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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 to learn about the theory of evolution and how it is permeated in all areas of scientific research.

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

Tree of Life

The Tree of Life is an ancient symbol that symbolizes the interconnectedness of all life. It is seen in a variety of religions and cultures as an emblem of unity and love. It can be used in many practical ways in addition to providing a framework for understanding the history of species and how they react to changes in environmental conditions.

Early attempts to describe the biological world were based on categorizing organisms based on their physical and metabolic characteristics. These methods, based on the sampling of different parts of living organisms or on small DNA fragments, greatly increased the variety of organisms that could be included in the tree of life2. These trees are largely composed by eukaryotes and bacteria are largely underrepresented3,4.

By avoiding the necessity for direct experimentation and observation genetic techniques have enabled us to represent the Tree of Life in a more precise way. Particularly, molecular techniques allow us to build trees by using sequenced markers such as the small subunit ribosomal gene.

Despite the rapid growth of the Tree of Life through genome sequencing, a lot of biodiversity awaits discovery. This is particularly true for microorganisms, which are difficult to cultivate and are typically only present in a single sample5. A recent analysis of all known genomes has created a rough draft of the Tree of Life, including many archaea and 에볼루션게이밍 bacteria that have not been isolated and their diversity is not fully understood6.

The expanded Tree of Life can be used to assess the biodiversity of a specific area and determine if certain habitats require special protection. This information can be used in a variety of ways, such as identifying new drugs, combating diseases and improving the quality of crops. It is also valuable in conservation efforts. It can help biologists identify areas that are likely to have cryptic species, which may have vital metabolic functions and be vulnerable to human-induced change. While funds to protect biodiversity are essential, ultimately the best way to preserve the world's biodiversity is for more people in developing countries to be empowered with the knowledge to act locally to promote conservation from within.

Phylogeny

A phylogeny (also called an evolutionary tree) illustrates the relationship between species. Scientists can create a phylogenetic chart that shows the evolutionary relationship of taxonomic categories using molecular information and morphological differences or similarities. The role of phylogeny is crucial in understanding the relationship between genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) determines the relationship between organisms that share similar traits that have evolved from common ancestors. These shared traits can be either homologous or analogous. Homologous characteristics are identical in terms of their evolutionary journey. Analogous traits might appear like they are but they don't share the same origins. Scientists organize similar traits into a grouping called a Clade. Every organism in a group share a characteristic, like amniotic egg production. They all evolved from an ancestor with these eggs. A phylogenetic tree is then built by connecting the clades to identify the organisms that are most closely related to each other.

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

Phylogenetic relationships can be affected by a number of factors that include the phenomenon of phenotypicplasticity. This is a type of behaviour that can change as a result of specific environmental conditions. This can make a trait appear more similar to a species than to the other and obscure the phylogenetic signals. However, this issue can be cured by the use of methods such as cladistics that incorporate a combination of analogous and homologous features into the tree.

Additionally, phylogenetics can help predict the duration and rate at which speciation takes place. This information can aid conservation biologists in deciding which species to protect from the threat of extinction. Ultimately, it is the preservation of phylogenetic diversity that will result in an ecosystem that is complete and balanced.

Evolutionary Theory

The main idea behind evolution is that organisms develop various characteristics over time as a result of their interactions with their surroundings. 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 develop according to its own requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical system of taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who believed that the usage or 에볼루션 블랙잭 (visit the following post) non-use of certain traits can result in changes that can be passed on to future generations.

In the 1930s & 1940s, theories from various fields, including natural selection, genetics & particulate inheritance, came together to form a contemporary evolutionary theory. This describes how evolution is triggered by the variations in genes within the population and how these variants change with time due to natural selection. This model, which is known as genetic drift or mutation, gene flow and sexual selection, is the foundation of the current evolutionary biology and is mathematically described.

Recent developments in the field of evolutionary developmental biology have demonstrated that variations can be introduced into a species via genetic drift, mutation, and reshuffling of genes in sexual reproduction, and also through the movement of populations. These processes, along with other ones like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution that is defined as changes in the genome of the species over time, and also the change in phenotype over time (the expression of that genotype within the individual).

Students can better understand phylogeny by incorporating evolutionary thinking into all aspects of biology. A recent study by Grunspan and colleagues, for instance revealed that teaching students about the evidence for evolution helped students accept the concept of evolution in a college-level biology course. For more details about how to teach evolution read The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily as a Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution through looking back--analyzing fossils, comparing species and studying living organisms. However, evolution isn't something that happened in the past; it's an ongoing process that is taking place today. Bacteria transform and resist antibiotics, viruses re-invent themselves and elude new medications and animals alter their behavior to the changing climate. The changes that result are often evident.

It wasn't until late 1980s that biologists realized that natural selection can be observed in action as well. The key to this is that different traits can confer the ability to survive at different rates as well as reproduction, and 에볼루션 무료체험 may be passed on from one generation to the next.

In the past, if one allele - the genetic sequence that determines color - was found in a group of organisms that interbred, it might become more common than other allele. 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 see evolutionary change when a species, such as bacteria, has a rapid generation turnover. Since 1988, 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 fifty thousand generations have been observed.

Lenski's research has revealed that mutations can drastically alter the efficiency with the rate at which a population reproduces, 에볼루션 바카라 무료게이밍 - Http://120.zsluoping.cn - and consequently, the rate at which it evolves. It also shows evolution takes time, a fact that is hard for some to accept.

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

The rapidity of evolution has led to an increasing recognition of its importance, especially in a world shaped largely by human activity. This includes pollution, 에볼루션게이밍 climate change, and habitat loss that prevents many species from adapting. Understanding the evolution process can help us make smarter decisions regarding the future of our planet as well as the lives of its inhabitants.