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The Academy's Evolution Site

Biology is one of the most important concepts in biology. The Academies have long been involved in helping those interested in science comprehend the concept of evolution and how it permeates every area of scientific inquiry.

This site provides students, teachers and general readers with a wide range of learning resources about evolution. It includes the most important video clips from NOVA and WGBH's 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 react to changes in environmental conditions.

The first attempts at depicting the world of biology focused on the classification of organisms into distinct categories that were identified by their physical and metabolic characteristics1. These methods, which relied on the sampling of different parts of living organisms or sequences of short fragments of their DNA significantly increased the variety that could be included in a tree of life2. However the trees are mostly made up of eukaryotes. Bacterial diversity remains vastly underrepresented3,4.

Genetic techniques have greatly broadened our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. We can create trees using molecular methods like the small-subunit ribosomal gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is a lot of biodiversity to be discovered. This is particularly true of microorganisms, which can be difficult to cultivate and 에볼루션게이밍 are often only found in a single specimen5. A recent analysis of all genomes produced an initial draft of a Tree of Life. This includes a wide range of bacteria, archaea and other organisms that haven't yet been identified or whose diversity has not been thoroughly understood6.

The expanded Tree of Life is particularly useful in assessing the diversity of an area, which can help to determine if specific habitats require protection. This information can be used in a variety of ways, 에볼루션 코리아 including finding new drugs, battling diseases and improving the quality of crops. The information is also incredibly useful in conservation efforts. It helps biologists discover areas that are most likely to be home to species that are cryptic, which could perform important metabolic functions, and could be susceptible to changes caused by humans. Although funding to protect biodiversity are crucial but the most effective way to ensure the preservation of biodiversity around the world is for more people in developing countries to be equipped with the knowledge to take action locally to encourage conservation from within.

Phylogeny

A phylogeny (also known as an evolutionary tree) shows the relationships between species. Using molecular data similarities and differences in morphology or ontogeny (the process of the development of an organism), scientists can build a phylogenetic tree that illustrates the evolutionary relationship between taxonomic categories. Phylogeny is crucial in understanding the evolution of biodiversity, evolution and genetics.

A basic phylogenetic Tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar traits and have evolved from an ancestor that shared traits. These shared traits can be either homologous or analogous. Homologous traits are similar in their evolutionary roots, while analogous traits look similar but do not have the same ancestors. Scientists group similar traits into a grouping called a clade. For instance, all of the organisms in a clade share the characteristic of having amniotic eggs. They evolved from a common ancestor who had these eggs. A phylogenetic tree is constructed by connecting the clades to identify the species who are the closest to each other.

For a more precise and 에볼루션 precise phylogenetic tree scientists make use of molecular data from DNA or RNA to determine the relationships between organisms. This information is more precise and gives evidence of the evolutionary history of an organism. Molecular data allows researchers to identify the number of species that have a common ancestor and to estimate their evolutionary age.

The phylogenetic relationships of a species can be affected by a variety of factors, including phenotypicplasticity. This is a kind of behavior that alters as a result of specific environmental conditions. This can cause a trait to appear more similar to one species than to the other, obscuring the phylogenetic signals. However, this problem can be reduced by the use of methods such as cladistics that include a mix of similar and homologous traits into the tree.

Furthermore, phylogenetics may aid in predicting the time and pace of speciation. This information can assist conservation biologists in making decisions about which species to safeguard from disappearance. It is ultimately the preservation of phylogenetic diversity which will lead to an ecosystem that is complete and balanced.

Evolutionary Theory

The central theme in evolution is that organisms alter over time because of their interactions with their environment. Many scientists have proposed 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 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 believed that the use or absence of traits can cause changes that are passed on to the

In the 1930s and 1940s, theories from various areas, including genetics, natural selection and particulate inheritance, merged to create a modern evolutionary theory. This defines how evolution occurs by the variation in genes within the population, and how these variants alter over time due to natural selection. This model, called genetic drift mutation, gene flow and sexual selection, is the foundation of current evolutionary biology, and can be mathematically explained.

Recent developments in the field of evolutionary developmental biology have demonstrated how variation can be introduced to a species through mutations, genetic drift or reshuffling of genes in sexual reproduction and migration between populations. These processes, as well as others, such as directionally-selected selection and erosion of genes (changes to the frequency of genotypes over time) can result in evolution. Evolution is defined by changes in the genome over time and changes in phenotype (the expression of genotypes in an individual).

Incorporating evolutionary thinking into all areas of biology education could increase student understanding of the concepts of phylogeny and evolution. In a study by Grunspan et al., it was shown that teaching students about the evidence for evolution increased their understanding of evolution in an undergraduate biology course. For more information on how to teach evolution, see The Evolutionary Potency in All Areas of Biology or Thinking Evolutionarily: a Framework for Integrating Evolution into Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution by looking back--analyzing fossils, comparing species, and observing living organisms. Evolution is not a distant event, but an ongoing process. Bacteria evolve and resist antibiotics, viruses re-invent themselves and are able to evade new medications and animals alter their behavior to the changing climate. The results are usually easy to see.

It wasn't until the 1980s that biologists began to realize that natural selection was at work. The key to this is that different traits confer the ability to survive at different rates 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 - appeared in a population of organisms that interbred, it could become more common than other allele. In time, this could mean that the number of black moths in the population could increase. The same is true for 에볼루션 many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to see evolutionary change when an organism, like bacteria, has a rapid generation turnover. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. bacteria that descend from a single strain. samples of each population are taken regularly and more than 50,000 generations have now been observed.

Lenski's work has demonstrated that mutations can drastically alter the efficiency with which a population reproduces--and so the rate at which it alters. It also demonstrates that evolution is slow-moving, a fact that some find hard to accept.

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

The speed of evolution taking place has led to a growing recognition of its importance in a world that is shaped by human activity--including climate change, pollution, and the loss of habitats that hinder the species from adapting. Understanding the evolution process can aid you in making better decisions regarding the future of the planet and 에볼루션사이트 its inhabitants.