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The Academy's Evolution Site

Biology is a key concept in biology. The Academies are committed to helping those interested in the sciences understand evolution theory and how it can be applied across all areas of scientific research.

This site provides a wide range of resources for teachers, students as well as general readers about evolution. It includes important video clips from NOVA and the WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol that represents the interconnectedness of all life. It is an emblem of love and harmony in a variety of cultures. It can be used in many practical ways in addition to providing a framework for understanding the history of species, and how they react to changes in environmental conditions.

Early attempts to describe the biological world were founded on categorizing organisms on their metabolic and physical characteristics. These methods, which are based on the collection of various parts of organisms or short DNA fragments, have significantly increased the diversity of a Tree of Life2. These trees are largely composed by eukaryotes, and the diversity of bacterial species is greatly underrepresented3,4.

By avoiding the necessity for direct observation and experimentation genetic techniques have allowed us to depict the Tree of Life in a more precise manner. In particular, molecular methods allow us to construct trees by using sequenced markers such as the small subunit ribosomal RNA gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is still a lot of diversity to be discovered. This is particularly the case for microorganisms which are difficult to cultivate, and are usually found in one sample5. A recent analysis of all genomes resulted in a rough draft of a Tree of Life. This includes a large number of bacteria, archaea and other organisms that have not yet been isolated, or their diversity is not thoroughly understood6.

This expanded Tree of Life is particularly useful for assessing the biodiversity of an area, which can help to determine if certain habitats require protection. This information can be utilized in a range of ways, from identifying new remedies to fight diseases to enhancing the quality of the quality of crops. This information is also extremely useful for conservation efforts. It can aid biologists in identifying areas most likely to be home to cryptic species, which may perform important metabolic functions and be vulnerable to the effects of human activity. While funds to protect biodiversity are essential, the best method to protect the world's biodiversity is to equip more people in developing nations with the knowledge they need to act locally and 에볼루션 블랙잭 에볼루션 무료 바카라 바카라 (head to fewpal.com) support conservation.

Phylogeny

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

A basic phylogenetic tree (see Figure PageIndex 10 ) is a method of identifying the relationships between organisms with similar traits that evolved from common ancestors. These shared traits could be analogous, or homologous. Homologous traits are similar in their evolutionary origins, while analogous traits look like they do, but don't have the same origins. Scientists put similar traits into a grouping known as a the clade. Every organism in a group have a common characteristic, for example, amniotic egg production. They all evolved from an ancestor who had these eggs. The clades are then linked to form a phylogenetic branch that can determine the organisms with the closest relationship.

To create a more thorough and precise phylogenetic tree scientists use molecular data from DNA or RNA to identify the relationships between organisms. This information is more precise than morphological data and provides evidence of the evolution history of an organism or group. Researchers can use Molecular Data to estimate the age of evolution of organisms and identify how many organisms share an ancestor common to all.

The phylogenetic relationship can be affected by a variety of factors, including phenotypicplasticity. This is a kind of behavior that changes due to specific environmental conditions. This can make a trait appear more similar to one species than to the other, obscuring the phylogenetic signals. This problem can be addressed by using cladistics, which is a a combination of homologous and analogous features in the tree.

In addition, phylogenetics can help predict the time and pace of speciation. This information can assist conservation biologists in deciding which species to safeguard from disappearance. In the end, it is the conservation of phylogenetic diversity that will result in an ecosystem that is balanced and complete.

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 could evolve according to its own needs and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who believed that the use or absence of certain traits can result in changes that are passed on to the

In the 1930s and 1940s, theories from various areas, including natural selection, genetics & particulate inheritance, came together to form a contemporary theorizing of evolution. This describes how evolution is triggered by the variation in genes within a population and how these variants change with time due to natural selection. This model, called genetic drift or mutation, gene flow, and sexual selection, is a key element of current evolutionary biology, and is mathematically described.

Recent discoveries in the field of evolutionary developmental biology have revealed that variations can be introduced into a species via mutation, genetic drift, and reshuffling of genes in sexual reproduction, and also by migration between populations. These processes, along with others such as directional selection or genetic erosion (changes in the frequency of the genotype over time) can result in evolution, which is defined by changes in the genome of the species over time, and the change in phenotype as time passes (the expression of that genotype in the individual).

Students can better understand phylogeny by incorporating evolutionary thinking in all areas of biology. A recent study by Grunspan and colleagues, for instance demonstrated that teaching about the evidence that supports evolution increased students' acceptance of evolution in a college biology course. To find out more about how to teach about evolution, see The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution into Life Sciences Education.

Evolution in Action

Traditionally scientists have studied evolution through looking back--analyzing fossils, comparing species, and studying living organisms. Evolution is not a distant event; it is a process that continues today. Bacteria transform and resist antibiotics, viruses evolve and are able to evade new medications, and animals adapt their behavior to the changing climate. The changes that occur are often visible.

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

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 other allele. Over time, that would mean that the number of black moths in a particular population could rise. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

It is easier to see evolution when an organism, like bacteria, has a rapid generation turnover. Since 1988, 에볼루션 무료체험 Richard Lenski, a biologist, has tracked twelve populations of E.coli that descend from a single strain. Samples from each population have been taken regularly, and more than 500.000 generations of E.coli have passed.

Lenski's work has demonstrated that mutations can drastically alter the rate at the rate at which a population reproduces, and consequently, the rate at which it evolves. It also demonstrates that evolution takes time, which is difficult for some to accept.

Another example of microevolution is how mosquito genes that confer resistance to pesticides appear more frequently in areas in which insecticides are utilized. This is due to the fact that the use of pesticides creates a pressure that favors people with resistant genotypes.

The speed at which evolution takes 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 which prevent many species from adapting. Understanding evolution can help you make better decisions about the future of our planet and its inhabitants.