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The Academy's Evolution Site The concept of biological evolution is a fundamental concept in biology. The Academies are committed to helping those who are interested in science to learn about the theory of evolution and how it is incorporated in all areas of scientific research. This site provides a range of tools for teachers, students as well as general readers about evolution. It contains important video clips from NOVA and WGBH's 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 cultures and spiritual beliefs as an emblem of unity and love. It has many practical applications in addition to 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 had been identified by their physical and metabolic characteristics1. These methods depend on the collection of various parts of organisms or DNA fragments, have significantly increased the diversity of a tree of Life2. These trees are largely composed by eukaryotes and the diversity of bacterial species is greatly underrepresented3,4. Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. We can create trees by using molecular methods, such as the small-subunit ribosomal gene. Despite the massive growth of the Tree of Life through genome sequencing, a lot of biodiversity awaits discovery. This is especially the case for microorganisms which are difficult to cultivate and are usually found in one sample5. A recent study of all genomes that are known has created a rough draft of the Tree of Life, including numerous bacteria and archaea that have not been isolated, and whose diversity is poorly understood6. The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, assisting to determine if certain habitats require special protection. This information can be used in a variety of ways, including finding new drugs, fighting diseases and enhancing crops. It is also beneficial for conservation efforts. It can help biologists identify the areas that are most likely to contain cryptic species with potentially significant metabolic functions that could be at risk from anthropogenic change. While funds to protect biodiversity are crucial but the most effective way to preserve the world's biodiversity is for more people in developing countries to be equipped with the knowledge to take action locally to encourage conservation from within. Phylogeny A phylogeny (also called an evolutionary tree) depicts the relationships between organisms. Scientists can build an phylogenetic chart which shows the evolutionary relationship of taxonomic categories using molecular information and morphological similarities or differences. Phylogeny is crucial in understanding evolution, biodiversity and genetics. A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar characteristics and have evolved from an ancestor with common traits. These shared traits may be analogous or homologous. Homologous traits are the same in their evolutionary paths. Analogous traits could appear similar but they don't share the same origins. Scientists put similar traits into a grouping known as a the clade. 에볼루션 블랙잭 of a clade share a trait, such as amniotic egg production. They all derived from an ancestor that had these eggs. The clades are then linked to form a phylogenetic branch that can identify organisms that have the closest connection to each other. For a more detailed and accurate phylogenetic tree scientists rely on molecular information from DNA or RNA to establish the connections between organisms. This information is more precise and gives evidence of the evolutionary history of an organism. Researchers can use Molecular Data to calculate the age of evolution of organisms and identify how many species have a common ancestor. Phylogenetic relationships can be affected by a number of factors such as the phenotypic plasticity. This is a type of behaviour that can change due to unique environmental conditions. This can cause a trait to appear more similar to a species than to another, obscuring the phylogenetic signals. However, this issue can be reduced by the use of methods such as cladistics which incorporate a combination of similar and homologous traits into the tree. Furthermore, phylogenetics may help predict the length and speed of speciation. This information can assist conservation biologists decide which species they should protect from the threat of extinction. In the end, it is the conservation of phylogenetic variety that will result in an ecosystem that is balanced and complete. Evolutionary Theory The fundamental concept in evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have proposed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its individual requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or absence of traits can cause changes that can be passed on to future generations. In the 1930s and 1940s, theories from various fields, including natural selection, genetics, and particulate inheritance—came together to form the current synthesis of evolutionary theory that explains how evolution is triggered by the variation of genes within a population, and how these variants change in time due to natural selection. This model, called genetic drift or mutation, gene flow, and sexual selection, is a key element of modern evolutionary biology and can be mathematically explained. Recent discoveries in the field of evolutionary developmental biology have revealed that genetic variation can be introduced into a species through mutation, genetic drift and reshuffling genes during sexual reproduction, as well as through migration between populations. 에볼루션게이밍 , as well as others, such as directional selection and gene erosion (changes to the frequency of genotypes over time) can lead to evolution. Evolution is defined by changes in the genome over time, as well as changes in the phenotype (the expression of genotypes in individuals). Incorporating evolutionary thinking into all aspects of biology education could increase students' understanding of phylogeny as well as evolution. In a recent study conducted by Grunspan et al. It was found that teaching students about the evidence for evolution increased their acceptance of evolution during an undergraduate biology course. For more information about how to teach evolution read The Evolutionary Power of Biology in All Areas of Biology or Thinking Evolutionarily as a Framework for Infusing Evolution into Life Sciences Education. Evolution in Action Scientists have studied evolution by looking in the past, analyzing fossils and comparing species. They also study living organisms. However, evolution isn't something that occurred in the past, it's an ongoing process, happening today. The virus reinvents itself to avoid new medications and bacteria mutate to resist antibiotics. Animals adapt their behavior in the wake of a changing environment. The changes that result are often evident. It wasn't until 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 can be transferred from one generation to the next. In the past, if a certain allele – the genetic sequence that determines colour – was found in a group of organisms that interbred, it could be more common than any other allele. Over time, that would mean 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. It is easier to observe evolution when the species, like bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that are descended from one strain. The samples of each population have been collected frequently and more than 500.000 generations of E.coli have passed. Lenski's research has revealed that mutations can alter the rate of change and the rate at which a population reproduces. It also shows that evolution takes time, a fact that is hard for some to accept. Another example of microevolution is that mosquito genes for resistance to pesticides show up more often in populations where insecticides are used. This is due to the fact that the use of pesticides causes a selective pressure that favors individuals who have resistant genotypes. The rapidity of evolution has led to an increasing recognition of its importance particularly in a world which is largely shaped by human activities. This includes pollution, climate change, and habitat loss that prevents many species from adapting. Understanding evolution will help you make better decisions regarding the future of the planet and its inhabitants.