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The Academy's Evolution Site Biology is a key concept in biology. The Academies have been active for a long time in helping people who are interested in science understand the theory of evolution and how it permeates every area of scientific inquiry. This site offers a variety of sources for students, teachers, and general readers on evolution. It has important video clips from NOVA and WGBH-produced science programs on DVD. Tree of Life The Tree of Life is an ancient symbol that represents the interconnectedness of life. It appears in many religions and cultures as an emblem of unity and love. It also has practical uses, like providing a framework for understanding the history of species and how they react to changes in the environment. The earliest attempts to depict the world of biology focused on separating organisms into distinct categories which had been distinguished by their physical and metabolic characteristics1. These methods are based on the collection of various parts of organisms, or DNA fragments, have greatly increased the diversity of a Tree of Life2. However, these trees are largely comprised of eukaryotes, and bacterial diversity is still largely unrepresented3,4. Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular methods enable us to create trees using sequenced markers, such as the small subunit ribosomal gene. The Tree of Life has been significantly expanded by genome sequencing. However, there is still much diversity to be discovered. This is particularly true for microorganisms that are difficult to cultivate and are typically found in one sample5. A recent study of all genomes that are known has produced a rough draft version of the Tree of Life, including many bacteria and archaea that are not isolated and which are not well understood. The expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine whether specific habitats require protection. This information can be utilized in a variety of ways, from identifying new treatments to fight disease to enhancing the quality of crops. It is also valuable for conservation efforts. It helps biologists discover areas that are likely to be home to cryptic species, which could have vital metabolic functions and be vulnerable to changes caused by humans. Although funding to protect biodiversity are essential, ultimately the best way to preserve the world's biodiversity is for more people living in developing countries to be empowered with the knowledge to act locally to promote conservation from within. Phylogeny A phylogeny (also known as an evolutionary tree) depicts the relationships between species. Using molecular data as well as morphological similarities and distinctions or ontogeny (the process of the development of an organism) scientists can create an phylogenetic tree that demonstrates the evolutionary relationships between taxonomic categories. The role of phylogeny is crucial in understanding the relationship between genetics, biodiversity and evolution. 에볼루션 코리아 (see Figure PageIndex 10 Finds the connections between organisms with similar traits and have evolved from an ancestor with common traits. These shared traits can be analogous or homologous. Homologous traits are similar in terms of their evolutionary paths. 에볼루션 코리아 may look like they are but they don't have the same origins. Scientists put similar traits into a grouping called a clade. For example, all of the species in a clade have the characteristic of having amniotic eggs and evolved from a common ancestor which had these eggs. A phylogenetic tree can be built by connecting the clades to determine the organisms that are most closely related to one another. To create a more thorough and accurate phylogenetic tree, scientists make use of molecular data from DNA or RNA to identify the relationships among organisms. This information is more precise and provides evidence of the evolution history of an organism. The analysis of molecular data can help researchers identify the number of organisms who share an ancestor common to them and estimate their evolutionary age. The phylogenetic relationship can be affected by a variety of factors that include the phenotypic plasticity. This is a type behaviour that can change in response to particular environmental conditions. This can cause a trait to appear more like a species another, clouding the phylogenetic signal. However, this problem can be reduced by the use of methods like cladistics, which incorporate a combination of similar and homologous traits into the tree. In addition, phylogenetics can aid in predicting the time and pace of speciation. This information can assist conservation biologists in making choices about which species to safeguard from extinction. In the end, it's the conservation of phylogenetic diversity which will create an ecosystem that is complete and balanced. Evolutionary Theory The fundamental concept of evolution is that organisms develop various characteristics over time as a result of their interactions with their surroundings. Many scientists have come up with theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that a living thing would evolve according to its individual requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical system of taxonomy and Jean-Baptiste Lamarck (1844-1829), who suggested that the use or absence of traits can lead to changes that are passed on to the next generation. In the 1930s and 1940s, ideas from a variety of fields—including genetics, natural selection, and particulate inheritance—came together to create the modern synthesis of evolutionary theory which explains how evolution occurs through the variations of genes within a population, and how those variants change over time as a result of natural selection. This model, which includes mutations, genetic drift, gene flow and sexual selection can be mathematically described mathematically. Recent advances in the field of evolutionary developmental biology have revealed how variations can be introduced to a species through genetic drift, mutations or reshuffling of genes in sexual reproduction and the movement between populations. These processes, in conjunction with others such as directional selection and gene erosion (changes to the frequency of genotypes over time), can lead towards evolution. Evolution is defined by changes in the genome over time as well as changes in the phenotype (the expression of genotypes within individuals). Incorporating evolutionary thinking into all aspects of biology education can improve students' understanding of phylogeny and evolutionary. In a study by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution boosted their acceptance of evolution during an undergraduate biology course. 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 Scientists have studied evolution through looking back in the past, studying fossils, and comparing species. They also study living organisms. But evolution isn't a thing that happened in the past. It's an ongoing process happening right now. Bacteria mutate and resist antibiotics, viruses reinvent themselves and elude new medications, and animals adapt their behavior to a changing planet. The changes that occur are often apparent. But it wasn't until the late-1980s that biologists realized that natural selection can be observed in action as well. The key is that various characteristics result in different rates of survival and reproduction (differential fitness), and can be passed from one generation to the next. In the past, if one particular allele, the genetic sequence that controls coloration – was present in a population of interbreeding organisms, it might quickly become more common than the other alleles. As time passes, that could mean the number of black moths in a particular population could rise. 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 rapid generation turnover such as bacteria. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from a single strain. The samples of each population were taken regularly and more than 50,000 generations of E.coli have been observed to have passed. Lenski's research has shown 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, a fact that is hard for some to accept. Another example of microevolution is that mosquito genes that confer resistance to pesticides are more prevalent in populations in which insecticides are utilized. This is due to pesticides causing an exclusive pressure that favors individuals who have resistant genotypes. The rapidity of evolution has led to a growing appreciation of its importance, especially in a world which is largely shaped by human activities. This includes pollution, climate change, and habitat loss that hinders many species from adapting. Understanding the evolution process can help us make better choices about the future of our planet, and the life of its inhabitants.