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The Academy's Evolution Site The concept of biological evolution is a fundamental concept in biology. The Academies have long been involved in helping people who are interested in science understand the concept of evolution and how it influences all areas of scientific exploration. This site provides teachers, students and general readers with a range of educational resources on evolution. It includes key video clip from NOVA and WGBH produced science programs on DVD. 에볼루션 슬롯게임 of Life The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is seen in a variety of spiritual traditions and cultures as symbolizing unity and love. It has many practical applications as well, such as providing a framework to understand the evolution of species and how they respond to changing environmental conditions. The earliest attempts to depict the world of biology focused on categorizing organisms into distinct categories that had been distinguished by their physical and metabolic characteristics1. These methods are based on the sampling of different parts of organisms or fragments of DNA, have greatly increased the diversity of a tree of Life2. These trees are largely composed by eukaryotes, and bacteria are largely underrepresented3,4. By avoiding the need for direct experimentation and observation, genetic techniques have enabled us to represent the Tree of Life in a more precise way. Trees can be constructed using molecular methods such as the small subunit ribosomal gene. The Tree of Life has been dramatically expanded through genome sequencing. However, there is still much diversity to be discovered. This is especially the case for microorganisms which are difficult to cultivate, and are typically found 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 which are not well understood. This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, helping to determine whether specific habitats require special protection. The information can be used in a variety of ways, from identifying the most effective remedies to fight diseases to enhancing crop yields. It is also beneficial in conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species that could have important metabolic functions that could be at risk of anthropogenic changes. Although funds to protect biodiversity are essential, ultimately the best way to ensure the preservation of biodiversity around the world 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 known as an evolutionary tree, shows the connections between various groups of organisms. Using molecular data as well as morphological similarities and distinctions or ontogeny (the process of the development of an organism), scientists can build a phylogenetic tree which illustrates the evolution of taxonomic categories. 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 ) is a method of identifying the relationships between organisms with similar traits that evolved from common ancestors. These shared traits may be analogous or homologous. Homologous characteristics are identical in their evolutionary journey. Analogous traits might appear like they are however they do not have the same origins. Scientists combine similar traits into a grouping called a clade. All organisms in a group have a common characteristic, for example, amniotic egg production. They all evolved from an ancestor who had these eggs. A phylogenetic tree is constructed by connecting the clades to identify the species that are most closely related to one another. For a more precise and accurate phylogenetic tree scientists use molecular data from DNA or RNA to establish the relationships between organisms. This information is more precise than morphological information and gives evidence of the evolutionary background of an organism or group. The analysis of molecular data can help researchers determine the number of species who share a common ancestor and to estimate their evolutionary age. The phylogenetic relationships of a species can be affected by a number of factors that include phenotypicplasticity. This is a type of behavior that changes as a result of unique environmental conditions. This can cause a trait to appear more resembling to one species than to another which can obscure the phylogenetic signal. However, this problem can be cured by the use of techniques such as cladistics that combine similar and homologous traits into the tree. Additionally, phylogenetics can help predict the duration and rate of speciation. This information can aid conservation biologists to decide which species to protect from extinction. In the end, it's the conservation of phylogenetic variety that will result in an ecosystem that is complete and balanced. Evolutionary Theory The fundamental concept in evolution is that organisms change over time due to their interactions with their environment. Many scientists have come up with theories of evolution, such as 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 developed the modern hierarchical system of taxonomy and Jean-Baptiste Lamarck (1844-1829), who believed that the use or absence of traits can lead to changes that are passed on to the In the 1930s & 1940s, ideas from different fields, including natural selection, genetics & particulate inheritance, were brought together to form a modern theorizing of evolution. This explains how evolution happens through the variation in genes within the population, and how these variations alter over time due to natural selection. This model, which includes mutations, genetic drift as well as gene flow and sexual selection can be mathematically described. Recent advances in the field of evolutionary developmental biology have shown the ways in which variation can be introduced to a species through genetic drift, mutations or reshuffling of genes in sexual reproduction and the movement between populations. These processes, along with other ones like directional selection and genetic erosion (changes in the frequency of the genotype over time), can lead to evolution, which is defined by changes in the genome of the species over time, and the change in phenotype as time passes (the expression of the genotype in the individual). Students can better understand phylogeny by incorporating evolutionary thinking throughout all areas of biology. A recent study by Grunspan and colleagues, for instance demonstrated that teaching about the evidence supporting evolution increased students' understanding of evolution in a college biology class. 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 into Life Sciences Education. Evolution in Action Traditionally, scientists have studied evolution by looking back, studying fossils, comparing species and studying living organisms. Evolution is not a distant event; it is an ongoing process that continues to be observed today. Viruses reinvent themselves to avoid new antibiotics and bacteria transform to resist antibiotics. Animals adapt their behavior because of a changing environment. The results are usually easy to see. It wasn't until the 1980s that biologists began realize that natural selection was in action. The key to this is that different traits confer an individual rate of survival and reproduction, and they can be passed on from one generation to another. In the past, if one allele – the genetic sequence that determines colour – was found in a group of organisms that interbred, it could become more prevalent than any other allele. Over time, that would mean the number of black moths within a particular population could rise. The same is true for many other characteristics—including morphology and behavior—that vary among populations of organisms. It is easier to track evolutionary change when the species, like bacteria, has a rapid generation turnover. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples of each population are taken on a regular basis, and over 500.000 generations have been observed. Lenski's research has revealed that mutations can drastically alter the speed at which a population reproduces and, consequently the rate at which it changes. It also proves that evolution is slow-moving, a fact that many find difficult to accept. Another example of microevolution is how mosquito genes that confer resistance to pesticides are more prevalent in populations in which insecticides are utilized. Pesticides create an enticement that favors those who have resistant genotypes. The rapid pace of evolution taking place has led to a growing awareness of its significance in a world that is shaped by human activity, including climate changes, pollution and the loss of habitats that hinder the species from adapting. Understanding the evolution process will aid you in making better decisions about the future of our planet and its inhabitants.