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The Academy's Evolution Site Biology is one of the most important concepts in biology. The Academies have been active for a long time in helping people who are interested in science understand the concept of evolution and how it affects every area of scientific inquiry. This site provides students, teachers and general readers with a wide range of educational resources on 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 that symbolizes the interconnectedness of all life. It is a symbol of love and unity in many cultures. It has many practical applications in addition to providing a framework to understand the history of species, and how they respond to changes in environmental conditions. The first attempts at depicting the world of biology focused on separating species into distinct categories that were distinguished by physical and metabolic characteristics1. These methods, based on the sampling of various parts of living organisms or on small fragments of their DNA significantly increased the variety that could be represented in a tree of life2. However these trees are mainly made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4. In avoiding the necessity of direct experimentation and observation genetic techniques have made it possible to depict the Tree of Life in a more precise way. We can create trees by using molecular methods like the small-subunit ribosomal gene. Despite the dramatic growth of the Tree of Life through genome sequencing, a lot of biodiversity remains to be discovered. This is especially true of microorganisms that are difficult to cultivate and are often only present in a single specimen5. Recent analysis of all genomes resulted in an unfinished draft of a Tree of Life. This includes a large number of bacteria, archaea and other organisms that haven't yet been isolated, or whose diversity has not been thoroughly understood6. The expanded Tree of Life can be used to evaluate the biodiversity of a particular area and determine if particular habitats need special protection. This information can be used in a variety of ways, such as identifying new drugs, combating diseases and improving crops. It is also useful to conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species with potentially important metabolic functions that could be at risk from anthropogenic change. Although funds to protect biodiversity are crucial but the most effective 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 is also known as an evolutionary tree, shows the relationships between different groups of organisms. By using molecular information similarities and differences in morphology, or ontogeny (the process of the development of an organism) scientists can create a phylogenetic tree which illustrates the evolutionary relationship between taxonomic groups. Phylogeny is essential in understanding evolution, biodiversity and genetics. A basic phylogenetic tree (see Figure PageIndex 10 Finds the connections between organisms that have similar characteristics and have evolved from an ancestor with common traits. These shared traits can be analogous, or homologous. Homologous traits share their evolutionary roots, while analogous traits look like they do, but don't have the identical origins. Scientists group similar traits together into a grouping known as a clade. 무료 에볼루션 in a group share a characteristic, for example, amniotic egg production. They all evolved from an ancestor with these eggs. The clades are then linked to create a phylogenetic tree to identify organisms that have the closest relationship. For a more precise and precise phylogenetic tree scientists use molecular data from DNA or RNA to establish the connections between organisms. This information is more precise and gives evidence of the evolution of an organism. The use of molecular data lets researchers identify the number of organisms that share an ancestor common to them and estimate their evolutionary age. The phylogenetic relationships between species are influenced by many factors, including phenotypic plasticity an aspect of behavior that alters in response to unique environmental conditions. This can cause a trait to appear more resembling to one species than another which can obscure the phylogenetic signal. However, this issue can be cured by the use of techniques such as cladistics that combine analogous and homologous features into the tree. Additionally, phylogenetics can 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 which will create an ecosystem that is complete and balanced. Evolutionary Theory The main idea behind evolution is that organisms develop various characteristics 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 could evolve according to its individual requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who believed that the usage or non-use of traits can lead to changes that are passed on to the In the 1930s and 1940s, concepts from a variety of fields — including natural selection, genetics, and particulate inheritance — came together to form the modern synthesis of evolutionary theory, which defines how evolution occurs through the variation of genes within a population, and how those variations change over time as a result of natural selection. This model, which encompasses mutations, genetic drift in gene flow, and sexual selection is 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 genes during sexual reproduction, and also through migration between populations. These processes, in conjunction with others such as directional selection and gene erosion (changes in the frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time, as well as changes in phenotype (the expression of genotypes in individuals). Incorporating evolutionary thinking into all aspects of biology education can increase students' understanding of phylogeny as well as evolution. A recent study conducted by Grunspan and colleagues, for example, showed that teaching about the evidence for evolution helped students accept the concept of evolution in a college biology class. To find out more about how to teach about evolution, please see The Evolutionary Potential in all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education. Evolution in Action Scientists have studied evolution by looking in the past, analyzing fossils and comparing species. They also study living organisms. However, evolution isn't something that happened in the past; it's an ongoing process, happening in the present. Bacteria transform and resist antibiotics, viruses reinvent themselves and are able to evade new medications and animals change their behavior to the changing climate. The changes that result are often visible. But it wasn't until the late 1980s that biologists realized that natural selection can be observed in action as well. The key to this is that different traits confer the ability to survive at different rates as well as reproduction, and may be passed on from one generation to the next. In the past, if a certain allele – the genetic sequence that determines colour – was present in a population of organisms that interbred, it could be more common than other allele. As time passes, that could mean that the number of black moths in a 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 see evolution when the species, like bacteria, has a high generation turnover. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples from each population are taken on a regular basis, and over 500.000 generations have been observed. Lenski's research has revealed that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also proves that evolution is slow-moving, a fact that some find difficult to accept. Another example of microevolution is the way mosquito genes for resistance to pesticides appear more frequently in populations in which insecticides are utilized. This is because pesticides cause a selective pressure which favors individuals who have resistant genotypes. The speed at which evolution can take place has led to an increasing awareness of its significance in a world that is shaped by human activity, including climate changes, pollution and the loss of habitats that prevent many species from adjusting. Understanding the evolution process will aid you in making better decisions about the future of the planet and its inhabitants.