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Panmixy
Panmixia (or panmixis) means uniform random fertilization, which means individuals do not select a mate based on physical traits. A panmictic population is one where all potential parents may contribute equally to the gamete pool, and that these gametes are uniformly distributed within the gamete population (gamodeme). This assumes that there are no hybridising restrictions within the parental population: neither genetics, cytogenetics nor behavioural; and neither spatial nor temporal (see also Quantitative genetics for further discussion). True panmixia is rarely, if ever, observed in natural populations. It is a theoretical model used as a null hypothesis in population genetics. It serves as a point of comparison to understand how deviations from random mating affect allele and genotype frequencieTherefore, all gamete recombination (fertilization) is uniformly possible. Both the Wahlund effect and the Hardy Weinberg equilibrium assume that the overall population is panmictic. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Genetics
Population genetics is a subfield of genetics that deals with genetic differences within and among populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as Adaptation (biology), adaptation, speciation, and population stratification, population structure. Population genetics was a vital ingredient in the emergence of the Modern synthesis (20th century), modern evolutionary synthesis. Its primary founders were Sewall Wright, J. B. S. Haldane and Ronald Fisher, who also laid the foundations for the related discipline of quantitative genetics. Traditionally a highly mathematical discipline, modern population genetics encompasses theoretical, laboratory, and field work. Population genetic models are used both for statistical inference from DNA sequence data and for proof/disproof of concept. What sets population genetics apart from newer, more phenotypic approaches to modelling evolution, such as evolutionary game theory and evolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interbreed
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different variety (botany), varieties, subspecies, species or genus, genera through sexual reproduction. Generally, it means that each cell has genetic material from two different organisms, whereas an individual where some cells are derived from a different organism is called a chimera (genetics), chimera. Hybrids are not always intermediates between their parents such as in blending inheritance (a now discredited theory in modern genetics by particulate inheritance), but can show Heterosis, hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductive isolation, reproductively isola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Eel
The American eel (''Anguilla rostrata'') is a facultative catadromous eel found on the eastern coast of North America. Anguillidae, Freshwater eels are fish belonging to the Elopomorpha, elopomorph superorder, a group of Phylogenetics, phylogenetically ancient teleosts. The American eel has a slender, supple, snake-like body that is covered with a mucus layer, which makes the eel appear to be naked and slimy despite the presence of minute Fish scale, scales. A long dorsal fin runs from the middle of the back and is continuous with a similar ventral fin. Pelvic fins are absent, and relatively small pectoral fin, pectoral fins can be found near the midline, followed by the head and gill covers. Variations exist in coloration, from olive green, brown shading to greenish-yellow and light gray or white on the belly. Eels from clear water are often lighter than those from dark, Blackwater river, tannic acid streams. The eel lives in fresh water and estuaries and only leaves these habi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantala Flavescens
''Pantala flavescens'', the globe skimmer, globe wanderer or wandering glider, is a wide-ranging dragonfly of the family Libellulidae. This species and ''Pantala hymenaea'', the "spot-winged glider", are the only members of the genus ''Pantala''. It was first described by Johan Christian Fabricius in 1798. It is considered to be the most widespread dragonfly on the planet, with good population on every continent except Antarctica, although rare in Europe. Globe skimmers make an annual multigenerational journey of some 18,000 km (about 11,200 miles); to complete the migration, individual globe skimmers fly more than 6,000 km (3,730 miles)—one of the farthest known migrations of all insect species. Characteristics Structure of the adult The dragonfly is up to 4.5 cm long, reaching wingspans between 7.2 cm and 8.4 cm. The front side of the head is yellowish to reddish. The thorax is usually yellow to golden coloured with a dark and hairy line. There were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amegilla Dawsoni
''Amegilla dawsoni'', sometimes called the Dawson's burrowing bee, is a species of bee that nests by the thousands in arid claypans in Western Australia. It is a long tongued bee, of the tribe Anthophorini and genus ''Amegilla,'' the second largest genus in Anthophorini. The Dawson's burrowing bee is one of the largest Australian bee species, growing to be in length and in wingspan. With the exception of their faces, the bees are covered in brown fur, if male, or brown and white fur if female. They are similar in size and coloring to Australian carpenter bees. They are known solitary nesters. Though each female bee will build her own nest, they aggregate in large communities that give the appearance of colonies. Their nests are dug into the ground, with individual capsules created for each brood cell. Each female will only breed once in their breeding season. The males of the species are dimorphic, based on brood provisioning strategies during development. The larger mal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatric Speciation
Sympatric speciation is the evolution of a new species from a surviving Common descent, ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography, ''sympatric'' and ''sympatry'' are terms referring to organisms whose Range (biology), ranges overlap so that they occur together at least in some places. If these organisms are closely related (e.g. sister species), such a distribution may be the result of sympatric speciation. Etymologically, sympatry is derived . The term was coined by Edward Bagnall Poulton in 1904, who explains the derivation. Sympatric speciation is one of three traditional geographic modes of speciation.Futuyma, D. J. 2001. ''Evolution'' (2nd edition). Sinauer Associates, Inc. Allopatric speciation is the evolution of species caused by the geographic isolation of two or more populations of a species. In this case, divergence is facilitated by the absence of gene flow. Parapatric speciation is the evolut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monostroma
''Monostroma'' is a genus of marine green algae (seaweed) in the family Monostromataceae. As the name suggests, algae of this genus are monostromatic (single cell layered). '' Monostroma kuroshiense'', an algae of this genus, is commercially cultivated in East Asia and South America for the edible product "hitoegusa-nori" or "hirohano-hitoegusa nori", popular sushi wraps. ''Monostroma'' oligosaccharides with degree of polymerization 6 prepared by agarase digestion from ''Monostroma nitidum'' polysaccharides have been shown to be an effective prophylactic agent during ''in vitro'' and ''in vivo'' tests against Japanese encephalitis viral infection. The sulfated oligosaccharides from ''Monostroma'' seem to be promising candidates for further development as antiviral agents. The genus ''Monostroma'' is the most widely cultivated genus among green seaweeds. Classification Species-level classification within this genus is quite problematic and no consensus exists among algal taxono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantala Flavescens-Kadavoor-2017-05-04-002
''Pantala'' is a genus of dragonfly in the family Libellulidae commonly called the rainpool gliders. They are found almost worldwide. Species of ''Pantala'' are medium-sized to large, dull orange-yellow dragonflies. Species The genus ''Pantala'' includes the following species: References External links * * {{Taxonbar, from=Q149707 Libellulidae Anisoptera genera Odonata of Africa Odonata of Asia Odonata of Australia Odonata of Oceania Taxa named by Hermann August Hagen Insects described in 1861 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monandrous
The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament and an anther which contains microsporangia. Most commonly, anthers are two-lobed (each lobe is termed a locule) and are attached to the filament either at the base or in the middle area of the anther. The sterile (i.e. nonreproductive) tissue between the lobes is called the connective, an extension of the filament containing conducting strands. It can be seen as an extension on the dorsal side of the anther. A pollen grain develops from a microspore in the microsporangium and contains the male gametophyte. The size of anthers differs greatly, from a tiny fraction of a millimeter in ''Wolfia'' spp up to five inches (13 centimeters) in '' Canna iridiflora'' and '' Strelitzia nicolai''. The stamens in a flower are collectively called the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Diversity
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It ranges widely, from the number of species to differences within species, and can be correlated to the span of survival for a species. It is distinguished from '' genetic variability'', which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral substitu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
