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The Academy's Evolution Site

The concept of biological evolution is a fundamental 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 influences all areas of scientific research.

This site provides a range of resources for teachers, 에볼루션 무료 바카라 [120.Zsluoping.Cn] students, and general readers on evolution. It contains key 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 appears in many religions and cultures as symbolizing unity and love. It also has many practical uses, like providing a framework to understand the evolution of species and how they react to changes in environmental conditions.

The first attempts at depicting the biological world focused on categorizing species into distinct categories that were distinguished by their physical and metabolic characteristics1. These methods, based on sampling of different parts of living organisms or on sequences of short fragments of their DNA, significantly expanded the diversity that could be included in a tree of life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.

Genetic techniques have greatly expanded our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. We can construct trees using molecular techniques such as the small subunit ribosomal gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is still a lot of biodiversity to be discovered. This is particularly true for microorganisms, which are difficult to cultivate and 에볼루션 코리아 are typically only found in a single specimen5. A recent analysis of all known genomes has created a rough draft of the Tree of Life, 에볼루션 코리아 including a large number of bacteria and archaea that are not isolated and which are not well understood.

This expanded Tree of Life can be used to evaluate the biodiversity of a specific region and determine if specific habitats need special protection. This information can be utilized in a range of ways, from identifying the most effective treatments to fight disease to enhancing the quality of crops. The information is also incredibly useful to conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species with potentially important metabolic functions that may be at risk from anthropogenic change. While funds to protect biodiversity are essential but the most effective way to ensure the preservation of biodiversity around the world is for more people living in developing countries to be equipped with the knowledge to take action locally to encourage conservation from within.

Phylogeny

A phylogeny, also known as an evolutionary tree, reveals the relationships between various groups of organisms. Using molecular data similarities and differences in morphology, or ontogeny (the process of the development of an organism), scientists can build a phylogenetic tree that illustrates the evolutionary relationship between taxonomic groups. The role of phylogeny is crucial in understanding the relationship between genetics, biodiversity and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 ) identifies the relationships between organisms with similar traits that evolved from common ancestors. These shared traits may be analogous, or homologous. Homologous traits are similar in their evolutionary roots and analogous traits appear similar but do not have the identical origins. Scientists combine similar traits into a grouping known as a the clade. For instance, all of the organisms that make up a clade share the characteristic of having amniotic eggs and evolved from a common ancestor which had these eggs. A phylogenetic tree can be constructed by connecting clades to determine the organisms that are most closely related to each other.

For a more detailed and accurate phylogenetic tree scientists use molecular data from DNA or RNA to establish the relationships between organisms. This data is more precise than morphological information and gives evidence of the evolutionary background of an organism or group. Researchers can utilize Molecular Data to estimate the evolutionary age of organisms and identify how many species share the same ancestor.

The phylogenetic relationships of a species can be affected by a number of factors that include the phenotypic plasticity. This is a kind of behavior that alters in response to unique environmental conditions. This can cause a trait to appear more similar in one species than other species, which can obscure the phylogenetic signal. This issue can be cured by using cladistics, which is a an amalgamation of analogous and homologous features in the tree.

Additionally, phylogenetics can help predict the duration and 에볼루션 무료체험, eric1819.com, rate at which speciation occurs. This information can assist conservation biologists in making choices about which species to safeguard from extinction. In the end, it is the preservation of phylogenetic diversity that will lead to an ecosystem that is balanced and complete.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time as a result of their interactions with their environment. Several theories of evolutionary change have been proposed by a variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop slowly according to its needs as well as the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits cause changes that can be passed on to the offspring.

In the 1930s and 1940s, ideas from various fields, including genetics, natural selection and particulate inheritance--came together to form the current evolutionary theory, which defines how evolution occurs through the variations of genes within a population, and how those variants change in time due to natural selection. This model, which includes mutations, genetic drift in gene flow, and sexual selection is mathematically described mathematically.

Recent discoveries in the field of evolutionary developmental biology have revealed that genetic variation can be introduced into a species through mutation, genetic drift, and reshuffling of genes during sexual reproduction, and also through the movement of populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time), can lead to evolution which is defined by changes in the genome of the species over time and also by changes in phenotype as time passes (the expression of the genotype within the individual).

Students can better understand phylogeny by incorporating evolutionary thinking into all areas of biology. A recent study conducted by Grunspan and colleagues, for instance revealed that teaching students about the evidence supporting evolution helped students accept the concept of evolution in a college biology class. To learn more about how to teach about evolution, please read The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution by looking back--analyzing fossils, comparing species and studying living organisms. Evolution is not a distant event; it is an ongoing process that continues to be observed today. Viruses evolve to stay away from new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior as a result of a changing environment. 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 the fact that different traits confer an individual rate of survival and reproduction, and they can be passed on from one generation to another.

In the past, 에볼루션 바카라 무료 (http://www.v0795.com/home.php?mod=space&uid=1433513) if an allele - the genetic sequence that determines colour appeared in a population of organisms that interbred, it could become more prevalent than any other allele. In time, this could mean the number of black moths within the population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to observe evolution when an organism, like bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that descend from a single strain. Samples from 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 a mutation can dramatically alter the speed at which a population reproduces and, consequently, the rate at which it evolves. It also demonstrates that evolution takes time, a fact that some people find hard to accept.

Another example of microevolution is that mosquito genes that confer resistance to pesticides are more prevalent in areas where insecticides are employed. This is due to pesticides causing a selective pressure which favors those who have resistant genotypes.

The rapidity of evolution has led to a growing awareness of its significance especially in a planet shaped largely by human activity. This includes the effects of climate change, pollution and habitat loss that hinders many species from adapting. Understanding the evolution process will help us make better decisions regarding the future of our planet, as well as the life of its inhabitants.