markharbor4

The Academy's Evolution Site Biology is one of the most fundamental concepts in biology. The Academies have been active for a long time in helping those interested in science comprehend the theory of evolution and how it influences all areas of scientific exploration. This site offers a variety of resources for teachers, students as well as general readers about 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, represents the interconnectedness of all life. It is a symbol of love and harmony in a variety of cultures. It can be used in many practical ways as well, such as providing a framework to understand the evolution of species and how they respond to changes in environmental conditions. Early approaches to depicting the world of biology focused on the classification of organisms into distinct categories that were distinguished by physical and metabolic characteristics1. These methods depend on the collection of various parts of organisms or short fragments of DNA have significantly increased the diversity of a Tree of Life2. However 에볼루션 블랙잭 Evolution are mostly comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4. By avoiding the necessity for direct experimentation and observation, genetic techniques have made it possible to represent the Tree of Life in a more precise way. Particularly, molecular methods enable us to create trees using sequenced markers like the small subunit of ribosomal RNA gene. Despite the rapid growth of the Tree of Life through genome sequencing, much biodiversity still remains to be discovered. This is particularly true for microorganisms, which are difficult to cultivate and are often only represented in a single sample5. A recent analysis of all genomes resulted in an unfinished draft of a Tree of Life. This includes a variety of archaea, bacteria and other organisms that have not yet been isolated, or the diversity of which is not fully understood6. This expanded Tree of Life can be used to evaluate the biodiversity of a specific area and determine if specific habitats need special protection. This information can be used in a range of ways, from identifying new treatments to fight disease to improving the quality of crops. The information is also valuable for conservation efforts. It can help biologists identify the areas that are most likely to contain cryptic species with significant metabolic functions that could be vulnerable to anthropogenic change. Although funds to protect biodiversity are essential, ultimately the best way to ensure the preservation of biodiversity around the world is for more people living in developing countries to be empowered with the knowledge to act locally in order to promote conservation from within. Phylogeny A phylogeny, also known as an evolutionary tree, illustrates the connections between various groups of organisms. Scientists can create a phylogenetic chart that shows the evolutionary relationships between taxonomic groups using molecular data and morphological differences or similarities. The phylogeny of a tree plays an important role in understanding the relationship between genetics, biodiversity and evolution. A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar traits and have evolved from an ancestor that shared traits. These shared traits could be either homologous or analogous. Homologous traits are similar in their evolutionary origins, while analogous traits look similar, but do not share the identical origins. Scientists organize similar traits into a grouping called a Clade. All organisms in a group share a trait, such as amniotic egg production. They all evolved from an ancestor with these eggs. The clades are then linked to form a phylogenetic branch that can identify organisms that have the closest relationship to. For a more detailed and accurate phylogenetic tree, scientists use molecular data from DNA or RNA to identify the relationships among organisms. This information is more precise and provides evidence of the evolutionary history of an organism. Researchers can use Molecular Data to determine the evolutionary age of organisms and determine the number of organisms that share an ancestor common to all. The phylogenetic relationships between species can be influenced by several factors including phenotypic plasticity, a kind of behavior that changes in response to unique environmental conditions. This can make a trait appear more resembling to one species than another which can obscure the phylogenetic signal. However, this problem can be solved through the use of techniques like cladistics, which include a mix of similar and homologous traits into the tree. In addition, phylogenetics can help predict the duration and rate of speciation. This information can help conservation biologists make decisions about which species to protect from extinction. In the end, it is the conservation of phylogenetic diversity that will result in an ecosystem that is balanced and complete. Evolutionary Theory The main idea behind evolution is that organisms acquire various characteristics over time due to their interactions with their environment. Many theories of evolution have been proposed by a wide range of scientists such as the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing gradually according to its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that could be passed onto offspring. In the 1930s & 1940s, concepts from various fields, such as genetics, natural selection and particulate inheritance, merged to create a modern theorizing of evolution. This explains how evolution occurs by the variations in genes within the population and how these variations change with time due to natural selection. This model, which includes mutations, genetic drift as well as gene flow and sexual selection, can be mathematically described. Recent advances in evolutionary developmental biology have demonstrated how variations can be introduced to a species by genetic drift, mutations or reshuffling of genes in sexual reproduction, and even migration between populations. These processes, along with other ones like directional selection and 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 also the change in phenotype over time (the expression of the genotype in the individual). Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking throughout all areas of biology. A recent study conducted by Grunspan and colleagues, for instance demonstrated that teaching about the evidence for evolution increased students' understanding of evolution in a college biology class. To learn more about how to teach about evolution, read The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution into Life Sciences Education. Evolution in Action Scientists have traditionally studied evolution by looking in the past—analyzing fossils and comparing species. They also observe living organisms. Evolution is not a distant event; it is an ongoing process that continues to be observed today. Bacteria mutate and resist antibiotics, viruses reinvent themselves and escape new drugs and animals change their behavior to a changing planet. The changes that result are often visible. However, it wasn't until late 1980s that biologists understood that natural selection could be observed in action as well. The key is that different traits have different rates of survival and reproduction (differential fitness), and 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 rapidly become more common than other alleles. In time, this could 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 evolutionary change when a species, such as bacteria, has a high generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from one strain. Samples from each population have been taken frequently and more than 50,000 generations of E.coli have been observed to have passed. Lenski's research has revealed that a mutation can profoundly alter the rate at which a population reproduces—and so, the rate at which it changes. It also shows evolution takes time, something that is difficult for some to accept. Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more prevalent in areas where insecticides have been used. This is because pesticides cause a selective pressure which favors individuals who have resistant genotypes. The rapidity of evolution has led to an increasing awareness of its significance particularly in a world which is largely shaped by human activities. This includes the effects of climate change, pollution and habitat loss that prevents many species from adapting. Understanding the evolution process can aid you in making better decisions regarding the future of the planet and its inhabitants.