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Exaptation
Exaptation and the related term co-option describe a shift in the function of a trait during evolution. For example, a trait can evolve because it served one particular function, but subsequently it may come to serve another. Exaptations are common in both anatomy and behaviour. Bird feathers are a classic example. Initially they may have evolved for temperature regulation, but later were adapted for flight. When feathers were first used to aid in flight, that was an exaptive use. They have since then been shaped by natural selection to improve flight, so in their current state they are best regarded as adaptations for flight. So it is with many structures that initially took on a function as an exaptation: once molded for a new function, they become further adapted for that function. Interest in exaptation relates to both the process and products of evolution: the process that creates complex traits and the products (functions, anatomical structures, biochemicals, etc.) that may b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Co-option (biology)
The term co-option refers to the capacity of intracellular parasites to use host-cell proteins to complete their vital cycle. Viruses use this mechanism, as their genome is small. It is also used in a different sense to refer to characters that have been Exaptation, exapted. Flu virus Because of its medical importance, the influenza A virus has been characterized to a large extent, and is mentioned here as an example of co-option. Its genome encodes only for 11 proteins, and it needs to use host-cell genes and proteins to carry out its lytic cycle. In 2010, a study was realized to determine which host-cell factors are necessary for the entry and replication of Influenza A virus. Using siRNA techniques, the effect of the disruption of more than 19,000 human genes on influenza life cycle was studied. That allowed identifying 295 host-cell genes needed for the virus to complete its lytic cycle, 23 of which are used during the entry steps, and the 219 remaining for the post-entr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephen Jay Gould
Stephen Jay Gould (; September 10, 1941 – May 20, 2002) was an American paleontologist, evolutionary biologist, and historian of science. He was one of the most influential and widely read authors of popular science of his generation. Gould spent most of his career teaching at Harvard University and working at the American Museum of Natural History in New York. In 1996, Gould was hired as the Vincent Astor Visiting Research Professor of Biology at New York University, after which he divided his time teaching between there and Harvard. Gould's most significant contribution to evolutionary biology was the theory of punctuated equilibrium developed with Niles Eldredge in 1972.Eldredge, Niles, and S. J. Gould (1972)"Punctuated equilibria: an alternative to phyletic gradualism."In T.J.M. Schopf, ed., ''Models in Paleobiology''. San Francisco: Freeman, Cooper and Company, pp. 82–115. The theory proposes that most evolution is characterized by long periods of evolutionary st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elisabeth Vrba
Elisabeth S. Vrba (born 17 May 1942) is a paleontologist at Yale University who developed the turnover-pulse hypothesis. Education Vrba earned her Ph.D. in Zoology and Palaeontology at the University of Cape Town, in 1974. Vrba studied zoology and mathematical statistics at the University of Cape Town to earn her undergraduate degree. She remained there for doctoral study in zoology and paleontology to earn her Ph.D. After receiving her doctorate, Vrba conducted her early research on African fossil records over the last several million years, tracking the sequence of fossils from analyzing the geological strata and analyzing the morphology of the fossils. She was the chief assistant to Charles Kimberlin Brain during his directorship of the Transvaal Museum. Career She has been a faculty member at the Department of Geology & Geophysics, Yale University, since the early 1980s. She is well known for developing the turnover-pulse hypothesis, as well as coining the word exaptati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jürgen Brosius
Jürgen Brosius (born 1948) in Saarbrücken) is a German molecular geneticist and evolutionary biologist. He was professor and director of the Institute of Experimental Pathology at the University of Münster. Some of his scientific contributions involve the first genetic sequencing of a ribosomal RNA operon, the design of plasmids for studying gene expression, expression vectors for high-level production of recombinant proteins and RNA, RNA biology, RNomics as well as the significance of retroposition for plasticity and evolution of genomes, genes and gene modules including regulatory sequences or elements. Biography Early life and education Brosius studied chemistry and pharmacy at the Goethe University of Frankfurt and in 1974 graduated and completed the Staatsexamen (state examination) in Pharmacy. Subsequently, he pursued his Ph.D. work in biochemistry and molecular biology at the Max Planck Institute for Molecular Genetics in Berlin Dahlem in which Heinz-Günter Wittmann w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which in his view is intentional, whereas natural selection is not. Variation exists within all populations of organisms. This occurs partly because random mutations arise in the genome of an individual organism, and their offspring can inherit such mutations. Throughout the lives of the individuals, their genomes interact with their environments to cause variations in traits. The environment of a genome includes the molecular biology in the cell, other cells, other individuals, populations, species, as well as the abiotic environment. Because individuals with certain variants of the trait tend to survive and reproduce more than individuals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which in his view is intentional, whereas natural selection is not. Variation exists within all populations of organisms. This occurs partly because random mutations arise in the genome of an individual organism, and their offspring can inherit such mutations. Throughout the lives of the individuals, their genomes interact with their environments to cause variations in traits. The environment of a genome includes the molecular biology in the cell, other cells, other individuals, populations, species, as well as the abiotic environment. Because individuals with certain variants of the trait tend to survive and reproduce more than individuals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retroposon
Retroposons are repetitive DNA fragments which are inserted into chromosomes after they had been reverse transcribed from any RNA molecule. Difference between retroposons and retrotransposons In contrast to retrotransposons, retroposons never encode reverse transcriptase (RT) (but see below). Therefore, they are non-autonomous elements with regard to transposition activity (as opposed to transposons). Non-long terminal repeat (LTR) retrotransposons such as the human LINE1 elements are sometimes falsely referred to as retroposons. However, this depends on the author. For example, Howard Temin published the following definition: Retroposons encode RT but are devoid of long terminal repeats (LTRs), for example long interspersed elements (LINEs). Retrotransposons also feature LTRs and retroviruses, in addition, are packaged as viral particles (virions). Retrosequences are non-autonomous elements devoid of RT. They are retroposed with the aid of the machinery of autonomous eleme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Bladder
The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ that contributes to the ability of many bony fish (but not cartilaginous fish) to control their buoyancy, and thus to stay at their current water depth without having to expend energy in swimming. Also, the dorsal position of the swim bladder means the center of mass is below the center of volume, allowing it to act as a stabilizing agent. Additionally, the swim bladder functions as a resonating chamber, to produce or receive sound. The swim bladder is evolutionarily homologous to the lungs. Charles Darwin remarked upon this in ''On the Origin of Species''.Darwin, Charles (1859''Origin of Species''Page 190, reprinted 1872 by D. Appleton. Darwin reasoned that the lung in air-breathing vertebrates had derived from a more primitive swim bladder. In the embryonic stages, some species, such as redlip blenny, have lost the swim bladder again, mostly bottom dwellers like the weather fish. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxic
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Zachary Blount
Zachary D. Blount is an American evolutionary biologist best known for his work on the evolution of a key innovation, aerobic growth on citrate, in one of the twelve populations of the ''E. coli'' long-term evolution experiment. Blount is a research assistant professor working with Richard Lenski at Michigan State University. He was previously a postdoctoral research assistant for Lenski, and was a visiting assistant professor of biology at Kenyon College from 2018 to 2019. Early life and education Zachary D. Blount was born and raised in Georgia where he developed an early interest in science. He earned high honors in Biology at Georgia Institute of Technology, where he was introduced to microbiology by professor emeritus Thomas Tornabene. He obtained his master's from the University of Cincinnati, where he worked on insertion sequence elements of hyperthermoacidophilic Archaea of the genus '' Sulfolobus'' under the guidance of Dennis Grogan. He moved to Michigan State Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citric Acid
Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in the metabolism of all aerobic organisms. More than two million tons of citric acid are manufactured every year. It is used widely as an acidifier, as a flavoring, and a chelating agent. A citrate is a derivative of citric acid; that is, the salts, esters, and the polyatomic anion found in solution. An example of the former, a salt is trisodium citrate; an ester is triethyl citrate. When part of a salt, the formula of the citrate anion is written as or . Natural occurrence and industrial production Citric acid occurs in a variety of fruits and vegetables, most notably citrus fruits. Lemons and limes have particularly high concentrations of the acid; it can constitute as much as 8% of the dry weight of these fruits (about 47 g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
