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The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies are committed to helping those interested in the sciences understand evolution theory and how it can be applied across all areas of scientific research.

This site provides students, teachers and general readers with a wide range of learning resources about evolution. It has 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 has many practical applications as well, such as providing a framework for understanding the history of species, 에볼루션 코리아 and how they respond to changing environmental conditions.

Early attempts to describe the world of biology were based on categorizing organisms based 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. However these trees are mainly made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4.

By avoiding the need for direct experimentation and observation genetic techniques have made it possible to depict the Tree of Life in a more precise manner. Particularly, molecular methods enable us to create trees using sequenced markers such as the small subunit ribosomal RNA gene.

Despite the massive expansion of the Tree of Life through genome sequencing, a large amount of biodiversity is waiting to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are typically only represented in a single specimen5. A recent analysis of all genomes produced a rough draft of a Tree of Life. This includes a wide range of archaea, bacteria, and other organisms that haven't yet been identified or their diversity is not thoroughly understood6.

This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, assisting to determine if specific habitats require protection. This information can be used in a variety of ways, from identifying new remedies to fight diseases to enhancing the quality of crops. This information is also valuable to conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species with important metabolic functions that could be at risk of anthropogenic changes. Although funds to protect biodiversity are crucial but the most effective way to preserve the world's biodiversity is for more people in developing countries to be empowered with the knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny, also known as an evolutionary tree, illustrates the connections between different groups of organisms. Utilizing molecular data similarities and differences in morphology, or ontogeny (the process of the development of an organism) scientists can create an phylogenetic tree that demonstrates the evolution of taxonomic groups. Phylogeny is crucial in understanding biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that evolved from common ancestors. These shared traits could be either analogous or homologous. Homologous traits share their underlying evolutionary path while analogous traits appear similar, but do not share the same origins. Scientists combine similar traits into a grouping known as a clade. For instance, all the organisms in a clade have the characteristic of having amniotic egg and evolved from a common ancestor who had eggs. The clades are then connected to create a phylogenetic tree to identify organisms that have the closest relationship to.

For a more detailed and accurate phylogenetic tree, scientists use molecular data from DNA or RNA to establish the relationships between organisms. This information is more precise than morphological information and gives evidence of the evolutionary background of an organism or group. The analysis of molecular data can help researchers determine the number of species who share an ancestor common to them and 무료에볼루션, Elitsy.Ru, estimate their evolutionary age.

The phylogenetic relationships between species are influenced by many factors, including phenotypic flexibility, a kind of behavior that alters in response to specific environmental conditions. This can cause a particular trait to appear more similar in one species than another, obscuring the phylogenetic signal. However, this issue can be cured by the use of techniques such as cladistics which include a mix of homologous and analogous features into the tree.

In addition, phylogenetics can help predict the duration and rate of speciation. This information can help conservation biologists decide which species they should protect from extinction. In the end, it is the conservation of phylogenetic diversity that will result in an ecosystem that is complete and balanced.

Evolutionary Theory

The central theme of evolution is that organisms acquire distinct characteristics over time as a result of their interactions with their surroundings. Several theories of evolutionary change have been developed by a variety of scientists, 에볼루션 슬롯게임 including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing gradually according to its needs and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits can cause changes that can be passed on to the offspring.

In the 1930s and 1940s, concepts from a variety of fields -- including natural selection, genetics, and particulate inheritance--came together to form the modern evolutionary theory that explains how evolution occurs through the variations of genes within a population, and how those variants change over time as a result of natural selection. This model, which encompasses genetic drift, mutations as well as gene flow and sexual selection can be mathematically described.

Recent discoveries in evolutionary developmental biology have shown how variations can be introduced to a species by genetic drift, mutations, reshuffling genes during sexual reproduction and the movement between populations. These processes, in conjunction with other ones like the directional selection process and the erosion of genes (changes in the frequency of genotypes over time) can lead to 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 gain a better understanding of the concept of phylogeny by using evolutionary thinking throughout all areas of biology. In a study by Grunspan and co. It was found that teaching students about the evidence for evolution increased their acceptance of evolution during an undergraduate biology course. For more information on how to teach about evolution, please see The Evolutionary Potential of all Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution through looking back, studying fossils, comparing species and studying living organisms. Evolution is not a distant event; it is an ongoing process that continues to be observed today. Viruses reinvent themselves to avoid new antibiotics and bacteria transform to resist antibiotics. Animals adapt their behavior as a result of the changing environment. The results are usually evident.

It wasn't until the late 1980s that biologists began realize that natural selection was in action. The key is the fact that different traits result in an individual rate of survival and reproduction, and they can be passed on from one generation to another.

In the past, if a certain allele - the genetic sequence that determines colour was present in a population of organisms that interbred, it could become more prevalent than any other allele. In time, 에볼루션 코리아 this could mean that the number of moths that have black pigmentation in a population may increase. 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 particular species has a fast generation turnover like bacteria. Since 1988, Richard Lenski, a biologist, has tracked twelve populations of E.coli that are descended from one strain. The samples of each population have been collected regularly and more than 50,000 generations of E.coli have passed.

Lenski's research has revealed that mutations can drastically alter the rate at which a population reproduces--and so the rate at which it changes. It also demonstrates that evolution takes time, a fact that is difficult for some to accept.

Another example of microevolution is how mosquito genes that confer resistance to pesticides appear more frequently in populations in which insecticides are utilized. This is because pesticides cause an enticement that favors individuals who have resistant genotypes.

The rapid pace at which evolution can take place has led to an increasing recognition of its importance in a world that is shaped by human activity, including climate change, pollution, and the loss of habitats that prevent the species from adapting. Understanding the evolution process can aid you in making better decisions about the future of the planet and its inhabitants.