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Klepton
In biology, a klepton (abbr. kl.) and synklepton (abbr sk.) is a species that requires input from another biological taxon (normally from a species which is closely related to the kleptonic species) to complete its reproductive cycle. Specific types of kleptons are ''zygokleptons'', which reproduce by zygogenesis; ''gynokleptons'' which reproduce by gynogenesis, and ''tychokleptons'', which reproduce by a combination of both systems. Kleptogenic reproduction results in three potential outcomes. A unisexual female may simply activate cell division in the egg through the presence of a male's sperm without incorporating any of his genetic material—this results in the production of clonal offspring. The female may also incorporate the male's sperm into her egg, but can do so without excising any of her genetic material. This results in increased ploidy levels that range from triploid to pentaploid in wild individuals. Finally, the female also has the option of replacing some of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gynogenesis
Gynogenesis, a form of parthenogenesis, is a system of asexual reproduction that requires the presence of sperm without the actual contribution of its DNA for completion. The paternal DNA dissolves or is destroyed before it can fuse with the egg. The egg cell of the organism is able to develop, unfertilized, into an adult using only maternal genetic material. Gynogenesis is often termed "sperm parasitism" in reference to the somewhat pointless role of male gametes. Gynogenetic species, "gynogens" for short, are unisexual, meaning they must mate with males from a closely related bisexual species that normally reproduces sexually. Gynogenesis is a disadvantageous mating system for males, as they are unable to pass on their DNA. The question as to why this reproductive mode exists, given that it appears to combine the disadvantages of both asexual and sexual reproduction, remains unsolved in the field of evolutionary biology. The male equivalent to this process is Androgenesis where the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apomixis
In botany, apomixis is asexual reproduction without fertilization. Its etymology is Greek for "away from" + "mixing". This definition notably does not mention meiosis. Thus "normal asexual reproduction" of plants, such as propagation from cuttings or leaves, has never been considered to be apomixis, but replacement of the seed by a plantlet or replacement of the flower by bulbils were categorized as types of apomixis. Apomictically produced offspring are genetically identical to the parent plant. Some authors included all forms of asexual reproduction within apomixis, but that generalization of the term has since died out. In flowering plants, the term "apomixis" is commonly used in a restricted sense to mean agamospermy, i.e., clonal reproduction through seeds. Although agamospermy could theoretically occur in gymnosperms, it appears to be absent in that group. Apogamy is a related term that has had various meanings over time. In plants with independent gametophytes (nota ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybridization In Green Frogs
Hybridization (or hybridisation) may refer to: * Hybridization (biology), the process of combining different varieties of organisms to create a hybrid * Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals * Nucleic acid hybridization, the process of joining two complementary strands of nucleic acids - RNA, DNA or oligonucleotides *In evolutionary algorithms, the merging two or more optimization techniques into a single algorithm **Memetic algorithm, a common template for hybridization *In linguistics, the process of one variety blending with another variety *The alteration of a vehicle into a hybrid electric vehicle *In globalization theory, the ongoing blending of cultures *Hybridization in political election campaign communication, the combining of campaign techniques developed in different countries *In paleoanthropology, the hypothesis of Neanderthal and human hybridization See also *Hybrid (other) *Hybridity Hybridity, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelophylax
''Pelophylax'' is a genus of true frogs widespread in Eurasia, with a few species ranging into northern Africa. This genus was erected by Leopold Fitzinger in 1843 to accommodate the green frogs of the Old World, which he considered distinct from the brown pond frogs of Carl Linnaeus' genus ''Rana''. They are also known as water frogs, as they spend much of the summer living in aquatic habitat; the pond frogs can be found more often, by comparison, on dry land, as long as there is sufficient humidity. Yet there are species of Eurasian green frogs – the Central Asian '' P. terentievi'', or the Sahara frog (''P. saharicus'') – which inhabit waterholes in the desert. Systematics and taxonomy Most authors throughout the 19th and 20th century disagreed with Fitzinger's assessment. The green frogs were included again with the brown frogs, in line with the tendency to place any frog similar in habitus to the common frog (''R. temporaria'') in ''Rana''. That gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biology Terminology
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology, and Glossary of scientific naming, or any of the organism-specific glossaries in :Glossaries of biology. A B C D E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asexual Reproduction
Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the full set of genes of their single parent and thus the newly created individual is genetically and physically similar to the parent or an exact clone of the parent. Asexual reproduction is the primary form of reproduction for single-celled organisms such as archaea and bacteria. Many eukaryotic organisms including plants, animals, and fungi can also reproduce asexually. In vertebrates, the most common form of asexual reproduction is parthenogenesis, which is typically used as an alternative to sexual reproduction in times when reproductive opportunities are limited. Komodo dragons and some monitor lizards can also reproduce asexually. While all prokaryotes reproduce without the formation and fusion of gametes, mechanisms for lateral g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unisexual
Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is biparental reproduction. Dioecy has costs, since only about half the population directly produces offspring. It is one method for excluding self-fertilization and promoting allogamy (outcrossing), and thus tends to reduce the expression of recessive deleterious mutations present in a population. Plants have several other methods of preventing self-fertilization including, for example, dichogamy, herkogamy, and self-incompatibility. Dioecy is a dimorphic sexual system, alongside gynodioecy and androdioecy. In zoology In zoology, dioecious species may be opposed to hermaphroditic species, meaning that an individual is either male or female, in which case the synonym gonochory is more often used. Most animal species are dio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryotes
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poecilia Formosa
''Poecilia'' is a genus of fishes in the family Poeciliidae of the order Cyprinodontiformes. These livebearers are native to fresh, brackish and salt water in the Americas, and some species in the genus are euryhaline. A few have adapted to living in waters that contain high levels of toxic hydrogen sulfide ()Palacios, Arias-Rodriguez, Plath, Eifert, Lerp, Lamboj, Voelker, & Tobler (2013). The Rediscovery of a Long Described Species Reveals Additional Complexity in Speciation Patterns of Poeciliid Fishes in Sulfide Springs.' PLoS ONE 8(8): e71069. and a population of '' P. mexicana'' lives in caves (other populations of this species are surface-living). Some common and widespread species are often kept as aquarium fish, while other have very small ranges and are seriously threatened. All species in ''Poecilia'' are called mollies except for the Endler's livebearer (''P. wingei'') and the well-known guppy (''P. reticulata'') which have a distinctly different body shape fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelophylax Bergeri
The Italian pool frog (''Pelophylax bergeri'') is a species of frog in the family Ranidae. Found on the mainland of Italy and the Mediterranean islands of Sicily, Elba, Corsica and Sardinia, its natural habitats are rivers, swamps, freshwater lakes and freshwater marshes. It is not considered threatened by the IUCN. Description The Italian pool frog grows to a snout-to-vent length of about and has a pointed snout and triangular-shaped head. The tongue is notched and it has vomerine teeth in the roof of its mouth. The skin is smooth and not warty. The colour is variable and depends on the animal's location, but is usually some shade of green with black spots, but may be reddish-brown or grey. There is a pale stripe running along the centre of the back. The underparts are greyish-white marked with dark blotches and the hind legs have dark stripes. Males have a pair of external vocal sacs on either side of the mouth which are only visible when the animal is calling. The voice is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
