies The extra pair of wings lack muscles The flies cannot fly—they are handicapped The extra pair of wings are not beneficial, they are detrimental Steve Badger 41 8. Four-Winged Fruit Flies This extra pair of wings does not provide evidence that DNA mutations produce beneficial changes in body structures The mutations were not “natural,” but “artificial”—under the control of an intelligent designer (human) Steve Badger 42 9. Fossil Horses & Directed Evolution Early in the development of the theory of evolution, the proposed reconstruction of the evolutionary history of horses was used to support the idea of “directed evolution” (orthogenesis). Now evolutionists claim that the new branched-tree theory of horse evolution argues against directed evolution. Steve Badger 43 9. Fossil Horses & Directed Evolution Neither straight-line nor branchingtree models argue for or against directed evolution. Undirected (purely random) evolution is a philosophical position, not a scientific observation. Steve Badger 44 10. From Ape to Human Evolutionists typically claim that humans evolved just as the other animals evolved Thus evolutionists typically see humans as animals that are more evolved Steve Badger 45 10. From Ape to Human The fossil evidence to support models of human evolution is even more subjective than that for models of evolution of other animals Much of what is offered as evidence is actually (speculative) interpretation Steve Badger 46 10. From Ape to Human Often the data are merely organized to fit the model! But the data fit other models just as well! Steve Badger 47 The point of this book… Most science textbooks continue to cite these “icons of evolution” as evidence to support this theory Scientists should know these have been discredited—many do not What does this show about the nature of the dialogue/argument? Steve Badger 48