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The Academy's Evolution Site The concept of biological evolution is a fundamental concept in biology. The Academies are involved in helping those interested in science to learn about the theory of evolution and how it is permeated across all areas of scientific research. This site provides teachers, students and general readers with a range of learning resources about evolution. It contains key video clips from NOVA and WGBH produced science programs on DVD. Tree of Life The Tree of Life is an ancient symbol of the interconnectedness of all life. It is an emblem of love and unity in many cultures. It also has many practical uses, like providing a framework for understanding the history of species and how they respond to changing environmental conditions. Early attempts to represent the world of biology were founded on categorizing organisms on their physical and metabolic characteristics. These methods are based on the collection of various parts of organisms, or fragments of DNA, have greatly increased the diversity of a tree of Life2. However these trees are mainly composed of eukaryotes; bacterial diversity is not represented in a large way3,4. By avoiding the need for direct experimentation and observation genetic techniques have enabled us to represent the Tree of Life in a more precise manner. Particularly, molecular methods allow us to construct trees by using sequenced markers, such as the small subunit of ribosomal RNA gene. Despite the dramatic growth of the Tree of Life through genome sequencing, a large amount of biodiversity remains to be discovered. This is especially relevant to microorganisms that are difficult to cultivate and are usually found in one sample5. Recent analysis of all genomes produced an initial draft of a Tree of Life. This includes a large number of archaea, bacteria, and other organisms that haven't yet been isolated or the diversity of which is not thoroughly understood6. The expanded Tree of Life can be used to assess the biodiversity of a particular area and determine if specific habitats require special protection. This information can be utilized in a variety of ways, including finding new drugs, battling diseases and enhancing crops. The information is also useful in conservation efforts. It helps biologists discover areas that are likely to be home to cryptic species, which could have vital metabolic functions and be vulnerable to changes caused by humans. While funds to protect biodiversity are important, the best way to conserve the world's biodiversity is to empower more people in developing countries with the necessary knowledge to take action locally and encourage conservation. Phylogeny A phylogeny (also called an evolutionary tree) depicts the relationships between organisms. Scientists can construct an phylogenetic chart which shows the evolution of taxonomic groups using molecular data and morphological similarities or differences. The phylogeny of a tree plays an important role in understanding the relationship between genetics, biodiversity and evolution. A basic phylogenetic Tree (see Figure PageIndex 10 ) identifies the relationships between organisms that share similar traits that have evolved from common ancestors. These shared traits can be homologous, or analogous. Homologous traits share their evolutionary roots and analogous traits appear similar, but do not share the identical origins. Scientists group similar traits into a grouping known as a clade. For example, all of the species in a clade share the trait of having amniotic egg and evolved from a common ancestor that had these eggs. A phylogenetic tree is then built by connecting the clades to determine the organisms who are the closest to each other. Scientists make use of DNA or RNA molecular data to create a phylogenetic chart that is more accurate and precise. This data is more precise than the morphological data and provides evidence of the evolution background of an organism or group. The analysis of molecular data can help researchers identify the number of species that have the same ancestor and estimate their evolutionary age. Phylogenetic relationships can be affected by a number of factors such as phenotypicplasticity. This is a kind of behavior that alters as a result of particular environmental conditions. This can cause a trait to appear more similar to one species than other species, which can obscure the phylogenetic signal. This problem can be mitigated by using cladistics, which is a the combination of analogous and homologous features in the tree. Furthermore, phylogenetics may help predict the time and pace of speciation. This information can aid conservation biologists to make decisions about the species they should safeguard from the threat of extinction. In the end, it's the preservation of phylogenetic diversity that will create a complete and balanced ecosystem. Evolutionary Theory The central theme in evolution is that organisms change over time due to their interactions with their environment. Many scientists have developed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism would evolve according to its own needs and needs, 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 certain traits can result in changes that can be passed on to future generations. In the 1930s and 1940s, ideas from a variety of fields—including genetics, natural selection, and particulate inheritance — came together to form the current evolutionary theory, which defines how evolution is triggered by the variation of genes within a population and how those variations change over time as a result of natural selection. This model, known as genetic drift mutation, gene flow, and sexual selection, is a cornerstone of modern evolutionary biology and can be mathematically described. Recent developments in the field of evolutionary developmental biology have revealed that variations can be introduced into a species via mutation, genetic drift and reshuffling of genes in sexual reproduction, as well as through the movement of populations. These processes, in conjunction with others, such as directionally-selected selection and erosion of genes (changes in the 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 within individuals). Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking throughout all aspects of biology. In a recent study conducted by Grunspan and colleagues. It was demonstrated that teaching students about the evidence for evolution boosted their understanding of evolution in an undergraduate biology course. To learn more about how to teach about evolution, read 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 studied evolution through looking back in the past—analyzing fossils and comparing species. They also observe living organisms. But 에볼루션 사이트 isn't just something that happened in the past. It's an ongoing process that is happening in the present. Viruses reinvent themselves to avoid new medications and bacteria mutate to resist antibiotics. Animals alter their behavior as a result of a changing environment. The changes that result are often apparent. It wasn't until late 1980s that biologists understood that natural selection can be observed in action as well. The reason is that different traits confer different rates of survival and reproduction (differential fitness), and can be passed from one generation to the next. In the past, if an allele – the genetic sequence that determines colour appeared in a population of organisms that interbred, it might become more common than any other allele. In time, this could 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 a species, such as bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from one strain. The samples of each population have been collected 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 effectiveness at which a population reproduces. It also shows that evolution takes time—a fact that some find difficult to accept. Microevolution is also evident in the fact that mosquito genes that confer resistance to pesticides are more common in populations that have used insecticides. This is due to the fact that the use of pesticides creates a selective pressure that favors those 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 prevent many species from adjusting. Understanding the evolution process can help us make smarter decisions regarding the future of our planet, as well as the lives of its inhabitants.