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The Academy's Evolution Site Biological evolution is a central concept in biology. 에볼루션 사이트 are committed to helping those who are interested in science to learn about the theory of evolution and how it can be applied throughout all fields of scientific research. This site provides teachers, students and general readers with a range of learning resources on evolution. 에볼루션 사이트 contains key video clips from NOVA and the WGBH-produced science programs on DVD. Tree of Life The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is seen in a variety of spiritual traditions and cultures as a symbol of unity and love. It also has important practical applications, like providing a framework for understanding the history of species and how they react to changes in the environment. The first attempts at depicting the world of biology focused on categorizing species into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods, which rely on the sampling of different parts of living organisms or small fragments of their DNA significantly expanded the diversity that could be included in the tree of life2. However the trees are mostly composed of eukaryotes; bacterial diversity is not represented in a large way3,4. Genetic techniques have greatly expanded our ability to depict the Tree of Life by circumventing the need for direct observation and experimentation. Trees can be constructed using molecular techniques, such as the small-subunit ribosomal gene. Despite the massive expansion of the Tree of Life through genome sequencing, a lot of biodiversity is waiting to be discovered. This is particularly true for microorganisms, which are difficult to cultivate and are often only represented in a single specimen5. A recent analysis of all known genomes has produced a rough draft version of the Tree of Life, including a large number of archaea and bacteria that have not been isolated, and their diversity is not fully understood6. The expanded Tree of Life can be used to evaluate the biodiversity of a specific region and determine if certain habitats require special protection. The information can be used in a range of ways, from identifying the most effective medicines to combating disease to enhancing crops. This information is also beneficial for conservation efforts. It helps biologists discover areas that are likely to have cryptic species, which could perform important metabolic functions and be vulnerable to human-induced change. While funding to protect biodiversity are essential, the best method to protect the world's biodiversity is to empower more people in developing countries with the necessary knowledge to act locally and support conservation. Phylogeny A phylogeny, also called an evolutionary tree, shows the connections between different groups of organisms. Utilizing molecular data, morphological similarities and differences or ontogeny (the course of development of an organism) scientists can construct a phylogenetic tree that illustrates the evolution of taxonomic groups. Phylogeny plays a crucial role in understanding genetics, biodiversity and evolution. A basic phylogenetic Tree (see Figure PageIndex 10 ) identifies the relationships between organisms that share similar traits that have evolved from common ancestral. 에볼루션 바카라 체험 shared traits can be analogous or homologous. Homologous traits share their evolutionary roots, while analogous traits look similar but do not have the identical origins. Scientists put similar traits into a grouping referred to as a Clade. All members of a clade have a common characteristic, for example, amniotic egg production. They all came from an ancestor with these eggs. The clades are then linked to form a phylogenetic branch to identify organisms that have the closest connection to each other. For a more detailed and accurate phylogenetic tree, scientists use molecular data from DNA or RNA to determine the connections between organisms. This data is more precise than morphological data and provides evidence of the evolution background of an organism or group. The analysis of molecular data can help researchers identify the number of organisms that share a common ancestor and to estimate their evolutionary age. The phylogenetic relationships between species are influenced by many factors, including phenotypic flexibility, a kind of behavior that alters in response to specific environmental conditions. This can cause a characteristic to appear more similar to one species than to the other which can obscure the phylogenetic signal. This issue can be cured by using cladistics, which is a the combination of homologous and analogous features in the tree. Additionally, phylogenetics can help predict the duration and rate at which speciation occurs. This information can help conservation biologists make decisions about which species they should protect from the threat of extinction. In the end, it's the preservation of phylogenetic diversity that will result in an ecosystem that is balanced and complete. Evolutionary Theory The main idea behind evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism could evolve according to its own requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy and Jean-Baptiste Lamarck (1844-1829), who believed that the use or absence of certain traits can result in changes that can be passed on to future generations. In the 1930s and 1940s, theories from a variety of fields — including natural selection, genetics, and particulate inheritance—came together to create the modern evolutionary theory synthesis which explains how evolution happens through the variations of genes within a population and how those variants change over time as a result of natural selection. This model, known as genetic drift mutation, gene flow and sexual selection, is the foundation of modern evolutionary biology and can be mathematically explained. Recent discoveries in the field of evolutionary developmental biology have demonstrated the ways in which variation can be introduced to a species via mutations, genetic drift, reshuffling genes during sexual reproduction, and even migration between populations. These processes, as well as others, such as directional selection and gene erosion (changes in the frequency of genotypes over time), can lead towards evolution. Evolution is defined by changes in the genome over time and changes in the phenotype (the expression of genotypes in individuals). Incorporating evolutionary thinking into all aspects of biology education can increase student understanding of the concepts of phylogeny and evolutionary. In a recent study conducted by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution boosted their acceptance of evolution during the course of a college biology. For more information on how to teach evolution read The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily A Framework for Integrating Evolution into Life Sciences Education. Evolution in Action Traditionally, scientists have studied evolution by looking back—analyzing fossils, comparing species, and observing living organisms. But evolution isn't just something that happened in the past. It's an ongoing process, that is taking place in the present. Viruses evolve to stay away from new medications and bacteria mutate to resist antibiotics. Animals alter their behavior in the wake of a changing environment. The results are usually visible. It wasn't until the late 1980s when biologists began to realize that natural selection was at work. The key is that different traits have different rates of survival and reproduction (differential fitness) and can be transferred from one generation to the next. In the past, if an allele – the genetic sequence that determines colour – appeared in a population of organisms that interbred, it might become more common than any other allele. Over time, this would mean that the number of moths sporting black pigmentation may increase. The same is true for many other characteristics—including morphology and behavior—that vary among populations of organisms. Observing evolutionary change in action is easier when a particular species has a fast generation turnover like bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples of each population are taken on a regular basis and over fifty thousand generations have passed. Lenski's research has shown that mutations can drastically alter the speed at which a population reproduces—and so, the rate at which it alters. It also demonstrates that evolution takes time—a fact that some people are unable to accept. Microevolution can also be seen in the fact that mosquito genes that confer resistance to pesticides are more prevalent in areas that have used insecticides. This is because the use of pesticides causes a selective pressure that favors those with resistant genotypes. The rapidity of evolution has led to an increasing awareness of its significance especially in a planet which is largely shaped by human activities. This includes the effects of climate change, pollution and habitat loss that prevents many species from adapting. Understanding evolution will help us make better decisions regarding the future of our planet, and the lives of its inhabitants.