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Science Evolution and Creationism CHAPTER THREE CREATIONIST PERSPECTIVES Creationist views reject scientific findings and methods. Advocates of the ideas collectively known as “creationism” and, recently, “intelligent design creationism” hold a wide variety of views. Most broadly, a “creationist” is someone who rejects natural scientific explanations of the known universe in favor of special creation by a supernatural entity. Creationism in its various forms is not the same thing as belief in God because, as was discussed earlier, many believers as well as many mainstream religious groups accept the findings of science, including evolution. Nor is creationism necessarily tied to Christians who interpret the Bible literally. Some non-Christian religious believers also want to replace scientific explanations with their own religion’s supernatural accounts of physical phenomena. In the United States, various views of creationism typically have been promoted by small groups of politically active religious fundamentalists who believe that only a supernatural entity could account for the physical changes in the universe and for the biological diversity of life on Earth. But even these creationists hold very different views. Some, known as “young Earth” creationists, believe the biblical account that the universe and the Earth were created just a few thousand years ago. Proponents of this form of creationism also believe that all living things, including humans, were created in a very short period of time in essentially the forms in which they exist today. Other creationists,
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Science Evolution and Creationism known as “old Earth” creationists, accept that the Earth may be very old but reject other scientific findings regarding the evolution of living things. No scientific evidence supports these viewpoints. On the contrary, as discussed earlier, several independent lines of evidence indicate that the Earth is about 4.5 billion years old and that the universe is about 14 billion years old. Rejecting the evidence for these age estimates would mean rejecting not just biological evolution but also fundamental discoveries of modern physics, chemistry, astrophysics, and geology. Some creationists believe that Earth’s present form and the distribution of fossils can be explained by a worldwide flood. But this claim also is at odds with observations and evidence understood scientifically. The belief that Earth’s sediments, with their fossils, were deposited in a short period does not accord either with the known processes of sedimentation or with the estimated volume of water needed to deposit sediments on the top of some of Earth’s highest mountains. Creationists sometimes cite what they claim to be an incomplete fossil record as evidence that living things were created in their modern forms. But this argument ignores the rich and extremely detailed record of evolutionary history that paleontologists and other biologists have constructed over the past two centuries and are continuing to construct. Paleontological research has filled in many of the parts of the fossil record that were incomplete in Charles Darwin’s time. The claim that the fossil record is “full of gaps” that undermine evolution is simply false. Indeed, paleontologists now know enough about the ages of sediments to predict where they will be able to find particularly significant transitional fossils, as happened with Tiktaalik and the ancestors of modern humans. Researchers also are using new techniques, such as computed axial tomography (CT), to learn even more about the internal structures and composition of delicate bones of fossils. Exciting new discoveries of fossils continue to be reported in both the scientific literature and popular media. [CT: A medical imaging technique that generates a three-dimensional view of some object by combining a series of two-dimensional X-ray images of “slices” of that object.] Another compelling feature of the fossil record is its consistency. Nowhere on Earth are fossils from dinosaurs, which went extinct 65 million years ago, found together with fossils from humans, who evolved in just the last few million years. Nowhere are the fossils of mammals found in sediments that are more than about 220 million years old. Whenever creationists point to sediments where these relationships appear to be altered or even reversed, scientists have clearly demonstrated that this reversal has resulted from the folding of geological strata over or under others. Sediments containing the fossils of only unicellular organisms appear earlier in the fossil record than do sediments containing the remains of both unicellular and multicellular organisms. The sequence of fossils across Earth’s sediments points unambiguously toward the occurrence of evolution.
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Science Evolution and Creationism Creationists sometimes argue that the idea of evolution must remain hypothetical because “no one has ever seen evolution occur.” This kind of statement also reveals that some creationists misunderstand an important characteristic of scientific reasoning. Scientific conclusions are not limited to direct observation but often depend on inferences that are made by applying reason to observations. Even with the launch of Earth-orbiting spacecraft, scientists could not directly see the Earth going around the Sun. But they inferred from a wealth of independent measurements that the Sun is at the center of the solar system. Until the recent development of extremely powerful microscopes, scientists could not observe atoms, but the behavior of physical objects left no doubt about the atomic nature of matter. Scientists hypothesized the existence of viruses for many years before microscopes became powerful enough to see them. Thus, for many areas of science, scientists have not directly observed the objects (such as genes and atoms) or the phenomena (such as the Earth going around the Sun) that are now well-established facts. Instead, they have confirmed them indirectly by observational and experimental evidence. Evolution is no different. Indeed, for the reasons described in this booklet, evolutionary science provides one of the best examples of a deep understanding based on scientific reasoning. This contention that nobody has seen evolution occurring further ignores the overwhelming evidence that evolution has taken place and is continuing to occur. The annual changes in influenza viruses and the emergence of bacteria resistant to antibiotics are both products of evolutionary forces. Another example of ongoing evolution is the appearance of mosquitoes resistant to various insecticides, which has contributed to a resurgence of malaria in Africa and elsewhere. The transitional fossils that have been found in abundance since Darwin’s time reveal how species continually give rise to successor species that, over time, produce radically changed body forms and functions. It also is possible to directly observe many of the specific processes by which evolution occurs. Scientists regularly do experiments using microbes and other model systems that directly test evolutionary hypotheses. Creationists reject such scientific facts in part because they do not accept evidence drawn from natural processes that they consider to be at odds with the Bible. But science cannot test supernatural possibilities. To young Earth creationists, no amount of empirical evidence that the Earth is billions of years old is likely to refute their claim that the world is actually young but that God simply made it appear to be old. Because such appeals to the supernatural are not testable using the rules and processes of scientific inquiry, they cannot be a part of science.
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Science Evolution and Creationism “Intelligent design” creationism is not supported by scientific evidence. Some members of a newer school of creationists have temporarily set aside the question of whether the solar system, the galaxy, and the universe are billions or just thousands of years old. But these creationists unite in contending that the physical universe and living things show evidence of “intelligent design.” They argue that certain biological structures are so complex that they could not have evolved through processes of undirected mutation and natural selection, a condition they call “irreducible complexity.” Echoing theological arguments that predate the theory of evolution, they contend that biological organisms must be designed in the same way that a mousetrap or a clock is designed — that in order for the device to work properly, all of its components must be available simultaneously. If one component is missing or changed, the device will fail to operate properly. Because even such ”simple” biological structures as the flagellum of a bacterium are so complex, proponents of intelligent design creationism argue that the probability of all of their components being produced and simultaneously available through random processes of mutation are infinitesimally small. The appearance of more complex biological structures (such as the vertebrate eye) or functions (such as the immune system) is impossible through natural processes, according to this view, and so must be attributed to a transcendent intelligent designer. Electron micrograph of a bacterium with hair-like flagella. However, the claims of intelligent design creationists are disproven by the findings of modern biology. Biologists have examined each of the molecular systems claimed to be the products of design and have shown how they could have arisen through natural processes. For example, in the case of the bacterial flagellum, there is no single, uniform structure that is found in all flagellar bacteria. There are many types of flagella, some simpler than others, and many species of bacteria do not have flagella to aid in their movement. Thus, other components of bacterial cell membranes are likely the precursors of the proteins found in various flagella. In addition, some bacteria inject toxins into other cells through proteins that are secreted from the bacterium and that are very similar in their molecular structure to the proteins in parts of flagella. This similarity indicates a common evolutionary origin, where small changes in the structure and organization of secretory proteins could serve as the basis
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Science Evolution and Creationism for flagellar proteins. Thus, flagellar proteins are not irreducibly complex. Eyes in living mollusks. The octopus eye (bottom) is quite complex, with components similar to those of the human eye, such as a cornea, iris, refractive lens, and retina. Other mollusks have simpler eyes. The simplest eye is found in limpets (top), consisting of only a few pigmented cells, slightly modified from typical epithelial (skin) cells. Slit-shell mollusks (second from top) have a slightly more advanced organ, consisting of some pigmented cells shaped as a cup. Further elaborations and increasing complexity are found in the eyes of Nautilus and Murex, which are not as complex as the eyes of the squid and octopus. Evolutionary biologists also have demonstrated how complex biochemical mechanisms, such as the clotting of blood or the mammalian immune system, could have evolved from simpler precursor systems. With the clotting of blood, some of the components of the mammalian system were present in earlier organisms, as demonstrated by the organisms living today (such as fish, reptiles, and birds) that are descended from these mammalian precursors. Mammalian clotting systems have built on these earlier components. Existing systems also can acquire new functions. For example, a particular system might have one task in a cell and then become adapted through evolutionary processes for different use. The Hox genes (described in the box on page 30) are a prime example of evolution finding new uses for existing systems. Molecular biologists have discovered that a particularly important mechanism through which biological systems acquire additional functions is gene duplication. Segments of DNA are frequently duplicated when cells divide, so that a cell has multiple copies of one or more genes. If these multiple copies are passed on to offspring, one copy of a gene can serve the original function in a cell while the other copy is able to accumulate changes that ultimately result in a new function. The biochemical mechanisms responsible for many cellular processes show clear evidence for historical duplications of DNA regions. In addition to its scientific failings, this and other standard creationist arguments are fallacious in that they are based on a false dichotomy. Even if their negative arguments against evolution were correct, that would not establish the creationists’ claims. There may be alternative explanations. For example, it would be incorrect to conclude that because there is no evidence that it is raining outside, it must be sunny. Other explanations also might be possible. Science requires testable evidence for a hypothesis, not just challenges against
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Science Evolution and Creationism Over millions of years, the Colorado River has cut through the rocks of the Colorado plateau, revealing sedimentary rocks deposited more than a billion years ago. one’s opponent. Intelligent design is not a scientific concept because it cannot be empirically tested. Creationists sometimes claim that scientists have a vested interest in the concept of biological evolution and are unwilling to consider other possibilities. But this claim, too, misrepresents science. Scientists continually test their ideas against observations and submit their work to their colleagues for critical peer review of ideas, evidence, and conclusions before a scientific paper is published in any respected scientific journal. Unexplained observations are eagerly pursued because they can be signs of important new science or problems with an existing hypothesis or theory. History is replete with scientists challenging accepted theory by offering new evidence and more comprehensive explanations to account for natural phenomena. Also, science has a competitive element as well as a cooperative one. If one scientist clings to particular ideas despite evidence to the contrary, another scientist will attempt to replicate relevant experiments and will not hesitate to publish conflicting evidence. If there were serious problems in evolutionary science, many scientists would be eager to win fame by being the first to provide a better testable alternative. That there are no viable alternatives to evolution in the scientific literature is not because of vested interests or censorship but because evolution has been and continues to be solidly supported by evidence. The potential utility of science also demands openness to new ideas. If petroleum geologists could find more oil and gas by interpreting the record of
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Science Evolution and Creationism sedimentary rocks (where deposits of oil and natural gas are found) as having resulted from a single flood, they would certainly favor the idea of such a flood, but they do not. Instead, petroleum geologists agree with other geologists that sedimentary rocks are the products of billions of years of Earth’s history. Indeed, petroleum geologists have been pioneers in the recognition of fossil deposits that were formed over millions of years in such environments as meandering rivers, deltas, sandy barrier beaches, and coral reefs. The arguments of creationists reverse the scientific process. They begin with an explanation that they are unwilling to alter — that supernatural forces have shaped biological or Earth systems — rejecting the basic requirements of science that hypotheses must be restricted to testable natural explanations. Their beliefs cannot be tested, modified, or rejected by scientific means and thus cannot be a part of the processes of science. The pressure to downplay evolution or emphasize nonscientific alternatives in public schools compromises science education. Despite the lack of scientific evidence for creationist positions, some advocates continue to demand that various forms of creationism be taught together with or in place of evolution in science classes. Many teachers are under considerable pressure from policy makers, school administrators, parents, and students to downplay or eliminate the teaching of evolution. As a result, many U.S. students lack access to information and ideas that are both integral to modern science and essential for making informed, evidence-based decisions about their own lives and our collective future. Regardless of the careers that they ultimately select, to succeed in today’s scientifically and technologically sophisticated world, all students need a sound education in science. Many of today’s fast-growing and high-paying jobs require a familiarity with the core concepts, applications, and implications of science. To make informed decisions about public policies, people need to know how scientific evidence supports those policies and whether that evidence was gathered using well-established scientific practice and principles. Learning about evolution is an excellent way to help students understand the nature, processes, and limits of science in addition to concepts about this fundamentally important contribution to scientific knowledge. Given the importance of science in all aspects of modern life, the science curriculum should not be undermined with nonscientific material. Teaching creationist ideas in science classes confuses what constitutes science and what does not. It compromises the objectives of public education and the goal of a high-quality science education.
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Science Evolution and Creationism Excerpts from Court Cases Since the 1925 trial of John Scopes, which investigated the legality of a Tennessee law that forbade the teaching in public schools of “any theory that denies the story of the Divine Creation of man as taught in the Bible,” a number of court cases have looked at laws involving the teaching of creationist ideas. Several court decisions, including the 1987 Supreme Court case Edwards v. Aguillard and, more recently, the 2005 federal district court case (in central Pennsylvania) of Kitzmiller v. Dover Area School District, have ruled that the various forms of creationism, including intelligent design creationism, are religion, not science, and that it is therefore unconstitutional to include them in public school science classes. Below are excerpts from three of the most prominent cases. Supreme Court of the United States, Epperson v. Arkansas, 1968 “Government in our democracy, state and national, must be neutral in matters of religious theory, doctrine, and practice. It may not be hostile to any religion or to the advocacy of non-religion, and it may not aid, foster, or promote one religion or religious theory against another or even against the militant opposite.” Supreme Court of the United States, Edwards v. Aguillard, 1987 “[The] primary purpose [of the Louisiana ‘Creation Act,’ which required the teaching of ‘creation science’ together with evolution in public schools] was to change the public school science curriculum to provide persuasive advantage to a particular religious doctrine that rejects the factual basis of evolution in its entirety. Thus, the Act is designed either to promote the theory of creation science that embodies a particular religious tenet or to prohibit the teaching of a scientific theory disfavored by certain religious sects. In either case, the Act violates the First Amendment.”
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Science Evolution and Creationism District Court for the Middle District of Pennsylvania, Kitzmiller v. Dover Area School District, 2005 “[W]e find that ID [intelligent design] is not science and cannot be adjudged a valid, accepted scientific theory, as it has failed to publish in peer-reviewed journals, engage in research and testing, and gain acceptance in the scientific community. ID, as noted, is grounded in theology, not science…. Moreover, ID’s backers have sought to avoid the scientific scrutiny which we have now determined that it cannot withstand by advocating that the controversy, but not ID itself, should be taught in science class. This tactic is at best disingenuous, and at worst a canard. The goal of the IDM [intelligent design movement] is not to encourage critical thought, but to foment a revolution which would supplant evolutionary theory with ID.” U.S. law does not forbid the mention or study of religion as an academic subject in public schools, and creationism might be discussed in, for example, a comparative religion class. But, as civil servants, public school teachers must be neutral with respect to religion, which means that they can neither promote nor inhibit its practice. If intelligent design creationism were to be discussed in public school, then Hindu, Islamic, Native American, and other non-Christian creationist views, as well as mainstream religious views that are compatible with science, also should be discussed. Because the Constitution of the United States forbids a governmental establishment of religion, it would be inappropriate to use public funds to teach the views of just one religion or one religious subgroup to all students. Moreover, even in such a class it would be improper to teach these viewpoints as though they were scientific.
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Science Evolution and Creationism