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The Academy's Evolution Site Biology is one of the most fundamental concepts in biology. The Academies have been for a long time involved in helping people who are interested in science comprehend the theory of evolution and how it influences all areas of scientific research. This site offers a variety of resources for students, teachers as well as general readers about evolution. It contains key video clips from NOVA and WGBH produced science programs on DVD. Tree of Life The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is a symbol of love and harmony in a variety of cultures. It has numerous practical applications in addition to providing a framework to understand the evolution of species and how they respond to changes in environmental conditions. The first attempts at depicting the world of biology focused on categorizing organisms into distinct categories that were identified by their physical and metabolic characteristics1. These methods, which are based on the collection of various parts of organisms or fragments of DNA have significantly increased the diversity of a tree of Life2. These trees are mostly populated of eukaryotes, while bacterial diversity is vastly underrepresented3,4. Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular techniques enable us to create trees by using sequenced markers such as the small subunit ribosomal gene. Despite the dramatic growth of the Tree of Life through genome sequencing, a large amount of biodiversity remains to be discovered. This is particularly relevant to microorganisms that are difficult to cultivate and are usually present in a single sample5. A recent study of all genomes known to date 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. This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, which can help to determine whether specific habitats require protection. This information can be used in a variety of ways, such as finding new drugs, fighting diseases and improving crops. The information is also incredibly useful to conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species with potentially important metabolic functions that may be at risk from anthropogenic change. Although funding to protect biodiversity are essential but the most effective way to preserve the world's biodiversity is for more people living in developing countries to be equipped with the knowledge to act locally to promote conservation from within. Phylogeny A phylogeny (also called an evolutionary tree) illustrates the relationship between different organisms. Scientists can build a phylogenetic chart that shows the evolutionary relationship of taxonomic groups based on molecular data and morphological similarities or differences. The phylogeny of a tree plays an important role in understanding genetics, biodiversity and evolution. A basic phylogenetic Tree (see Figure PageIndex 10 ) identifies the relationships between organisms with similar traits that have evolved from common ancestors. These shared traits can be analogous, or homologous. Homologous traits are similar in their underlying evolutionary path while analogous traits appear like they do, but don't have the identical origins. Scientists combine similar traits into a grouping called a clade. Every organism in a group have a common characteristic, for example, amniotic egg production. They all evolved from an ancestor with these eggs. The clades are then linked to form a phylogenetic branch that can determine which organisms have the closest relationship to. Scientists make use of DNA or RNA molecular information to build a phylogenetic chart which is more precise and precise. This information is more precise and provides evidence of the evolutionary history of an organism. The use of molecular data lets researchers determine the number of organisms that have an ancestor common to them and estimate their evolutionary age. The phylogenetic relationships between organisms can be influenced by several factors, including phenotypic flexibility, a kind of behavior that alters in response to specific environmental conditions. This can cause a trait to appear more similar to one species than to another which can obscure the phylogenetic signal. However, this problem can be cured by the use of methods such as cladistics that incorporate a combination of analogous and homologous features into the tree. In addition, phylogenetics helps determine the duration and rate of speciation. This information can assist conservation biologists make decisions about which species to protect from extinction. In the end, it is the conservation of phylogenetic variety which will create an ecosystem that is complete and balanced. Evolutionary Theory The fundamental concept in evolution is that organisms change over time due to their interactions with their environment. A variety of theories about evolution have been proposed by a variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve slowly in accordance with its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits cause changes that can be passed on to offspring. In the 1930s and 1940s, ideas from a variety of fields — including genetics, natural selection and particulate inheritance—came together to create the modern evolutionary theory synthesis that explains how evolution happens through the variation of genes within a population and how these variants change in time due to natural selection. This model, which encompasses mutations, genetic drift in gene flow, and sexual selection, can be mathematically described. Recent developments in the field of evolutionary developmental biology have revealed that variations can be introduced into a species through mutation, genetic drift and reshuffling of genes during sexual reproduction, and also through migration between populations. These processes, in conjunction with others, such as directional selection and gene erosion (changes in frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time, as well as changes in phenotype (the expression of genotypes in individuals). Incorporating evolutionary thinking into all aspects of biology education could increase student understanding of the concepts of phylogeny as well as evolution. In a recent study by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution increased their understanding of evolution in the course of a college biology. To learn more about how to teach about evolution, read The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily A Framework for Infusing 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 past moment; it is an ongoing process. Bacteria evolve and resist antibiotics, viruses reinvent themselves and elude new medications and animals alter their behavior to the changing climate. The changes that result are often easy to see. But it wasn't until the late 1980s that biologists understood that natural selection can be observed in action as well. The key is the fact that different traits result in a different rate of survival and reproduction, and can be passed down from one generation to another. In the past, if one allele – the genetic sequence that determines colour appeared in a population of organisms that interbred, it could become more common than any other allele. As time passes, this could mean that the number of moths that have black pigmentation could 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, as with bacteria. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that are descended from one strain. Samples of each population have been collected regularly and more than 50,000 generations of E.coli have passed. Lenski's work has shown that mutations can alter the rate at which change occurs and the efficiency of a population's reproduction. It also demonstrates that evolution takes time, a fact that is difficult for some to accept. Microevolution can be observed in the fact that mosquito genes for pesticide resistance are more prevalent in areas where insecticides are used. This is due to the fact that the use of pesticides causes a selective pressure that favors people who have resistant genotypes. 에볼루션코리아 of evolution has led to a growing recognition of its importance particularly in a world which is largely shaped by human activities. This includes climate change, pollution, and habitat loss that hinders many species from adapting. Understanding the evolution process will aid you in making better decisions about the future of our planet and its inhabitants.