By: Shelby Sherman To: Tyler A. Wunder Re: Theory of evolution TAW+gt; Would someone +quot

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By: Shelby Sherman To: Tyler A. Wunder Re: Theory of evolution TAW> Would someone "in-the-know" kindly lay out an evolutionary theory or TAW> two so Bill Wolff will provide us with his theory of creationism, or at TAW> least be unable to honestly gainsay the request for his theory? AN INTRODUCTION TO EVOLUTIONARY BIOLOGY -- BY CHRIS COLBY ********************************************************* INTRODUCTION ------------ Evolution is one of the most powerful theories science has ever known. For a variety of reasons, however, it is also one of the most misunderstood. One common misunderstanding is that the phrase "survival of the fittest" summarizes evolutionary theory. In fact, it does not. The phrase is both incomplete and misleading. Two other common misinterpretations are that evolution is progress and organisms can be arranged on an evolutionary ladder from bacteria to man. This post is an outline of the basics of evolutionary biology. It is intended to be a brief overview of the concepts and mechanisms of evolution. Creationist arguments are not addressed directly here; nor is a "laundry list" of reasons to believe in evolution provided. Many interesting topics in evolutionary biology are not covered (symbiosis and endosymbiosis, origins of life, evolution of sex, human evolution and much more) because I can't include everything and keep this down to a readable length. WHAT IS EVOLUTION? Evolution is a change in the gene pool of a population over time. The gene pool is the set of all genes of a species or population. The English moth, _Biston__betularia_, is a frequently cited example of observed evolution. In this moth, rare black variants spread through the population as a result of their habitat becoming darkened by soot from factories. Birds could see the lighter colored moths more readily and ate more of them. The moth population changed from mostly light colored moths to mostly dark colored moths. Since their color was determined by a single gene, the change in frequency of dark colored moths represented a change in the gene pool. This change was, by definition, evolution. The kind of evolution documented above is called "microevolution". Larger changes (taking more time) are termed "macroevolution". Some biologists feel the mechanisms of macroevolution are different from those of microevolutionary change. Others, including myself, feel the distinction between the two is arbitrary. Macroevolution is cumulative microevolution. In any case, evolution is defined as a change in the gene pool. This means that evolution is a population level phenomena. Only groups of organisms evolve. An individual organism does not evolve, nor do subunits of organisms evolve (with limited exceptions). So, when thinking of evolution, is neccessary to view populations as a collection of individuals. I have defined evolution, here, as a process and that is how I will use the term in this essay. Keep in mind, however, that in everyday use evolution often refers to a variety of things. The fact that all organisms are linked via descent to a common ancestor is often called evolution. The theory that life arose solely via natural processes is often called evolution (instead of abiogenesis). And frequently, people use the word evolution when they really mean natural selection -- one of the many mechanisms of evolution. WHAT ISN'T EVOLUTION? For many people evolution is equated with morphological change, i.e. organisms changing shape or size over time. An example would be a dinosaur species slowly turning into a bird species. It is important to note that evolution is often accompanied by morphological change, but this need not be the case. Evolution can occur without morphological change; and morphological change can occur without evolution. For instance, humans are larger now than in the past few hundred years, but this is not an evolutionary change. Better diet and medicine brought about this change, so it is not an example of evolution. The gene pool did not change -- only its manifestation did. An organism's phenotype is determined by both its genes and its environment. Phenotype means the morphological, physiological, bio- chemical, behavioral and other properties exhibited by a living organism. Phenotypic changes induced solely by changes in environment do not count as evolution because this change is not heritable. In other words the change is not passed on to the organism's offspring. Most changes due to environment are fairly subtle (e.g. size differences). Large scale phenotypic changes (such as dinosaur to bird) are obviously due to genetic changes, and therefore are evolution. WHAT EVOLUTION ISN'T Evolution is not progress. Organisms simply adapt to their current surroundings and do not necessarily become "better" over time. A trait or strategy that is successful for an organism at one time may be deleterious at another. Studies in yeast have shown that "more evolved" strains of yeast can sometimes be competitively inferior to "less evolved" strains. An organism's success or failure depends to a great deal on the behavior of its contemporaries; for most traits or behaviors there is likely no optimal design or strategy, only contingent designs or strategies. HOW DOES EVOLUTION WORK? If evolution is a change in the gene pool; what causes the gene pool to change? Several mechanisms can bring about a change in the gene pool, among them: natural selection, genetic drift, gene flow, mutation and recombination. I will discuss these in more detail later. It is important to understand the difference between evolution (change in the gene pool) and the mechanisms that bring about this change. GENETIC VARIATION ----------------- Bringing about a change in the gene pool assumes that there is genetic variation in the population to begin with, or a way to generate it. Genetic variation is "grist for the evolutionary mill". For example, if there were no dark moths, the population could not have evolved from mostly light to mostly dark. In order for continuing evolution there must be mechanisms to both increase genetic variation, or create it, (e.g. mutation) and decrease variation (e.g. natural selection and genetic drift). HOW IS GENETIC VARIATION DESCRIBED? Genetic variation has two components: allelic diversity and non-random associations of alleles. Alleles are different versions of the same gene at a given locus. For example, at the blood group locus (locus means location) humans can have an A, B or O allele. There are subtypes of these alleles as well. Most animals, including humans, are diploid. This means they contain two alleles for every gene at every locus. If the two alleles are the same type (for instance two A alleles) the individual would be termed "homozygous" for that locus. An individual with two different alleles at a locus is called "heterozygous". Allelic diversity is simply the number of alleles at each locus scaled by their frequency in the gene pool. At any given locus there can be many different alleles in the gene pool. It is important to realize that there can be more alleles in the gene pool at any locus than any single organism can possess. Linkage disequilibrium is a measure of association of alleles at different loci. If each gene assorted entirely independently, the gene pool would be at linkage equilibrium. However, if some alleles were often found together in organisms (ie. did not assort randomly) these alleles would be in linkage disequilibrium. Linkage disequilibrium can be the result of physical proximity of the genes or maintained by natural selection if some combinations of alleles work better as a team. WHAT IS EVOLUTION? version 2, January 22, 1993 Most non-scientists seem to be quite confused about precise definitions of biological evolution. Such confusion is due in large part to the inability of scientists to communicate effectively to the general public and also to confusion among scientists themselves about how to define such an important term. When discussing evolution it is important to distinguish between the existence of evolution and various theories about the mechanism of evolution. And when referring to the existence of evolution it is important to have a clear definition in mind. What, exactly, do biologist mean when they say that they have observed evolution or that humans and chimps have evolved from a common ancestor. One of the most respected evolutionary biologists has defined biological evolution as follows, "In the broadest sense, evolution is merely change, and so is all-pervasive; galaxies, languages, and political systems all evolve. Biological evolution ... is change in the properties of populations of organisms that transend the lifetime of a single individual. The ontogeny of an individual is not considered evolution; individual organisms do not evolve. The changes in populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next. Biological evolution may be slight or substantial; it embraces everything from slight changes in the proportion of different alleles within a population (such as those determining blood types) to the successive alterations that led from the earliest protoorganism to snails, bees, giraffes, and dandelions." Douglas J. Futuyma in Evolutionary Biology, Sinauer Associates 1986 It is important to note that biological evolution refers to populations and not to individuals and that the changes must be passed on to the next generation. In practice this means that, Evolution is a process that results in heritable changes in a population spread over many generations This is a good working scientific definition of evolution; one that can be used to distinguish between evolution and similar changes that are not evolution. Another common short definition of evolution can be found in many textbooks, "In fact, evolution can be precisely defined as any change in the frequency of alleles within a gene pool from one generation to the next." Helena Curtis and N. Sue Barnes BIOLOGY 5th ed. 1989 Worth Publishers, p.974 One can quibble about the accuracy of such a definition (and we have often quibbled on these newsgroups) but it also conveys the essence of what evolution really is. When biologists say that they have observed evolution they mean that they have detected a change in the frequency of genes in a population. (Often the genetic change is inferred from phenotypic changes that are heritable.) When biologists say that humans and chimps have evolved from a common ancestor they mean that there have been successive heritable changes in the two separated populations since they became isolated. Unfortunately the common definitions of evolution outside of the scientific community are different. For example, in the Oxford Concise Science Dictionary we find the following definition; "evolution: The gradual process by which the present diversity of plant and animal life arose from the earliest and most primitive organisms, which is believed to have been continuing for the past 3000 million years." This is inexcusable for a dictionary of science. Not only does this definition exclude prokaryotes, protozoa, and fungi, but it specifically includes a term "gradual process" which should not be part of the definition. More importantly the definition seems to refer more to the history of evolution than to evolution itself. Using this definition it is possible to debate whether evolution is still occurring but the definition provides no easy way of distinguishing evolution from other processes. For example, is the increase in height among Caucasians over the past several hundred years an example of evolution? Are the color changes in the peppered moth population examples of evolution? This is not a scientific definition. Standard dictionaries are even worse. "evolution: ...the doctrine according to which higher forms of life have gradually arisen out of lower.." Chambers "evolution: ...the development of a species, organsim, or organ from its original or primitive state to its present or specialized state; phylogeny or ontogeny: Webster's These definitions are simply wrong. Unfortunately it is common for non- scientists to enter into a discussion about evolution with such a definition in mind. This often leads to fruitless debate since the experts are thinking about evolution from a different perspective. When someone claims that they don't believe in evolution they cannot be referring to an acceptable scientific definition of evolution because that would be denying something which is easy to demonstrate. It would be like saying that they don't believe in gravity! Recently I read a statement from a creationist who claimed that scientists are being dishonest when they talk about evolution. This person believed that evolution was being misrepresented to the public. The real problem is that the public, and creationists, do not understand what evolution is all about. This person's definition of evolution was very different from the common scientific definition and as a consequence he was unable to understand what evolutionary biology really meant. This is the same person who claimed that one could not "believe" in evolution and still be religious! But once we realize that evolution is simply "a process that results in heritable changes in a population spread over many generations" it seems a little silly to pretend that this excludes religion! Scientists such as myself, must share the blame for the lack of public understanding of science. We need to work harder to convey the correct information. Sometimes we don't succeed very well but that does not mean that we are dishonest. On the other hand, the general public, and creationists in particular, need to also work a little harder in order to understand science. Reading a textbook would help. Laurence A. Moran (Larry) ==* MORAN EVOLUTION FACT_AND_THEORY REFS EVOLUTION AS A FACT AND A THEORY version 2.1 (January 22, 1993) When non-biologists talk about biological evolution they often confuse two different aspects of the definition. On the one hand there is the question of whether or not modern organisms have evolved from older ancestral organisms or whether modern species are continuing to change over time. On the other hand there are questions about the mechanism of the observed changes... how did evolution occur? Biologists consider the existence of biological evolution to be a FACT. It can be demonstrated today and the historical evidence for it's occurrence in the past is overwhelming. However, biologists readily admit that they are less certain of the exact MECHANISM of evolution; there are several THEORIES of the mechanism of evolution. Stephan J. Gould has put this as well as anyone else, "In the American vernacular, "theory" often means "imperfect fact" - part of a hierarchy of confidence running downhill from fact to theory to hypothesis to guess. Thus the power of the creationist argument: evolution is "only" a theory and intense debate now rages about many aspects of the theory. If evolution is worse than a fact, and scientists can't even make up their minds about the theory, then what confidence can we have in it? Indeed, President Reagan echoed this argument before an evangelical group in Dallas when he said (in what I devoutly hope was campaign rhetoric): 'Well, it is a theory. It is a scientific theory only, and it has in recent years been challenged in the world of science - that is, not believed in the scientific community to be as infallible as it once was.' Well evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape-like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered. Moreover, 'fact' doesn't mean 'absolute certainty'; there ain't no such animal in an exciting and complex world. The final proofs of logic and mathematics flow deductively from stated premises and achieve certainty only because they are NOT about the empirical world. Evolutionists make no claim for perpetual truth, though creationists often do (and then attack us falsely for a style of argument that they themselves favor). In science 'fact' can only mean 'confirmed to such a degree that it would be perverse to withhold provisional consent'. I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms. Evolutionists have been very clear about this distinction of fact and theory from the very beginning, if only because we have always acknowledged how far we are from completely understanding the mechanisms (theory) by which evolution (fact) occurred. Darwin continually emphasized the difference between his two great and separate accomplishments: establishing the fact of evolution, and proposing a theory - natural selection - to explain the mechanism of evolution." Stephen J. Gould "Evolution as Fact and Theory"; Discover, May 1981 Gould is stating the prevailing view of the scientific community. In other words, the experts on evolution consider it to be a FACT. This is not an idea that originated with Gould as the following quotations indicate; "Let me try to make crystal clear what is established beyond reasonable doubt, and what needs further study, about evolution. Evolution as a process that has always gone on in the history of the earth can be doubted only by those who are ignorant of the evidence or are resistant to evidence, owing to emotional blocks or to plain bigotry. By contrast, the mechanisms that bring evolution about certainly need study and clarification. There are no alterantives to evolution as history that can withstand critical examination. Yet we are constantly learning new and important facts about evolutionary mechanisms." Theodosius Dobzhansky "Nothing in Biology Makes Sense Except in the Light of Evolution", American Biology Teacher vol.35 (March 1973) reprinted in EVOLUTION VERSUS CREATIONISM, J. Peter Zetterberg ed., ORYX Press, Phoenix AZ 1983 ----------------------------------------------- "It is time for students of the evolutionary process, especially those who have been misquoted and used by the creationists, to state clearly that evolution is a FACT, not theory, and that what is at issue within bology are questions of details of the process and the relative importance of different mechanisms of evolution. It is a FACT that the earth with liquid water, is more than 3.6 billion years old. It is a FACT that cellular life has been around for at least half of that period and that organized multicellular life is at least 800 million years old. It is a FACT that major life forms now on earth were not at all represented in the past. There were no birds or mammals 250 million years ago. It is a FACT that major life forms of the past are no longer living. There used to be dinosaurs and Pithecanthropus, and there are none now. It is a FACT that all living forms come from previous living forms. Therefore, all present forms of life arose from ancestral forms that were different. Birds arose from nonbirds and humans from nonhumans. No person who pretends to any understanding of the natural world can deny these facts any more than she or he can deny that the earth is round, rotates on its axis, and revolves around the sun. The controversies about evolution lie in the realm of the relative importance of various forces in molding evolution." R. C. Lewontin "Evolution/Creation Debate: A Time for Truth" Bioscience 31, 559 (1981) reprinted in EVOLUTION VERSUS CREATIONISM op cit. There are readers of these newsgroups who reject evolution for religious reasons. In general these readers oppose both the FACT of evolution and THEORIES of mechanisms although some anti-evolutionists have come to realize that there is a difference between the two concepts. That is why we see some leading anti-evolutionists admitting to the fact of "microevolution" - they know that evolution can be demonstrated. These readers will not be convinced of the "facthood" of (macro)evolution by any logical argument and it is a waste of time to make the attempt. The best that we can hope for is that they understand the argument that they oppose. Even this simple hope is rarely fulfilled. There are some readers who are not anti-evolutionist but still claim that evolution is "only" a theory which can't be proven. This group needs to distinguish between the fact that evolution occurs and the theory of the mechanism of evolution. We also need to distinguish between facts that are easy to demonstrate and those that are more circumstantial. Examples of evolution that are readily apparent include the fact that modern populations are evolving and the fact that two closely related species share a common ancestor. The evidence that Homo sapiens and chimpanzees share a recent common ancestor falls into this catagory. There is so much evidence in support of this aspect of primate evolution that it qualifies as a fact by any common definition of the word "fact". In other cases the available evidence is less strong. For example, the relationships of some of the major phyla are still being worked out. Also, the statement that all organisms have descended from a single common ancestor is strongly supported by the available evidence, and there is no opposing evidence. However, it is not yet appropriate to call this a "fact" since there are reasonable alternatives. Finally, there is an epistemological argument against evolution as fact. Some readers of these newsgroups point out that nothing in science can ever be "proven" and this includes evolution. According to this argument, the probability that evolution is the correct explanation of life as we know it may approach 99.9999...9% but it will never be 100%. Thus evolution cannot be a fact. This kind of argument might be appropriate in a philosophy class (it is essentially correct) but it won't do in the real world. A "fact", as Stephen J. Gould pointed out (see above), means something that is so highly probable that it would be silly not to accept it. This point has also been made by others who contest the nit-picking epistemologists. "The honest scientist, like the philosopher, will tell you that nothing whatever can be or has been proved with fully 100% certainty, not even that you or I exist, nor anyone except himself, since he might be dreaming the whole thing. Thus there is no sharp line between speculation, hypothesis, theory, principle, and fact, but only a difference along a sliding scale, in the degree of probability of the idea. When we say a thing is a fact, then, we only mean that its probability is an extremely high one: so high that we are not bothered by doubt about it and are ready to act accordingly. Now in this use of the term fact, the only proper one, evolution is a fact. For the evidence in favor of it is as voluminous, diverse, and convincing as in the case of any other well established fact of science concerning the existence of things that cannot be directly seen, such as atoms, neutrons, or solar gravitation .... So enormous, ramifying, and consistant has the evidence for evolution become that if anyone could now disprove it, I should have my conception of the orderliness of the universe so shaken as to lead me to doubt even my own existence. If you like, then, I will grant you that in an absolute sense evolution is not a fact, or rather, that it is no more a fact than that you are hearing or reading these words." H. J. Muller, "One Hundred Years Without Darwin Are Enough" School Science and Mathematics 59, 304-305. (1959) reprinted in EVOLUTION VERSUS CREATIONISM op cit. In any meaningful sense evolution is a fact but there are various theories concerning the mechanism of evolution. -- Brett J. Vickers "Don't go around saying the world owes you bvickers@ics.uci.edu a living. The world owes you nothing. It was here first." - Mark Twain I was asked by somebody in another echo to post this article in here. It was written by Ranse Traxler, the Executive Director of the St. Louis Association for the Teaching of Evolution (SLATE) and originally published in The American Rationalist. The REALL News (official newsletter of the Rational Examination Association of Lincoln Land) reprinted the article with permission in its third issue. If anybody wishes to reprint this article further, you must get the permission of The American Rationalist (see end of article for address). The REALL News issue may be FReq'ed from 2430/2112 as REALL1-3.ZIP. Issues 2 and 4 are also available. ========================================================================= The Misconceptions of Evolution By Ransom R. Traxler In spite of our technical society and our public school system, most people believe in many misconceptions about evolution. This is due, in part, to educators who wish to avoid controversy or who do not fully understand the subject they teach. Furthermore, anti-evolutionists knowingly propagate these erroneous beliefs in their religious crusade against science. As a systematic biologist (in whose field organic evolution begins), I wish to correct a few of these myths. These statements are not just personal beliefs--they are facts and concepts supported by volumes of research and agreed upon by those scientists who are most knowledgeable about the subject. _Evolution is just a theory._ Evolution is a valid scientific theory, just like electricity, gravity, atoms, light, cells, and disease-causing germs are valid scientific theories also. For example, we are taught that the earth orbits the sun; scientists call this the heliocentric theory. A theory in science is a highly-tested, verified and demonstrated explanation for observed facts, not "a guess or conjecture." To state that evolution is only a theory is the same as stating that gravity is only a theory. Knowing this, who would still wish to contest it by jumping off a building? _Evolution is not based on facts._ There are facts and theories about evolution. The facts of evolution are that the earth is billions of years old and that the life on it has changed over that time. The fossil record is clear that life living today differs greatly from that living, say, 300 million years ago. In between we have a vast collection of fossils that, as one looks at younger and younger specimens, become more modern-looking. The theories of evolution are about what caused this metamorphosis. We know several mechanisms that can produce changes in organisms: natural selection, genetic drift, the founder effect, genetic recombination and mutations are just a few. The debates scientists have are about the mechanism of evolution, not the fact that it has occurred. Practicing scientists do not doubt evolution. _Darwin invented evolution._ Would one say that Newton invented gravity or Einstein invented time? The evidence for evolution had been known by scientists for centuries. In the sixteenth, seventeenth and eighteenth centuries the early naturalists, who were also clergy, discovered that the earth was very old and that life was very different in the past. However, evolution was not generally accepted because no one knew how it was happening. In the nineteenth century Darwin was the first to propose a valid mechanism to explain what produced evolution. Since then his mechanism, natural selection, has been thoroughly tested and was rapidly accepted by scientists everywhere. Likewise, continental drift was thought of since Benjamin Franklin's time, but it was not until the 1960's that a valid mechanism, plate tectonics, was discovered. Today scientists accept it as they accept evolution. We now have several mechanisms that explain how evolution occurs, discovered by many scientists over the last century. _Evolution is caused by blind chance._ In all aspects of evolution (cosmic, chemical and organic) natural laws and principles can explain what has occurred. These influences act as a controlling force that guides evolution to predictable outcomes. Cosmic evolution is governed by the laws of physics, not chance. Gravity and nuclear reactions cause the birth and death of stars and planets (we have witnessed these events with telescopes). Chemical evolution abides by the laws of molecular reactions which can produce complicated organic molecules naturally (we have witnessed this in the laboratory). Organic evolution is directed by biological principles such as natural selection and genetics, which again we have observed in the laboratory. The odds are, at the moment of conception, over 70,000,000,000,000 (70 million million) to one that your genes will not come together in the combination now in your body. However, you are here and it was all controlled by the principles of genetics. Natural forces and laws govern and direct evolution, not "blind chance." _Complex organisms, such as ourselves, must have been designed by a more complex, intelligent creator._ This argument has been shown to be logically and scientifically false for at least a hundred years, yet it is still used by anti-evolutionists in their religious crusade. Logically for their argument to be true, two criteria must be adhered to: One: everything as complex as a living organism must have been designed. No exceptions, or else we could be here not by design but by the natural process of evolution. Two: everything as complex as a living organism must have a designer even more complex than it is. If this was not true, then we could have been designed by a less complex primate who, in turn was designed by a less complex mammal, and on and on to a primordial cell. This is a teleologic view of evolution. Since the two conditions above must be true or the design argument fails miserably then who designed our more- complex-than-we-are-designer? And who, in turn, designed him? These two conditions require an infinite number of designers, each one more complex than the one he designed. Scientifically, there is another choice instead of a designer or blind chance; evolution, which is guided by the laws and forces of nature. We have documented cases of changes produced by natural selection, which acts as a "designing force" to make organisms better suited to their environment. However, it is not as perfect as an omnipotent designer would be. There are thousands of examples of poor design in nature. Many organisms use modified organs that barely suit their need; many organisms have vestigial parts that do not help them but could actually harm (wisdom teeth and appendix in us, hind limbs in whales and snakes, and much more). If this is the work of a designer, then it was a terrible job. We, with artificial selection (breeding) and genetic changes, are improving on some of the poor designs of nature. _Creationism is another scientific explanation._ This is definitely not true. Creationism is a religious belief based on the Bible. Evolution is a scientific explanation based on observation, experimentation and objective evaluation. None of the vast store of scientific data we have supports a literal interpretation of the Book of Genesis. The small amount of "scientific" evidence propagated by "scientific creationists" has been investigated by the scientific community using the scientific method (just like evolution has been for over 150 years). Most of these claims were abandoned by scientists over two centuries ago because the data and experiments did not support them. The newest claims were found to be distortions and misrepresentations of firmly established data. Creationism is a religious belief and, as such, everyone is free to believe it or not; but as a scientific explanation, it has no support whatsoever in fact. _Creationism should be given equal time in the science class because so many people believe in it._ Many people believe in astrology; should it be given time in an astronomy class? Or how about alchemy in a chemistry class? Numerology in a mathematics class? Atlantis and ancient astronauts in a history class? Flat-earth in a geography class? If some people believe that 6x9=42, should we give the students two multiplication tables and let them choose which one they will use? The science classroom is not where religious beliefs should be presented as fact for the student to accept or reject as he/she wants. Instead, the classroom is where the current knowledge in the field is presented to students to increase their understanding of that subject. _Evolution should not be taught because it is unimportant._ Evolution is to biology as atoms are to chemistry. It is the unifying concept that connects genetics, anatomy, medical science, taxonomy and many others into a comprehensible framework. It is THE central idea of biology that ties together all its subparts. Evolutionary biology explains the distribution of life on this planet, tissue rejection in transplants, and how our body works. In other fields cosmic evolution is the center of astronomy (it tells us how the universe and stars function) and earth evolution is the basic concept of geology (it tells us how the earth came to be as it is today). What would chemistry be like without atoms to explain how and why chemicals react as they do; or physics without the concept of energy being able to convert into different forms to explain how a steam engine works? What if a teacher felt that atoms or energy were unimportant and ignored them in his/her chemistry or physics class? Without the why and how explained by evolution, much of science becomes a meaningless collection of facts with no logical association or understanding. _Evolution should not be taught because it is contrary to some people's religious beliefs._ First of all our government is religiously neutral according to our Constitution. Therefore, religion cannot be a factor in determining the curriculum. Secondly, the teacher has the obligation to present the students all the knowledge of the subject being taught based on their level of understanding. Any science teacher who fails to present evolution properly to the students betrays the trust placed in them by the public and acts in an unprofessional manner. _Evolution should not be taught because it promotes the religion of secular humanism._ Evolution is a science and that is all it is. People are free to form whatever philosophies or religions they want based on whatever source they want. Some people have formed their belief system around old books variously translated through the years. Primitive people use a god or gods to explain ordinary occurrences in nature because that is the only way they can comprehend the world around them. Scientists of all religions accept evolution because it is the best scientific explanation we have not because of some religious reason. As a religiously-neutral science, it should be taught in the classroom. _Evolution is anti-God._ Impossible, for science just like mathematics is neutral towards any religious belief. Science and religion are two separate philosophies dealing with different realms. Religion deals with the supernatural and cannot be supported by experimentation--it must be accepted by faith alone. Science deals with the natural universe and its discoveries can be confirmed or disproved by experimentation--scientific ideas are accepted by the scientific community based on evidence. Evolution, as any science, can never say anything about the "Ultimate Cause" of the universe and our existence; these can only be answered by religion. Since these two philosophies deal with different realms, there is no basic conflict between them. _Evolutionists are atheists._ Many scientists and science teachers are devoutly Christian or Jewish. Some of the great founders of evolutionary biology were strong theists. A few of us are atheists. This is because we are able to separate the two realms of our lives--the spiritual and the material. Since evolution does not deny the existence of a Supreme Being, one is free to hold whatever beliefs there are in one. Saying that "evolutionists are atheists" is just like saying "apple-lovers are orange- haters." One can like (or dislike) both apples and oranges. _Scientists believe in evolution as their religion since they do not believe in God._ The religious beliefs of scientists are as varied as it is in any group of professional people. Unfortunately our secondary school textbooks and various media sources like to use the phrase "Scientists believe..." whenever they present evolution as if the scientists hold a unique religious belief. This is especially harmful when facts are presented, because it gives the student or layperson the idea that the facts are not supported by evidence and can be accepted as questionable. What would happen if a teacher were to say, "Mathematicians believe that 5x6=30" or "Historians believe that we fought a civil war in the 1860's?" Instead of saying "Scientists believe in evolution" one should say "Scientists accept evolution based on the overwhelming objective evidence in its favor." _Evolution is "The Big Lie" that Satan tempted Eve with in the Garden of Eden._ This may not sound like a scientific statement, but it is repeated frequently by the "scientific creationists." In fact one such group, the Institute for Creation Research, publishes a book entitled The Lie: Evolution with a large poster showing a serpent holding an apple marked EVOLUTION. These people state that scientists lie while they spread "The Truth." So then what is "The Truth?" Creationists are the masters of prevarication. In their presentations they frequently make false statements about science and scientists; anyone familiar with biology or geology can spot them. Then why do they do it? One reason could be that they are ignorant about science and, therefore, make many mistakes. However, they say that they are experts on evolution and have some degree in engineering or theology to prove it. A practicing scientist knows these statements are false and ridiculous; many of us have exposed them as such. Then why are they still frequently repeated? The other possibility is that these anti-evolutionists know the statements are false, yet repeat them anyway. Many of the "scientific creationist" debaters make statements they cannot prove; in fact, many scientists have proved their claims as false and they have admitted their error. Yet in their next debate or presentation, they repeat these falsehoods unabatedly. I can show anyone the scientific evidence to support what I said above. This is more than what "scientific creationists" can do. In this country anybody can hold whatever religious beliefs they want to; however, when they say that these beliefs are scientific and should be taught in public schools, they must produce evidence to support what they say. I have always found it amazing how many falsehoods and distortions are said by those spreading "The Truth." There are many more misunderstandings about evolution which a quality science education will expose. Until such teaching becomes the standard, we scientists and educators need to reveal these myths for what they are--an attempt to mislead the public and discredit the scientists and teachers who have devoted their lives to increasing our knowledge of the universe solely for the purpose of converting students and the public to a specific religious belief system. -------------- [This article was the basis for Traxler's lecture before the Missouri Association for Creationism meeting in April, 1991. Ransom R. Traxler is the Director of the St. Louis Association for the Teaching of Evolution (SLATE), P.O. Box 462, O'Fallon, IL 62269-0462. This article reprinted with permission from the May/June 1991 issue of _The American Rationalist_. Permission to reprint this article must be obtained in writing from _The American Rationalist_, P.O. Box 994, St. Louis, MO 63188.]

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