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The Academy's Evolution Site

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

This site provides students, teachers and general readers with a variety of educational resources on evolution. It has important video clips from NOVA and 무료에볼루션 the WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is an emblem of love and harmony in a variety of cultures. It has many practical applications as well, including providing a framework to understand the history of species, 에볼루션코리아 and how they react to changing environmental conditions.

The earliest attempts to depict the biological world focused on separating organisms into distinct categories which had been distinguished by their physical and metabolic characteristics1. These methods, based on sampling of different parts of living organisms, or sequences of short fragments of their DNA significantly expanded the diversity that could be represented in the tree of life2. These trees are largely composed of eukaryotes, while bacteria are largely underrepresented3,4.

Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the requirement for direct observation and 에볼루션 블랙잭 experimentation. We can construct trees by using molecular methods, such as the small-subunit ribosomal gene.

The Tree of Life has been dramatically expanded through genome sequencing. However there is a lot of biodiversity to be discovered. This is particularly true for microorganisms that are difficult to cultivate and are usually only found in a single specimen5. A recent study of all genomes known to date 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 their diversity is not fully understood6.

The expanded Tree of Life can be used to evaluate the biodiversity of a specific area and determine if specific habitats need special protection. This information can be used in a variety of ways, from identifying the most effective medicines to combating disease to improving crops. This information is also extremely valuable in conservation efforts. It can help biologists identify the areas most likely to contain cryptic species with potentially important metabolic functions that could be at risk from anthropogenic change. Although funds to safeguard biodiversity are vital however, the most effective method to ensure the preservation of biodiversity around the world 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 known as an evolutionary tree) depicts the relationships between different organisms. Scientists can create an phylogenetic chart which shows the evolutionary relationships between taxonomic categories using molecular information and morphological differences or similarities. Phylogeny is essential in understanding the evolution of biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 Determines the relationship between organisms that have similar traits and evolved from an ancestor with common traits. These shared traits may be analogous, or homologous. Homologous characteristics are identical in their evolutionary paths. Analogous traits may look similar, but they do not have the same origins. Scientists group similar traits together into a grouping called a Clade. For instance, all of the organisms that make up a clade share the trait of having amniotic eggs and evolved from a common ancestor which had eggs. The clades then join to form a phylogenetic branch to determine which organisms have the closest connection to each other.

To create a more thorough and accurate phylogenetic tree, scientists rely on molecular information from DNA or RNA to establish the relationships among organisms. This information is more precise than morphological information and provides evidence of the evolutionary history of an organism or group. Molecular data allows researchers to determine the number of species who share the same ancestor and estimate their evolutionary age.

The phylogenetic relationship can be affected by a variety of factors, including the phenotypic plasticity. This is a type of behavior that alters due to specific environmental conditions. This can cause a particular trait to appear more like a species another, clouding the phylogenetic signal. This issue can be cured by using cladistics. This is a method that incorporates an amalgamation of homologous and analogous traits in the tree.

Additionally, phylogenetics can help determine the duration and rate at which speciation occurs. This information can aid conservation biologists to make decisions about the species they should safeguard from extinction. Ultimately, it is the preservation of phylogenetic diversity which will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time as a result of their interactions with their environment. Many scientists have developed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its individual requirements, the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern taxonomy system that is hierarchical and Jean-Baptiste Lamarck (1844-1829), who believed that the usage or non-use of traits can lead to changes that can be passed on to future generations.

In the 1930s and 1940s, concepts from various fields, including genetics, natural selection, and particulate inheritance - came together to form the current synthesis of evolutionary theory that explains how evolution occurs through the variation of genes within a population, and how these variants change over time due to natural selection. This model, known as genetic drift mutation, gene flow and sexual selection, is the foundation of the current evolutionary biology and can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have shown that variations can be introduced into a species via mutation, genetic drift and reshuffling of genes during sexual reproduction, as well as through the movement of populations. These processes, along with others such as directionally-selected selection and erosion of genes (changes in frequency of genotypes over time), can lead towards evolution. Evolution is defined as changes in the genome over time, as well as changes in the phenotype (the expression of genotypes within individuals).

Students can better understand the concept of phylogeny by using evolutionary thinking throughout all areas of biology. In a recent study conducted by Grunspan and co. It was found that teaching students about the evidence for evolution increased their acceptance of evolution during a college-level course in biology. To learn more about how to teach about evolution, 에볼루션 바카라 체험 look up The Evolutionary Potential in all Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Scientists have studied evolution by looking in the past--analyzing fossils and comparing species. They also study living organisms. But evolution isn't just something that occurred in the past, it's an ongoing process taking place right now. Bacteria transform and resist antibiotics, viruses re-invent themselves and elude new medications, and animals adapt their behavior to the changing climate. The changes that result are often evident.

It wasn't until late 1980s that biologists began to realize that natural selection was also at work. The key to this is that different traits can confer a different rate of survival and reproduction, and can be passed on from one generation to another.

In the past, if one allele - the genetic sequence that determines color - was found in a group of organisms that interbred, it could become more prevalent than any other allele. Over time, this would mean that the number of moths sporting black pigmentation in a population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

Monitoring evolutionary changes in action is easier when a species has a fast generation turnover like bacteria. Since 1988, Richard Lenski, a biologist, has studied twelve populations of E.coli that are descended from a single strain. The samples of each population were taken regularly, and more than 50,000 generations of E.coli have passed.

Lenski's research has revealed that mutations can alter the rate of change and the rate at which a population reproduces. It also demonstrates that evolution takes time, which is hard for some to accept.

Another example of microevolution is that mosquito genes that are resistant to pesticides appear more frequently in areas where insecticides are used. This is due to the fact that the use of pesticides creates a pressure that favors people with resistant genotypes.

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