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The Academy's Evolution Site

Biology is one of the most important concepts in biology. The Academies are involved in helping those interested in the sciences understand evolution theory and how it is incorporated throughout all fields of scientific research.

This site provides a range of tools for students, teachers and general readers of evolution. It contains important video clips from NOVA and WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol that represents the interconnectedness of all life. It is an emblem of love and harmony in a variety of cultures. It also has important practical applications, such as providing a framework to understand the evolution of species and how they respond to changing environmental conditions.

The first attempts to depict the biological world were based on categorizing organisms based on their physical and metabolic characteristics. These methods, which rely on the sampling of various parts of living organisms or on sequences of short fragments of their DNA significantly expanded the diversity that could be represented in a tree of life2. These trees are largely composed of eukaryotes, while bacterial diversity is vastly underrepresented3,4.

In avoiding the necessity of direct experimentation and observation genetic techniques have allowed us to represent the Tree of Life in a much more accurate way. We can construct trees using molecular methods, such as the small-subunit ribosomal gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of diversity to be discovered. This is especially relevant to microorganisms that are difficult to cultivate, and are usually found in a single specimen5. A recent study of all known genomes has produced a rough draft version of the Tree of Life, including a large number of bacteria and archaea that have not been isolated and which are not well understood.

This expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, assisting to determine if certain habitats require special protection. This information can be utilized in a variety of ways, including identifying new drugs, combating diseases and improving the quality of crops. This information is also valuable in conservation efforts. It can help biologists identify areas that are likely to have cryptic species, which may have important metabolic functions and be vulnerable to changes caused by humans. While funds to protect biodiversity are important, the best method to protect the world's biodiversity is to equip more people in developing nations with the information they require to act locally and 에볼루션바카라사이트 support conservation.

Phylogeny

A phylogeny is also known as an evolutionary tree, shows the relationships between different groups of organisms. Using molecular data similarities and differences in morphology or 에볼루션 바카라사이트 ontogeny (the process of the development of an organism) scientists can create a phylogenetic tree which illustrates the evolutionary relationships between taxonomic categories. The role of phylogeny is crucial in understanding genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar characteristics and have evolved from an ancestor 에볼루션 바카라사이트 with common traits. These shared traits are either analogous or homologous. Homologous traits share their evolutionary roots and analogous traits appear like they do, but don't have the same origins. Scientists organize similar traits into a grouping called a the clade. All members of a clade have a common characteristic, for example, amniotic egg production. They all derived from an ancestor with these eggs. The clades are then linked to create a phylogenetic tree to identify organisms that have the closest relationship to.

For a more precise and precise phylogenetic tree scientists rely on molecular information from DNA or RNA to establish the relationships among organisms. This data is more precise than morphological data and gives evidence of the evolutionary history of an individual or group. The analysis of molecular data can help researchers determine the number of organisms who share the same ancestor and estimate their evolutionary age.

The phylogenetic relationships between species are influenced by many 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 to another, obscuring the phylogenetic signals. This problem can be mitigated by using cladistics, which is a the combination of homologous and analogous traits in the tree.

Additionally, phylogenetics can aid in predicting 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 lead to an ecosystem that is balanced and complete.

Evolutionary Theory

The main idea behind 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 wide range of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve gradually according to its requirements as well as the Swedish botanist Carolus Linnaeus (1707-1778) who conceived modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that can be passed onto offspring.

In the 1930s and 1940s, ideas from a variety of fields--including genetics, natural selection and particulate inheritance - came together to create the modern synthesis of evolutionary theory which explains how evolution is triggered by the variation of genes within a population and how those variants change in time due to natural selection. This model, which encompasses genetic drift, mutations as well as gene flow and sexual selection is mathematically described mathematically.

Recent advances in evolutionary developmental biology have demonstrated how variation can be introduced to a species through genetic drift, mutations and reshuffling of genes during sexual reproduction and migration between populations. These processes, as well as others, such as directionally-selected selection and erosion of genes (changes in frequency of genotypes over time) can result in evolution. Evolution is defined by changes in the genome over time as well as changes in phenotype (the expression of genotypes in individuals).

Students can better understand the concept of phylogeny through incorporating evolutionary thinking in all aspects of biology. A recent study conducted by Grunspan and colleagues, for instance demonstrated that teaching about the evidence for evolution helped students accept the concept of evolution in a college biology course. For 에볼루션 코리아 more details on how to teach about evolution look up The Evolutionary Potential in All Areas of Biology or Thinking Evolutionarily: a Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Scientists have studied evolution by looking in the past, analyzing fossils and comparing species. They also observe living organisms. Evolution is not a distant event, but a process that continues today. Bacteria transform and resist antibiotics, 에볼루션코리아 viruses re-invent themselves and are able to evade new medications, and animals adapt their behavior to a changing planet. The changes that result are often apparent.

It wasn't until late 1980s that biologists realized that natural selection can be observed in action as well. The key is that various traits have different rates of survival and reproduction (differential fitness) and are transferred from one generation to the next.

In the past, if an allele - the genetic sequence that determines colour - appeared in a population of organisms that interbred, it might become more common than other allele. Over time, this would mean that the number of moths that have black pigmentation may increase. The same is true for 에볼루션 게이밍 many other characteristics--including morphology and behavior--that vary among populations of organisms.

The ability to observe evolutionary change is easier when a particular species has a rapid generation turnover like bacteria. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain; samples of each are taken on a regular basis, and over fifty thousand generations have passed.

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

Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more prevalent in populations where insecticides are used. This is because pesticides cause an enticement that favors those with resistant genotypes.

The rapidity of evolution has led to a growing appreciation of its importance, especially in a world 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 can help us make better decisions regarding the future of our planet, and the lives of its inhabitants.