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The Academy's Evolution Site Biological evolution is one of the most central concepts in biology. The Academies are involved in helping those who are interested in the sciences understand evolution theory and how it is incorporated in all areas of scientific research. This site offers a variety of tools for teachers, students, and general readers on 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 across many cultures. It also has important practical uses, like providing a framework to understand the history of species and how they respond to changes in environmental conditions. Early attempts to describe the world of biology were built on categorizing organisms based on their physical and metabolic characteristics. These methods, based on sampling of different parts of living organisms, or sequences of small fragments of their DNA, significantly increased the variety that could be represented in the tree of life2. These trees are largely composed of eukaryotes, while bacterial diversity is vastly underrepresented3,4. Genetic techniques have greatly broadened our ability to represent the Tree of Life by circumventing the requirement for direct observation and experimentation. Trees can be constructed by using molecular methods like the small-subunit ribosomal gene. The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of diversity to be discovered. This is especially true of microorganisms that are difficult to cultivate and are usually only found in a single specimen5. A recent study of all genomes known to date has produced a rough draft version of the Tree of Life, including a large number of bacteria and archaea that have not been isolated, and which are not well understood. The expanded Tree of Life can be used to assess the biodiversity of a specific region and determine if particular habitats require special protection. This information can be utilized in a variety of ways, from identifying new remedies to fight diseases to enhancing the quality of crops. This information is also beneficial to conservation efforts. It can help biologists identify areas most likely to have cryptic species, which could have important metabolic functions and be vulnerable to the effects of human activity. While conservation funds are essential, the best method to preserve the world's biodiversity is to empower the people of developing nations with the knowledge they need to act locally and promote conservation. Phylogeny A phylogeny (also called an evolutionary tree) illustrates the relationship between different organisms. Using molecular data as well as morphological similarities and distinctions, or ontogeny (the course of development of an organism) scientists can create an phylogenetic tree that demonstrates the evolution of taxonomic categories. Phylogeny is essential in understanding the evolution of biodiversity, evolution and genetics. A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms that share similar traits that have evolved from common ancestors. These shared traits could be homologous, or analogous. Homologous traits are similar in their evolutionary origins while analogous traits appear similar, but do not share the identical origins. Scientists group similar traits into a grouping called a Clade. Every organism in a group have a common trait, such as amniotic egg production. They all came from an ancestor with these eggs. A phylogenetic tree is constructed by connecting 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 identify the connections between organisms. This information 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 determine the number of species that have a common ancestor and to estimate their evolutionary age. The phylogenetic relationships of a species can be affected by a number of factors such as the phenotypic plasticity. This is a type of behavior that changes due to particular environmental conditions. This can cause a particular trait to appear more similar to one species than other species, which can obscure the phylogenetic signal. However, this problem can be cured by the use of methods such as cladistics which combine analogous and homologous features into the tree. Additionally, phylogenetics aids predict the duration and rate of speciation. This information can assist conservation biologists in making decisions about which species to safeguard from disappearance. In the end, it's the preservation of phylogenetic diversity that will lead to an ecologically balanced and complete ecosystem. Evolutionary Theory The main idea behind evolution is that organisms develop distinct characteristics over time as a result of their interactions with their environments. 에볼루션바카라사이트 of evolution have been developed by a wide variety of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing gradually according to its requirements, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that could be passed on to offspring. In the 1930s & 1940s, theories from various areas, including natural selection, genetics & particulate inheritance, merged to create a modern evolutionary theory. This describes how evolution is triggered by the variations in genes within the population and how these variants change with time due to natural selection. This model, which incorporates mutations, genetic drift as well as gene flow and sexual selection, can be mathematically described. Recent discoveries in the field of evolutionary developmental biology have demonstrated how variations can be introduced to a species via mutations, genetic drift, reshuffling genes during sexual reproduction, and even migration between populations. These processes, along with other ones like directional selection and genetic erosion (changes in the frequency of a genotype over time) can result in evolution which is defined by change in the genome of the species over time and also by changes in phenotype as time passes (the expression of that genotype in the individual). Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking in all aspects of biology. In a recent study by Grunspan and colleagues. It was demonstrated that teaching students about the evidence for evolution boosted their understanding of evolution in a college-level course in biology. To learn 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 Traditionally, scientists have studied evolution through studying fossils, comparing species and studying living organisms. Evolution is not a past event, but an ongoing process. Bacteria mutate and resist antibiotics, viruses reinvent themselves and elude new medications and animals change their behavior in response to a changing planet. The changes that result are often apparent. It wasn't until late 1980s that biologists realized that natural selection could be seen in action, as well. The main reason is that different traits confer an individual rate of survival and reproduction, and they can be passed on from generation to generation. In the past when one particular allele – the genetic sequence that controls coloration – was present in a population of interbreeding organisms, it might quickly become more prevalent than other alleles. In time, this could mean that the number of moths with black pigmentation in a group may increase. The same is true for many other characteristics—including morphology and behavior—that vary among populations of organisms. The ability to observe evolutionary change is easier when a particular species has a fast generation turnover such as bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from a single strain. Samples from each population have been taken frequently and more than 500.000 generations of E.coli have passed. Lenski's research has revealed that a mutation can dramatically alter the speed at which a population reproduces—and so the rate at which it changes. It also shows that evolution takes time, which is hard for some to accept. Microevolution can also be seen in the fact that mosquito genes that confer resistance to pesticides are more common in populations where insecticides have been used. 에볼루션카지노 create an enticement that favors individuals who have resistant genotypes. The rapidity of evolution has led to an increasing appreciation of its importance especially in a planet that is largely shaped by human activity. This includes pollution, climate change, and habitat loss, which prevents many species from adapting. Understanding 바카라 에볼루션 will assist you in making better choices about the future of our planet and its inhabitants.