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The Academy's Evolution Site Biological evolution is a central concept in biology. The Academies are committed to helping those who are interested in science comprehend the evolution theory and how it can be applied in all areas of scientific research. This site offers a variety of sources for teachers, students and general readers of evolution. It has important 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 seen in a variety of spiritual traditions and cultures as an emblem of unity and love. It has numerous practical applications as well, such as providing a framework for understanding the evolution of species and how they respond to changes in environmental conditions. Early approaches to depicting the world of biology focused on separating organisms into distinct categories which were distinguished by physical and metabolic characteristics1. These methods, which rely on sampling of different parts of living organisms, or small DNA fragments, significantly increased the variety that could be represented in a tree of life2. These trees are largely composed of eukaryotes, while bacterial diversity is vastly underrepresented3,4. In avoiding the necessity of direct observation and experimentation genetic techniques have enabled us to represent the Tree of Life in a much more accurate way. Particularly, molecular methods enable us to create trees by using sequenced markers, such as the small subunit of ribosomal RNA gene. The Tree of Life has been dramatically expanded through genome sequencing. However, there is still much biodiversity to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are often only present in a single sample5. Recent analysis of all genomes produced an initial draft of the Tree of Life. 에볼루션 바카라 무료체험 includes a large number of archaea, bacteria and other organisms that have not yet been isolated, or the diversity of which is not well understood6. The expanded Tree of Life can be used to evaluate the biodiversity of a specific region and determine if certain habitats need special protection. This information can be used in a range of ways, from identifying new medicines to combating disease to enhancing crops. It is also beneficial for conservation efforts. It helps biologists discover areas that are likely to have cryptic species, which may have important metabolic functions and are susceptible to human-induced change. Although funding to protect biodiversity are essential but the most effective way to ensure the preservation of biodiversity around the world is for more people living in developing countries to be equipped with the knowledge to act locally in order to promote conservation from within. Phylogeny A phylogeny is also known as an evolutionary tree, shows the relationships between various groups of organisms. Scientists can build an phylogenetic chart which shows the evolutionary relationships between taxonomic categories using molecular information and morphological differences or similarities. The role of phylogeny is crucial in understanding biodiversity, genetics and evolution. A basic phylogenetic tree (see Figure PageIndex 10 Determines the relationship between organisms with similar traits and have evolved from an ancestor that shared traits. These shared traits could be either homologous or analogous. Homologous traits are similar in their evolutionary journey. Analogous traits might appear like they are but they don't share the same origins. Scientists group similar traits together into a grouping known as a the clade. For example, all of the organisms that make up a clade share the trait of having amniotic eggs. They evolved from a common ancestor which had eggs. The clades are then connected to form a phylogenetic branch to identify organisms that have the closest connection to each other. Scientists utilize molecular DNA or RNA data to construct a phylogenetic graph which is more precise and detailed. This data is more precise than the morphological data and provides evidence of the evolution history of an organism or group. The use of molecular data lets researchers identify the number of species who share a common ancestor and to estimate their evolutionary age. The phylogenetic relationships between organisms can be influenced by several factors, including phenotypic flexibility, a kind of behavior that changes in response to unique environmental conditions. This can cause a trait to appear more similar to one species than another, obscuring the phylogenetic signal. This problem can be addressed by using cladistics, which is a a combination of analogous and homologous features in the tree. Furthermore, phylogenetics may aid in predicting the time and pace of speciation. This information will assist conservation biologists in deciding which species to save from the threat of extinction. It is ultimately the preservation of phylogenetic diversity which will result in a complete and balanced ecosystem. Evolutionary Theory The main idea behind evolution is that organisms develop various characteristics over time based on their interactions with their surroundings. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism would evolve according to its own requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern taxonomy system that is hierarchical as well as 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 and 1940s, ideas from different fields, including natural selection, genetics & particulate inheritance, came together to form a contemporary synthesis of evolution theory. This explains how evolution occurs by the variation in genes within the population and how these variations alter over time due to natural selection. This model, which includes genetic drift, mutations, gene flow and sexual selection, can be mathematically described mathematically. Recent discoveries in evolutionary developmental biology have revealed how variations can be introduced to a species via genetic drift, mutations and reshuffling of genes during sexual reproduction, and even migration between populations. These processes, along with other ones like directionally-selected selection and erosion of genes (changes in frequency of genotypes over time), can lead towards 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 the concept of phylogeny by using evolutionary thinking into all aspects of biology. In a recent study conducted by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution boosted their understanding of evolution during a college-level course in biology. For more information on how to teach about evolution, look up The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution in Life Sciences Education. Evolution in Action Scientists have traditionally studied evolution by looking in the past—analyzing fossils and comparing species. They also observe living organisms. But evolution isn't a thing that occurred in the past. It's an ongoing process that is happening today. Bacteria evolve and resist antibiotics, viruses reinvent themselves and escape new drugs and animals alter their behavior in response to a changing planet. The changes that result are often apparent. However, it wasn't until late 1980s that biologists understood that natural selection could be seen in action, as well. The key is that different characteristics result in different rates of survival and reproduction (differential fitness) and are passed from one generation to the next. In the past, if one particular allele, the genetic sequence that determines coloration—appeared in a population of interbreeding organisms, it might quickly become more common than all other alleles. In time, this could mean that the number of moths with black pigmentation in a population could increase. The same is true for many other characteristics—including morphology and behavior—that vary among populations of organisms. Monitoring evolutionary changes in action is easier when a particular species has a rapid turnover of its generation like bacteria. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples from each population are taken every day, and over 500.000 generations have been observed. Lenski's research has shown that mutations can drastically alter the efficiency with the rate at which a population reproduces, and consequently, the rate at which it changes. It also shows that evolution is slow-moving, a fact that some people are unable to accept. Another example of microevolution is that mosquito genes for resistance to pesticides show up more often in areas where insecticides are used. This is because the use of pesticides creates a selective pressure that favors individuals with resistant genotypes. The rapidity of evolution has led to an increasing awareness of its significance 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 can help you make better decisions regarding the future of the planet and its inhabitants.