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The Academy's Evolution Site

Biological evolution is one of the most central concepts in biology. The Academies are involved in helping those interested in science comprehend the evolution theory and how it can be applied across all areas of scientific research.

This site provides teachers, students and general readers with a range of educational resources on 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 that represents the interconnectedness of life. It is a symbol of love and unity across many cultures. It also has important practical uses, like providing a framework to understand the history of species and how they react to changes in the environment.

The first attempts to depict the biological world were built on categorizing organisms based on their physical and metabolic characteristics. These methods depend on the collection of various parts of organisms or short fragments of DNA have significantly increased the diversity of a tree of Life2. However the trees are mostly comprised of eukaryotes, and bacterial diversity is not represented in a large way3,4.

Genetic techniques have greatly broadened our ability to represent the Tree of Life by circumventing the requirement for direct observation and experimentation. Trees can be constructed using molecular methods like the small-subunit ribosomal gene.

Despite the rapid growth of the Tree of Life through genome sequencing, much biodiversity still remains to be discovered. This is especially true of microorganisms that are difficult to cultivate and are often only present in a single specimen5. A recent study of all known genomes has produced a rough draft of the Tree of Life, including a large number of bacteria and archaea that are not isolated and which are not well understood.

This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, 에볼루션코리아 - Bbs.pku.Edu.cn, helping to determine if certain habitats require protection. The information can be used in a variety of ways, from identifying the most effective treatments to fight disease to enhancing the quality of crops. This information is also extremely useful in conservation efforts. It helps biologists determine the areas that are most likely to contain cryptic species with important metabolic functions that may be at risk of anthropogenic changes. While funding to protect biodiversity are essential, the best method to preserve the world's biodiversity is to empower more people in developing nations with the necessary knowledge to act locally and promote conservation.

Phylogeny

A phylogeny (also called an evolutionary tree) shows the relationships between species. Scientists can construct an phylogenetic chart which shows the evolution of taxonomic categories using molecular information and morphological similarities or differences. The concept of phylogeny is fundamental to understanding evolution, biodiversity and genetics.

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

Scientists use DNA or RNA molecular data to construct a phylogenetic graph that is more precise and detailed. This information is more precise than morphological data and gives evidence of the evolutionary background of an organism or group. Researchers can utilize Molecular Data to determine the evolutionary age of organisms and identify the number of organisms that share a common ancestor.

The phylogenetic relationships between organisms 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 particular trait to appear more similar to one species than other species, which can obscure the phylogenetic signal. However, this problem can be cured by the use of methods such as cladistics which incorporate a combination of homologous and analogous features into the tree.

Additionally, phylogenetics can aid in predicting the length and speed of speciation. This information can assist conservation biologists in making decisions about which species to save from the threat of extinction. In the end, it's the preservation of phylogenetic diversity which will create a complete and balanced ecosystem.

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, 에볼루션 바카라 체험 에볼루션 바카라 체험 에볼루션 바카라 무료 (Www.Bioguiden.Se) such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism could evolve according to its own requirements as well as 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 usage 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 synthesis of evolutionary theory that explains how evolution happens through the variation of genes within a population and how these variants change in time as a result of natural selection. This model, which includes mutations, genetic drift, gene flow and sexual selection can be mathematically described.

Recent discoveries in the field of evolutionary developmental biology have demonstrated how variation can be introduced to a species through mutations, genetic drift, reshuffling genes during sexual reproduction, and even migration between populations. These processes, in conjunction with others, such as the directional selection process and the erosion of genes (changes in 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 within individuals).

Incorporating evolutionary thinking into all aspects of biology education can increase students' understanding of phylogeny as well as evolution. A recent study conducted by Grunspan and colleagues, for 에볼루션 바카라 무료 instance, showed that teaching about the evidence that supports evolution increased students' understanding of evolution in a college-level biology course. For more details about how to teach evolution read The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily A Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Scientists have studied evolution through looking back 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 that is happening in the present. Bacteria mutate and resist antibiotics, viruses reinvent themselves and are able to evade new medications and animals alter their behavior to a changing planet. The changes that result are often apparent.

It wasn't until late 1980s that biologists realized that natural selection could be seen in action, as well. The key to this is that different traits can confer an individual rate of survival and reproduction, and they can be passed on from generation to generation.

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 common than any other allele. As time passes, this could mean that the number of moths with 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.

The ability to observe evolutionary change is much easier when a species has a fast generation turnover, as with 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 been observed to have passed.

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

Microevolution can be observed in the fact that mosquito genes for 에볼루션 바카라사이트 pesticide resistance are more common in populations where insecticides are used. This is because the use of pesticides creates a pressure that favors people with resistant genotypes.

The rapid pace of evolution taking place has led to a growing appreciation of its importance in a world that is shaped by human activities, including climate change, pollution, and the loss of habitats that hinder many species from adapting. Understanding evolution can help us make better decisions regarding the future of our planet, 에볼루션 바카라 무료 as well as the lives of its inhabitants.