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The Academy's Evolution Site Biology is one of the most fundamental concepts in biology. The Academies are committed to helping those who are interested in science to comprehend the evolution theory and how it can be applied throughout all fields of scientific research. This site provides teachers, students and general readers with a variety of learning 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, an ancient symbol, symbolizes the interconnectedness of all life. 무료에볼루션 is an emblem of love and unity across many cultures. It also has many practical uses, like providing a framework to understand the history of species and how they react to changing environmental conditions. The first attempts at depicting the biological world focused on the classification of species into distinct categories that were distinguished by their physical and metabolic characteristics1. These methods are based on the collection of various parts of organisms or DNA fragments have greatly increased the diversity of a tree of Life2. However, these trees are largely comprised of eukaryotes, and bacterial diversity is still largely unrepresented3,4. In avoiding the necessity of direct observation and experimentation, genetic techniques have allowed us to represent the Tree of Life in a more precise way. Particularly, molecular methods allow us to build trees by using sequenced markers such as the small subunit of ribosomal RNA gene. Despite the rapid growth of the Tree of Life through genome sequencing, a large amount of biodiversity awaits discovery. This is especially true for microorganisms that are difficult to cultivate, and are typically found in one sample5. Recent analysis of all genomes produced an unfinished draft of a Tree of Life. This includes a large number of archaea, bacteria and other organisms that have not yet been identified or their diversity is not thoroughly understood6. The expanded Tree of Life can be used to assess the biodiversity of a specific region and determine if specific habitats need special protection. This information can be utilized in a variety of ways, including identifying new drugs, combating diseases and improving the quality of crops. It is also beneficial for conservation efforts. It helps biologists determine the areas that are most likely to contain cryptic species with potentially important metabolic functions that could be at risk of anthropogenic changes. Although funds to protect biodiversity are essential, ultimately the best way to preserve the world's biodiversity is for more people in developing countries to be empowered with the knowledge to act locally to promote conservation from within. Phylogeny A phylogeny (also known as an evolutionary tree) depicts the relationships between different organisms. Using molecular data as well as morphological similarities and distinctions, or ontogeny (the course of development of an organism), scientists can build a phylogenetic tree which illustrates the evolutionary relationships between taxonomic groups. Phylogeny plays a crucial role in understanding genetics, biodiversity and evolution. A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that evolved from common ancestral. These shared traits could be analogous or homologous. Homologous traits share their evolutionary origins while analogous traits appear similar, but do not share the same ancestors. Scientists put similar traits into a grouping called a the clade. For instance, all the organisms in a clade have the characteristic of having amniotic egg and evolved from a common ancestor which had these eggs. The clades are then connected to form a phylogenetic branch that can determine the organisms with the closest relationship. For a more precise and accurate phylogenetic tree scientists use molecular data from DNA or RNA to identify the connections between organisms. This information is more precise than morphological data and provides evidence of the evolution background of an organism or group. The analysis of molecular data can help researchers determine the number of species that have an ancestor common to them and estimate their evolutionary age. The phylogenetic relationships of organisms can be affected by a variety of factors, including phenotypic plasticity an aspect of behavior that changes in response to specific environmental conditions. This can cause a trait to appear more similar to one species than to another and obscure 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. Additionally, phylogenetics aids determine the duration and speed of speciation. 에볼루션사이트 can aid conservation biologists in making choices about which species to save from extinction. In the end, it is the preservation of phylogenetic diversity that will result in an ecosystem that is complete and balanced. Evolutionary Theory The central theme in evolution is that organisms alter over time because of their interactions with their environment. A variety of theories about evolution have been developed by a wide variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing slowly according to its requirements, the Swedish botanist Carolus Linnaeus (1707-1778) who designed modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits can cause changes that can be passed onto offspring. 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, which defines how evolution happens through the variation of genes within a population and how those variations change in time as a result of natural selection. This model, which incorporates mutations, genetic drift as well as gene flow and sexual selection is mathematically described. Recent developments in the field of evolutionary developmental biology have demonstrated that genetic variation can be introduced into a species via genetic drift, mutation, and reshuffling of genes in sexual reproduction, as well as through migration between populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of a genotype over time), can lead to evolution that is defined as change in the genome of the species over time and the change in phenotype over time (the expression of that genotype in an individual). Incorporating evolutionary thinking into all areas of biology education can improve student understanding of the concepts of phylogeny and evolutionary. In a recent study by Grunspan and colleagues., it was shown that teaching students about the evidence for evolution boosted their acceptance of evolution during a college-level course in biology. To find out more about how to teach about evolution, please look up The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily A Framework for Infusing the Concept of Evolution into Life Sciences Education. Evolution in Action Scientists have traditionally studied evolution by looking in the past, studying 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, happening right now. Bacteria evolve and resist antibiotics, viruses reinvent themselves and escape new drugs, and animals adapt their behavior to the changing environment. The resulting changes are often visible. However, it wasn't until late 1980s that biologists realized that natural selection could be observed in action as well. The key to this is that different traits can confer an individual rate of survival and reproduction, and they can be passed on from one generation to the next. In the past when one particular allele, the genetic sequence that defines color in a group of interbreeding species, it could rapidly become more common than all other alleles. Over time, that would mean that the number of black moths within the 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 easier when a species has a rapid generation turnover, as with bacteria. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from one strain. Samples of each population have been taken regularly, and more than 50,000 generations of E.coli have been observed to have passed. Lenski's research has revealed that mutations can alter the rate of change and the efficiency at which a population reproduces. It also shows evolution takes time, a fact that is hard for some to accept. Microevolution is also evident in the fact that mosquito genes for resistance to pesticides are more common in populations where insecticides are used. This is because the use of pesticides creates a selective pressure that favors people who have resistant genotypes. The rapid pace of evolution taking place has led to an increasing recognition of its importance in a world that is shaped by human activities, including climate change, pollution and the loss of habitats that hinder many species from adjusting. Understanding the evolution process can help us make better decisions regarding the future of our planet, as well as the lives of its inhabitants.