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The Academy's Evolution Site

Biology is a key concept in biology. The Academies are committed to helping those who are interested in the sciences 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 wide range of educational resources on 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 symbolizes the interconnectedness of all life. It appears in many religions and cultures as an emblem of unity and love. It can be used in many practical ways as well, such as providing a framework for understanding the evolution of species and how they respond to changes in environmental conditions.

Early approaches to depicting the world of biology focused on categorizing organisms into distinct categories that had been distinguished by their physical and metabolic characteristics1. These methods, which rely on the sampling of various parts of living organisms, or short DNA fragments, significantly expanded the diversity that could be represented in the tree of life2. These trees are mostly populated by eukaryotes and bacterial diversity is vastly underrepresented3,4.

In avoiding the necessity of direct observation and experimentation genetic techniques have enabled us to depict the Tree of Life in a more precise way. Trees can be constructed by using molecular methods, such as the small-subunit ribosomal gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However there is still a lot of biodiversity to be discovered. This is especially true for microorganisms that are difficult to cultivate, and are typically present in a single sample5. Recent analysis of all genomes resulted in an unfinished 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.

The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, helping to determine if specific habitats require special protection. This information can be utilized in a range of ways, from identifying the most effective remedies to fight diseases to improving crops. This information is also extremely beneficial for conservation efforts. It can help biologists identify those areas that are most likely contain cryptic species with significant metabolic functions that could be at risk of anthropogenic changes. Although funding to protect biodiversity are crucial, ultimately the best way to ensure the preservation of biodiversity around the world is for more people in developing countries to be empowered with the necessary knowledge to act locally in order to promote conservation from within.

Phylogeny

A phylogeny (also known as an evolutionary tree) shows the relationships between different organisms. Using molecular data, morphological similarities and differences or ontogeny (the process of the development of an organism) scientists can construct an phylogenetic tree that demonstrates the evolution of taxonomic groups. The phylogeny of a tree plays an important role in understanding genetics, biodiversity and evolution.

A basic phylogenetic tree (see Figure PageIndex 10 ) identifies the relationships between organisms with similar traits that evolved from common ancestral. These shared traits could be either homologous or analogous. Homologous traits are identical in their evolutionary roots while analogous traits appear similar, but do not share the same origins. Scientists organize similar traits into a grouping called a the clade. For instance, all of the organisms in a clade have the characteristic of having amniotic eggs. They evolved from a common ancestor who had these eggs. A phylogenetic tree can be constructed by connecting clades to identify the organisms that are most closely related to one another.

Scientists make use of DNA or RNA molecular data to build a phylogenetic chart which is more precise and detailed. This information is more precise than the morphological data and provides evidence of the evolutionary history of an individual or group. The analysis of molecular data can help researchers identify the number of species who share a common ancestor and to estimate their evolutionary age.

The phylogenetic relationships between organisms can be affected by a variety of factors, including phenotypic plasticity a type of behavior 에볼루션 코리아 that changes in response to specific environmental conditions. This can cause a characteristic to appear more like a species another, obscuring the phylogenetic signal. However, this problem can be solved through the use of techniques such as cladistics that include a mix of analogous and homologous features into the tree.

Additionally, phylogenetics aids determine the duration and speed at which speciation takes place. This information can help conservation biologists decide which species they should protect from extinction. In the end, it is the conservation of phylogenetic variety that will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept of evolution is that organisms acquire various characteristics over time based on their interactions with their environment. Many scientists have come up with theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would develop according to its own needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of traits can lead to changes that are passed on to the next generation.

In the 1930s and 1940s, ideas from a variety of fields -- including genetics, natural selection and particulate inheritance - came together to form the current evolutionary theory that explains how evolution is triggered by the variations of genes within a population and how those variations change over time as a result of natural selection. This model, which incorporates genetic drift, mutations as well as gene flow and 에볼루션 사이트 에볼루션 룰렛 (Fakenews.Win) sexual selection can be mathematically described mathematically.

Recent advances in evolutionary developmental biology have shown the ways in which variation can be introduced to a species via mutations, genetic drift and reshuffling of genes during sexual reproduction and migration between populations. These processes, as well as others such as directional selection or genetic erosion (changes in the frequency of a 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 as time passes (the expression of the genotype within the individual).

Incorporating evolutionary thinking into all areas of biology education can increase students' understanding of phylogeny as well as evolution. In a recent study conducted by Grunspan and co. It was demonstrated that teaching students about the evidence for evolution boosted their understanding of evolution in an undergraduate biology course. For more details on how to teach evolution look up The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily: a Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally, scientists have studied evolution through looking back, studying fossils, comparing species and observing living organisms. Evolution is not a past event; it is an ongoing process that continues to be observed today. Viruses reinvent themselves to avoid new medications and 에볼루션 코리아 bacteria mutate to resist antibiotics. Animals alter their behavior in the wake of a changing world. The changes that occur are often visible.

However, it wasn't until late 1980s that biologists understood that natural selection can be seen in action, as well. The key is that different traits have different rates of survival and reproduction (differential fitness), and can be passed from one generation to the next.

In the past, if a certain allele - the genetic sequence that determines color - was present in a population of organisms that interbred, it could be more common than any other allele. Over time, this would mean that the number of moths with black pigmentation in a group may 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 much easier when a species has a rapid turnover of its generation like bacteria. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain; samples from each population are taken on a regular basis, and 에볼루션바카라 over 50,000 generations have now been observed.

Lenski's research has shown that a mutation can dramatically alter the rate at which a population reproduces--and so the rate at which it evolves. It also shows evolution takes time, a fact that is difficult for some to accept.

Microevolution can also be seen in the fact that mosquito genes for resistance to pesticides are more prevalent in populations where insecticides have been used. That's because the use of pesticides creates a pressure that favors individuals who have resistant genotypes.

The rapidity of evolution has led to a greater awareness of its significance particularly in a world shaped largely by human activity. This includes the effects of climate change, pollution and habitat loss that hinders many species from adapting. Understanding evolution can assist you in making better choices about the future of the planet and its inhabitants.