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The Academy's Evolution Site The concept of biological evolution is a fundamental concept in biology. The Academies have long been involved in helping people who are interested in science understand the theory of evolution and how it permeates all areas of scientific exploration. This site provides a wide range of tools for students, teachers and general readers of evolution. It contains important video clips from NOVA and WGBH's science programs on DVD. Tree of Life The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is a symbol of love and harmony in a variety of cultures. It can be used in many practical ways as well, including providing a framework to understand the evolution of species and how they respond to changes in environmental conditions. Early approaches to depicting the biological world focused on categorizing species into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods, based on the sampling of various parts of living organisms or small DNA fragments, significantly increased the variety that could be represented in the tree of life2. The trees are mostly composed of eukaryotes, while bacteria are largely underrepresented3,4. By avoiding the necessity for direct observation and experimentation genetic techniques have enabled us to represent the Tree of Life in a more precise manner. Particularly, molecular methods allow us to construct trees by using sequenced markers such as the small subunit ribosomal gene. The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of diversity to be discovered. This is particularly true of microorganisms, which are difficult to cultivate and are usually only found in a single specimen5. Recent analysis of all genomes resulted in a rough draft of a Tree of Life. This includes a wide range of bacteria, archaea and other organisms that have not yet been isolated or their diversity is not well understood6. The expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine whether specific habitats require protection. This information can be utilized in a variety of ways, including finding new drugs, battling diseases and enhancing crops. This information is also extremely useful in conservation efforts. It can help biologists identify the areas most likely to contain cryptic species that could have important metabolic functions that could be at risk from anthropogenic change. While funds to safeguard biodiversity are vital, ultimately the best way to ensure the preservation of biodiversity around the world is for more people in developing countries to be empowered with the knowledge to act locally in order to promote conservation from within. Phylogeny A phylogeny (also known as an evolutionary tree) illustrates the relationship between different organisms. Scientists can construct a phylogenetic chart that shows the evolutionary relationship of taxonomic groups using molecular data and morphological similarities or differences. The role of phylogeny is crucial in understanding the relationship between genetics, biodiversity and evolution. A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that evolved from common ancestors. These shared traits can be analogous, or homologous. Homologous traits are identical in their evolutionary roots while analogous traits appear like they do, but don't have the identical origins. Scientists combine similar traits into a grouping referred to as a Clade. All members of a clade have a common characteristic, for example, amniotic egg production. 에볼루션 바카라사이트 evolved from an ancestor who had these eggs. The clades are then connected to create a phylogenetic tree to determine which organisms have the closest relationship to. Scientists make use of molecular DNA or RNA data to build a phylogenetic chart which is more precise and precise. This information is more precise and gives evidence of the evolutionary history of an organism. Researchers can use Molecular Data to calculate the age of evolution of organisms and identify the number of organisms that have the same ancestor. The phylogenetic relationships between organisms are influenced by many factors, including phenotypic flexibility, an aspect of behavior that changes in response to unique environmental conditions. This can cause a trait to appear more similar to one species than other species, which can obscure the phylogenetic signal. However, this issue can be reduced by the use of methods like cladistics, which include a mix of similar and homologous traits into the tree. In 에볼루션 코리아 , phylogenetics helps predict the duration and rate at which speciation takes place. This information can assist conservation biologists in making choices about which species to protect from disappearance. In the end, it's the preservation of phylogenetic diversity which will lead to a complete and balanced ecosystem. Evolutionary Theory The fundamental concept of evolution is that organisms develop different features over time due to their interactions with their environment. Many theories of evolution have been developed by a variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop slowly according to its requirements, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits causes changes that could be passed onto offspring. In the 1930s and 1940s, theories from various areas, including genetics, natural selection and particulate inheritance, came together to form a contemporary evolutionary theory. This describes how evolution occurs by the variation of genes in the population and how these variants change with time due to natural selection. This model, which is known as genetic drift, mutation, gene flow, and sexual selection, is a key element of the current evolutionary biology and can be mathematically described. Recent developments in the field of evolutionary developmental biology have revealed that genetic variation can be introduced into a species via mutation, genetic drift, and reshuffling of genes in sexual reproduction, and also through migration between populations. These processes, as well as others like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution, which is defined by changes in the genome of the species over time, and the change in phenotype over time (the expression of that genotype in an individual). Students can better understand the concept of phylogeny through incorporating evolutionary thinking throughout all areas of biology. A recent study by Grunspan and colleagues, for instance, showed that teaching about the evidence for evolution helped students accept the concept of evolution in a college biology class. To find out more about how to teach about evolution, please see The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education. Evolution in Action Traditionally, scientists have studied evolution by looking back, studying fossils, comparing species, and studying living organisms. Evolution is not a distant event; it is an ongoing process that continues to be observed today. Bacteria transform and resist antibiotics, viruses re-invent themselves and are able to evade new medications and animals alter their behavior in response to the changing climate. The changes that occur are often evident. But it wasn't until the late 1980s that biologists realized that natural selection can be observed in action as well. The key is that different traits confer different rates of survival and reproduction (differential fitness) and can be transferred from one generation to the next. In the past, when one particular allele—the genetic sequence that determines coloration—appeared in a group of interbreeding species, it could quickly become more common than the other alleles. In time, this could mean that the number of moths that have black pigmentation may increase. The same is true for many other characteristics—including morphology and behavior—that vary among populations of organisms. It is easier to see evolution when an organism, like bacteria, has a rapid generation turnover. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain. samples of each are taken regularly and over 500.000 generations have passed. Lenski's work has demonstrated that a mutation can dramatically alter the speed at which a population reproduces—and so the rate at which it evolves. It also proves that evolution takes time—a fact that some people are unable to accept. Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more prevalent in areas where insecticides are used. Pesticides create an exclusive pressure that favors individuals who have resistant genotypes. The rapidity of evolution has led to a growing appreciation of its importance particularly in a world shaped largely by human activity. This includes climate change, pollution, and habitat loss that prevents many species from adapting. Understanding evolution will help us make better choices about the future of our planet and the lives of its inhabitants.