에볼루션코리아 Site
The concept of biological evolution is a fundamental concept in biology. The Academies have been for a long time involved in helping people who are interested in science understand the concept of evolution and how it affects all areas of scientific research.
This site provides teachers, students and general readers with a variety of learning resources on evolution. It contains key video clips from NOVA and WGBH produced science programs on DVD.
Tree of Life
The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is a symbol of love and harmony in a variety of cultures. It also has practical applications, such as providing a framework for understanding the evolution of species and how they respond to changing environmental conditions.
The earliest attempts to depict the world of biology focused on the classification of organisms into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods, which rely on the collection of various parts of organisms, or fragments of DNA, have significantly increased the diversity of a Tree of Life2. However, these trees are largely comprised of eukaryotes, and bacterial diversity is still largely unrepresented3,4.
By avoiding the need for direct observation and experimentation genetic techniques have allowed us to represent the Tree of Life in a much more accurate way. In particular, molecular methods allow us to build trees by using sequenced markers, such as the small subunit ribosomal RNA gene.
Despite the massive growth of the Tree of Life through genome sequencing, a lot of biodiversity is waiting to be discovered. This is particularly true for microorganisms that are difficult to cultivate and are usually only represented in a single sample5. Recent analysis of all genomes produced an initial draft of the Tree of Life. This includes a variety of archaea, bacteria and other organisms that haven't yet been identified or the diversity of which is not fully understood6.
This expanded Tree of Life can be used to determine the diversity of a specific area and determine if certain habitats require special protection. This information can be used in a variety of ways, from identifying new medicines to combating disease to improving the quality of crops. It is also valuable in conservation efforts. It can aid biologists in identifying areas that are most likely to have cryptic species, which could have vital metabolic functions and be vulnerable to human-induced change. While conservation funds are important, the most effective way to conserve the biodiversity of the world is to equip the people of developing nations with the knowledge they need to act locally and promote conservation.
Phylogeny
A phylogeny (also known as an evolutionary tree) depicts the relationships between different organisms. Scientists can build a phylogenetic diagram that illustrates the evolutionary relationship of taxonomic categories using molecular information and morphological differences or similarities. Phylogeny plays a crucial 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 that shared traits. These shared traits are either homologous or analogous. 에볼루션코리아 are identical in their evolutionary roots, while analogous traits look similar, but do not share the same origins. Scientists organize similar traits into a grouping known as a Clade. For instance, all the organisms in a clade share the trait of having amniotic eggs. They evolved from a common ancestor which had eggs. The clades then join to create a phylogenetic tree to determine which organisms have the closest relationship to.
Scientists make use of DNA or RNA molecular data to create a phylogenetic chart which is more precise and detailed. This information is more precise and gives evidence of the evolution of an organism. Researchers can utilize Molecular Data to determine the evolutionary age of organisms and determine how many species share the same ancestor.
Phylogenetic relationships can be affected by a variety of factors, including the phenomenon of phenotypicplasticity. This is a kind of behaviour that can change in response to particular environmental conditions. This can cause a trait to appear more similar to one species than another, obscuring the phylogenetic signals. This problem can be addressed by using cladistics, which incorporates the combination of analogous and homologous features in the tree.
In addition, phylogenetics helps determine the duration and rate at which speciation takes place. This information can aid conservation biologists in deciding which species to protect from extinction. In the end, it's the conservation of phylogenetic variety that will lead to an ecosystem that is complete and balanced.
Evolutionary Theory
The central theme of evolution is that organisms develop various characteristics over time based on their interactions with their environment. Many scientists have come up with theories of evolution, such as the Islamic naturalist Nasir al-Din al-Tusi (1201-274), who believed that an organism would evolve according to its own requirements as well as the Swedish taxonomist Carolus Linnaeus (1707-1778), who created the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1844-1829), who suggested that the use or non-use of certain traits can result in changes that can be passed on to future generations.
In the 1930s & 1940s, concepts from various fields, such as genetics, natural selection and particulate inheritance, were brought together to create a modern evolutionary theory. This defines how evolution occurs by the variations in genes within the population, and how these variants change over time as a result of natural selection. This model, which encompasses mutations, genetic drift as well as gene flow and sexual selection is mathematically described.
Recent advances in the field of evolutionary developmental biology have revealed the ways in which variation can be introduced to a species by mutations, genetic drift or reshuffling of genes in sexual reproduction, and even migration between populations. These processes, as well as other ones like directional selection and gene erosion (changes in frequency of genotypes over time) can result in evolution. Evolution is defined by changes in the genome over time and changes in the phenotype (the expression of genotypes within individuals).
Incorporating evolutionary thinking into all areas of biology education could increase student understanding of the concepts of phylogeny and evolution. In a recent study by Grunspan and colleagues., it was shown that teaching students about the evidence for evolution increased their acceptance of evolution during a college-level course in biology. For more information on how to teach about evolution, read The Evolutionary Potential of All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing Evolution in 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. Evolution is not a past event; it is an ongoing process. Viruses reinvent themselves to avoid new drugs and bacteria evolve to resist antibiotics. Animals adapt their behavior as a result of a changing world. The resulting changes are often easy to see.
But it wasn't until the late 1980s that biologists realized that natural selection can be observed in action as well. The key is that different traits confer different rates of survival and reproduction (differential fitness) and are passed from one generation to the next.
In the past, if a certain 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. 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 biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain. samples of each are taken regularly and more than fifty thousand generations have passed.
Lenski's research has revealed that mutations can alter the rate of change and the effectiveness of a population's reproduction. It also shows that evolution takes time, a fact that some find difficult to accept.
Another example of microevolution is the way mosquito genes for resistance to pesticides are more prevalent in populations in which insecticides are utilized. That's because the use of pesticides causes a selective pressure that favors individuals with resistant genotypes.
The speed at which evolution can take place has led to an increasing recognition of its importance in a world shaped by human activity--including climate change, pollution, and the loss of habitats that hinder many species from adapting. Understanding the evolution process will help us make better decisions regarding the future of our planet, and the life of its inhabitants.