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The Academy's Evolution Site Biological evolution is a central concept in biology. The Academies are committed to helping those interested in science to learn about the theory of evolution and how it can be applied throughout all fields of scientific research. This site provides a range of tools for teachers, students as well as general readers about evolution. It includes key video clip 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 used in many cultures and spiritual beliefs as symbolizing unity and love. It also has many practical uses, like providing a framework for understanding the evolution of species and how they respond to changes in environmental conditions. The first attempts to depict the biological world were founded on categorizing organisms on their physical and metabolic characteristics. These methods depend on the sampling of different parts of organisms, or DNA fragments have greatly increased the diversity of a tree of Life2. The trees are mostly composed of eukaryotes, while bacterial diversity is vastly underrepresented3,4. By avoiding the necessity for direct observation and experimentation, genetic techniques have made it possible to depict the Tree of Life in a more precise way. Particularly, molecular methods enable us to create trees using sequenced markers such as the small subunit ribosomal gene. Despite the massive growth of the Tree of Life through genome sequencing, a lot of biodiversity is waiting to be discovered. This is particularly the case for microorganisms which are difficult to cultivate, and which are usually only found in one sample5. A recent analysis of all genomes known to date has produced a rough draft of the Tree of Life, including a large number of bacteria and archaea that have not been isolated and their diversity is not fully understood6. The expanded Tree of Life is particularly useful in assessing the diversity of an area, helping to determine whether specific habitats require protection. This information can be used in a variety of ways, including identifying new drugs, combating diseases and enhancing crops. The information is also beneficial in conservation efforts. It can aid biologists in identifying areas that are likely to have cryptic species, which may have vital metabolic functions and are susceptible to the effects of human activity. While conservation funds are important, the most effective way to conserve the world's biodiversity is to empower more people in developing countries with the knowledge they need to take action locally and encourage conservation. Phylogeny A phylogeny, also called an evolutionary tree, reveals the relationships between different groups of organisms. Scientists can create a phylogenetic chart that shows the evolutionary relationship of taxonomic groups based on molecular data and morphological similarities or differences. Phylogeny is crucial in understanding biodiversity, evolution and genetics. A basic phylogenetic Tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar traits and evolved from an ancestor that shared traits. These shared traits can be either homologous or analogous. Homologous traits are similar in their evolutionary path. Analogous traits might appear like they are, but they do not have the same origins. Scientists combine similar traits into a grouping known as a Clade. For instance, all of the organisms that make up a clade share the characteristic of having amniotic eggs. They evolved from a common ancestor that had these eggs. The clades are then connected to form a phylogenetic branch that can identify organisms that have the closest relationship. To create a more thorough and precise phylogenetic tree scientists make use of molecular data from DNA or RNA to establish the relationships between organisms. This information is more precise and provides evidence of the evolutionary history of an organism. The analysis of molecular data can help researchers identify the number of species that share a common ancestor and to estimate their evolutionary age. The phylogenetic relationships between organisms can be affected by a variety of factors, including phenotypic flexibility, an aspect of behavior that changes in response to specific environmental conditions. This can cause a trait to appear more similar in one species than other species, which can obscure the phylogenetic signal. This problem can be addressed by using cladistics, which is a the combination of analogous and homologous features in the tree. Additionally, phylogenetics aids determine the duration and speed at which speciation occurs. This information will assist conservation biologists in making choices about which species to protect from disappearance. In the end, it is the conservation of phylogenetic diversity that will lead to an ecosystem that is complete and balanced. Evolutionary Theory The main idea behind evolution is that organisms develop various characteristics over time as a result of their interactions with their environments. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its individual requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern taxonomy system that is hierarchical and Jean-Baptiste Lamarck (1844-1829), who believed that the usage or non-use of traits can lead to changes that are passed on to the In the 1930s and 1940s, concepts from various areas, including natural selection, genetics & particulate inheritance, came together to create a modern evolutionary theory. This describes how evolution occurs by the variation of genes in the population, and how these variations change over time as a result of natural selection. This model, which encompasses mutations, genetic drift as well as gene flow and sexual selection, can be mathematically described. 에볼루션 카지노 in evolutionary developmental biology have demonstrated how variations can be introduced to a species through mutations, genetic drift, reshuffling genes during sexual reproduction and migration between populations. These processes, as well as others like directional selection and genetic erosion (changes in the frequency of the genotype over time) can result in evolution which is defined by changes in the genome of the species over time and also the change in phenotype as time passes (the expression of the genotype in the individual). Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking into all areas of biology. A recent study conducted by Grunspan and colleagues, for instance, showed that teaching about the evidence supporting evolution increased students' understanding of evolution in a college-level biology course. To learn more about how to teach about evolution, please 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 through looking back in the past—analyzing fossils and comparing species. They also study living organisms. Evolution is not a past event, but a process that continues today. Bacteria evolve and resist antibiotics, viruses re-invent themselves and are able to evade new medications and animals alter their behavior to a changing planet. The changes that result are often visible. It wasn't until the late 1980s that biologists began to realize that natural selection was also at work. The key is that various traits have 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 controls coloration – was present in a population of interbreeding species, it could quickly become more common than the other alleles. In time, this could mean that the number of black moths in a population 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 much easier when a species has a rapid turnover of its generation such as bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from one strain. Samples from each population were taken regularly, and more than 500.000 generations of E.coli have passed. 에볼루션 코리아 has revealed that mutations can alter the rate of change and the efficiency of a population's reproduction. It also shows that evolution takes time, a fact that many are unable to accept. Another example of microevolution is how mosquito genes that confer resistance to pesticides are more prevalent in areas in which insecticides are utilized. This is due to pesticides causing a selective pressure which favors those who have resistant genotypes. The speed at which evolution takes place has led to an increasing awareness of its significance in a world that is shaped by human activity, including climate change, pollution and the loss of habitats that hinder many species from adjusting. Understanding the evolution process can assist you in making better choices about the future of the planet and its inhabitants.