members of their species. This was an early description of the process of allopatricspeciation geographic speciation by means of the founder effect . Another formulation of this idea came later Organisms ... that geographical isolation could play a key role in speciation . From 1852 1855, together with Karl ... , August Weismann Weismann attacked Wagner s idea of geographic speciation, and it suffered a long decline until in 1942 it was reintroduced by Mayr. ref name Mayr The importance of geographic speciation ... Coyne and H. Allen Orr , ref name C&O Coyne J. and Orr, H. Allen 2004. Speciation Sinauer. ISBN 0878930892 ref argue that Wagner pioneered the idea geographical speciation, and that Darwin had not appreciated ..., and agreed that geographic isolation was important although not the only cause of speciation , and pointed out that he had in fact dealt with geographic speciation in The Origin of Species ... of Wagner s geographic speciation ideas in a paper which is often cited as providing early support of geographical speciation. ref Jordan D.S. 1905. The origin of species through isolation. Science ... significant in keeping geographical speciation on the evolutionary menu. ref Rensch, Bernhard ... cause of speciation, even when the geographical milieu is in isolation. ref name C&O ref Schilthuizen ... ref , but his inferences about geographical speciation were important insights gained by observation ...... agreed that this geographical approach was the way to solve the problem of speciation... a new ... and speciation, and links to publications http www.zsm.mwn.de ich coll wagner.htm Short biography ... more details
on this Cquote ...the origin of a species, whether Allopatricspeciationallopatric or Sympatric speciation sympatric , is a process, not an event. For the formation of a new species, like the boiling ... to speciation and can occur if conditions in a local environment change dramatically through space ... can be thought of as precursory steps of potential speciation . Notes references group note See also Portal box Evolutionary biology Environment Ecology Earth sciences Evolution Adaptation Speciation ... more details
Taxobox name White bellied Parrot image Pionites leucogaster two perching 8a.jpg image width 300px status LC status system IUCN3.1 regnum Animalia phylum Chordata classis Aves ordo Psittaciformes superfamilia True parrot Psittacoidea familia Psittacidae subfamilia Neotropical parrot Arinae genus Caique Pionites species P. leucogaster binomial Pionites leucogaster binomial authority Heinrich Kuhl Kuhl , 1820 synonyms The White bellied Parrot Pionites leucogaster , in aviculture often referred to as the White bellied Caique , is one of the two species in the genus Pionites of the Psittacidae family the other species being the Allopatric speciation allopatric Black headed Parrot . Both species are popular Caique Aviculture as pets . It is found in humid forest and nearby wooded habitats in the Amazon Basin Amazon south of the Amazon River in Bolivia , Brazil , and Peru . It is generally fairly common throughout its range and is easily seen in a wide range of protected areas, such as the Man National Park and Tambopata Candamo in Peru, Cristalino State Park near Alta Floresta , Xingu National Park and Amaz nia National Park in Brazil, and Madidi National Park in Bolivia. Description The White bellied Parrot has an orange yellow head and vent, a white belly, green wings and back, bluish primary feathers, a pinkish horn beak, and pinkish legs and feet. Juvenile organism Juvenile s have brownish or black feathers on the head and nape, yellow feathers on the white belly, and greyish legs. Generally, the off colored feathers will be lost and replaced by orange or white feathers respectively as the bird matures. Young birds also have dark brown Iris anatomy irises , which will change to a rust or orange with age. Subspecies File Pionites leucogaster Parque de las Aves Foz de Iguazu 6a 4c.jpg left thumb Green thighed Caique Green thighed Parrot Caique Pionites leucogaster leucogaster . Found in the eastern part of its range. It has green thighs and upper tail. Yellow thighed ... more details
one species has undergone allopatricspeciation and the two new populations regain contact after a period ... gene flow Barton and Hewitt, 1989 . They are useful in the study of the processes of speciation as they provide ... contact in which parapatric speciation is taking place. As a population spreads across a contiguous ... parapatric speciation those in the new environment adapting to the different conditions. The point ... that were previously allopatric. This distinction may not be a very useful one as in practice it can ... between these populations and it is believed that they are close to full speciation. They are probably .... They hypothesized that such zones occurred between two populations that were close to full speciation ... 424. Bazykin AD. 1969 Hypothetical mechanism of speciation. Evolution 23 685 87 Endler JA. 1982 Problems ... York Oxford University Press. Jiggins CD, Mallet J. 2000 Bimodal hybrid zones and speciation. Trends ... 302 Category Speciation Category Population genetics pt Zona h brida ... more details
. ref Their paper built upon Ernst Mayr Ernst Mayr s theory of allopatricspeciation geographic speciation ... extension of Ernst Mayr Ernst Mayr s concept of Founder effect genetic revolutions by allopatricspeciationallopatric and especially peripatric speciation as applied to the fossil record. Although ... s standard mechanism of allopatricspeciation might suggest a possible resolution. ref name eldredge1971 ... 3881 1 Tremaux on species.pdf Tr maux on species A theory of allopatricspeciation and punctuated ... Species and Evolution . Cambridge, MA Harvard University Press. ref Allopatricspeciation suggests ... of allopatricspeciation then evidence of gradual evolution in the fossil record should be rare. This stimulating ... 179 . As time went on Gould moved away from wedding punctuated equilibrium to allopatricspeciation, particularly as evidence accumulated in support of other modes of speciation. ref Gould, S. J. 1982 ... of Evolution . New York Columbia Univ. Press, p. 390. ref Eldredge and Gould relied upon ordinary speciation, particularly Ernst Mayr s concept of allopatricspeciation. Lastly, and perhaps most significantly ... not studied evolutionary theory and either did not know about allopatricspeciation or had not considered ... events of branching speciation called cladogenesis . Cladogenesis is the process by which a species ... journal doi 10.2307 2406508 author Eldredge, Niles year 1971 title The allopatric model and phylogeny in Paleozoic invertebrates url http www.nileseldredge.com pdf files Allopatric Model Phylogeny Paleozoic ... of speciation. Gould recalls that Eldredge s 1971 publication on Paleozoic trilobite s had presented ... mechanisms Punctuational change When Eldredge and Gould published their 1972 paper, allopatricspeciation was considered the standard theory of speciation. ref name pe1972 This theory was popularized ... once speciation is complete, they are not claiming that there is no change at all between one generation ... last1 Wright first1 Sewall year 1982 title Character change, speciation, and the higher taxa ... more details
File Rudolf Kaufmann00.jpg thumb Rudolf Kaufmann 3 April 1909 East Prussia c1941 , son of the physicist Walter Kaufmann physicist Walter Kaufmann , was a palaeontologist and geologist, and is best remembered for his work on allopatric speciation and punctuated equilibrium in the trilobite genus Olenus trilobite Olenus in the Upper Cambrian of Sweden and on the island of Bornholm . ref http www.ajsonline.org content 244 11 808.abstract ref He was a brother in law of ftp rock.geosociety.org pub Memorials v28 teichert.pdf Curt Teichert the well known German American palaeontologist and geologist. Studying the Upper Cambrian alum shales in Sweden, Kaufmann found that the trilobite genus Olenus occurred in an unbroken sequence of sediments covering a considerable period of geological time. He was thereby in a position to track the phylogenetic evolution of Olenus , that is, the rise and fall of species within the genus and the changes in their morphology. He coined the idea of Artabwandlung , which is the tendency of clade elements in the same environment to show the same morphological trends. ref Genetics, Paleontology and Macroevolution Jeffrey S. Levinton ref With the 1930s onset of the Nazi regime in Germany, Kaufmann, who had Jewish roots, but had been baptised an evangelical Christian, was dismissed from his position at Greifswald University. He had studied at K nigsberg and at Greifswald University under Serge von Bubnoff 1888 1957 . His 1933 dissertation dealt with speciation and punctuated equilibrium in Cambrian trilobites in Sk ne . He left Germany for Copenhagen in 1933. Here he was denied employment as a geologist, and worked as a photographer and gave instruction in athletics. He found himself ill at ease in Denmark, and after a spell in Italy, returned to Germany where in October 1935 he started teaching at a Jewish school in Coburg , and was arrested on a charge of miscegenation he was being treated for a sexually transmitted disease acquired from a prost ... more details
Taxobox image Oplurus Cuvieri Kirindy Madagascar.jpg image width 240px image caption Oplurus cuvieri name Opluridae regnum Animal ia phylum Chordate Chordata classis reptile Sauropsida ordo Squamata subordo Lacertilia infraordo Iguania familia Opluridae subdivision ranks Genera subdivision 2 genera 7 recognized species , see article . The Opluridae , or Madagascan iguanas , are a family of moderately sized lizards native to Madagascar . There are seven species in two genera , with most of the species being in Oplurus . The family includes species that live amongst rocks, some that live in tree s, and one that inhabits sand dune s. All of the species lay Egg biology eggs , and have teeth that resemble those of the true iguana s. ref name EoR cite book editor Cogger, H.G. & Zweifel, R.G. author Bauer, Aaron M. year 1998 title Encyclopedia of Reptiles and Amphibians publisher Academic Press location San Diego pages 145 isbn 0 12 178560 2 ref A study of Mitochondrion mitochondria l DNA sequences has dated the split between Opluridae and Iguanidae within which Opluridae is sometimes Iguanidae Classification of Iguanidae classified as the subfamily Oplurinae at about 165 million years ago, during the Middle Jurassic . ref name Okajima Cite journal last Okajima first Y. authorlink coauthors Kumazawa, Y. title Mitogenomic perspectives into iguanid phylogeny and biogeography Gondwanan vicariance for the origin of Madagascan oplurines journal Gene journal Gene volume 441 issue 1 2 pages 28 35 publisher Elsevier location date 2009 07 15 url doi 10.1016 j.gene.2008.06.011 id accessdate pmid 18598742 ref The study supported the monophyletic monophyly of the expanded Iguanidae, and put Oplurinae in the basal phylogenetics basal position. This dating is consistent with a Allopatric speciation vicariant origin of the Madagascan iguanians, since Madagascar is believed to have separated from Africa during the Gondwana Breakup breakup of Gondwana around 140 million years ago. ref name ... more details
mainland Equatorial Guinea Rio Muni , Gabon and into the Congo. The two species are Allopatricspeciationallopatric across the Sanaga River. References Reflist External links Wikispecies Mandrillus ... more details
size, pitcher lip thickness, and pitcher leaf morphology. All of this evidence, combined with the allopatricspeciationallopatric distribution that does not overlap with S. purpurea , lead the authors ... more details
speciation of a marine bryozoan taxon journal Proceedings. Biological Sciences the Royal Society date ... paraponerae Diptera Phoridae Category Scientific classification Category Speciation ca Complex d esp cies ... more details
describes allopatricspeciation . Allopatricspeciation is where new gene pools arise out of natural selection in isolated gene pools. Island Biogeography is also useful in considering sympatric speciation ... between the two differently adapted species would prevent speciation, but in some species, sympatric speciation appears to have occurred. See also Disturbance ecology Island ecology Mammals of the Caribbean ... more details
Taxobox name Vampire Finch image regnum Animal ia phylum Chordate Chordata classis bird Aves ordo Passeriformes familia Emberizidae genus Geospiza species Geospiza difficilis G. difficilis subspecies G. d. septentrionalis trinomial Geospiza difficilis septentrionalis trinomial authority Walter Rothschild, 2nd Baron Rothschild Rothschild & Ernst Hartert Hartert , 1899 The Vampire Finch Geospiza difficilis septentrionalis is a small bird native to the Gal pagos Islands . It is a very distinct subspecies of the Sharp beaked Ground Finch Geospiza difficilis endemism endemic to Wolf Island Wolf and Darwin Island s. ref name grant Grant , Peter R. Grant, B. Rosemary & Petren, Kenneth 2000 The allopatric phase of speciation the sharp beaked ground finch Geospiza difficilis on the Gal pagos islands. Biological Journal of the Linnean Society Biol. J. Linn. Soc. 69 3 287 317. DOI 10.1006.bijl.1999.0382 seems broken http www.biology.uc.edu faculty petren LAB publications 2000GrantPetrenBJLS.pdf PDF fulltext ref The Vampire Finch is sexual dimorphism sexually dimorphic as typical for its genus , with the males being primarily black and the females grey with brown streaks. It has the largest and most pointed beak of all G. difficilis subspecies, and overall looks like a miniature Common Cactus Finch rather than, as the other subspecies do, a large Small Ground Finch with a straight bill ref name schu Schluter , Dolph & Grant , Peter R. 1984 Ecological Correlates of Morphological Evolution in a Darwin s Finch, Geospiza difficilis . Evolution journal Evolution 38 4 856 869. small DOI 10.2307 2408396 small HTML abstract and first page image ref . It has a lilting song on Wolf, a buzzing song on Darwin, and whistling calls on both islands only on Wolf, a drawn out, buzzing call is also uttered. ref name grant This bird is most famous for its unusual diet. The Vampire Finch occasionally feeds by drinking the blood of other birds, chiefly the Nazca Booby Nazca and Blue footed Booby Bl ... more details
Unreferenced date November 2010 A concept in selective breeding and zoology , outbreeding depression refers to cases when offspring from cross fertilization crosses between individuals from different populations have lower fitness than progeny from crosses between individuals from the same population. In selective breeding, the concept is opposed to inbreeding depression . This phenomenon can occur in two ways. First, selection in one population might produce a large body size, whereas in another population small body size might be more advantageous. Gene flow between these populations may lead to individuals with intermediate body sizes, which may not be adaptive in either population. It might be that, in a certain environment, having either a large or a small body is advantageous, whereas an intermediate sized body is comparatively disadvantageous. A second way outbreeding depression can occur is by the breakdown of biochemical or physiological compatibilities between genes in the different breeding populations. Within local, isolated breeding populations, allele s are selected for their positive, overall effects on the local genetic background. Due to nonadditive gene action, the same genes may have rather different average effects in different genetic backgrounds hence, the potential evolution of locally coadaptation coadapted gene complex es. However, on the other hand, according to the overdominance hypothesis in genetics, it is believed that certain combinations of alleles which can only be obtained by outbreeding are especially heterozygote advantage advantageous when paired in a heterozygous individual , which is one explanation for the existence of hybrid vigor . A third, but neutral, effect of outbreeding is the loss of allopatric speciation of a particular group, that lends its distinctness and contributes to the diversity of said types in either group by the exclusive retention of select traits. Considering the second manner of outbreeding depression ci ... more details
Image Emil Selenka.jpg thumb Emil Selenka, around 1870 Emil Selenka Braunschweig , February 27, 1842 Munich , February 20, 1902 was a German zoologist . He is known for his research on invertebrates and apes and the scientific expeditions he organized to Southeast Asia and South America. Selenka was the son of bookbinder Johannes Selenka 1801 1871 . He studied natural history at the University of G ttingen , and following his dissertation on Holothuroidea , he remained in G ttingen as an assistant to Wilhelm Moritz Keferstein 1833 1870 . His research was in this period mainly on the anatomy, taxonomy and embryology of marine invertebrates , especially organisms from the phylum Echinodermata . In 1868 he became a professor of zoology and comparative anatomy at the University of Leiden , and in 1874 relocated to the University of Erlangen . In 1895 he was given an honorary professorship at the University of Munich . He was co founder of the journal Biologisches Zentralblatt . His later research was on mammals . He studied the early development of the embryo and the development of the germ layer in mammals, and did comparative anatomy comparative anatomic research on apes , especially gibbon s and orangutan s. He found evidence that the lateral distribution of orangutan races was caused by geographic isolation a process called allopatric speciation . Selenka also examined the evolution biology evolution of marsupials and their morphology biology morphologic relation with reptiles . One problem he was intereted in, was the evolutionary relation between Australian and South American marsupials. To collect material Selenka organized expeditions to Tropics tropical countries. In 1877 he undertook an expedition to Brasil . From 1892 he led an expedition that lasted two years to Southeast Asia, it visited Ceylon , the Dutch East Indies , Japan , China and Australia . Among the participants was his second wife, the zoologist and feminist Margarethe Selenka 1860 1922 , with wh ... more details
Taxobox image Coloured Figures of English Fungi or Mushrooms t. 238.png image width 235px image caption Illustration of a half free morel, 1799 regnum Fungus Fungi divisio Ascomycota classis Pezizomycetes ordo Pezizales familia Morchellaceae genus Morchella species M. semilibera binomial Morchella semilibera binomial authority Augustin Pyramus de Candolle DC. 1805 synonyms Mitrophora semilibera small DC. L v 1846 small br Morchella patula var. semilibera small DC. S. Imai 1954 small mycomorphbox name Morchella semilibera whichGills no capShape conical capShape2 ovate hymeniumType smooth stipeCharacter bare ecologicalType mycorrhizal ecologicalType2 saprotrophic sporePrintColor cream sporePrintColor2 yellow howEdible choice Morchella semilibera , commonly called the half free morel , is a species of fungi in the Morchellaceae family native to Europe and Asia . ref name mexp ref name pnwkc ref name Kuo2012 Molecular phylogenetics DNA analysis has shown that the half free morels, which appear nearly identical on a macroscopic scale , are a cryptic species complex , consisting of at least three allopatric speciation geographically isolated species. ref name odon11 Because Augustin Pyramus de Candolle de Candolle originally described the species based on specimens from Europe, the binomial nomenclature scientific name M. semilibera should be restricted to the European species. ref name mexp In 2012, Morchella populiphila was described from western North America, while Charles Horton Peck Peck s 1903 species name Morchella punctipes was reaffirmed for eastern North American half free morels. ref name Kuo2012 M. semilibera and the other half free morels are closely related to the black morels Morchella elata M. elata and others . ref name odon11 References Reflist refs ref name mexp cite web url http www.mushroomexpert.com morchella half free.html title Half free morels Morchella species publisher MushroomExpert.com author Kuo M. date April 2006 accessdate 2011 04 18 ref r ... more details
Work Orr is an evolutionary geneticist whose research focuses on the genetics of speciation and the genetics ... of much of the current research on speciation. ref Jerry A. Coyne and H. Allen Orr Evolution, Vol ... of Rochester announcement ref Speciation His book Speciation , ref Coyne, J. A. and Orr, H. A. 2004 . Speciation . Sinauer Associates Inc., Sunderland, MA, USA, ISBN 0 87893 091 4 ref co authored with Jerry ..., pp. 612 613 ref They consider that studying speciation is largely synonymous with studying reproductive .... Following Ernst Mayr they argue that speciation usually occurs where populations are geographically isolated or allopatric . They present evidence for the primacy of natural and sexual selection over genetic drift in driving speciation. Signatures of positive selection on genes involved in postzygotic ... Books Speciation . 2004. ISBN 0 87893 091 4. Scientific publications Orr s more notable papers include ... genetics of speciation , Philosophical Transactions of the Royal Society Phil. Trans. Roy. Soc. Lond. B ref Coyne, J. A. and H. A. Orr. 1998. The evolutionary genetics of speciation. Phil. Trans ... more details
The Mentawai macaques or Mentawai island macaques are two allopatric species of macaque s that until recently were considered conspecific Pagai Island Macaque , Macaca pagensis on the islands of North Pagai, South Pagai and Sipora Siberut Macaque , Macaca siberu on the island of Siberut Disambig de Mentawai Makak ... more details
, principally by means of allopatricspeciation, and in an arena extending over most of the area ... to biotic dispersal and gene flow, that tend to subdivide species and biotas, leading to speciation ... more details
Encyclopedia
top
