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The Academy's Evolution Site Biology is one of the most central concepts in biology. The Academies have long been involved in helping people who are interested in science understand the concept of evolution and how it permeates every area of scientific inquiry. This site provides a range of sources for students, teachers and general readers of evolution. It has the most important video clips from NOVA and the WGBH-produced science programs on DVD. Tree of Life The Tree of Life is an ancient symbol that symbolizes the interconnectedness of all life. It appears in many religions and cultures as an emblem of unity and love. It also has important practical uses, like providing a framework to understand the evolution of species and how they respond to changing environmental conditions. Early attempts to describe the biological world were based on categorizing organisms based on their physical and metabolic characteristics. These methods are based on the sampling of different parts of organisms, or DNA fragments, have greatly increased the diversity of a Tree of Life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity is not represented in a large way3,4. By avoiding the need for direct experimentation and observation, genetic techniques have made it possible to represent the Tree of Life in a more precise way. We can create trees by using molecular methods such as the small subunit ribosomal gene. Despite the rapid growth of the Tree of Life through genome sequencing, a lot of biodiversity remains to be discovered. This is particularly true of microorganisms, which can be difficult to cultivate and are often only found in a single specimen5. A recent study of all known genomes has produced a rough draft of the Tree of Life, including many bacteria and archaea that have not been isolated and which are not well understood. This expanded Tree of Life can be used to evaluate the biodiversity of a specific region and determine if specific habitats require special protection. This information can be utilized in a variety of ways, from identifying new treatments to fight disease to enhancing crop yields. It is also beneficial to conservation efforts. It can help biologists identify areas that are likely to be home to cryptic species, which could have important metabolic functions and are susceptible to human-induced change. While conservation funds are essential, the best method to preserve the world's biodiversity is to equip more people in developing countries with the necessary knowledge to take action locally and encourage conservation. Phylogeny A phylogeny is also known as an evolutionary tree, reveals the connections between different groups of organisms. Utilizing 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 that illustrates the evolution of taxonomic groups. The role of phylogeny is crucial in understanding the relationship between genetics, biodiversity and evolution. A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms with similar characteristics and have evolved from a common ancestor. These shared traits could be analogous, or homologous. Homologous traits are identical in their evolutionary roots and analogous traits appear similar but do not have the same ancestors. Scientists arrange similar traits into a grouping known as a the clade. For instance, all the organisms that make up a clade share the trait of having amniotic egg and evolved from a common ancestor which had eggs. The clades then join to form a phylogenetic branch that can determine the organisms with the closest connection to each other. To create a more thorough and accurate phylogenetic tree, scientists use molecular data from DNA or RNA to identify the relationships between organisms. This information is more precise and provides evidence of the evolution history of an organism. Researchers can use Molecular Data to determine the evolutionary age of organisms and identify the number of organisms that have an ancestor common to all. The phylogenetic relationships of organisms are influenced by many factors, including phenotypic plasticity an aspect of behavior that changes in response to specific environmental conditions. This can cause a characteristic to appear more similar to one species than to another which can obscure the phylogenetic signal. However, this issue can be reduced by the use of techniques such as cladistics that include a mix of similar and homologous traits into the tree. Additionally, phylogenetics can help predict the duration and rate of speciation. This information can help conservation biologists make decisions about the species they should safeguard from the threat of extinction. In the end, it is the preservation of phylogenetic diversity that will result in an ecosystem that is balanced and complete. Evolutionary Theory The fundamental concept in evolution is that organisms alter over time because of 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 would evolve according to its own requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern taxonomy system that is hierarchical as well as Jean-Baptiste Lamarck (1844-1829), who believed that the usage or non-use of certain traits can result in changes that are passed on to the In the 1930s and 1940s, concepts from various fields, including natural selection, genetics & particulate inheritance, came together to form a modern synthesis of evolution theory. This defines how evolution occurs by the variations in genes within the population, and how these variations change over time as a result of natural selection. This model, called genetic drift, mutation, gene flow, and sexual selection, is the foundation of current evolutionary biology, and can be mathematically explained. Recent developments in the field of evolutionary developmental biology have shown that variation can be introduced into a species through mutation, genetic drift, and reshuffling genes during sexual reproduction, as well as through the movement of populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution, which is defined by change in the genome of the species over time, and also the change in phenotype as time passes (the expression of that genotype within the individual). Incorporating evolutionary thinking into all aspects of biology education could increase students' understanding of phylogeny and evolutionary. In a recent study by Grunspan and colleagues., it was shown that teaching students about the evidence for evolution increased their understanding of evolution in a college-level course in biology. For more information on how to teach about evolution, please look up The Evolutionary Potential of 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—analyzing fossils, comparing species and studying living organisms. Evolution is not a past event; it is an ongoing process that continues to be observed today. Viruses reinvent themselves to avoid new medications and bacteria mutate to resist antibiotics. Animals adapt their behavior in the wake of the changing environment. The results are often apparent. It wasn't until late 1980s when biologists began to realize that natural selection was in action. The main reason is that different traits can confer an individual rate of survival and reproduction, and can be passed down from generation to generation. In the past when one particular allele—the genetic sequence that controls coloration – was present in a group of interbreeding species, it could rapidly become more common than all other alleles. 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 evolution when the species, like bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from one strain. The samples of each population have been collected regularly, and more than 500.000 generations of E.coli have passed. Lenski's research has revealed that mutations can alter the rate of change and the efficiency of a population's reproduction. It also shows that evolution takes time, a fact that many find hard to accept. Microevolution can be observed in the fact that mosquito genes that confer resistance to pesticides are more prevalent in populations where insecticides have been used. This is because pesticides cause a selective pressure which favors those who have resistant genotypes. The speed at which evolution takes place has led to an increasing recognition of its importance in a world that is shaped by human activity—including climate change, pollution and the loss of habitats that hinder the species from adapting. Understanding 에볼루션 바카라 체험 will aid you in making better decisions about the future of the planet and its inhabitants.