The mysterious origins of life on Earth - Luka Seamus Wright
4:56Myths and misconceptions about evolution - Alex Gendler
4:22I took in evolution many years ago and when writing of it have tried to use the most recent info at hand as I taught myself a science my Christian education wouldn't permit. However, for those Christians needing help here is one voice besides my own in the video immediately below. The academic here is very direct, highly informative, and relentless. For myself, I no longer engage with Christians in this manner anymore having done so between the years of 2010-2014. Enjoy.
R.E. Slater
November 31, 2024
In evolutionary biology, key terms include: adaptation (a trait that enhances an organism's survival in its environment), natural selection (the process where organisms with advantageous traits survive and reproduce more readily), allele (alternative forms of a gene), mutation (a change in DNA sequence), speciation (the formation of new species), gene flow (movement of genes between populations), genetic drift (random changes in allele frequencies), fossil (preserved remains of an ancient organism), and phylogeny (the evolutionary history of a group of organisms); while related fields of science include paleontology (study of fossils), genetics (study of genes and inheritance), population genetics (study of genetic variation within populations), comparative anatomy (comparing anatomical structures across species), and molecular biology (studying evolution at the molecular level). - AI
The Proud Scientific Ignorance of a Christian Nationalist
by Gutsick Gibbon | 2:10:08
Books & Publications - https://www.nationalacademies.org/evolution/resources
Three sections:
> DEFINITIONS
> EVOLUTION & SOCIETY
> EVOLUTION, SCIENCE & RELIGION
Definitions of Evolutionary Terms
Adaptation:
The adjustment or changes in behavior, physiology, and structure of an organism to become more suited to an environment. According to Charles Darwin's theory of evolution by natural selection, organisms that possess heritable traits that enable them to better adapt to their environment compared with other members of their species will be more likely to survive, reproduce, and pass more of their genes on to the next generation.
Chromosome:
A double stranded DNA molecule that contains a series of specific genes along its length. In most sexually reproducing organisms, chromosomes occur in pairs, with one member of the pair being inherited from each parent.
DNA:
Deoxyribonucleic acid. A large biological molecule composed of subunits known as nucleotides strung together in long chains. The sequences of these nucleotides contain the information that cells need in order to grow, to divide into daughter cells, and to manufacture new proteins. Changes in DNA result in mutations, which may be beneficial, neutral, or deleterious to the organism. If these changes occur to DNA in sperm or egg cells, they could be passed onto the next generation.
Evolution:
Evolution consists of changes in the heritable traits of a population of organisms as successive generations replace one another. It is populations of organisms that evolve, not individual organisms.
Fact:
In science, a "fact" typically refers to an observation, measurement, or other form of evidence that can be expected to occur the same way under similar circumstances. However, scientists also use the term "fact" to refer to a scientific explanation that has been tested and confirmed so many times that there is no longer a compelling reason to keep testing it or looking for additional examples.
Fossil:
A remnant or trace of an organism of a past geologic age, such as a skeleton or leaf imprint, embedded, and preserved in the Earth's crust, usually in stratified rock.
Hypothesis:
A tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation. Scientific hypotheses must be posed in a form that allows them to be rejected.
Genomics:
A recent branch of genetics that studies organisms in terms of their complete genetic material, including genes and their functions.
Macroevolution:
Large-scale evolution occurring over geologic time that results in the formation of new species and broader taxonomic groups.
Microevolution:
Changes in the traits of a group of organisms within a species that do not result in a new species.
Mimicry:
In biology, mimicry is the superficial resemblance of one species of organism to another species or to a natural object in its surroundings. Some kinds of mimicry result in a selective advantage for concealment and protection from predators. Another type of mimicry enables protection to the mimic through its resemblance to another species that is toxic or in some other way dangerous.
Mutation:
A change in the sequence of one or more nucleotides in DNA. Such changes can alter the structure of proteins or the regulation of protein production. In some cases mutations result in the organism possessing these altered traits to have a greater or lesser chance of surviving and reproducing in a given environment than other members of its species.
Natural selection:
Differential survival and reproduction of organisms as a consequence of the characteristics of the environment.
Paleontologist:
A scientist who studies fossils to learn about ancient organisms.
Protein:
A large molecule consisting of a chain of smaller molecules called amino acids. The sequence of amino acids and the molecule's three-dimensional structure are coded by the instructions in DNA and determine a protein's specific function in cells or organisms.
Population:
A group of organisms of the same species that are in close enough proximity to allow them to interbreed.
RNA:
Ribonucleic acid. A molecule related to DNA that consists of nucleotide subunits strung together in chains. RNA serves a number of cellular functions, including providing a template for the synthesis of proteins and catalyzing certain biochemical reactions. The structure of RNA is determined by the sequence of nucleotides on DNA.
Science:
The use of evidence to construct testable explanations and predictions of natural phenomena, as well as the knowledge generated through this process.
Sedimentary:
Rocks formed of particles deposited by water, wind, or ice.
Selective breeding:
The intentional breeding of organisms with desirable traits in an attempt to produce offspring with enhanced characteristics or traits that humans consider desirable. This process is also known as "artifical selection" (compare with "natural selection").
Speciation:
The evolutionary processes through which new species arise from existing species.
Species:
In sexually reproducing organisms, species consist of individuals that can interbreed with each other.
Survival of the fittest:
A term that refers to the survival of only those organisms best able (fittest) to obtain and utilize resources, resulting in the evolution of organisms that are best adapted to the environment. Darwin used metaphorically to describe "natural selection." The phrase was invented by the 19th century philosopher Herbert Spencer It has been misapplied through history to explain and justify social and economic inequities in human populations ("social Darwinism") or as a method for improving the human condition through selective breeding (eugenics). Survival alone is insufficient for evolution - it's reproduction - passing on of genes that really counts. Most modern biologists no longer use this term when describing or discussing natural selection.
Theory:
A plausible or scientifically acceptable, well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena and predict the characteristics of as yet unobserved phenomena.
Trait:
A physical or behavioral characteristic of an organism.
* * * * * *
Evolution and Society
Introduction
Agriculture
Industry
Medicine
Introduction
Science and science-based technologies have transformed modern life. They have led to major improvements in living standards, public welfare, health, and security. They have changed how we view the universe and how we think about ourselves in relation to the world around us.
Biological evolution is one of the most important ideas of modern science. Evolution is supported by abundant evidence from many different fields of scientific investigation. It underlies the modern biological sciences, including the biomedical sciences, and has applications in many other scientific and engineering disciplines.
As individuals and societies, we are now making decisions that will have profound consequences for future generations. How should we balance the need to preserve the Earth's plants, animals, and natural environment against other pressing concerns? Should we alter our use of fossil fuels and other natural resources to enhance the well-being of our descendants? To what extent should we use our new understanding of biology on a molecular level to alter the characteristics of living things?
None of these decisions can be made wisely without considering biological evolution. People need to understand evolution, its role within the broader scientific enterprise, and its vital implications for some of the most pressing social, cultural, and political issues of our time.
Science and technology are so pervasive in modern society that students increasingly need a sound education in the core concepts, applications, and implications of science. Because evolution has and will continue to serve as a critical foundation of the biomedical and life sciences, helping students learn about and understand the scientific evidence, mechanisms, and implications of evolution are fundamental to a high-quality science education.
Science and religion are different ways of understanding. Needlessly placing them in opposition reduces the potential of both to contribute to a better future.
Agriculture
The Domestication of Wheat
When humans understand a phenomenon that occurs in nature, they often gain increased control over it or can adapt it to new uses. The domestication of wheat is a good example.
By recovering seeds from different archaeological sites and noticing changes in their characteristics over the centuries, scientists have hypothesized how wheat was altered by humans over time. About 11,000 years ago, people in the Middle East began growing plants for food rather than relying entirely on the wild plants and animals they could gather or hunt. These early farmers began saving seeds from plants with particularly favorable traits and planting those seeds in the next growing season. Through this process of "artificial selection," they created a variety of crops with characteristics particularly suited for agriculture. For example, farmers over many generations modified the traits of wild wheat so that seeds remained on the plant when ripe and could easily be separated from their hulls. Over the next few millennia, people around the world used similar processes of evolutionary change to transform many other wild plants and animals into the crops and domesticated animals we rely on today.
In recent years, plant scientists have begun making hybrids of wheat with some of their wild relatives from the Middle East and elsewhere. Using these hybrids, they have bred wheat varieties that are increasingly resistant to droughts, heat, and pests. Most recently, molecular biologists have been identifying the genes in the DNA of plants that are responsible for their advantageous traits so that these genes can be incorporated into other crops. These advances rely on an understanding of evolution to analyze the relationships among plants and to search for the traits that can be used to improve crops.
Industry
Putting Natural Selection to Work
The concept of natural selection has been applied in many fields outside biology. For example, chemists have applied principles of natural selection to develop new molecules with specific functions. First they create variants of an existing molecule using chemical techniques. They then test the variants for the desired function. The variants that do the best job are used to generate new variants. Repeated rounds of this selection process result in molecules that have a greatly enhanced ability to perform a given task. This technique has been used to create new enzymes that can convert cornstalks and other agricultural wastes into ethanol with increased efficiency.
Medicine
Combating New Infectious Diseases
In late 2002 several hundred people in China came down with a severe form of pneumonia caused by an unknown infectious agent. Dubbed "severe acute respiratory syndrome," or SARS, the disease soon spread to Vietnam, Hong Kong, and Canada and led to hundreds of deaths. In March 2003 a team of researchers at the University of California, San Francisco, received samples of a virus isolated from the tissues of a SARS patient. Using a new technology known as a DNA microarray, within 24 hours the researchers had identified the virus as a previously unknown member of a particular family of viruses -- a result confirmed by other researchers using different techniques. Immediately, work began on a blood test to identify people with the disease (so they could be quarantined), on treatments for the disease, and on vaccines to prevent infection with the virus.
An understanding of evolution was essential in the identification of the SARS virus. The genetic material in the virus was similar to that of other viruses because it had evolved from the same ancestor virus. Furthermore, knowledge of the evolutionary history of the SARS virus gave scientists important information about the disease, such as how it is spread. Knowing the evolutionary origins of human pathogens will be critical in the future as existing infectious agents evolve into new and more dangerous forms.
* * * * * *
Science and Religion
Introduction
Is Evolution a Theory or a Fact?
Compatibility
Religious Leader Statements
Scientist Statements
Creationist Perspectives
Intelligent Design
Evolution and Creationism in Schools
Introduction
Scientific and technological advances have had profound effects on human life. In the 19th century, most families could expect to lose one or more children to disease. Today, in the United States and other developed countries, the death of a child from disease is uncommon. Every day we rely on technologies made possible through the application of scientific knowledge and processes. The computers and cell phones which we use, the cars and airplanes in which we travel, the medicines that we take, and many of the foods that we eat were developed in part through insights obtained from scientific research. Science has boosted living standards, has enabled humans to travel into Earth’s orbit and to the moon, and has given us new ways of thinking about ourselves and the universe.
Evolutionary biology has been and continues to be a cornerstone of modern science. This booklet documents some of the major contributions that an understanding of evolution has made to human well-being, including its contributions to preventing and treating human disease, developing new agricultural products, and creating industrial innovations. More broadly, evolution is a core concept in biology that is based both in the study of past life forms and in the study of the relatedness and diversity of present-day organisms. The rapid advances now being made in the life sciences and in medicine rest on principles derived from an understanding of evolution. That understanding has arisen both through the study of an ever-expanding fossil record and, equally importantly, through the application of modern biological and molecular sciences and technologies to the study of evolution. Of course, as with any active area of science, many fascinating questions remain, and this booklet highlights some of the active research that is currently under way that addresses questions about evolution.
However, polls show that many people continue to have questions about our knowledge of biological evolution. They may have been told that scientific understanding of evolution is incomplete, incorrect, or in doubt. They may be skeptical that the natural process of biological evolution could have produced such an incredible array of living things, from microscopic bacteria to whales and redwood trees, from simple sponges on coral reefs to humans capable of contemplating life’s history on this planet. They may wonder if it is possible to accept evolution and still adhere to religious beliefs.
This Web site speaks to those questions. It is written to serve as a resource for people who find themselves embroiled in debates about evolution. It provides information about the role that evolution plays in modern biology and the reasons why only scientifically based explanations should be included in public school science courses. Interested readers may include school board members, science teachers and other education leaders, policymakers, legal scholars, and others in the community who are committed to providing students with quality science education. This site is also directed to the broader audience of high-quality school and college students as well as adults who wish to become more familiar with the many strands of evidence supporting evolution and to understand why evolution is both a fact and a process that accounts for the diversity of life on Earth.
Is Evolution a Theory or a Fact?
It is both. But that answer requires looking more deeply at the meanings of the words "theory" and "fact."
In everyday usage, "theory" often refers to a hunch or a speculation. When people say, "I have a theory about why that happened," they are often drawing a conclusion based on fragmentary or inconclusive evidence.
The formal scientific definition of theory is quite different from the everyday meaning of the word. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence.
Many scientific theories are so well-established that no new evidence is likely to alter them substantially. For example, no new evidence will demonstrate that the Earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the Earth is not divided into solid plates that have moved over geological timescales (the theory of plate tectonics). Like these other foundational scientific theories, the theory of evolution is supported by so many observations and confirming experiments that scientists are confident that the basic components of the theory will not be overturned by new evidence. However, like all scientific theories, the theory of evolution is subject to continuing refinement as new areas of science emerge or as new technologies enable observations and experiments that were not possible previously.
One of the most useful properties of scientific theories is that they can be used to make predictions about natural events or phenomena that have not yet been observed. For example, the theory of gravitation predicted the behavior of objects on the moon and other planets long before the activities of spacecraft and astronauts confirmed them. The evolutionary biologists who discovered Tiktaalik predicted that they would find fossils intermediate between fish and limbed terrestrial animals in sediments that were about 375 million years old. Their discovery confirmed the prediction made on the basis of evolutionary theory. In turn, confirmation of a prediction increases confidence in that theory.
In science, a "fact" typically refers to an observation, measurement, or other form of evidence that can be expected to occur the same way under similar circumstances. However, scientists also use the term "fact" to refer to a scientific explanation that has been tested and confirmed so many times that there is no longer a compelling reason to keep testing it or looking for additional examples. In that respect, the past and continuing occurrence of evolution is a scientific fact. Because the evidence supporting it is so strong, scientists no longer question whether biological evolution has occurred and is continuing to occur. Instead, they investigate the mechanisms of evolution, how rapidly evolution can take place, and related questions.
Compatibility
Science is not the only way of knowing and understanding. But science is a way of knowing that differs from other ways in its dependence on empirical evidence and testable explanations. Because biological evolution accounts for events that are also central concerns of religion — including the origins of biological diversity and especially the origins of humans — evolution has been a contentious idea within society since it was first articulated by Charles Darwin and Alfred Russel Wallace in 1858.
Acceptance of the evidence for evolution can be compatible with religious faith. Today, many religious denominations accept that biological evolution has produced the diversity of living things over billions of years of Earth’s history. Many have issued statements observing that evolution and the tenets of their faiths are compatible. Scientists and theologians have written eloquently about their awe and wonder at the history of the universe and of life on this planet, explaining that they see no conflict between their faith in God and the evidence for evolution. Religious denominations that do not accept the occurrence of evolution tend to be those that believe in strictly literal interpretations of religious texts.
Science and religion are based on different aspects of human experience. In science, explanations must be based on evidence drawn from examining the natural world. Scientifically based observations or experiments that conflict with an explanation eventually must lead to modification or even abandonment of that explanation. Religious faith, in contrast, does not depend only on empirical evidence, is not necessarily modified in the face of conflicting evidence, and typically involves supernatural forces or entities. Because they are not a part of nature, supernatural entities cannot be investigated by science. In this sense, science and religion are separate and address aspects of human understanding in different ways. Attempts to pit science and religion against each other create controversy where none needs to exist.
Religious Leader Statements
Excerpts of Statements by Religious Leaders Who See No Conflict Between Their Faith and Science
Many religious denominations and individual religious leaders have issued statements acknowledging the occurrence of evolution and pointing out that evolution and faith do not conflict.
"[T]here is no contradiction between an evolutionary theory of human origins and the doctrine of God as Creator."
— General Assembly of the Presbyterian Church
"[S]tudents' ignorance about evolution will seriously undermine their understanding of the world and the natural laws governing it, and their introduction to other explanations described as 'scientific' will give them false ideas about scientific methods and criteria."
— Central Conference of American Rabbis
"In his encyclical Humani Generis (1950), my predecessor Pius XII has already affirmed that there is no conflict between evolution and the doctrine of the faith regarding man and his vocation, provided that we do not lose sight of certain fixed points…. Today, more than a half-century after the appearance of that encyclical, some new findings lead us toward the recognition of evolution as more than an hypothesis. In fact it is remarkable that this theory has had progressively greater influence on the spirit of researchers, following a series of discoveries in different scholarly disciplines. The convergence in the results of these independent studies — which was neither planned nor sought — constitutes in itself a significant argument in favor of the theory.”
— Pope John Paul II, Message to the Pontifical Academy of Sciences, October 22, 1996.
"We the undersigned, Christian clergy from many different traditions, believe that the timeless truths of the Bible and the discoveries of modern science may comfortably coexist. We believe that the theory of evolution is a foundational scientific truth, one that has stood up to rigorous scrutiny and upon which much of human knowledge and achievement rests. To reject this truth or to treat it as 'one theory among others' is to deliberately embrace scientific ignorance and transmit such ignorance to our children. We believe that among God's good gifts are human minds capable of critical thought and that the failure to fully employ this gift is a rejection of the will of our Creator…. We urge school board members to preserve the integrity of the science curriculum by affirming the teaching of the theory of evolution as a core component of human knowledge. We ask that science remain science and that religion remain religion, two very different, but complementary, forms of truth."
—"The Clergy Letter Project" signed by more than 10,000 Christian clergy members.
Scientist Statements
Excerpts of Statements by Scientists Who See No Conflict Between Their Faith and Science
Scientists, like people in other professions, hold a wide range of positions about religion and the role of supernatural forces or entities in the universe. Some adhere to a position known as scientism, which holds that the methods of science alone are sufficient for discovering everything there is to know about the universe. Others ascribe to an idea known as deism, which posits that God created all things and set the universe in motion but no longer actively directs physical phenomena. Others are theists, who believe that God actively intervenes in the world. Many scientists who believe in God, either as a prime mover or as an active force in the universe, have written eloquently about their beliefs.
"Creationists inevitably look for God in what science has not yet explained or in what they claim science cannot explain. Most scientists who are religious look for God in what science does understand and has explained."
— Kenneth Miller, professor of biology at Brown University and author of Finding Darwin’s God: A Scientist’s Search for Common Ground Between God and Religion. Quote is excerpted from an interview available here.
"In my view, there is no conflict in being a rigorous scientist and a person who believes in a God who takes a personal interest in each one of us. Science’s domain is to explore nature. God’s domain is in the spiritual world, a realm not possible to explore with the tools and language of science. It must be examined with the heart, the mind, and the soul."
— Francis Collins, director of the Human Genome Project and of the National Human Genome Research Institute at the National Institutes of Health. Excerpted from his book, The Language of God: A Scientist Presents Evidence for Belief (p. 6).
"Our scientific understanding of the universe … provides for those who believe in God a marvelous opportunity to reflect upon their beliefs."
— Father George Coyne, Catholic priest and former director of the Vatican Observatory. Quote is from a talk, "Science Does Not Need God, or Does It? A Catholic Scientist Looks at Evolution," at Palm Beach Atlantic University, January 31, 2006.
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, 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.
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.
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.
Intelligent Design
"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.
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 for flagellar proteins. Thus, flagellar proteins are not irreducibly complex.
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 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 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.
Evolution and Creationism in Schools
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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