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The Academy's Evolution Site Biology is one of the most central concepts in biology. The Academies are committed to helping those who are interested in science to understand evolution theory and how it is incorporated in all areas of scientific research. This site provides a wide range of tools 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 is an ancient symbol that 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 react to changes in environmental conditions. Early attempts to represent the biological world were built on categorizing organisms based on their metabolic and physical characteristics. These methods, based on the sampling of various parts of living organisms, or small DNA fragments, greatly increased the variety of organisms that could be included in the tree of life2. These trees are mostly populated by eukaryotes and bacterial diversity is vastly underrepresented3,4. Genetic techniques have greatly broadened our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular methods allow us to build trees using sequenced markers like the small subunit of ribosomal RNA gene. The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of biodiversity to be discovered. This is particularly true of microorganisms that are difficult to cultivate and are usually only present in a single sample5. A recent analysis of all genomes has produced a rough draft of the Tree of Life. This includes a large number of archaea, bacteria and other organisms that have not yet been isolated or their diversity is not fully understood6. This expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, helping to determine if certain habitats require special protection. The information can be used in a variety of ways, from identifying the most effective medicines to combating disease to enhancing crop yields. It is also beneficial in conservation efforts. It can aid biologists in identifying those areas that are most likely contain cryptic species with important metabolic functions that may be at risk of anthropogenic changes. While funding to protect biodiversity are important, the best way to conserve the world's biodiversity is to equip more people in developing countries with the necessary knowledge to act locally and support conservation. Phylogeny A phylogeny (also known as an evolutionary tree) depicts the relationships between different organisms. Scientists can build a phylogenetic chart that shows the evolutionary relationship of taxonomic groups using molecular data and morphological differences or similarities. The phylogeny of a tree plays an important role in understanding biodiversity, genetics and evolution. A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar traits and have evolved from an ancestor that shared traits. These shared traits may be analogous or homologous. Homologous characteristics are identical in terms of their evolutionary journey. Analogous traits could appear like they are, but they do not have the same origins. Scientists combine similar traits into a grouping known as a the clade. For instance, all the organisms in a clade share the characteristic of having amniotic egg and evolved from a common ancestor which had these eggs. The clades then join to form a phylogenetic branch to determine which organisms have the closest relationship. Scientists make use of DNA or RNA molecular information to construct a phylogenetic graph that is more precise and detailed. 에볼루션 바카라사이트 is more precise than the morphological data and provides evidence of the evolution history of an individual or group. Researchers can use Molecular Data to determine the age of evolution of organisms and determine how many species have a common ancestor. The phylogenetic relationships between organisms can be influenced by several factors, including phenotypic plasticity a type of behavior that alters in response to specific environmental conditions. This can cause a trait to appear more similar to one species than another which can obscure the phylogenetic signal. However, this problem can be solved through the use of methods such as cladistics which combine analogous and homologous features into the tree. Additionally, phylogenetics can aid in predicting the time and pace of speciation. This information can help conservation biologists make decisions about which species to protect from extinction. In the end, it's the preservation of phylogenetic diversity that will result in an ecologically balanced and complete ecosystem. Evolutionary Theory The main idea behind evolution is that organisms develop different features over time based on their interactions with their environment. Many theories of evolution have been developed by a wide variety of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop slowly according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that can be passed on to the offspring. In the 1930s and 1940s, concepts from various fields, including natural selection, genetics, 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 those variants change in time as a result of natural selection. This model, called genetic drift, mutation, gene flow, and sexual selection, is a cornerstone of current evolutionary biology, and is mathematically described. Recent discoveries in the field of evolutionary developmental biology have demonstrated how variation can be introduced to a species via genetic drift, mutations and reshuffling of genes during sexual reproduction and migration between populations. These processes, as well as other ones like directional selection and genetic erosion (changes in the frequency of a genotype over time) can lead to evolution which is defined by changes in the genome of the species over time and also by changes in phenotype over time (the expression of the genotype within the individual). Incorporating evolutionary thinking into all aspects of biology education can increase students' understanding of phylogeny and evolutionary. A recent study by Grunspan and colleagues, for instance revealed that teaching students about the evidence for evolution helped students accept the concept of evolution in a college-level biology class. For more information on 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 studying fossils, comparing species and studying living organisms. Evolution isn't a flims event; it is a process that continues today. The virus reinvents itself to avoid new medications and bacteria mutate to resist antibiotics. Animals alter their behavior as a result of a changing world. The results are usually evident. It wasn't until the late 1980s that biologists began to realize that natural selection was in action. The main reason is that different traits can confer a different rate of survival as well as reproduction, and may be passed on from generation to generation. In the past, if one particular allele – the genetic sequence that defines color in a population of interbreeding species, it could quickly become more common than other alleles. Over time, that would mean that the number of black moths within a particular population could rise. The same is true for many other characteristics—including morphology and behavior—that vary among populations of organisms. The ability to observe evolutionary change is easier when a particular species has a rapid turnover of its generation, as with bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain. samples of each are taken every day and more than 50,000 generations have now been observed. Lenski's research has demonstrated that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also demonstrates that evolution takes time, a fact that some find hard to accept. Another example of microevolution is how mosquito genes that are resistant to pesticides appear more frequently in populations where insecticides are used. That's because the use of pesticides causes a selective pressure that favors individuals with resistant genotypes. The rapidity of evolution has led to an increasing recognition of its importance especially in a planet shaped largely by human activity. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding the evolution process will assist you in making better choices about the future of the planet and its inhabitants.