The Academy's Evolution Site
Biology is a key concept in biology. The Academies have been active for a long time in helping people who are interested in science understand the theory of evolution and how it permeates all areas of scientific research.
This site provides teachers, students and general readers with a range of learning resources about evolution. It has the most important video clips from NOVA and the WGBH-produced science programs on DVD.
Tree of Life
The Tree of Life, an ancient symbol, symbolizes the interconnectedness of all life. It is a symbol of love and harmony in a variety of cultures. It has many practical applications in addition to providing a framework for understanding the history of species and how they respond to changing environmental conditions.
Early attempts to represent the world of biology were founded on categorizing organisms on their metabolic and physical characteristics. These methods are based on the sampling of different parts of organisms, or fragments of DNA have greatly increased the diversity of a tree of Life2. However these trees are mainly comprised of eukaryotes, and bacterial diversity is still largely unrepresented3,4.
Genetic techniques have greatly broadened our ability to depict the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular techniques enable us to create trees using sequenced markers, such as the small subunit of ribosomal RNA gene.
The Tree of Life has been dramatically expanded through genome sequencing. However, there is still much diversity to be discovered. This is especially true of microorganisms, which can be difficult to cultivate and are often only represented in a single specimen5. A recent analysis of all genomes that are known has created a rough draft of the Tree of Life, including a large number of bacteria and archaea that are not isolated and their diversity is not fully understood6.
This expanded Tree of Life can be used to determine the diversity of a particular area and determine if certain habitats need special protection. The information can be used in a variety of ways, from identifying new remedies to fight diseases to improving crops. The information is also incredibly useful in conservation efforts. It helps biologists discover areas that are likely to be home to species that are cryptic, which could perform important metabolic functions, and could be susceptible to human-induced change. While funding to protect extra resources are important, the most effective method to protect the biodiversity of the world is to equip more people in developing countries with the necessary knowledge to act locally and support conservation.
Phylogeny
A phylogeny, also called an evolutionary tree, illustrates the connections between groups of organisms. Scientists can create a phylogenetic chart that shows the evolution of taxonomic groups using molecular data and morphological differences or similarities. The role of phylogeny is crucial in understanding the relationship between genetics, biodiversity and evolution.
A basic phylogenetic tree (see Figure PageIndex 10 ) identifies the relationships between organisms with similar traits that evolved from common ancestors. These shared traits could be either analogous or homologous. Homologous characteristics are identical in their evolutionary paths. Analogous traits could appear similar, but they do not have the same ancestry. Scientists group similar traits into a grouping known as a the clade. Every organism in a group have a common trait, such as amniotic egg production. They all came from an ancestor that had these eggs. The clades are then connected to create a phylogenetic tree to determine which organisms have the closest relationship to.
To create a more thorough and accurate phylogenetic tree, scientists make use of molecular data from DNA or RNA to identify the relationships between organisms. This information is more precise than morphological information and provides evidence of the evolutionary history of an organism or group. Molecular data allows researchers to identify the number of species who share an ancestor common to them and estimate their evolutionary age.
The phylogenetic relationships of a species can be affected by a variety of factors, including the phenomenon of phenotypicplasticity. This is a kind of behaviour that can change due 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 issue can be cured by using cladistics, which incorporates an amalgamation of analogous and homologous features in the tree.
Furthermore, phylogenetics may help predict the time and pace of speciation. This information can assist conservation biologists in making choices about which species to save from extinction. In the end, it's 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 alter over time because of their interactions with their environment. Many scientists have developed theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274) who believed that an organism would develop according to its own needs and needs, the Swedish taxonomist Carolus Linnaeus (1707-1778) who developed the modern hierarchical taxonomy as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or absence of certain traits can result in changes that are passed on to the next generation.
In the 1930s and 1940s, ideas from different fields, including genetics, natural selection, and particulate inheritance, came together to create a modern synthesis of evolution theory. This defines how evolution occurs by the variations in genes within the population and how these variations change with time due to natural selection. This model, which is known as genetic drift or mutation, gene flow and sexual selection, is a cornerstone of modern evolutionary biology and is mathematically described.
Recent discoveries in evolutionary developmental biology have revealed the ways in which variation can be introduced to a species through genetic drift, mutations or reshuffling of genes in sexual reproduction and the movement between populations. These processes, as well as other ones like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution that is defined as change in the genome of the species over time and also by changes in phenotype as time passes (the expression of that genotype in the individual).
Students can better understand phylogeny by incorporating evolutionary thinking into all areas of biology. In a recent study by Grunspan and colleagues. It was found that teaching students about the evidence for evolution boosted their understanding of evolution in an undergraduate biology course. To find out more about how to teach about evolution, please see The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing 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 observe living organisms. Evolution is not a distant event, but a process that continues today. Bacteria mutate and resist antibiotics, viruses re-invent themselves and elude new medications and animals change their behavior in response to the changing climate. The results are often visible.
It wasn't until late 1980s that biologists began realize that natural selection was in play. sneak a peek at this web-site is that different traits have different rates of survival and reproduction (differential fitness) and can be transferred from one generation to the next.
In the past, if one allele - the genetic sequence that determines colour was found in a group of organisms that interbred, it could be more common than any other allele. In time, this could mean that the number of moths that have black pigmentation in a group may increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
It is easier to observe evolutionary change when the species, like bacteria, has a high generation turnover. Since 1988 biologist Richard Lenski has been tracking twelve populations of E. 에볼루션 게이밍 that descended from a single strain; samples from each population are taken every day and more than 50,000 generations have now passed.
Lenski's research has revealed that mutations can alter the rate at which change occurs and the effectiveness of a population's reproduction. It also shows that evolution takes time, which is difficult for some to accept.
Microevolution can be observed in the fact that mosquito genes that confer resistance to pesticides are more common in populations where insecticides are used. This is because the use of pesticides causes a selective pressure that favors individuals who have resistant genotypes.
The rapid pace at which evolution takes place has led to a growing awareness of its significance in a world shaped by human activity--including climate changes, pollution and the loss of habitats that prevent many species from adapting. Understanding the evolution process will help you make better decisions about the future of the planet and its inhabitants.