Misconceptions about Evolution and the Mechanisms of Evolution Misconception 1: “Evolution is a theory about the origin of life.” Evolutionary theory deals mainly with how life changed after its origin. Regardless of how life started, afterwards it branched and diversified. Evolution mainly studies how life forms branch and diversify Misconception 2: “Evolution is like a climb up a ladder of progress; organisms are always getting better.” It is true that natural selection weeds out individuals that are unfit in a particular situation, but for evolution, “good enough” is good enough. No organism has to be perfect. For example, many organisms (like some mosses, protists, fungi, sharks, and crayfish) have changed little over great expanses of time. Other groups may have changed and diversified a great deal—but that doesn’t mean they got “better.” After all, climates change, rivers shift course, new competitors invade— and what was “better” a million years ago, may not be “better” today. What works “better” in one location might not work so well in another. Fitness is linked to environment, not to progress. Sometimes changes are not needed to survive. Many species have changed little over great expanses of time Misconception 3: “Evolution is like a climb up a ladder of progress and man is at the pinnacle of animal evolution” Aristotle’s vision of a Great Chain of Being, above. We now know that this idea is incorrect. This statement suggests that human evolved from apes, and human being the panicle of evolution. Both are incorrect! Man considers himself superior to other creatures; from years of cultural and religious belief he considers himself the centre of the universe, the pinnacle and even the purpose of creation; and that all creation revolves around him; and that other creatures are here merely to serve his purpose and are therefore not considered as beings in their own right. Misconception 3.1: Humans evolve from chimpanzees It is important to remember that evolution dosn’t say Humans evolve from chimpanzees. Humans and chimpanzees are evolutionary cousins and share a recent common ancestor that was neither chimpanzee nor human. Humans are not “higher” or “more evolved” than other living lineages. Since our lineages split, humans and chimpanzees have each evolved traits unique to their own lineages. Misconception 4: “Gaps in the fossil record disprove evolution.” The fact that some transitional fossils are not preserved does not disprove evolution. The environmental conditions for forming good fossils are not that common. So, science actually predicts that for many evolutionary changes there will be gaps in the record. Also, scientists have found many transitional fossils. For example, there are fossils of transitional organisms between modern birds and their dinosaur ancestors, and between whales and their terrestrial mammal ancestors. Misconception 5: Individual organisms evolve during their lifetimes Natural selection acts on individuals but populations evolve Misconception 6: “Natural selection involves organisms ‘trying’ to adapt.” Natural selection leads to adaptation, but the process doesn’t involve “trying.” Natural selection involves genetic variation and selection among variants present in a population. Either an individual has genes that are good enough to survive and reproduce, or it does not— but it can’t get the right genes by “trying.” Misconception 7: “Evolution means that life changed ‘by chance.’ ” The streamlined shape yellow fin tuna is no accident. A more streamlined shape allows these fish to move through the water faster. During their evolution, natural selection favored the more streamlined tuna and other aquatic swimmers. eg. Shark, dolphin, penguin Evolution is NOT a random process. The genetic variation on which natural selection acts may occur randomly, but natural selection itself is not random at all. The survival and reproductive success of an individual is directly related to the ways its inherited traits function in the context of its local environment. Whether or not an individual survives and reproduces depends on whether it has genes that produce traits that are well adapted to its environment. Misconception 8: “Living organisms must be the product of careful and conscious design, so perfectly formed that they cannot be explained by the random workings of evolution alone.” E.g. The human eye_an intelligent design? The human eye is an organ of great complexity, both in structure and function. The proponents of intelligent design (creationism) assert that the combination of nerves, sensory cells, muscles, and lens tissue in the eye could only have been "designed" from scratch. After all, how could evolution, acting on one gene at a time, start with a sightless organism and produce an eye with so many independent parts, such as a retina, which would itself be useless without a lens, or a lens, which would be useless without a retina? Building an eye: step-by-step criterion can be applied to building a complex organ like the eye We begin with the simplest possible case: a small animal with a few light-sensitive cells. We could then ask, at each stage, whether natural selection would favor the incremental changes that are shown, knowing that if it would not, the final structure could not have evolved, no matter how beneficial. Starting with the simplest light-sensing device, a single photoreceptor cell, it is possible to draw a series of incremental changes that would lead directly to the lens-and-retina eye: an increase in cell number, a change in surface curvature, a slight increase in transparency. This incremental process is the real reason why it is unfair to characterize evolution as mere chance. Chance plays a role in presenting random genetic variations. But natural selection, which is not random, determines which variations will become fixed in the species. Critics might ask what good that first tiny step, perhaps only five percent of an eye, might be. As the saying goes, in the land of the blind the one-eyed man is king. Likewise, in a population with limited ability to sense light, every improvement in vision, no matter how slight, would be favored -- and favored dramatically -- by natural selection. Design flaws - Another way to respond to the theory of intelligent design is to carefully examine complex biological systems for errors that no intelligent designer would have committed. On the left is the vertebrate eye with the nerve fibers facing out towards the light source and on the right is an octopus eye with the nerve fibers pointing in towards the brain Because intelligent design works from a clean sheet of paper, it should produce organisms that have been optimally designed for the tasks they perform. Conversely, because evolution is confined to modifying existing structures, it should not necessarily produce perfection. Which is it? Photoreceptor cells in the retina pass impulses to a series of interconnecting cells that eventually pass information to the optic nerve which leads to the brain. Light passes through the lens to the retina, and then to the brain. An intelligent designer, working with the components of this wiring, would choose the orientation that produces the highest degree of visual quality. No one, for example, would suggest that the neural connections should be placed in front of the photoreceptor cells - thus blocking the light from reaching them -rather than behind the retina. Less-than-perfect vision Incredibly, this is exactly how the human retina is constructed some eye features seemed poorly ‘designed’: 1. 2. 3. 4. The nerve fibers from the retinal rods and cones extend not inward toward the brain but outward toward the chamber of the eye and source of light. They have to gather into a bundle, the optic nerve, inside the eye, and exit via a hole in the retina. Even though the obstructing layer is microscopically thin, some light is lost from having to pass through the layer of nerve fibers and ganglia and especially the blood vessels that serve them. The eye is blind where the optic nerve exits through its hole. It would not be if the nerve fibers passed through the sclera and formed the optic nerve behind the eye. This functionally sensible arrangement is in fact what is found in the eye of a squid and other mollusks, but our eyes, and those of all other vertebrates, have the functionally stupid upside-down orientation of the retina. Vulnerable to wear and tear, prone to break down and rendered helpless by microscopic organisms - the human body is in fact an inefficient evolutionary bodge-job. Read more: http://www.dailymail.co.uk/health/article-476607/The-tantalising-design-flaws-bodged-bodies.html#ixzz0p7mS3WuZ The odd things in nature illustrate best how natural selection works. Giant Pandas eat bamboo relatively well despite the fact that they are bears. They possess a relatively dexterous hand with an opposable thumb. This hand would win no prize for design. In contrast to ours it is very clumsy. It is not constructed like our hand either. There are five Panda fingers and a thumb. The thumb is actually a part of the wrist known as the radial sesamoid. Giant Pandas are not good at what they do. They were designed to do what other bears normally do. Their hand is not well designed but it works effectively based on what was available. Pandas don't process their food well either, why? Their reproductive success as a whole is not good. Yet, they survive. Giant Pandas are examples of how nature juryrigs from available components and does not necessarily do a "well designed" job either. "Poor design" is consistent with the predictions of the scientific theory of evolution by means of natural selection. This predicts that features that were evolved for certain uses, are then reused or co-opted for different uses Misconception 9: “Evolution is not science because it is not observable or testable.” Evolution is observable and testable. The misconception here is that science is limited to controlled experiments that are conducted in laboratories by people in white lab coats. Actually, much of science is accomplished by gathering evidence from the real world and inferring how things work. Astronomers cannot hold stars in their hands and geologists cannot go back in time, but in both cases scientists can learn a great deal by using multiple lines of evidence to make valid and useful inferences about their objects of study. The same is true of the study of the evolutionary history of life on Earth, and as a matter of fact, many mechanisms of evolution are studied through direct experimentation as in more familiar sciences. Misconception: 10 “Evolution is ‘just’ a theory.” In science, a theory is a rigorously tested statement of general principles that explains observable and recorded aspects of the world. A scientific theory therefore describes a higher level of understanding that ties "facts" together. A scientific theory stands until proven wrong -- it is never proven correct. The Darwinian theory of evolution has withstood the test of time and thousands of scientific experiments; nothing has disproved it since Darwin first proposed it more than 150 years ago. Indeed, many scientific advances, in a range of scientific disciplines including physics, geology, chemistry, and molecular biology, have supported, refined, and expanded evolutionary theory far beyond anything Darwin could have imagined. Misconception: 11 “Most biologists have rejected ‘Darwinism’ (i.e., no longer really agree with the ideas put forth by Darwin and Wallace).” Evolution by natural selection has been demonstrated at many levels of biological system and is recognized as the unifying concept in Biology. Darwin’s idea that evolution generally proceeds at a slow, deliberate pace has been modified to include the idea that evolution can proceed at a relatively rapid pace under some circumstances. In this sense, “Darwinism” is continually being modified. Thus far, however, there have been no credible challenges to the basic Darwinian principles that evolution proceeds primarily by the mechanism of natural selection acting upon variation in populations and that different species share common ancestors. Scientists have not rejected Darwin’s natural selection, but have improved and expanded it as more information has become available. For example, we now know (although Darwin did not) that genetic mutations are the source of variation acted on by natural selection, but we haven’t rejected Darwin’s idea of natural selection— we’ve just added to it. Misconception: 12 “Evolution supports the idea that ‘might makes right’ and rationalizes the oppression of some people by others.” Social Darwinism is the belief that all personal and social problems were inherited. The proponents of social Darwinism believed poverty and many other social ills were the result of bad genes. In the 1920s, eugenics movements were popular in many countries, including the United States and Germany. Eugenics is the study of human improvement by genetic means. Many eugenicists saw themselves as visionaries who would one day create a world free of poverty, and physical and mental illness. In the nineteenth and early twentieth centuries, a philosophy called “Social Darwinism” arose from a misguided effort to apply lessons from biological evolution to society. According to this view, society should allow the weak and less fit to fail and die, and that this is not only good policy, but morally right. Supposedly, evolution by natural selection provided support for these ideas. Pre-existing prejudices were rationalized by the notion that colonized nations, poor people, or disadvantaged minorities must have deserved their situations because they were “less fit” than those who were better off. This misapplication of science was used to promote social and political agendas. The “science” of Social Darwinism was refuted. Biological evolution has stood the test of time, but Social Darwinism has not. Misconception: 13 “Evolution and religion are incompatible.” Religion and science (evolution) are very different things. In science, only natural causes are used to explain natural phenomena, while religion deals with beliefs that are beyond the natural world. The misconception that one always has to choose between science and religion is incorrect. Of course, some religious beliefs explicitly contradict science (e.g., the belief that the world and all life on it was created in six literal days); however, most religious groups have no conflict with the theory of evolution or other scientific findings. In fact, many religious people, including theologians, feel that a deeper understanding of nature actually enriches their faith. Moreover, in the scientific community there are thousands of scientists who are devoutly religious and also accept evolution. Pope John Paul II embraces evolution "In a major statement of the Roman Catholic Church's position on the theory of evolution, Pope John Paul II has proclaimed that the theory is 'more than just a hypothesis' and that evolution is compatible with Christian faith: "It is indeed remarkable that this theory has progressively taken root in the minds of researchers following a series of discoveries made in different spheres of knowledge', the pope said in his message Wednesday. 'The convergence, neither sought nor provoked, of results of studies undertaken independently from each other constitutes, in itself, a significant argument in favor of this theory..." "If taken literally, the Biblical view of the beginning of life and Darwin's scientific view would seem irreconcilable. In Genesis, the creation of the world, and Adam, the first human, took six days. Evolution's process of genetic mutation and natural selection-the survival and proliferation of the fittest new species-has taken billions of years, according to scientists ..." "The Pope's message went much further in accepting the theory of evolution as a valid explanation of the development of life on Earth, with one major exception: the human soul. 'If the human body has its origin in living material which preexists it, the spiritual soul is immediately created by God', the Pope said."