Template Evolutionary biology Speciation is the evolution ary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term speciation for the splitting ... contributor to speciation is the subject matter of much ongoing discussion. There are four geographic modes of speciation in nature, based on the extent to which speciating populations are geographically isolated from one another allopatric speciation allopatric , peripatric speciation peripatric , parapatric speciation parapatric , and sympatric speciation sympatric . Speciation may also be induced ... kind of speciation are provided throughout. ref http www.talkorigins.org faqs faq speciation.html Observed Instances of Speciation by Joseph Boxhorn. Retrieved 8 June 2009. ref Natural speciation All forms of natural speciation have taken place over the course of evolution however it still remains a subject ... journal title Adaptive speciation The role of natural selection in mechanisms of geographic and non geographic speciation author J.M. Baker journal Studies in History and Philosophy of Biological and Biomedical ... One example of natural speciation is the diversity of the three spined stickleback , a Marine ocean marine fish that, after the last ice age, has undergone speciation into new freshwater colonies ... American, p. 57 ref There is debate as to the rate at which speciation events occur over geologic time. While some evolutionary biologists claim that speciation events have remained relatively constant ... usually remain unchanged over long stretches of time, and that speciation occurs only over relatively brief intervals, a view known as punctuated equilibrium . Allopatric Image Speciation modes.svg right thumb 300px Comparison of allopatric speciation allopatric , peripatric speciation peripatric , parapatric speciation parapatric and sympatric speciation . Main allopatric speciation During allopatric from the ancient Greek allos , other Greek patr , fatherland speciation, a population splits ... more details
Speciation may refer to Speciation biology , evolutionary process by which new biological species arise Speciation chemistry , distribution of chemical elements disambig it Speciazione ... more details
Template Evolutionary biology Image Speciation modes.svg left thumb 300px Comparison of allopatric speciation allopatric , peripatric, parapatric speciation parapatric and sympatric speciation sympatric speciation . Peripatric and peripatry are terms from biogeography , referring to organism s whose ranges are closely adjacent but do not overlap, being separated where these organisms do not occur &ndash for example a wide river or a mountain range. Such organisms are usually closely related e.g. sister species , their distribution being the result of peripatric speciation . Peripatric speciation is a form of speciation , the formation of new species through evolution . In this form, new species are formed in isolated peripheral populations this is similar to allopatric speciation in that populations are isolated and prevented from exchanging genes. However, peripatric speciation, unlike allopatric speciation, proposes that one of the populations is much smaller than the other. Peripatric speciation was originally proposed by Ernst Mayr , and is related to the founder effect , because small living populations may undergo selection bottlenecks. ref cite journal author Provine WB title Ernst Mayr Genetics and speciation url http www.genetics.org cgi content full 167 3 1041 journal Genetics volume 167 issue 3 pages 1041 6 date 1 July 2004 pmid 15280221 pmc 1470966 ref Genetic drift is often proposed to play a significant role in peripatric speciation. ref cite journal author Templeton AR title The theory of speciation via the founder principle url http www.genetics.org cgi reprint 94 4 1011 journal Genetics volume 94 issue 4 pages 1011 38 date 1 April 1980 pmid 6777243 pmc 1214177 ref speciation show no evolution show no References Reflist DEFAULTSORT Peripatric Speciation Category Ecology Category Evolutionary biology Category Speciation Category Scientific classification Category Taxonomy pt Especia o perip trica ru ... more details
Image Speciation modes.svg right thumb 300px Comparison of allopatric speciation allopatric , peripatric speciation peripatric , parapatric speciation parapatric and sympatric speciation sympatric speciation . Heteropatric and heteropatry are terms from biogeography , referring to organism s whose geographical ranges overlap or are even identical, so that they occur together at least in some places, but which occupy ecological niche s distinct enough to prevent frequent Hybrid biology hybridization . Such organisms are usually closely related e.g. sister species , their distribution and ecology being the result of heteropatric speciation . Heteropatric speciation is a special case of sympatric speciation that occurs when different ecotypes or Race biology race s of the same species geographically ... speciation is a refinement of our notion of sympatric speciation in that it represents a behavioral .... The importance of behavioral separation as a mechanism for promoting sympatric speciation in a heterogeneous ... speciation . ref J. Maynard Smith, 1966. Sympatric speciation. The American Naturalist 110 637 ... Biology 36 34 58. ref of conditions that facilitate sympatric speciation . Although some evolutionary biologists still regard sympatric speciation as a highly contentious issue, both theoretical ref D. I. Bolnick, 2006. Multispecies outcomes in a common model of sympatric speciation. Journal .... Habitat avoidance overlooking an important aspect of host specific mating and sympatric speciation. Evolution 59 1552 1559. ref studies increasingly support sympatric speciation as a likely process ... resolves the issue of sympatric speciation by reducing it to a scaling issue in terms of the way ... into account. See also Adaptive radiation Sympatry Allopatry Cladistics Phylogenetics speciation sympatric speciation allopatric speciation References references speciation DEFAULTSORT Heteropatric Speciation Category Biogeography Category Speciation evolution stub ... more details
Template Evolutionary biology Hybrid speciation is the process wherein Hybrid biology hybridization between two different closely related species leads to a distinct phenotype . This phenotype in very rare cases can also be fitter than the parental lineage and as such natural selection may then favor these individuals. Eventually, if reproductive isolation is achieved, it may lead to a separate species. However, reproductive isolation between hybrids and their parents is particularly difficult to achieve and thus hybrid speciation is considered an extremely rare event. Hybridization without change in chromosome number is called homoploid hybrid speciation. It is considered very rare but has been shown in Heliconius butterfly butterflies and in sunflower s. Polyploid speciation, which involves changes in chromosome number, is a more common phenomenon, especially in plant species. See also Mariana Mallard Pomarine Skua New Mexico Whiptail Genetic pollution References references Mavarez, J., Salazar, C.A., Bermingham, E., Salcedo, C., Jiggins, C.D. , Linares, M. 2006 Speciation by hybridization in Heliconius butterflies. Nature. evolution stub speciation Category Hybridisation biology Category Genetics Category Speciation Category Evolutionary biology terminology ... more details
Template Evolutionary biology Image Speciation modes.svg left thumb 300px Comparison of allopatric speciation allopatric , peripatric speciation peripatric , parapatric and sympatric speciation sympatric speciation . Parapatric and parapatry are terms from biogeography , referring to organism s whose ranges do not significantly overlap but are immediately adjacent to each other they only occur together in the narrow contact zone, if at all. Such organisms are usually closely related e.g. sister species , their distribution being the result of parapatric speciation . Parapatric speciation is a form of speciation that occurs due to variations in the mating system mating habits of a population within a continuous geographical area. In this model, the parent species lives in a continuous habitat , in contrast with allopatric allopatric speciation and peripatric speciation where subpopulations become geographically isolated. Ecological niche Niche s in this habitat can differ along an environmental gradient , hampering gene flow , and thus creating a Cline population genetics cline . In parapatric speciation there is no specific extrinsic barrier to gene flow. The population is continuous, but nonetheless, the population does not mate randomly. Individuals are more likely to mate with their geographic neighbors than with individuals in a different part of the population s range. In this mode ... ref of this is the grass Anthoxanthum , which has been known to undergo parapatric speciation in such cases ... evidence for parapatric speciation in Tennessee cave salamander s, involving divergence with gene ... online ref Another example are ring species . See also Allopatry Speciation Adaptive radiation ... evolibrary article 0 0 speciationmodes 04 Parapatric speciation. in Understanding Evolution ... evolution 101 speciation show yes evolution show no DEFAULTSORT Parapatric Speciation Category Ecology Category Evolutionary biology Category Speciation Category Scientific classification Category ... more details
Evolutionary biology Sympatric speciation is the process through which new species evolve from a single ... related e.g. sister species , such a distribution may be the result of sympatric speciation . Etymological ... for the phenomenon of speciation. In contrast to Allopatric speciation allopatry , populations undergoing sympatric speciation are not geographically isolated by, for example, a mountain or a river. In multicellular Eukaryotes eukaryotic organisms, sympatric speciation is thought to be an uncommon ... of Genetics publisher Oxford University Press edition 7th year 2006 ref Evidence Image Speciation modes.svg frame left Comparison of allopatric speciation allopatric , peripatric speciation peripatric , parapatric speciation parapatric and sympatric speciation A number of models have been proposed to account for this mode of speciation. The most popular, which invokes the disruptive selection model, was first put forward by John Maynard Smith in 1966. ref cite journal title Sympatric Speciation ... would be favoured over heterozygosity, eventually leading to speciation. Sympatric divergence could ... may drive speciation because they also affect mating signals. In this case, different beak phenotype ... ref A well studied circumstance of sympatric speciation is when insects feed on more than one species ... speciation. The apple feeding race of this species appears to have spontaneously emerged from the Crataegus ... speciation. For example, Nicaragua crater lake cichlid fishes include at least one species that has evolved by sympatric speciation ref Sympatric speciation in Nicaraguan crater lake cichlid fish ... speciation has taken place, as many examples exist of recently diverged sister taxon sister taxa allochronic species. Sympatric speciation events are vastly more common in plants, as they are prone to developing ... isolated. A rare example of sympatric speciation in animals is the divergence of resident ... Controversy Debated almost since the beginning of popular evolutionary thought, sympatric speciation ... more details
Evolutionary biology Allopatric speciation from the ancient Greek allos, other Greek patrida, fatherland or geographic speciation is speciation that occurs when biological populations of the same species .... Allopatric isolation is a key factor in speciation and a common process by which new species arise ... , is a consequence of allopatric speciation among island populations. Isolating Mechanisms Image Speciation modes.svg right thumb 360px Comparison of allopatric , peripatric speciation peripatric , parapatric speciation parapatric and sympatric speciation sympatric speciation Allopatric speciation ... species , such a distribution is usually the result of allopatric speciation . Separation may ... the two groups is disrupted, speciation becomes a possibility. Allopatric speciation in peripheral populations Main Peripatric speciation When populations become genetically isolated, heritable variations ... do not evolve as a consequence of external forces that drive populations toward speciation. Rather, the evolution of reproductive isolation, leading to speciation, is generally thought to be an incidental ... viable, fertile offspring with members of other species. Mayr, a proponent of allopatric speciation ... of other types of speciation, such as sympatric speciation , parapatric speciation , and heteropatric speciation , is debated. Proponents of peripatric speciation contend that small population ... a role in many cases of speciation. Alternative Modes of Speciation Sympatric speciation represents an alternative method of speciation that does not require physical separation instead speciation ... the geographic range of its parent population. In parapatric speciation there is no physical barrier ... 2002 p 473 ref Allopatric speciation is thought to be the dominant mode of speciation. ref Harvnb Futuyma 1980 p 254 ref Examples Image Drosophila speciation experiment.svg right thumb 425px Allopatric speciation among Drosophila melanogaster fruit flies The African Elephant has always been regarded ... more details
Speciation of ions refers to the changing concentration of varying forms of an ion as the pH of the solution changes. Image Weak acid speciation3.png thumb 200px right The ratio of acid, AH and conjugate base, A sup &minus sup , concentrations varies as the difference between the pH and the p K sub a sub varies, in accordance with the Henderson Hasselbalch equation . The pH of a solution of a monoprotic weak acid can be expressed in terms of the extent of dissociation. After rearranging the expression defining the acid dissociation constant , and putting pH log sub 10 sub H sup sup , one obtains pH p K sub a sub log AH A sup sup This is a form of the Henderson Hasselbalch equation . It can be deduced from this expression that when the acid is 1 dissociated, that is, when AH A sup sup 100, pH p K sub a sub 2 when the acid is 50 dissociated, that is, when AH A sup sup 1, pH p K sub a sub when the acid is 99 dissociated, that is, when AH A sup sup 0.01, pH p K sub a sub 2 It follows that the range of pH within which there is partial dissociation of the acid is about p K sub a sub 2. This is shown graphically at the right. A practical application of these results is that the pH transition range of a pH indicator is approximately p K sub a sub 1 the colour of the indicator in its acid form is different from the colour of the conjugate base form. In the transition range both forms are in equilibrium, so the colour is intermediate. Outside the transition range the concentration of acid or conjugate base is less than 10 and the colour of the major species dominates. Image Citric acid speciation.png thumb 200 px Species concentrations calculated with the program http www.hyperquad.co.uk hyss.htm HySS for a 10mM solution of citric acid. p K sub a1 sub 3.13, p K sub a2 sub 4.76, p K sub a3 sub 6.40. A weak acid may be defined as an acid with p K sub a sub greater than about 2. An acid with p K sub a sub 2 would be 99 dissociated at pH 0, that is, in a 1 M HCl solution. Any acid ... more details
Summary Geographic illustration of SPATIAL ASPECTS OF SPECIATION allopatric speciation physical barrier divides population parapatric speciation founding population leaves original sympatric speciationspeciation occurs without physical separation Based on http www.bio.miami.edu dana 160 speciation.jpg from http www.bio.miami.edu dana 160 160S04 6.html Adapted from Spring 2006, Lecture Notes for EVOLUTION AND BIODIVERSITY class BIL 160 Section HJ by Dr. Dana Krempels, dana at miami dot edu. Licensing self2 GFDL with disclaimers cc by sa 2.5,2.0,1.0 migration relicense ... more details
Multiple issues unreferenced December 2007 orphan November 2006 Speciation is a process that occurs naturally in evolution and is modeled explicitly in some genetic algorithms . Speciation in nature occurs when two similar reproducing beings evolve to become too dissimilar to share genetic information effectively or correctly. In the case of living organisms , they are incapable of mating to produce offspring . Interesting special cases of different species being able to breed exist, such as a horse and a donkey mating to produce a mule . However in this case the Mule is usually infertile, and so the genetic isolation of the two parent species is maintained. In implementations of genetic search algorithms, the event of speciation is defined by some mathematical function that describes the similarity between two candidate solutions usually described as individuals in the population. If the result of the similarity is too low, the chromosomal crossover crossover Operation mathematics operator is disallowed between those individuals. See also DEFAULTSORT Speciation Genetic Algorithm Category Evolutionary algorithms Category Genetic algorithms ... more details
Sibling Species are species very similar in appearance, behavior and other characteristics while they are Reproductive isolation reproductively isolated . See also Sympatric speciation Category Evolutionary biology Category Population genetics Category Speciation de Zwillingsart es Especies gemelas it Sibling species ru stq Twillingstaxa ... more details
Unreferenced date April 2008 Expert subject Genetics date April 2008 A genetic isolate is population of organisms that has little genetic mixing with other organisms within the same species. This may result in speciation , but this is not necessarily the case. Genetic isolates may form new species in several ways allopatric speciation , in which two populations of the same species are geographically isolated from one another by an extrinsic barrier, and evolve intrinsic genetic reproductive isolation peripatric speciation , in which a small group of a population is separated from the main population, and experiences genetic drift parapatric speciation , in which zones of two diverging populations are separate, but do overlap somewhat partial separation is afforded by geography, so individuals of each species may come in contact from time to time, but selection for specific behaviours or mechanisms may prevent breeding between the two groups. sympatric speciation , a contentious method of speciation in which species diverge while inhabiting the same place. Human influences on genetic isolates include restricted Dog breeding breeding of dogs , or a community living secluded away from others such as Tristan da Cunha or Pitcairn Islands . A far larger and less secluded human genetic isolate is the ethnic Finns , natives of Finland see Finnish disease heritage . See also Language isolate Linkage disequilibrium DEFAULTSORT Genetic Isolate Category Speciation ... more details
Summary Author User Cody.pope Source Compiled from data from Haffer, Jurgen. 1969. Speciation in Amazonian Forest Birds. Science. Vol. 165 131 137. Licensing PD self date December 2006 ... more details
Summary Speciation results Testing for arsenic in Napoleon s hair. This image is granted permission by the International Napoleonic Society under the terms of the GNU Free Documentation License. Available online at http www.napoleonicsociety.com english 2juina.htm Licensing GFDL migration relicense ... more details
The Bateson Dobzhansky Muller Model ref citejournal title Isolating Mechanisms author J.L.B. Mather journal Encyclopaedia of Ecology and Environmental Management year 1998 http abacus.gene.ucl.ac.uk jim Sp isolmech.html ref ref http www.ncbi.nlm.nih.gov pmc articles PMC1207686 pdf ge14441331.pdf Dobzhansky, Bateson, and the genetics of speciation. ref is a model of the evolution of genetic incompatibility. It assumes a selective pressure against a combination of allele s in the heterozygous state, i.e. F1 hybrids have reduced fertility or viability. The end result of this evolved incompatibility is speciation divergence into separate species . For this speciation to occur number of isolation mechanisms may be needed, including but not limited to behavioral differences, habitat isolation, and hybrid infertility. An example of this is the lack of fertility in mule s, which are hybrids of horses and donkeys. references Category Evolutionary biology Orphan date July 2009 ... more details
Summary This is an image adapted from Haffer, J 1969 Speciation in Amazonian Forest Birds. Science 165 131 137. It was retrieved from http www.geo.arizona.edu Antevs ecol438 amazon.gif on Jan. 10, 2005. Licensing Non free fair use in Refugia This image is used only to illustrate a concept. ... more details
italic title Taxobox name Diachasma alloeum regnum Animal ia phylum Arthropod a classis Insect a ordo Hymenoptera superfamilia Ichneumonoidea familia Braconidae subfamilia Opiinae genus Diachasma species D. alloeum binomial Diachasma alloeum binomial authority Muesebeck , 1956 Diachasma alloeum is a small wasp in the family Braconidae . It is a parasitoid of Rhagoletis pomonella , the apple maggot . The wasp lays its eggs into third instar larvae of the fly, which then develop after the larvae have pupated. The immature wasps then eat the fly larvae and overwinter inside the fly puparia. Diachasma alloeum wasps attacking Rhagoletis pomonella in apples appear to be undergoing a speciation event in concert with their hosts. ref Forbes, A.A., L.L. Stelinski, T.H.Q. Powell, J.J. Smith and J.L. Feder. 2009. Sequential sympatric speciation across trophic levels. Science 323 776 779. ref This is an example of sequential sympatric speciation . References Reflist Category Braconidae Category Animals described in 1956 Wasp stub ... more details
Unreferenced stub auto yes date December 2009 Systematics and the Origin of Species from the Viewpoint of a Zoologist is a book written by zoologist and evolutionary biologist Daniel Busby that was first published in 1942. The book became one of the canonical publications on the modern evolutionary synthesis . Based on Mayr s Jesup Lectures delivered at Columbia University in 1941, the book combines concepts of zoology and genetics and features Mayr s species biological species concept . The biological species concept developed by Mayr defines a species in terms of biological factors such as biological reproduction reproduction , taking into account ecology, geography, and life history it remains an important and useful idea in biology, particularly for animal speciation. In December 2004 the United States National Academy of Sciences National Academy of Sciences held a colloquium in honour of Mayr s 100th birthday. Systematics and the Origin of Species On Ernst Mayr s 100th Anniversary was also published in commemoration. Contents The Methods and Principles of Systematics Taxonomic Characters and Their Variation Phenomena of Geographic Variation Some Aspects of Geographic Variation The Systematic Categories and the New Species Concept The Polytypic Species, in Nature and in Systematics The Species in Evolution Nongeographic Speciation The Biology of Speciation The Higher Categories and Evolution DEFAULTSORT Systematics And The Origin Of Species Category Books about evolution Category 1942 books Science book stub Evolution stub pt Systematics and the Origin of Species ... more details
Unreferenced date December 2009 Orphan date December 2009 The term allochrony is used in ecology to describe a situation where two biological entities typically species occur in the same area, and are thus sympatric , but are never or rarely active simultaneously. The most common temporal scale at which this is seen is seasonal, and greater emphasis is placed on the phenomenon when the two entities share a common resource for which they would otherwise be in competition for example, feeding on the same host biology host plant, or consuming the same prey . Allochrony is one of the few ecological phenomena that lend clear support to models and theories of sympatric speciation the idea that related lineages can differentiate into independent gene pool s while still sharing the same physical environment, simply by virtue of changes in the life cycle that lead to separation in time of different portions of the ancestral population. Category Ecological processes Category Speciation ... more details
A species complex is a group of closely related species, where the exact demarcation between species is often unclear or cryptic owing to their recent and usually still incomplete reproductive isolation . Ring species , superspecies and cryptic species complex are example of species complex. Such groups of species with complex relationship between species may occur in a line undergoing rapid speciation or where such speciaton recently have occurred, so that species separation mechanisms has yet to be fully developed. In such cases speciation may leave some species paraphyletic at the species level. Species complexes are more common among plants , but animal examples exist, such as the dog wolf coyote complex the genus Canis and the cobras genus Naja . Often such complexes only become evident when a new species is introduced into the system, breaking down existing species barriers. An example is the introduction of Spanish slug in Northern Europe , where interbreeding with the local black slug and red slug , traditionally considered clearly separate species that did not interbreed, shows these may actually be subspecies of the same species. ref da icon Engelke, S. 2006? Til Snegleforeningen Note to the Danish Slug society . http www.dansksnegleforening.dk Af 20Sabine 20Engelke.htm Article in Danish ref Examples of known species complexes Animals The wolf dog coyote dingo group, genus Canis The cobras, genus Naja Some species of the roundback slugs, genus Arion gastropod Arion The jellyfish genus Cyanea jellyfish Cyanea , with from 1 to 14 species, depending on author. References reflist speciation Category Speciation Category Evolutionary biology no Artskompleks ... more details
Summary Information Description speciation diagram Source I User Petergans Petergans User talk Petergans talk created this work entirely by myself. Date 13 42, 17 March 2010 UTC Author User Petergans Petergans User talk Petergans talk other versions Licensing PD self date March 2010 ... more details
been invoked to explain sympatric speciation . For some populations there are two different resources ... assortative mating is believed to be the cause of the speciation of a daughter species from the parent ... species surrounds the daughter species so there is no Allopatric speciation geographic isolation . The speciation in the early stages would depend on assortative mating in which the evolving goby ... for sympatric speciation by host shift in the sea. Current Biology 14 16 , pp. 1498 1504. ref Footnotes ... speciation Category Reproduction Category Sexual selection Category Demography Category Fertility ... more details
Unreferenced stub auto yes date December 2009 Genetic divergence is the process in which two or more populations of an ancestral species accumulate independent genetic changes mutations through time, often after the populations have become Reproductive isolation reproductively isolated for some period of time. In some cases, subpopulations living in ecology ecologically distinct peripheral environments can exhibit genetic divergence from the remainder of a population, especially where the range of a population is very large see parapatric speciation . The genetic differences among divergent populations can involve silent mutations that have no effect on the phenotype or give rise to significant Morphology biology morphological and or physiology physiological changes. Genetic divergence will always accompany reproductive isolation, either due to novel adaptation s via selection or due to genetic drift , and is the principal mechanism underlying speciation . Evolution DEFAULTSORT Genetic Divergence Category Evolutionary biology Category Genetics Genetics stub bg de Divergenz Biologie et Divergents bioloogia ... more details
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