|
Wallace Effect
Reinforcement is a process of speciation where natural selection increases the reproductive isolation (further divided to pre-zygotic isolation and post-zygotic isolation) between two populations of species. This occurs as a result of selection acting against the production of hybrid individuals of low fitness. The idea was originally developed by Alfred Russel Wallace and is sometimes referred to as the Wallace effect. The modern concept of reinforcement originates from Theodosius Dobzhansky. He envisioned a species separated allopatrically, where during secondary contact the two populations mate, producing hybrids with lower fitness. Natural selection results from the hybrid's inability to produce viable offspring; thus members of one species who do not mate with members of the other have greater reproductive success. This favors the evolution of greater prezygotic isolation (differences in behavior or biology that inhibit formation of hybrid zygotes). Reinforcement is on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speciation By Reinforcement Schematic
Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within lineages. Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book '' On the Origin of Species''. He also identified sexual selection as a likely mechanism, but found it problematic. There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, parapatric, and sympatric. Speciation may also be induced artificially, through animal husbandry, agriculture, or laboratory experiments. Whether genetic drift is a minor or major contributor to speciation is the subject of much ongoing discussion. Rapid sympatric speciation can take place through polyploidy, such as by doubling of chromosom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrate
Vertebrates () comprise all animal taxon, taxa within the subphylum Vertebrata () (chordates with vertebral column, backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates comprise such groups as the following: * Agnatha, jawless fish, which include hagfish and lampreys * Gnathostomata, jawed vertebrates, which include: ** Chondrichthyes, cartilaginous fish (sharks, Batoidea, rays, and Chimaeriformes, ratfish) ** Euteleostomi, bony vertebrates, which include: *** Actinopterygii, ray-fins (the majority of living Osteichthyes, bony fish) *** lobe-fins, which include: **** coelacanths and lungfish **** tetrapods (limbed vertebrates) Extant taxon, Extant vertebrates range in size from the frog species ''Paedophryne amauensis'', at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastrophryne
''Gastrophryne'', the narrowmouth toads (also American narrowmouth toads, North American narrow-mouthed toads), is a genus of microhylid frogs found in the Americas between Honduras and southern United States. Its name means ‘belly-toad’, referring to its large belly, from the Ancient Greek ' (, ‘belly, stomach’) and ' (, ‘toad’). ''Gastrophryne'' is closely related to '' Hypopachus''. Some species that were earlier placed in ''Gastrophryne'' were more closely related to ''Hypopachus'', rendering the genus paraphyletic. This has been rectified by moving some species (''Gastrophryne usta'' and ''Gastrophryne pictiventris'') to ''Hypopachus''. ''Gastrophryne'' frogs were the first species to be recognized to be experiencing speciation by reinforcement and lead to the coining of the term reinforcement by W. Frank Blair in 1955;Sætre, Glenn-Peter. (2012). Reinforcement. ''eLS''. a concept proposed by Theodosius Dobzhansky decades earlier. Species The currently recogn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maria R
Maria may refer to: People * Mary, mother of Jesus * Maria (given name), a popular given name in many languages Place names Extraterrestrial * 170 Maria, a Main belt S-type asteroid discovered in 1877 * Lunar maria (plural of ''mare''), large, dark basaltic plains on Earth's Moon Terrestrial * Maria, Maevatanana, Madagascar *Maria, Quebec, Canada *Maria, Siquijor, the Philippines * María, Spain, in Andalusia *Îles Maria, French Polynesia * María de Huerva, Aragon, Spain * Villa Maria (other) Arts, entertainment, and media Films * ''Maria'' (1947 film), Swedish film * ''Maria'' (1975 film), Swedish film * ''Maria'' (2003 film), Romanian film * ''Maria'' (2019 film), Filipino film * ''Maria'' (2021 film), Canadian film directed by Alec Pronovost * ''Maria'' (Sinhala film), Sri Lankan upcoming film Literature * ''María'' (novel), an 1867 novel by Jorge Isaacs * ''Maria'' (Ukrainian novel), a 1934 novel by the Ukrainian writer Ulas Samchuk * ''Maria'' (play), a 1935 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mohamed Noor
Mohamed Noor is the Interim Dean of Arts & Sciences and a Professor in the Biology Department at Duke University (formerly holding the rotating titles of Earl D. McLean Professor, department chair, and dean of natural sciences). His specialties include evolution, genetics and genomics. Noor has a BS from the College of William and Mary in 1992 and a PhD from University of Chicago (1996), together with a postdoctoral residency at Cornell University (1996–1998). He specializes in Drosophila evolution. His team's research approaches have included both classical genetic mapping, as well as analyses of whole genome sequences. Likewise, Noor was one of the first scientists to demonstrate by experiment speciation by reinforcement, that is, as a result of natural selection mating preferences diverge against deleterious hybridization and reduce gene flow between species. He is also known for developing (along with others) a model wherein regions of restricted recombination, as b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Speciation By Reinforcement Schematic")
