Introduction to evolution Wikipedia. This article is a non technical introduction to the subject. For the main encyclopedia article, see Evolution. The Paleontological Tree of the Vertebrates, from the 5th edition of The Evolution of Man London, 1. I/21m7WO4tW8L._SR600%2C315_PIWhiteStrip%2CBottomLeft%2C0%2C35_PIStarRatingTHREE%2CBottomLeft%2C360%2C-6_SR600%2C315_SCLZZZZZZZ_.jpg' alt='Evolution Futuyma 3Rd Edition Pdf' title='Evolution Futuyma 3Rd Edition Pdf' />Ernst Haeckel. The evolutionary history of species has been described as a tree, with many branches arising from a single trunk. While Haeckels tree is somewhat outdated, it illustrates clearly the principles that more complex modern reconstructions can obscure. Evolution is the process of change in all forms of life over generations, and evolutionary biology is the study of how evolution occurs. Biological populations evolve through genetic changes that correspond to changes in the organisms observable traits. Genetic changes include mutations, which are caused by damage or replication errors in an organisms DNA. As the genetic variation of a population drifts randomly over generations, natural selection gradually leads traits to become more or less common based on the relative reproductive success of organisms with those traits. The age of the Earth is about 4. Understanding Evolution History, Theory, Evidence, and Implications. By March 5, 2006 Updated May 2, 2006. Index. Introduction Origin Mythology. The earliest undisputed evidence of life on Earth dates at least from 3. Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean Eon. There are microbial matfossils found in 3. Western Australia. Other early physical evidences of life include graphite, a biogenic substance, in 3. Greenland1. 0 and, in 2. Western Australia. According to one of the researchers, If life arose relatively quickly on Earth. More than 9. 9 percent of all species, amounting to over five billion species,1. Earth are estimated to be extinct. Estimates on the number of Earths current species range from 1. More recently, in May 2. Earth currently with only one thousandth of one percent described. Evolution does not attempt to explain the origin of life covered instead by abiogenesis, but it does explain how the extremely simple early lifeforms evolved into the complex ecosystem that we see today. Based on the similarities between all present day organisms, all life on Earth originated through common descent from a last universal ancestor from which all known species have diverged through the process of evolution. All individuals have hereditary material in the form of genes that are received from their parents, then passed on to any offspring. For alternative betydninger, se Evolution flertydig. Se ogs artikler, som begynder med Evolution flertydig Evolution af latin e ud volvere rulle. Evolution is change in the heritable characteristics of biological populations over successive generations. Evolutionary processes give rise to biodiversity at every. Evolution Futuyma 3Rd Edition Pdf' title='Evolution Futuyma 3Rd Edition Pdf' />Among offspring there are variations of genes due to the introduction of new genes via random changes called mutations or via reshuffling of existing genes during sexual reproduction. The offspring differs from the parent in minor random ways. If those differences are helpful, the offspring is more likely to survive and reproduce. This means that more offspring in the next generation will have that helpful difference and individuals will not have equal chances of reproductive success. In this way, traits that result in organisms being better adapted to their living conditions become more common in descendant populations. These differences accumulate resulting in changes within the population. This process is responsible for the many diverse life forms in the world. The forces of evolution are most evident when populations become isolated, either through geographic distance or by other mechanisms that prevent genetic exchange. Over time, isolated populations can branch off into new species. The majority of genetic mutations neither assist, change the appearance of, nor bring harm to individuals. Through the process of genetic drift, these mutated genes are neutrally sorted among populations and survive across generations by chance alone. In contrast to genetic drift, natural selection is not a random process because it acts on traits that are necessary for survival and reproduction. Natural selection and random genetic drift are constant and dynamic parts of life and over time this has shaped the branching structure in the tree of life. The modern understanding of evolution began with the 1. Charles Darwins On the Origin of Species. In addition, Gregor Mendels work with plants helped to explain the hereditary patterns of genetics. Fossil discoveries in paleontology, advances in population genetics and a global network of scientific research have provided further details into the mechanisms of evolution. Scientists now have a good understanding of the origin of new species speciation and have observed the speciation process in the laboratory and in the wild. Evolution is the principal scientific theory that biologists use to understand life and is used in many disciplines, including medicine, psychology, conservation biology, anthropology, forensics, agriculture and other social cultural applications. Simple overvieweditThe main ideas of evolution may be summarized as follows Life forms reproduce and therefore have a tendency to become more numerous. Factors such as predation and competition work against the survival of individuals. Each offspring differs from their parents in minor, random ways. If these differences are beneficial, the offspring is more likely to survive and reproduce. This makes it likely that more offspring in the next generation will have beneficial differences and fewer will have detrimental differences. These differences accumulate over generations, resulting in changes within the population. Over time, populations can split or branch off into new species. Adobe Premiere Pro Video Play Modules Complementaires on this page. These processes, collectively known as evolution, are responsible for the many diverse life forms seen in the world. Natural selectioneditIn the 1. The European expansion and naval expeditions employed naturalists and curators of grand museums showcasing preserved and live specimens of the varieties of life. Charles Darwin was an English graduate who was educated and trained in the disciplines of natural history science. Such natural historians would collect, catalogue, describe and study the vast collections of specimens stored and managed by curators at these museums. Darwin served as a ships naturalist on board the HMS Beagle, assigned to a five year research expedition around the world. During his voyage, he observed and collected an abundance of organisms, being very interested in the diverse forms of life along the coasts of South America and the neighboring Galpagos Islands. Darwin noted that orchids exhibit a variety of complex adaptations to ensure pollination all derived from basic floral parts. Darwin gained extensive experience as he collected and studied the natural history of life forms from distant places. Through his studies, he formulated the idea that each species had developed from ancestors with similar features. In 1. 83. 8, he described how a process he called natural selection would make this happen. The size of a population depends on how much and how many resources are able to support it. For the population to remain the same size year after year, there must be an equilibrium, or balance between the population size and available resources. Since organisms produce more offspring than their environment can support, not all individuals can survive out of each generation. There must be a competitive struggle for resources that aid in survival. As a result, Darwin realised that it was not chance alone that determined survival. Instead, survival of an organism depends on the differences of each individual organism, or traits, that aid or hinder survival and reproduction. Well adapted individuals are likely to leave more offspring than their less well adapted competitors. Traits that hinder survival and reproduction would disappear over generations. Traits that help an organism survive and reproduce would accumulate over generations. Darwin realised that the unequal ability of individuals to survive and reproduce could cause gradual changes in the population and used the term natural selection to describe this process.