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The Academy's Evolution Site The concept of biological evolution is among the most fundamental concepts in biology. 에볼루션 룰렛 are committed to helping those interested in the sciences understand evolution theory and how it is incorporated in all areas of scientific research. This site provides teachers, students and general readers with a wide range of educational resources on evolution. It has the most important video clips from NOVA and WGBH's science programs on DVD. Tree of Life The Tree of Life is an ancient symbol that represents the interconnectedness of life. It is an emblem of love and unity across many cultures. It can be used in many practical ways as well, such as providing a framework for understanding the history of species, and how they respond to changes in environmental conditions. Early approaches to depicting the biological world focused on the classification of organisms into distinct categories that were identified by their physical and metabolic characteristics1. These methods depend on the collection of various parts of organisms, or fragments of DNA have significantly increased the diversity of a tree of Life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity is not represented in a large way3,4. Genetic techniques have significantly expanded our ability to depict 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 RNA gene. The Tree of Life has been dramatically expanded through genome sequencing. However, there is still much diversity to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are often only represented in a single specimen5. A recent study of all genomes that are known has produced a rough draft of the Tree of Life, including numerous archaea and bacteria that have not been isolated, and their diversity is not fully understood6. The expanded Tree of Life can be used to determine the diversity of a particular area and determine if particular habitats require special protection. The information can be used in a range of ways, from identifying new treatments to fight disease to enhancing crop yields. The information is also incredibly valuable for conservation efforts. It helps biologists determine the areas that are most likely to contain cryptic species that could have important metabolic functions that could be vulnerable to anthropogenic change. While conservation funds are essential, the best way to conserve the world's biodiversity is to empower more people in developing countries with the information they require to take action locally and encourage conservation. Phylogeny A phylogeny, also known as an evolutionary tree, shows the relationships between different groups of organisms. Using molecular data similarities and differences in morphology or ontogeny (the course of development of an organism), scientists can build an phylogenetic tree that demonstrates the evolutionary relationship between taxonomic groups. The concept of phylogeny is fundamental to understanding biodiversity, evolution and genetics. A basic phylogenetic tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms that share similar traits that have evolved from common ancestral. These shared traits can be analogous or homologous. Homologous traits share their underlying evolutionary path and analogous traits appear similar, but do not share the same origins. Scientists group similar traits into a grouping referred to as a Clade. Every organism in a group have a common characteristic, for example, amniotic egg production. They all evolved from an ancestor that had these eggs. A phylogenetic tree is constructed by connecting clades to determine the organisms which are the closest to each other. Scientists make use of DNA or RNA molecular data to construct a phylogenetic graph that is more accurate and precise. This information is more precise and provides evidence of the evolution history of an organism. The analysis of molecular data can help researchers identify the number of organisms that share a common ancestor and to estimate their evolutionary age. Phylogenetic relationships can be affected by a number of factors that include the phenotypic plasticity. This is a type behaviour that can change in response to specific environmental conditions. This can cause a trait to appear more similar to one species than to the other, obscuring the phylogenetic signals. This problem can be mitigated by using cladistics. This is a method that incorporates a combination of analogous and homologous features in the tree. In addition, phylogenetics helps predict the duration and rate of speciation. This information can aid conservation biologists in deciding which species to save from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity which will result in an ecosystem that is complete and balanced. Evolutionary Theory The main idea behind evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have proposed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism could develop according to its own requirements and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical system of taxonomy and Jean-Baptiste Lamarck (1844-1829), who believed that the usage or non-use of traits can lead to changes that can be passed on to future generations. In the 1930s and 1940s, concepts from a variety of fields — including genetics, natural selection, and particulate inheritance – came together to form the modern evolutionary theory that explains how evolution happens through the variations of genes within a population, and how those variations change in time due to natural selection. This model, called genetic drift mutation, gene flow and sexual selection, is a key element of the current evolutionary biology and can be mathematically explained. Recent developments in the field of evolutionary developmental biology have shown that genetic variation can be introduced into a species via genetic drift, mutation, and reshuffling genes during sexual reproduction, as well as through migration between populations. These processes, along with other ones like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can result in 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 that genotype within the individual). Incorporating evolutionary thinking into all aspects of biology education could increase students' understanding of phylogeny as well as evolution. A recent study conducted by Grunspan and colleagues, for instance revealed that teaching students about the evidence supporting evolution helped students accept the concept of evolution in a college-level biology class. To find out more about how to teach about evolution, see The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution in Life Sciences Education. Evolution in Action Traditionally scientists have studied evolution by looking back, studying fossils, comparing species, and studying living organisms. However, evolution isn't something that occurred in the past. It's an ongoing process that is taking place today. 에볼루션 게이밍 and resist antibiotics, viruses re-invent themselves and escape new drugs, and animals adapt their behavior in response to a changing planet. The results are usually evident. It wasn't until late 1980s that biologists understood that natural selection can be observed in action as well. The key to this is that different traits confer a different rate of survival and reproduction, and can be passed on from one generation to the next. In the past when one particular allele—the genetic sequence that controls coloration – was present in a group of interbreeding organisms, it might quickly become more prevalent than all other alleles. Over time, that would mean that the number of black moths in the 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 much easier when a species has a rapid generation turnover such as bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from one strain. The samples of each population have been taken frequently and more than 500.000 generations of E.coli have passed. 에볼루션 슬롯 has revealed that a mutation can dramatically alter the efficiency with the rate at which a population reproduces, and consequently the rate at which it evolves. It also shows that evolution takes time, something that is difficult for some to accept. Microevolution can be observed in the fact that mosquito genes that confer resistance to pesticides are more prevalent in areas where insecticides are used. This is due to the fact that the use of pesticides creates a selective pressure that favors people with resistant genotypes. The rapidity of evolution has led to a growing appreciation of its importance, especially in a world that is largely shaped by human activity. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding evolution can help you make better decisions about the future of the planet and its inhabitants.