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The Academy's Evolution Site Biology is a key concept in biology. 에볼루션게이밍 have been active for a long time in helping those interested in science comprehend the concept of evolution and how it affects every area of scientific inquiry. This site provides teachers, students and general readers with a variety of learning resources on evolution. It also includes important video clips from NOVA and WGBH produced science programs on DVD. Tree of Life The Tree of Life is an ancient symbol that symbolizes the interconnectedness of life. It is a symbol of love and unity in many cultures. It also has many practical uses, like providing a framework for understanding the history of species and how they respond to changes in environmental conditions. The earliest attempts to depict the world of biology focused on separating organisms into distinct categories that were distinguished by physical and metabolic characteristics1. These methods, which relied on the sampling of different parts of living organisms or on sequences of small fragments of their DNA greatly increased the variety of organisms that could be represented in a tree of life2. However the trees are mostly made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4. By avoiding the need for direct experimentation and observation genetic techniques have made it possible to represent the Tree of Life in a more precise way. We can create trees using molecular methods, such as the small-subunit ribosomal gene. The Tree of Life has been significantly expanded by genome sequencing. However, there is still much diversity to be discovered. This is particularly the case for microorganisms which are difficult to cultivate, and which are usually only found in a single specimen5. A recent analysis of all genomes has produced a rough draft of the Tree of Life. This includes a wide range of archaea, bacteria, and other organisms that have not yet been isolated or whose diversity has not been thoroughly understood6. The expanded Tree of Life can be used to determine the diversity of a specific area and determine if particular habitats require special protection. This information can be utilized in a variety of ways, including finding new drugs, battling diseases and improving crops. This information is also valuable to conservation efforts. It can aid biologists in identifying areas that are likely to be home to species that are cryptic, which could have important metabolic functions and are susceptible to human-induced change. While conservation funds are essential, the best method to preserve the world's biodiversity is to equip more people in developing countries with the knowledge they need to act locally and support conservation. Phylogeny A phylogeny, also known as an evolutionary tree, reveals the relationships between groups of organisms. Scientists can build an phylogenetic chart which shows the evolution of taxonomic groups based on molecular data and morphological similarities or differences. The concept of phylogeny is fundamental to understanding the evolution of biodiversity, evolution and genetics. A basic phylogenetic tree (see Figure PageIndex 10 Determines the relationship between organisms with similar traits and have evolved from a common ancestor. These shared traits can be analogous, or homologous. Homologous traits are similar in their underlying evolutionary path, while analogous traits look similar but do not have the same origins. Scientists combine similar traits into a grouping referred to as a clade. For instance, all of the organisms that make up a clade share the trait of having amniotic eggs. They evolved from a common ancestor that had eggs. The clades are then connected to form a phylogenetic branch that can determine which organisms have the closest connection to each other. Scientists use DNA or RNA molecular data to build a phylogenetic chart that is more precise and detailed. This data is more precise than morphological data and gives evidence of the evolutionary history of an individual or group. Researchers can utilize Molecular Data to estimate the age of evolution of organisms and determine the number of organisms that share an ancestor common to all. The phylogenetic relationships between species can be influenced by several factors including phenotypic plasticity, an aspect of behavior that alters in response to unique environmental conditions. This can cause a characteristic to appear more similar to one species than another, clouding the phylogenetic signal. However, this problem can be reduced by the use of methods such as cladistics which combine similar and homologous traits into the tree. Additionally, phylogenetics can help predict the duration and rate at which speciation occurs. This information can assist conservation biologists decide which species they should protect from the threat of extinction. In the end, it's the conservation of phylogenetic variety that will result in an ecosystem that is balanced and complete. Evolutionary Theory The central theme of evolution is that organisms develop different features over time due to their interactions with their surroundings. Many scientists have proposed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that a living thing would evolve according to its own requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern taxonomy system that is hierarchical and Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of certain traits can result in changes that can be passed on to future generations. In the 1930s & 1940s, ideas from different fields, including genetics, natural selection and particulate inheritance, were brought together to form a contemporary evolutionary theory. This explains how evolution occurs by the variation of genes in the population, and how these variants alter over time due to natural selection. This model, which encompasses genetic drift, mutations as well as gene flow and sexual selection can be mathematically described mathematically. Recent advances in the field of evolutionary developmental biology have revealed how variations can be introduced to a species by mutations, genetic drift and reshuffling of genes during sexual reproduction and the movement between populations. These processes, in conjunction with others, such as directional selection and gene erosion (changes in frequency of genotypes over time) can lead to evolution. Evolution is defined by changes in the genome over time, as well as changes in phenotype (the expression of genotypes in individuals). Students can better understand phylogeny by incorporating evolutionary thinking throughout all aspects of biology. In a recent study conducted by Grunspan and colleagues., it was shown that teaching students about the evidence for evolution increased their acceptance of evolution during an undergraduate biology course. To learn more about how to teach about evolution, look up The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education. Evolution in Action Traditionally scientists have studied evolution through studying fossils, comparing species and observing living organisms. Evolution is not a past moment; it is a process that continues today. Viruses evolve to stay away from new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior as a result of a changing world. The changes that result are often evident. It wasn't until late-1980s that biologists realized that natural selection could be seen in action, as well. The key is the fact that different traits confer an individual rate of survival and reproduction, and they can be passed on from one generation to the next. In the past, if an allele – the genetic sequence that determines colour was present in a population of organisms that interbred, it could be more common than other allele. As time passes, that could mean that the number of black moths within the population could increase. The same is true for many other characteristics—including morphology and behavior—that vary among populations of organisms. It is easier to track evolutionary change when a species, such as bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from a single strain. Samples from each population have been taken regularly, and more than 50,000 generations of E.coli have been observed to have passed. Lenski's research has revealed that a mutation can profoundly alter the rate at which a population reproduces and, consequently the rate at which it alters. It also shows evolution takes time, which is hard for some to accept. Another example of microevolution is that mosquito genes for resistance to pesticides are more prevalent in areas where insecticides are employed. This is because pesticides cause a selective pressure which favors those who have resistant genotypes. The rapid pace at which evolution can take place has led to a growing appreciation of its importance in a world shaped by human activity—including climate changes, pollution and the loss of habitats that hinder the species from adapting. Understanding evolution can help us make smarter decisions regarding the future of our planet, as well as the lives of its inhabitants.