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The Academy's Evolution Site

The concept of biological evolution is among the most important concepts in biology. The Academies have been for a long time involved in helping those interested in science comprehend the concept of evolution and how it influences every area of scientific inquiry.

This site provides students, teachers and general readers with a range of learning 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, an ancient symbol, represents the interconnectedness of all life. It is an emblem of love and 에볼루션 무료 바카라에볼루션 바카라사이트 - evolution-korea97811.wikinewspaper.com - unity across many cultures. It can be used in many practical ways as well, including providing a framework for understanding the history of species and how they respond to changes in environmental conditions.

Early approaches to depicting the biological world focused on separating organisms into distinct categories that were distinguished by physical and metabolic characteristics1. These methods depend on the collection of various parts of organisms, or DNA fragments, have significantly increased the diversity of a tree of Life2. However these trees are mainly composed of eukaryotes; bacterial diversity is not represented in a large way3,4.

In avoiding the necessity of direct experimentation and observation genetic techniques have enabled us to represent the Tree of Life in a more precise manner. We can construct trees by using molecular methods like the small-subunit ribosomal gene.

Despite the massive growth of the Tree of Life through genome sequencing, a large amount of biodiversity remains to be discovered. This is especially true for microorganisms that are difficult to cultivate, and which are usually only found in one sample5. A recent analysis of all genomes produced a rough draft of the Tree of Life. This includes a variety of bacteria, archaea and other organisms that haven't yet been isolated or their diversity is not well understood6.

This expanded Tree of Life can be used to assess the biodiversity of a particular area and determine if specific habitats need special protection. This information can be utilized in a variety of ways, from identifying new treatments to fight disease to enhancing crops. This information is also beneficial for conservation efforts. It can help biologists identify areas that are most likely to have cryptic species, which could have vital metabolic functions, and could be susceptible to the effects of human activity. While funding to protect biodiversity are important, the most effective method to protect the biodiversity of the world is to equip more people in developing countries with the information they require to act locally and promote conservation.

Phylogeny

A phylogeny (also called an evolutionary tree) shows the relationships between different organisms. Scientists can build an phylogenetic chart which shows the evolutionary relationships between taxonomic groups using molecular data and morphological similarities or differences. Phylogeny is essential in understanding evolution, biodiversity and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar characteristics and have evolved from an ancestor with common traits. These shared traits may be homologous, or analogous. Homologous traits are similar in their evolutionary roots, while analogous traits look like they do, but don't have the same origins. Scientists group similar traits into a grouping called a Clade. For instance, all the organisms that make up a clade have the characteristic of having amniotic egg and evolved from a common ancestor which had these eggs. A phylogenetic tree is constructed by connecting the clades to identify the organisms that are most closely related to one another.

For a more detailed and precise phylogenetic tree scientists rely on molecular information from DNA or RNA to determine the relationships among organisms. This information is more precise and provides evidence of the evolution of an organism. Molecular data allows researchers to identify the number of species that have the same ancestor and estimate their evolutionary age.

The phylogenetic relationships between species can be affected by a variety of factors, including phenotypic flexibility, a kind of behavior that alters in response to specific environmental conditions. This can cause a characteristic to appear more similar to one species than another, clouding the phylogenetic signal. This problem can be mitigated by using cladistics, which incorporates the combination of analogous and homologous features in the tree.

Additionally, phylogenetics can help determine the duration and speed of speciation. This information can help conservation biologists decide which species they should protect from extinction. It is ultimately the preservation of phylogenetic diversity that will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The fundamental concept in evolution is that organisms change over time due to their interactions with their environment. 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 would evolve according to its individual needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created 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 can be passed on to future generations.

In the 1930s & 1940s, concepts from various fields, such as genetics, natural selection and particulate inheritance, were brought together to create a modern synthesis of evolution theory. This defines how evolution is triggered by the variations in genes within the population, and how these variations change over time as a result of natural selection. This model, known as genetic drift, mutation, gene flow and sexual selection, is a key element of the current evolutionary biology and can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated that variation can be introduced into a species through mutation, genetic drift, and reshuffling genes during sexual reproduction, and also through migration between populations. These processes, along with other ones like directional selection and 무료 에볼루션 genetic erosion (changes in the frequency of a genotype over time) can result in evolution, which is defined by change in the genome of the species over time, and the change in phenotype over time (the expression of the genotype within the individual).

Incorporating evolutionary thinking into all areas of biology education can increase students' understanding of phylogeny and 에볼루션 블랙잭 evolutionary. In a study by Grunspan et al. It was demonstrated that teaching students about the evidence for evolution increased their understanding of evolution during an undergraduate biology course. For more information on how to teach evolution, see The Evolutionary Power of Biology in All Areas of Biology or Thinking Evolutionarily as a Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Scientists have traditionally studied evolution by looking in the past, analyzing fossils and comparing species. They also study living organisms. However, evolution isn't something that occurred in the past; it's an ongoing process, happening today. Bacteria evolve and resist antibiotics, viruses evolve and elude new medications and animals change their behavior in response to the changing climate. The results are often evident.

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 various characteristics result in different rates of survival and reproduction (differential fitness), 에볼루션 슬롯 and can be transferred from one generation to the next.

In the past, if an allele - the genetic sequence that determines colour - was found in a group of organisms that interbred, it might become more common than any other allele. Over time, that would mean the number of black moths in a population could 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 much easier when a species has a fast generation turnover such as 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 regularly and over 500.000 generations have been observed.

Lenski's research has revealed that mutations can alter the rate of change and the rate of a population's reproduction. It also shows that evolution takes time--a fact that some people are unable to accept.

Microevolution can also be seen in the fact that mosquito genes for pesticide resistance are more prevalent in areas that have used insecticides. This is because pesticides cause an enticement that favors individuals who have resistant genotypes.

The rapid pace of evolution taking place has led to an increasing appreciation of its importance in a world that is shaped by human activity, including climate change, pollution, and the loss of habitats which prevent many species from adjusting. Understanding the evolution process can help us make smarter choices about the future of our planet and the life of its inhabitants.