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The Academy's Evolution Site

Biology is one of the most fundamental concepts in biology. The Academies have been active for a long time in helping people who are interested in science understand the concept of evolution and how it affects every area of scientific inquiry.

This site provides teachers, students and general readers with a range of learning resources about evolution. It contains key video clips from NOVA and WGBH produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol of the interconnectedness of life. It is seen in a variety of cultures and spiritual beliefs as symbolizing unity and love. It has numerous practical applications as well, including providing a framework for understanding the history of species, and how they respond to changes in environmental conditions.

The earliest attempts to depict the world of biology focused on categorizing species into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods rely on the collection of various parts of organisms or short fragments of DNA, 에볼루션 룰렛 have greatly increased the diversity of a Tree of Life2. The trees are mostly composed of eukaryotes, while bacterial diversity is vastly underrepresented3,4.

Genetic techniques have significantly expanded our ability to visualize the Tree of Life by circumventing the need for direct observation and experimentation. Trees can be constructed by using molecular methods like the small-subunit ribosomal gene.

Despite the dramatic expansion of the Tree of Life through genome sequencing, a large amount of biodiversity is waiting to be discovered. This is particularly true of microorganisms, which can be difficult to cultivate and are typically only found in a single specimen5. A recent study of all genomes that are known has created a rough draft of the Tree of Life, including numerous archaea and bacteria that have not been isolated and which are not well understood.

This expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, which can help to determine if specific habitats require protection. This information can be utilized in a variety of ways, from identifying new medicines to combating disease to enhancing the quality of crop yields. This information is also extremely valuable to conservation efforts. It can aid biologists in identifying areas most likely to have cryptic species, which could have important metabolic functions and be vulnerable to human-induced change. While funds to protect biodiversity are important, the best method to protect the biodiversity of the world is to equip the people of developing nations with the knowledge they need to act locally and support conservation.

Phylogeny

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

A basic phylogenetic Tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar characteristics and have evolved from an ancestor 에볼루션 무료체험 that shared traits. These shared traits are either analogous or homologous. Homologous traits are similar in their underlying evolutionary path and analogous traits appear similar, but do not share the identical origins. Scientists organize similar traits into a grouping known as a the clade. For instance, all the organisms in a clade have the characteristic of having amniotic eggs and evolved from a common ancestor which had these eggs. A phylogenetic tree can be constructed by connecting the clades to determine the organisms that are most closely related to each other.

For a more detailed and 에볼루션 바카라사이트 accurate phylogenetic tree scientists make use of molecular data from DNA or RNA to identify the relationships among 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 identify the number of species that share a common ancestor and to estimate their evolutionary age.

The phylogenetic relationships of organisms are influenced by many factors, including phenotypic plasticity a type of behavior that changes in response to unique environmental conditions. This can cause a particular trait to appear more like a species other species, which can obscure the phylogenetic signal. This problem can be addressed by using cladistics. This is a method that incorporates an amalgamation of analogous and homologous features in the tree.

Furthermore, phylogenetics may help predict the duration and 에볼루션 코리아 rate of speciation. This information can help conservation biologists make decisions about the species they should safeguard from the threat of extinction. In the end, it is the conservation of phylogenetic variety that will lead to an ecosystem that is balanced and complete.

Evolutionary Theory

The fundamental concept in evolution is that organisms alter over time because of their interactions with their environment. Many theories of evolution have been developed by a variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing slowly according to its needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits causes changes that could be passed on to the offspring.

In the 1930s and 1940s, theories from various fields, 에볼루션 코리아 such as natural selection, genetics & particulate inheritance, merged to form a contemporary synthesis of evolution theory. This describes how evolution occurs by the variation of genes in the population, and how these variations change with time due to natural selection. This model, called genetic drift or mutation, gene flow and sexual selection, is a cornerstone of modern evolutionary biology and can be mathematically explained.

Recent discoveries in the field of evolutionary developmental biology have demonstrated that variations can be introduced into a species through mutation, genetic drift and reshuffling of genes during sexual reproduction, and also by migration between populations. These processes, along with others, such as the directional selection process and the erosion of genes (changes to the frequency of genotypes over time) can lead to evolution. Evolution is defined as changes in the genome over time, as well as changes in phenotype (the expression of genotypes in individuals).

Incorporating evolutionary thinking into all aspects of biology education can improve student understanding of the concepts of phylogeny and evolutionary. In a recent study conducted by Grunspan et al. It was demonstrated that teaching students about the evidence for evolution increased their acceptance of evolution during a college-level course in biology. For more details about how to teach evolution look up The Evolutionary Potency in all Areas of Biology or Thinking Evolutionarily: 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 observe living organisms. But evolution isn't a thing that occurred in the past, it's an ongoing process that is that is taking place right now. Bacteria evolve and resist antibiotics, 에볼루션 무료체험 viruses re-invent themselves and elude new medications and animals alter their behavior to the changing climate. The results are often apparent.

It wasn't until the late 1980s when biologists began to realize that natural selection was also in action. The key is the fact that different traits confer the ability to survive at different rates and reproduction, and can be passed down from generation to generation.

In the past when one particular allele, the genetic sequence that controls coloration - was present in a population of interbreeding organisms, it might rapidly become more common than other alleles. Over time, this would mean that the number of moths sporting black pigmentation in a group may increase. The same is true for 에볼루션 무료체험 many other characteristics--including morphology and behavior--that vary among populations of organisms.

Monitoring evolutionary changes in action is easier when a particular species has a rapid 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 from each population are taken regularly and more than 500.000 generations have passed.

Lenski's work has demonstrated that a mutation can profoundly alter the speed at which a population reproduces and, consequently the rate at which it evolves. It also proves that evolution takes time, a fact that some find difficult to accept.

Microevolution can be observed in the fact that mosquito genes for resistance to pesticides are more prevalent in areas where insecticides have been used. That's because the use of pesticides creates a pressure that favors those with resistant genotypes.

The rapidity of evolution has led to an increasing recognition of its importance 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 will assist you in making better choices about the future of the planet and its inhabitants.