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The Academy's Evolution Site Biological evolution is one of the most important concepts in biology. The Academies are involved in helping those interested in the sciences comprehend the evolution theory and how it can be applied in all areas of scientific research. This site provides a wide range of sources for teachers, students and general readers of evolution. It contains the most important video clips from NOVA and WGBH's science programs on DVD. Tree of Life The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is an emblem of love and unity in many cultures. It also has important practical applications, such as providing a framework to understand the history of species and how they react to changes in the environment. The first attempts to depict the biological world were founded on categorizing organisms on their metabolic and physical characteristics. These methods, which relied on the sampling of different parts of living organisms or small DNA fragments, greatly increased the variety of organisms that could be represented in the tree of life2. These trees are mostly populated by eukaryotes, and bacteria are largely underrepresented3,4. In avoiding the necessity of direct observation and experimentation genetic techniques have made it possible to represent the Tree of Life in a more precise way. We can construct trees using molecular methods like the small-subunit ribosomal gene. Despite the dramatic expansion of the Tree of Life through genome sequencing, a lot of biodiversity awaits discovery. This is particularly true for microorganisms, which can be difficult to cultivate and are often only represented in a single specimen5. Recent analysis of all genomes resulted in a rough draft of a Tree of Life. This includes a wide range of bacteria, archaea and other organisms that have not yet been isolated or whose diversity has not been fully understood6. The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, which can help to determine if certain habitats require protection. click through the next site is useful in a variety of ways, such as identifying new drugs, combating diseases and improving crops. The information is also beneficial to conservation efforts. It can aid biologists in identifying areas that are likely to be home to cryptic species, which may have vital metabolic functions and be vulnerable to changes caused by humans. While funds to safeguard biodiversity are vital however, the most effective method to ensure the preservation of biodiversity around the world is for more people in developing countries to be empowered with the knowledge to take action locally to encourage conservation from within. Phylogeny A phylogeny (also called an evolutionary tree) shows the relationships between species. 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 evolutionary relationship between taxonomic categories. Phylogeny is essential in understanding evolution, biodiversity and genetics. A basic phylogenetic Tree (see Figure PageIndex 10 ) identifies the relationships between organisms with similar traits that have evolved from common ancestral. These shared traits can be homologous, or analogous. Homologous traits are similar in their evolutionary origins and analogous traits appear similar but do not have the same ancestors. Scientists organize similar traits into a grouping referred to as a Clade. All members of a clade have a common characteristic, like amniotic egg production. They all came from an ancestor who had these eggs. The clades are then linked to form a phylogenetic branch to identify organisms that have the closest relationship. Scientists utilize molecular DNA or RNA data to build a phylogenetic chart which is more precise and detailed. This information is more precise than the morphological data and provides evidence of the evolution background of an organism or group. Researchers can utilize Molecular Data to calculate the evolutionary age of organisms and determine how many organisms share the same ancestor. The phylogenetic relationships between species can be influenced by several factors, including phenotypic plasticity a type of behavior that alters in response to unique environmental conditions. This can make a trait appear more similar to one species than to another which can obscure the phylogenetic signal. This problem can be mitigated by using cladistics, which is a an amalgamation of homologous and analogous features in the tree. Additionally, phylogenetics aids determine the duration and rate of speciation. This information will assist conservation biologists in making decisions about which species to save from disappearance. In the end, it is the conservation of phylogenetic variety which will create 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. Several theories of evolutionary change have been proposed by a wide range of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing slowly according to its needs and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who developed modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits causes changes that could be passed on to offspring. In the 1930s and 1940s, theories from a variety of fields — including genetics, natural selection, and particulate inheritance – came together to create the modern synthesis of evolutionary theory, which defines how evolution is triggered by the variation of genes within a population and how those variants change over time due to natural selection. This model, known as genetic drift, mutation, gene flow and sexual selection, is a cornerstone of current evolutionary biology, and is mathematically described. Recent discoveries 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, and also by migration between populations. These processes, as well as others such as directional selection or genetic erosion (changes in the frequency of a genotype over time), can lead to evolution that is defined as changes in the genome of the species over time and the change in phenotype as time passes (the expression of the genotype in an individual). Incorporating evolutionary thinking into all aspects of biology education can improve student understanding of the concepts of phylogeny and evolutionary. In a recent study conducted by Grunspan and colleagues., it was shown that teaching students about the evidence for evolution increased their acceptance of evolution during a college-level course in biology. For more information on 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 through looking back in the past—analyzing fossils and comparing species. They also study living organisms. Evolution is not a distant event, but an ongoing process. Bacteria transform and resist antibiotics, viruses reinvent themselves and elude new medications and animals alter their behavior to the changing climate. The results are usually evident. However, it wasn't until late 1980s that biologists understood that natural selection could be observed in action as well. The key is the fact that different traits result in an individual rate of survival and reproduction, and they can be passed down from one generation to the next. In the past, when one particular allele, the genetic sequence that defines color in a population of interbreeding species, it could quickly become more prevalent than the other alleles. Over time, this would mean that the number of moths sporting black pigmentation could increase. The same is true for many other characteristics—including morphology and behavior—that vary among populations of organisms. Observing evolutionary change in action is easier when a particular species has a fast generation turnover, as with bacteria. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that are descended from a single strain. Samples of each population have been taken regularly, and more than 50,000 generations of E.coli have been observed to have passed. Lenski's research has revealed that mutations can drastically alter the speed at which a population reproduces—and so, the rate at which it alters. It also proves that evolution takes time, a fact that many are unable to accept. Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more common in populations where insecticides have been used. Pesticides create an exclusive pressure that favors those who have resistant genotypes. The rapid pace of evolution taking 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 prevent many species from adapting. Understanding evolution can help us make better decisions regarding the future of our planet, as well as the life of its inhabitants.