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The Academy's Evolution Site Biology is a key concept in biology. The Academies are involved in helping those interested in science to understand evolution theory and how it is incorporated throughout all fields of scientific research. This site provides students, teachers and general readers with a variety of learning resources about evolution. It also includes important 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 life. It is seen in a variety of religions and cultures as symbolizing unity and love. It can be used in many practical ways as well, such as providing a framework for understanding the evolution of species and how they respond to changing environmental conditions. Early attempts to describe the world of biology were founded on categorizing organisms on their metabolic and physical characteristics. These methods, which depend on the collection of various parts of organisms or short DNA fragments, have significantly increased the diversity of a tree of Life2. However these trees are mainly composed of eukaryotes; bacterial diversity remains vastly underrepresented3,4. By avoiding the need for direct observation and experimentation genetic techniques have enabled us to depict the Tree of Life in a much more accurate way. In particular, molecular methods allow us to construct trees using sequenced markers like the small subunit of ribosomal RNA gene. The Tree of Life has been greatly expanded thanks to genome sequencing. However, there is still much biodiversity to be discovered. This is especially true for microorganisms that are difficult to cultivate, and which are usually only present in a single sample5. A recent analysis of all known genomes has produced a rough draft version of the Tree of Life, including many archaea and bacteria that have not been isolated and their diversity is not fully understood6. The expanded Tree of Life can be used to evaluate the biodiversity of a specific area and determine if particular habitats need special protection. This information can be utilized in a variety of ways, from identifying new medicines to combating disease to improving crop yields. The information is also beneficial to conservation efforts. It can aid biologists in identifying areas most likely to be home to species that are cryptic, which could perform important metabolic functions and be vulnerable to human-induced change. While funding to protect biodiversity are important, the most effective method to preserve the world's biodiversity is to equip more people in developing countries with the knowledge they need to act locally and promote conservation. Phylogeny A phylogeny (also known as an evolutionary tree) depicts the relationships between different organisms. Scientists can create an phylogenetic chart which shows the evolutionary relationship of taxonomic categories using molecular information and morphological similarities or differences. The phylogeny of a tree plays an important role in understanding genetics, biodiversity and evolution. A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms that have similar characteristics and have evolved from a common ancestor. These shared traits can be analogous or homologous. Homologous traits are similar in their underlying evolutionary path, while analogous traits look similar but do not have the same origins. Scientists group similar traits together into a grouping referred to as a the clade. For example, all of the species in a clade share the trait of having amniotic egg and evolved from a common ancestor who had eggs. The clades are then connected to form a phylogenetic branch that can determine which organisms have the closest relationship. To create a more thorough and accurate phylogenetic tree, scientists rely on molecular information from DNA or RNA to identify the connections between organisms. This information is more precise than morphological data and provides evidence of the evolution history of an organism or group. The use of molecular data lets researchers identify the number of organisms that have the same ancestor and estimate their evolutionary age. The phylogenetic relationships of a species can be affected by a number of factors such as phenotypicplasticity. This is a kind of behaviour that can change as a result of unique environmental conditions. This can make a trait appear more resembling to one species than to the other which can obscure the phylogenetic signal. This problem can be mitigated by using cladistics, which is a an amalgamation of homologous and analogous traits in the tree. Additionally, phylogenetics aids predict the duration and rate at which speciation occurs. This information can aid conservation biologists to make decisions about the species they should safeguard from extinction. In the end, it's the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced. Evolutionary Theory The fundamental concept in evolution is that organisms change over time as a result of their interactions with their environment. Many theories of evolution have been developed by a variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve slowly according to its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits cause changes that can be passed on to the offspring. In the 1930s & 1940s, concepts from various areas, including genetics, natural selection, and particulate inheritance, merged to create a modern synthesis of evolution theory. This defines how evolution is triggered by the variation in genes within the population and how these variants alter over time due to natural selection. This model, called genetic drift or mutation, gene flow and sexual selection, is a cornerstone of the current evolutionary biology and can be mathematically explained. Recent developments in the field of evolutionary developmental biology have revealed that genetic variation can be introduced into a species by mutation, genetic drift and reshuffling of genes in sexual reproduction, as well as through migration between populations. 에볼루션 바카라사이트 , along with others such as directional selection and gene erosion (changes in frequency of genotypes over time) can lead to evolution. Evolution is defined by changes in the genome over time and 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 and evolutionary. A recent study by Grunspan and colleagues, for example revealed that teaching students about the evidence for evolution helped students accept the concept of evolution in a college biology class. For more information on how to teach evolution, see The Evolutionary Potency in all Areas of Biology or Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education. Evolution in Action Traditionally, scientists have studied evolution through looking back—analyzing fossils, comparing species, and studying living organisms. Evolution is not a distant event, but an ongoing process. Viruses evolve to stay away from new medications and bacteria mutate to resist antibiotics. Animals alter their behavior in the wake of a changing world. The results are often visible. However, it wasn't until late 1980s that biologists realized that natural selection could be seen in action, as well. The key is the fact that different traits result in an individual rate of survival as well as reproduction, and may be passed down from one generation to the next. In the past, when one particular allele – the genetic sequence that controls coloration – was present in a population of interbreeding organisms, it could quickly become more prevalent than all other alleles. In time, this could mean that 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 evolutionary change when the species, like bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that are descended from one strain. The samples of each population have been collected frequently and more than 50,000 generations of E.coli have passed. Lenski's research has shown that mutations can drastically alter the rate at the rate at which a population reproduces, and consequently the rate at which it alters. It also proves that evolution takes time—a fact that some are unable to accept. Another example of microevolution is the way mosquito genes for resistance to pesticides show up more often in populations where insecticides are employed. Pesticides create a selective pressure which favors those who have resistant genotypes. The rapidity of evolution has led to an increasing awareness of its significance, especially in a world that is largely shaped by human activity. This includes pollution, climate change, and habitat loss, which prevents many species from adapting. Understanding evolution can aid you in making better decisions about the future of our planet and its inhabitants.