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The Academy's Evolution Site

The concept of biological evolution is among the most central concepts in biology. The Academies are involved in helping those who are interested in science to comprehend the evolution theory and how it can be applied in all areas of scientific research.

This site provides a wide range of tools for teachers, students and general readers of evolution. It also includes 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 seen in a variety of religions and cultures as a symbol of unity and love. It has numerous practical applications as well, including providing a framework to understand the history of species and how they respond to changing environmental conditions.

Early approaches to depicting the world of biology focused on categorizing organisms into distinct categories which were identified by their physical and metabolic characteristics1. These methods rely on the collection of various parts of organisms, or fragments of DNA, have significantly increased the diversity of a Tree of Life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.

By avoiding the necessity for direct observation and experimentation genetic techniques have enabled us to depict the Tree of Life in a much more accurate way. In particular, molecular methods allow us to build trees by using sequenced markers, such as the small subunit of ribosomal RNA gene.

Despite the massive expansion of the Tree of Life through genome sequencing, a lot of biodiversity is waiting to be discovered. This is particularly true for microorganisms that are difficult to cultivate and are typically only represented in a single specimen5. Recent analysis of all genomes resulted in a rough draft of a Tree of Life. This includes a variety of bacteria, archaea and other organisms that haven't yet been identified or whose diversity has not been well understood6.

The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, helping to determine whether specific habitats require protection. This information can be used in a variety of ways, including finding new drugs, fighting diseases and improving crops. It is also valuable for conservation efforts. It helps biologists discover areas that are most likely to be home to species that are cryptic, which could have vital metabolic functions and 에볼루션 사이트 be vulnerable to changes caused by humans. While funds to protect biodiversity are essential, the best method to preserve the world's biodiversity is to equip more people in developing countries with the information they require to act locally and promote conservation.

Phylogeny

A phylogeny is also known as an evolutionary tree, 에볼루션 shows the relationships between different groups of organisms. Scientists can create an phylogenetic chart which shows the evolutionary relationship of taxonomic categories using molecular information and morphological differences or similarities. The role of phylogeny is crucial in understanding genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 Finds the connections between organisms that have similar traits and have evolved from a common ancestor. These shared traits may be analogous, or homologous. Homologous traits are identical in their underlying evolutionary path while analogous traits appear similar, but do not share the identical origins. Scientists put similar traits into a grouping known as a clade. For example, all of the organisms that make up a clade share the trait of having amniotic eggs and evolved from a common ancestor that had eggs. A phylogenetic tree is constructed by connecting the clades to identify the organisms which are the closest to each other.

For a more detailed and precise phylogenetic tree scientists make use of molecular data from DNA or RNA to determine the connections between organisms. This information is more precise than morphological data and provides evidence of the evolutionary background of an organism or group. The analysis of molecular data can help researchers determine the number of species that share an ancestor common to them and estimate their evolutionary age.

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

Furthermore, phylogenetics may aid in predicting the time and pace of speciation. This information can assist conservation biologists in deciding which species to protect from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity that will create an ecologically balanced and complete ecosystem.

Evolutionary Theory

The central theme of evolution is that organisms develop various characteristics over time as a result of their interactions with their surroundings. Many scientists have proposed 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 own needs and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy and Jean-Baptiste Lamarck (1844-1829), who suggested that the usage or non-use of traits can lead to changes that are passed on to the

In the 1930s and 에볼루션바카라사이트 1940s, theories from various fields, including natural selection, genetics, and particulate inheritance--came together to create the modern synthesis of evolutionary theory that explains how evolution occurs through the variations of genes within a population, 에볼루션 사이트 and how those variants change over time due to natural selection. This model, which includes mutations, genetic drift in gene flow, and 에볼루션 사이트 sexual selection is mathematically described mathematically.

Recent discoveries in the field of evolutionary developmental biology have shown that variations can be introduced into a species through genetic drift, mutation, and reshuffling genes during sexual reproduction, and also by migration between populations. These processes, along with others such as directional selection or 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 the change in phenotype as time passes (the expression of that genotype in the individual).

Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking throughout all aspects of biology. A recent study conducted by Grunspan and colleagues, for instance, showed that teaching about the evidence that supports evolution increased students' understanding of evolution in a college biology course. For more information on how to teach about evolution, see 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 studied evolution through looking back in the past--analyzing fossils and comparing species. They also observe living organisms. But evolution isn't a thing that happened in the past, it's an ongoing process, taking place in the present. Viruses evolve to stay away from new medications and 에볼루션 게이밍 bacteria mutate to resist antibiotics. Animals alter their behavior because of the changing environment. The changes that result are often evident.

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

In the past, if one allele - the genetic sequence that determines colour - was found in a group of organisms that interbred, it might become more prevalent than any other allele. In time, this could mean that 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.

The ability to observe evolutionary change is easier when a particular species has a rapid turnover of its generation, as with bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples of each are taken on a regular basis, and over 50,000 generations have now passed.

Lenski's research has revealed that mutations can alter the rate at which change occurs and the effectiveness of a population's reproduction. It also proves that evolution takes time--a fact that some find hard to accept.

Another example of microevolution is the way mosquito genes for resistance to pesticides are more prevalent in areas where insecticides are employed. That's because the use of pesticides creates a pressure that favors those with resistant genotypes.

The rapidity of evolution has led to a growing recognition of its importance especially in a planet which is largely shaped by human activities. This includes climate change, pollution, and habitat loss, which prevents many species from adapting. Understanding evolution can aid you in making better decisions about the future of the planet and its inhabitants.