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The Academy's Evolution Site

Biology is a key concept in biology. The Academies are involved in helping those who are interested in science understand evolution theory and how it can be applied throughout all fields of scientific research.

This site provides teachers, students and general readers with a range of learning resources about evolution. It contains key video clips from NOVA and WGBH produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol of the interconnectedness of all life. It is seen in a variety of cultures and spiritual beliefs as symbolizing unity and 에볼루션 코리아 바카라 (turkbellek.Org) love. It has many practical applications as well, such as providing a framework for understanding the history of species and how they react to changing environmental conditions.

Early attempts to represent the world of biology were founded on categorizing organisms on their metabolic and physical characteristics. These methods, based on the sampling of various parts of living organisms, or sequences of small fragments of their DNA significantly increased the variety that could be included in a tree of life2. The trees are mostly composed of eukaryotes, 에볼루션 게이밍 [Http://Www.Fuxiaoshun.Cn] while the diversity of bacterial species is greatly underrepresented3,4.

In avoiding the necessity of direct experimentation and observation, genetic techniques have made it possible to represent the Tree of Life in a more precise manner. Trees can be constructed using molecular techniques, such as the small-subunit ribosomal 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 relevant to microorganisms that are difficult to cultivate, and which are usually only found in a single specimen5. A recent analysis of all genomes has produced an initial draft of the Tree of Life. This includes a large number of archaea, bacteria, and other organisms that haven't yet been isolated or their diversity is not fully understood6.

The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, assisting to determine if certain habitats require protection. This information can be utilized in a range of ways, from identifying new remedies to fight diseases to enhancing the quality of the quality of crops. The information is also incredibly valuable in conservation efforts. It can help biologists identify areas most likely to have species that are cryptic, which could perform important metabolic functions, and could be susceptible to the effects of human activity. While funds to protect biodiversity are crucial but the most effective way to protect the world's biodiversity is for more people living in developing countries to be empowered with the necessary knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny (also known as an evolutionary tree) shows the relationships between organisms. Scientists can construct an phylogenetic chart which shows the evolutionary relationships between taxonomic groups based on molecular data and morphological similarities or differences. The role of phylogeny is crucial in understanding biodiversity, genetics and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms with similar characteristics and have evolved from an ancestor with common traits. These shared traits can be analogous, or homologous. Homologous traits are identical in their evolutionary roots while analogous traits appear similar, but do not share the identical origins. Scientists group similar traits into a grouping known as a the clade. All organisms in a group share a characteristic, for example, amniotic egg production. They all evolved from an ancestor who had these eggs. A phylogenetic tree is constructed by connecting clades to identify the organisms which are the closest to one another.

For a more detailed and accurate phylogenetic tree scientists rely on molecular information from DNA or RNA to establish the connections between organisms. This information is more precise and provides evidence of the evolution of an organism. The use of molecular data lets researchers identify the number of species who share a common ancestor and to estimate their evolutionary age.

The phylogenetic relationships of a species can be affected by a variety of factors such as the phenotypic plasticity. This is a type behavior that changes in response to particular environmental conditions. This can cause a trait to appear more resembling to one species than to the other which can obscure the phylogenetic signal. This issue can be cured by using cladistics. This is a method that incorporates the combination of analogous and homologous features in the tree.

Furthermore, phylogenetics may aid in predicting the duration and rate of speciation. This information will assist conservation biologists in deciding which species to protect from disappearance. Ultimately, it is the preservation of phylogenetic diversity which will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept of evolution is that organisms develop distinct characteristics over time as a result of their interactions with their environment. Many scientists have come up with theories of evolution, including the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its individual needs as well as the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of certain traits can result in changes that are passed on to the

In the 1930s and 1940s, ideas from different fields, including genetics, natural selection and particulate inheritance, came together to form a modern synthesis of evolution theory. This defines how evolution occurs by the variation of genes in a population and how these variants alter over time due to natural selection. This model, which is 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 discoveries in the field of evolutionary developmental biology have shown the ways in which variation can be introduced to a species by mutations, genetic drift or reshuffling of genes in sexual reproduction and migration between populations. These processes, along with others such as directional selection and gene erosion (changes in frequency of genotypes over time) can lead to evolution. Evolution is defined by changes in the genome over time as well as changes in phenotype (the expression of genotypes in an individual).

Incorporating evolutionary thinking into all aspects of biology education can improve students' understanding of phylogeny and evolution. In a study by Grunspan et al. It was found that teaching students about the evidence for evolution increased their acceptance of evolution during a college-level course in biology. For more information on how to teach about evolution, please see The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution in 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. However, evolution isn't something that occurred in the past. It's an ongoing process that is taking place right now. Bacteria evolve and resist antibiotics, viruses evolve and elude new medications and animals alter their behavior to a changing planet. The results are usually evident.

It wasn't until late 1980s that biologists began realize that natural selection was in play. The key to this is that different traits can confer the ability to survive at different rates and reproduction, and can be passed on from generation to generation.

In the past, if one particular allele--the genetic sequence that controls coloration - was present in a population of interbreeding species, it could quickly become more common than all other alleles. In time, 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 observe evolutionary change when the species, like bacteria, has a high generation turnover. Since 1988, 에볼루션바카라사이트 biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples of each are taken every day and over 50,000 generations have now been observed.

Lenski's work has shown that mutations can alter the rate of change and the efficiency of a population's reproduction. It also demonstrates that evolution takes time, a fact that some find hard to accept.

Another example of microevolution is how mosquito genes that confer resistance to pesticides appear more frequently in areas where insecticides are employed. Pesticides create an exclusive pressure that favors those who have resistant genotypes.

The speed at which evolution can take place has led to an increasing appreciation of its importance in a world that is shaped by human activity--including climate change, pollution and the loss of habitats that hinder many species from adapting. Understanding evolution can aid you in making better decisions about the future of the planet and its inhabitants.