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The Academy's Evolution Site

Biological evolution is a central concept in biology. The Academies are involved in helping those who are interested in science learn about the theory of evolution and how it is permeated throughout all fields of scientific research.

This site provides students, teachers and general readers with a wide range of learning resources on evolution. It includes important video clips from NOVA and WGBH's 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 the environment.

Early attempts to represent the world of biology were based on categorizing organisms based on their metabolic and physical characteristics. These methods, based on the sampling of different parts of living organisms, or small DNA fragments, greatly increased the variety of organisms that could be included in the tree of life2. However the trees are mostly made up of eukaryotes. Bacterial diversity is not represented in a large way3,4.

By avoiding the need for direct experimentation and observation genetic techniques have enabled us to represent the Tree of Life in a more precise way. Trees can be constructed using molecular techniques such as the small subunit ribosomal gene.

Despite the rapid growth of the Tree of Life through genome sequencing, much biodiversity still awaits discovery. This is especially true of microorganisms, which can be difficult to cultivate and are typically only represented in a single sample5. A recent study of all genomes that are known has created a rough draft of the Tree of Life, including many archaea and bacteria that have not been isolated and whose diversity is poorly understood6.

This expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, assisting to determine if specific habitats require special protection. This information can be utilized in a variety of ways, such as finding new drugs, battling diseases and improving crops. This information is also beneficial for conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species that could have significant metabolic functions that could be vulnerable to anthropogenic change. While funds to protect biodiversity are essential but the most effective way to protect the world's biodiversity is for more people living 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 various groups of organisms. Utilizing molecular data similarities and differences in morphology, or ontogeny (the course of development of an organism), scientists can build a phylogenetic tree that illustrates the evolution of taxonomic categories. Phylogeny is essential in understanding evolution, biodiversity and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms that share similar traits that have evolved from common ancestors. These shared traits could be either homologous or analogous. Homologous traits are identical in their evolutionary roots and analogous traits appear similar but do not have the same ancestors. Scientists arrange similar traits into a grouping referred to as a the clade. Every organism in a group share a characteristic, for example, amniotic egg production. They all evolved from an ancestor who had these eggs. The clades then join to form a phylogenetic branch to identify organisms that have the closest relationship.

Scientists make use of molecular DNA or RNA data to build a phylogenetic chart that is more accurate and detailed. This information is more precise than morphological information and provides evidence of the evolutionary background of an organism or group. The use of molecular data lets researchers determine the number of organisms who share an ancestor common to them and 에볼루션 사이트 estimate their evolutionary age.

The phylogenetic relationships between organisms can be affected by a variety of factors including phenotypic plasticity, an aspect of behavior that alters in response to unique environmental conditions. This can cause a characteristic to appear more similar to one species than to another, obscuring the phylogenetic signals. This issue can be cured by using cladistics. This is a method that incorporates the combination of homologous and analogous features in the tree.

In addition, phylogenetics helps predict the duration and rate at which speciation takes place. This information can assist conservation biologists make decisions about which species to protect from the threat of extinction. In the end, it is the conservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind evolution is that organisms acquire different features over time due to their interactions with their surroundings. Many scientists have developed theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that a living thing would evolve according to its individual needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical system of taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or absence of certain traits can result in changes that can be passed on to future generations.

In the 1930s & 1940s, ideas from different fields, including genetics, natural selection and particulate inheritance, came together to create a modern theorizing of evolution. This explains how evolution occurs by the variation in genes within the population and how these variants change with time due to natural selection. This model, known as genetic drift, mutation, gene flow and sexual selection, is the foundation of current evolutionary biology, and can be mathematically described.

Recent advances in evolutionary developmental biology have shown the ways in which variation can be introduced to a species via genetic drift, mutations, reshuffling genes during sexual reproduction and migration between populations. These processes, in conjunction with other ones like the directional selection process and 에볼루션 바카라 사이트 카지노 사이트 (additional resources) the erosion of genes (changes in frequency of genotypes over time) can result in evolution. Evolution is defined as changes in the genome over time as well as changes in phenotype (the expression of genotypes within individuals).

Incorporating evolutionary thinking into all aspects of biology education can improve students' understanding of phylogeny and evolutionary. A recent study by Grunspan and colleagues, for example demonstrated that teaching about the evidence that supports evolution helped students accept the concept of evolution in a college-level biology class. To learn more about how to teach about evolution, 에볼루션 코리아 please look up The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution by studying fossils, comparing species, and observing living organisms. Evolution isn't a flims moment; it is a process that continues today. The virus reinvents itself to avoid new medications and bacteria mutate to resist antibiotics. Animals alter their behavior as a result of a changing environment. The results are usually evident.

It wasn't until the late 1980s that biologists began to realize that natural selection was also at work. The reason is that different traits confer different rates of survival and reproduction (differential fitness), and can be transferred from one generation to the next.

In the past, if one allele - the genetic sequence that determines colour - was present in a population of organisms that interbred, it could be more prevalent than any other allele. Over time, this would mean that the number of moths sporting black pigmentation in a population could increase. The same is true for many other characteristics--including morphology and [empty] behavior--that vary among populations of organisms.

Observing evolutionary change in action is easier when a particular species has a fast generation turnover like bacteria. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from a single strain. Samples from each population have been collected regularly and more than 500.000 generations of E.coli have been observed to have passed.

Lenski's work has demonstrated that mutations can drastically alter the speed at which a population reproduces and, consequently, the rate at which it alters. It also shows that evolution takes time, which is hard for some to accept.

Another example of microevolution is how mosquito genes for resistance to pesticides appear more frequently in populations in which insecticides are utilized. This is due to pesticides causing a selective pressure which favors individuals who have resistant genotypes.

The rapid pace at which evolution takes place has led to a growing awareness of its significance in a world that is shaped by human activity--including climate change, pollution and the loss of habitats which prevent the species from adapting. Understanding evolution can help us make better decisions about the future of our planet, and the life of its inhabitants.