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The Academy's Evolution Site

Biological evolution is one of the most fundamental concepts in biology. The Academies have long been involved in helping people who are interested in science comprehend the concept of evolution and how it permeates all areas of scientific research.

This site provides teachers, students and general readers with a variety of educational resources 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, symbolizes the interconnectedness of all life. It is used in many spiritual traditions and cultures as an emblem of unity and love. It also has important practical applications, such as providing a framework for understanding the evolution of species and how they respond to changes in environmental conditions.

Early attempts to describe the biological world were founded on categorizing organisms on their metabolic and physical characteristics. These methods, which are based on the collection of various parts of organisms or fragments of DNA, have greatly increased the diversity of a tree of Life2. These trees are mostly populated by eukaryotes and 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 way. Particularly, molecular methods allow us to build trees using sequenced markers, such as the small subunit ribosomal RNA gene.

The Tree of Life has been dramatically expanded through genome sequencing. However, there is still much biodiversity to be discovered. This is particularly relevant to microorganisms that are difficult to cultivate and are typically found in a single specimen5. A recent study of all genomes known to date has created a rough draft of the Tree of Life, including many bacteria and archaea that have not been isolated, and 에볼루션 블랙잭사이트; Www.bioguiden.Se, whose diversity is poorly understood6.

The expanded Tree of Life is particularly useful in assessing the diversity of an area, assisting to determine if specific habitats require protection. The information can be used in a range of ways, from identifying the most effective remedies to fight diseases to enhancing crop yields. It is also useful for 에볼루션바카라사이트 (Douerdun.com) conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species with potentially important metabolic functions that could be at risk from anthropogenic change. While funds to protect biodiversity are crucial, ultimately the best way to preserve the world's biodiversity is for more people in developing countries to be equipped with the knowledge to take action locally to encourage conservation from within.

Phylogeny

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

A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar traits and have evolved from an ancestor that shared traits. These shared traits may be homologous, or analogous. Homologous traits share their underlying evolutionary path and analogous traits appear similar but do not have the identical origins. Scientists combine similar traits into a grouping referred to as a the clade. For example, all of the organisms in a clade have the characteristic of having amniotic eggs. They evolved from a common ancestor who had these eggs. The clades are then linked to create a phylogenetic tree to identify organisms that have the closest relationship.

Scientists make use of DNA or RNA molecular data to construct a phylogenetic graph which is more precise and detailed. This information is more precise than morphological information and gives evidence of the evolutionary history of an individual or group. Molecular data allows researchers to determine the number of organisms that share the same ancestor and estimate their evolutionary age.

The phylogenetic relationships of organisms can be affected by a variety of factors, including phenotypic plasticity a type of behavior that changes in response to specific environmental conditions. This can make a trait appear more resembling to one species than another and obscure the phylogenetic signals. This problem can be addressed by using cladistics, which incorporates a combination of homologous and analogous traits in the tree.

Additionally, phylogenetics can help predict the duration and rate of speciation. This information can assist conservation biologists decide which species to protect from the threat of extinction. It is ultimately the preservation of phylogenetic diversity which will create an ecologically balanced and complete ecosystem.

Evolutionary Theory

The main idea behind evolution is that organisms acquire different features over time as a result of their interactions with their environment. Many scientists have developed 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 individual requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical system of taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or absence of certain traits can result in changes that can be passed on to future generations.

In the 1930s and 1940s, concepts from various areas, including genetics, natural selection, and particulate inheritance, were brought together to form a modern theorizing of evolution. This defines how evolution occurs by the variations in genes within the population and how these variations change with time due to natural selection. This model, known as genetic drift mutation, gene flow, and sexual selection, is a cornerstone of current evolutionary biology, and can be mathematically explained.

Recent advances in the field of evolutionary developmental biology have revealed how variations can be introduced to a species through genetic drift, mutations, reshuffling genes during sexual reproduction and the movement between populations. These processes, 에볼루션 바카라사이트 as well as others, such as the directional selection process and the erosion of genes (changes to the frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time, as well as changes in phenotype (the expression of genotypes in an individual).

Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking in all areas of biology. In a study by Grunspan et al., it was shown that teaching students about the evidence for evolution boosted their acceptance of evolution during an undergraduate biology course. For more details about how to teach evolution look up The Evolutionary Potency in all Areas of Biology or Thinking Evolutionarily as 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 study living organisms. Evolution is not a distant event, but an ongoing process that continues to be observed today. Viruses evolve to stay away from new drugs and bacteria evolve to resist antibiotics. Animals alter their behavior because of a changing environment. The results are usually visible.

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

In the past, if a certain allele - the genetic sequence that determines colour was found in a group of organisms that interbred, it could become more common than any other allele. As time passes, that could mean that the number of black moths in a particular population could rise. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

Observing evolutionary change in action is easier when a species has a rapid generation turnover like bacteria. 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 shown that mutations can drastically alter the efficiency with which a population reproduces--and so, the rate at which it evolves. It also shows evolution takes time, something that is hard for 에볼루션 슬롯게임 바카라 사이트 (visit) some to accept.

Another example of microevolution is how mosquito genes that are resistant to pesticides are more prevalent in areas where insecticides are used. This is because pesticides cause an exclusive pressure that favors those with resistant genotypes.

The rapidity of evolution has led to a growing recognition of its importance particularly in a world that is largely shaped by human activity. This includes pollution, climate change, and habitat loss, which prevents many species from adapting. Understanding the evolution process can help us make better choices about the future of our planet, and the lives of its inhabitants.