mouthegg51

The Academy's Evolution Site The concept of biological evolution is a fundamental concept in biology. The Academies are involved in helping those interested in science learn about the theory of evolution and how it can be applied in all areas of scientific research. This site provides a range of tools for teachers, students, and general readers on evolution. It also includes important video clips from NOVA and WGBH produced science programs on DVD. Tree of Life The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is a symbol of love and unity in many cultures. It also has practical applications, such as providing a framework to understand the evolution of species and how they respond to changes in environmental conditions. The first attempts at depicting the world of biology focused on separating organisms into distinct categories that were distinguished by their physical and metabolic characteristics1. These methods, which are based on the sampling of different parts of organisms or DNA fragments, have greatly increased the diversity of a Tree of Life2. These trees are mostly populated of eukaryotes, while bacterial diversity is vastly underrepresented3,4. In avoiding the necessity of direct experimentation and observation, genetic techniques have enabled us to depict the Tree of Life in a more precise manner. In particular, molecular methods allow us to construct trees by using sequenced markers like the small subunit ribosomal RNA gene. The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of biodiversity to be discovered. This is particularly true for microorganisms, which are difficult to cultivate and are typically only represented in a single sample5. Recent analysis of all genomes produced an initial draft of a Tree of Life. This includes a large number of archaea, bacteria, and other organisms that have not yet been identified or whose diversity has not been fully understood6. The expanded Tree of Life is particularly useful in assessing the diversity of an area, assisting to determine if certain habitats require special protection. This information can be used in a range of ways, from identifying new remedies to fight diseases to enhancing the quality of the quality of crops. It is also valuable to conservation efforts. It helps biologists discover areas most likely to be home to cryptic species, which could have vital metabolic functions and are susceptible to changes caused by humans. While funds to protect biodiversity are important, the most effective method to preserve the world's biodiversity is to equip more people in developing countries with the necessary knowledge to act locally and promote conservation. Phylogeny A phylogeny, also called an evolutionary tree, shows the connections between different groups of organisms. Scientists can construct an phylogenetic chart which shows the evolutionary relationships between taxonomic groups using molecular data and morphological similarities or differences. Phylogeny is essential in understanding biodiversity, evolution and genetics. A basic phylogenetic Tree (see Figure PageIndex 10 Determines the relationship between organisms with similar traits and have evolved from a common ancestor. These shared traits can be homologous, or analogous. Homologous characteristics are identical in their evolutionary journey. Analogous traits might appear like they are however they do not share the same origins. Scientists combine similar traits into a grouping known as a the clade. All organisms in a group have a common characteristic, like amniotic egg production. They all came from an ancestor with these eggs. The clades are then linked to create a phylogenetic tree to determine which organisms have the closest connection to each other. Scientists make use of molecular DNA or RNA data to create a phylogenetic chart that is more accurate and detailed. This information is more precise and gives evidence of the evolution of an organism. Researchers can use Molecular Data to calculate the evolutionary age of organisms and identify how many species share the same ancestor. The phylogenetic relationships of organisms can be affected by a variety of factors, including phenotypic flexibility, a type of behavior that alters in response to unique environmental conditions. This can cause a trait to appear more similar to a species than to the other which can obscure the phylogenetic signal. This problem can be addressed by using cladistics, which is a the combination of homologous and analogous traits in the tree. In addition, phylogenetics helps predict the duration and rate at which speciation occurs. This information can assist conservation biologists make decisions about which species they should protect from extinction. In the end, it is the conservation of phylogenetic variety that will result in an ecosystem that is balanced and complete. Evolutionary Theory The fundamental concept of evolution is that organisms develop distinct characteristics over time due to their interactions with their environments. Many scientists have proposed 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 own requirements and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who believed that the usage or non-use of traits can cause changes that are passed on to the In the 1930s and 1940s, ideas from various fields, including genetics, natural selection and particulate inheritance — came together to create the modern evolutionary theory that explains how evolution occurs through the variations of genes within a population, and how those variations change in time as a result of natural selection. This model, known as genetic drift or mutation, gene flow, and sexual selection, is a key element 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 via genetic drift, mutation, and reshuffling of genes during sexual reproduction, as well as through the movement of populations. These processes, as well as others such as directional selection or genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution that is defined as change in the genome of the species over time, and also by changes in phenotype over time (the expression of the genotype in the individual). Incorporating evolutionary thinking into all areas of biology education can improve student understanding of the concepts of phylogeny as well as evolution. A recent study conducted by Grunspan and colleagues, for instance demonstrated that teaching about the evidence that supports evolution increased students' understanding of evolution in a college biology class. For more information on how to teach about evolution, please read The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution in Life Sciences Education. Evolution in Action Traditionally scientists have studied evolution through looking back—analyzing fossils, comparing species and studying living organisms. But evolution isn't a thing that happened in the past, it's an ongoing process, that is taking place in the present. Read Significantly more reinvents itself to avoid new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior as a result of the changing environment. The changes that occur are often visible. But it wasn't until the late-1980s that biologists realized that natural selection could be observed in action as well. The key is the fact that different traits confer a different rate of survival and reproduction, and can be passed on from generation to generation. In the past, if one allele – the genetic sequence that determines colour was found in a group of organisms that interbred, it could be more common than other allele. As time passes, this could mean that the number of moths with black pigmentation in a group could increase. The same is true for many other characteristics—including morphology and behavior—that vary among populations of organisms. It is easier to track evolutionary change when an organism, like bacteria, has a high generation turnover. 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 have been collected frequently and more than 50,000 generations of E.coli have been observed to have passed. Lenski's work has shown that mutations can alter the rate of change and the effectiveness at which a population reproduces. It also proves that evolution takes time—a fact that some are unable to accept. Another example of microevolution is the way mosquito genes that are resistant to pesticides show up more often in populations where insecticides are used. This is because the use of pesticides creates a selective pressure that favors those with resistant genotypes. The rapid pace of evolution taking place has led to a growing appreciation of its importance in a world that is shaped by human activity, including climate changes, pollution and the loss of habitats that hinder many species from adapting. Understanding the evolution process can help us make smarter choices about the future of our planet, as well as the lives of its inhabitants.