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Androdioecy
Androdioecy is a reproductive system characterized by the coexistence of males and hermaphrodites. Androdioecy is rare in comparison with the other major reproductive systems: dioecy, gynodioecy and hermaphroditism. In animals, androdioecy has been considered a stepping stone in the transition from dioecy to hermaphroditism, and vice versa. Androdioecy is sometimes referred to as a mixed breeding system with trioecy and gynodioecy. It is a dimorphic sexual system in plants alongside gynodioecy and dioecy. Evolution of androdioecy The fitness requirements for androdioecy to arise and sustain itself are theoretically so improbable that it was long considered that such systems do not exist. Particularly, males and hermaphrodites have to have the same fitness, in other words the same number of offspring, in order to be maintained. However, males only have offspring by fertilizing eggs or ovules of hermaphrodites, while hermaphrodites have offspring both through fertilizing eggs or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual System
A sexual system is a pattern of sex allocation or a distribution of male and female function across organisms in a species. Terms like reproductive system and mating system have also been used as synonyms. The distinction between sexual systems is not always clear due to phenotypic plasticity. Sexual systems are viewed as a key factor for genetic variation and reproductive success, and may have also led to the origin or extinction of certain species. Interests in sexual systems go back to Charles Darwin, Darwin, who found that barnacles contain species that are Androdioecy, androdioecious and some that are Dioecy, dioecious. Types of sexual systems In plants there are monomorphic sexual systems where a species has hermaphrodite, male and/or female flowers on the same plant. Monomorphic sexual systems include Monoecious (botany), monoecy, gynomonoecy, andromonoecy and trimonoecy. There are also dimorphic sexual systems like dioecy, gynodioecy and androdioecy. Mixed sexual syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trioecy
Trioecy, or subdioecy, is a rare sexual system characterized by the coexistence of males, females, and hermaphrodites. It has been found in both plants and animals. Trioecy is sometimes referred to as a mixed mating system alongside androdioecy and gynodioecy. Evolution of trioecy Many speculate trioecy is a transient state and is often associated with evolutionary transitioning from gynodioecy to dioecy. Other studies show that trioecious populations originated from gonochoristic ancestors which were invaded by a mutant selfing hermaphrodite, creating a trioecious population. It has been suggested that chromosomal duplication is an important part in the evolution of trioecy. Evolutionary stability Trioecy is usually viewed as evolutionarily unstable, but its exact stability is unclear. Like in brachiopod species trioecy usually breaks into androdioecy or gynodioecy. But one study found that trioecy can be stable under nucleocytoplasmic sex determination. Another theoretical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermaphrodites
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the female or male. For example, the great majority of tunicates, pulmonate molluscs, opisthobranch, earthworms, and slugs are hermaphrodites. Hermaphroditism is also found in some fish species and to a lesser degree in other vertebrates. Most plants are also hermaphrodites. Animal species having different sexes, male and female, are called gonochoric, which is the opposite of hermaphrodite. There are also species where hermaphrodites exist alongside males (called androdioecy) or alongside females (called gynodioecy), or all three exist in the same species (called trioecy); these three systems are so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gynodioecy
Gynodioecy is a rare breeding system that is found in certain flowering plant species in which female and hermaphroditic plants coexist within a population. Gynodioecy is the evolutionary intermediate between hermaphroditism (exhibiting both female and male parts) and dioecy (having two distinct morphs: male and female). Gynodioecy is sometimes considered a mixed breeding system alongside trioecy and androdioecy. It is also considered a dimorphic sexual system alongside dioecy and androdioecy. Gynodioecy occurs as a result of a genetic mutation that inhibits a hermaphroditic plant from producing pollen, while keeping the female reproductive parts intact. Gynodioecy is extremely rare, with fewer than 1% of angiosperm species exhibiting the breeding system. Some notable taxa that exhibit a gynodioecious mating system include ''Beta vulgaris'' (wild beet), ''Lobelia siphilitica'', ''Silene'', and Lamiaceae. Evolution Gynodioecy is often referred to as the evolutionary intermed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermaphroditism
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the female or male. For example, the great majority of tunicates, pulmonate molluscs, opisthobranch, earthworms, and slugs are hermaphrodites. Hermaphroditism is also found in some fish species and to a lesser degree in other vertebrates. Most plants are also hermaphrodites. Animal species having different sexes, male and female, are called gonochoric, which is the opposite of hermaphrodite. There are also species where hermaphrodites exist alongside males (called androdioecy) or alongside females (called gynodioecy), or all three exist in the same species (called trioecy); these three systems are so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trioecy
Trioecy, or subdioecy, is a rare sexual system characterized by the coexistence of males, females, and hermaphrodites. It has been found in both plants and animals. Trioecy is sometimes referred to as a mixed mating system alongside androdioecy and gynodioecy. Evolution of trioecy Many speculate trioecy is a transient state and is often associated with evolutionary transitioning from gynodioecy to dioecy. Other studies show that trioecious populations originated from gonochoristic ancestors which were invaded by a mutant selfing hermaphrodite, creating a trioecious population. It has been suggested that chromosomal duplication is an important part in the evolution of trioecy. Evolutionary stability Trioecy is usually viewed as evolutionarily unstable, but its exact stability is unclear. Like in brachiopod species trioecy usually breaks into androdioecy or gynodioecy. But one study found that trioecy can be stable under nucleocytoplasmic sex determination. Another theoretical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscheius Tipulae
''Oscheius tipulae'' is a species of nematodes, described in association of the leatherjacket, the larva of ''Tipula paludosa''. ''O. tipulae'' is a satellite developmental genetic model organism used to study vulva formation.Polymorphism and evolution of vulval precursor cell lineages within two nematode genera, Caenorhabditis and Oscheius. M Delattre, MA Félix - Current Biology, 2001 It is an androdioecious Androdioecy is a reproductive system characterized by the coexistence of males and hermaphrodites. Androdioecy is rare in comparison with the other major reproductive systems: dioecy, gynodioecy and hermaphroditism. In animals, androdioecy has bee ... species characterized by the coexistence of males and hermaphrodites. References External links Rhabditidae Nematodes described in 1971 Animal models {{Rhabditida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caenorhabditis Tropicalis
''Caenorhabditis tropicalis'' is a species of ''Caenorhabditis'' nematodes, belonging to the ''Elegans'' super-group and ''Elegans'' group within the genus. It is a close relative of ''C. wallacei.'' ''C. tropicalis'' is collected frequently in tropical South America, Caribbean islands, and various islands in the Indian and Pacific Oceans from rotting fruit, flowers and stems. ''C. tropicalis'' was referred to as “''C.'' sp. 11” prior to 2014. Anatomy The mean body lengths of adult hermaphroditic and adult male ''C. tropicalis'' were calculated as 1378.63µm and 992.85µm, respectively, making ''C. tropicalis'' males and hermaphrodites on average larger than other hermaphroditic species like ''C. elegans'' and ''C. briggsae''. Spicule shape The spicules of ''C. tropicalis'' males consist of a long, slender, pointed, and simple morphology, which is a common feature among Caenorhabditis species outside of the Elegans super-group (with the exception of ''C. japonica'' and ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broad range of environments. Less formally, they are categorized as Helminths, but are taxonomically classified along with Arthropod, arthropods, Tardigrade, tardigrades and other moulting animalia, animals in the clade Ecdysozoa, and unlike platyhelminthe, flatworms, have tubular digestion, digestive systems with openings at both ends. Like tardigrades, they have a reduced number of Hox genes, but their sister phylum Nematomorpha has kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum. Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species described to date vary by author and may change rapidly over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhabditidae
The Rhabditidae are a family of nematodes which includes the model organism '' Caenorhabditis elegans''. Genera ''Bursilla'' *''Bursilla monhysteria'' (Butschli, 1873) ''Caenorhabditis'' *''Caenorhabditis brenneri'' Sudhaus & Kiontke, 2007 *''Caenorhabditis briggsae'' *''Caenorhabditis dolichura'' *'' Caenorhabditis elegans'' Maupas, 1900 *''Caenorhabditis rara'' ''Diploscapter'' Genus ''Diploscapter'' *''Diploscapter bicornis'' *''Diploscapter coronata'' (Cobb, 1893) *''Diploscapter lycostoma'' *''Diploscapter pachys'' ''Halicephalobus'' *''Halicephalobus gingivalis'' (Stefanski, 1954) Andrássy, 1984 *''Halicephalobus mephisto'' Borgonie, García-Moyano, Litthauer, Bert, Bester, van Heerden, Möller, Erasmus & Onstott, 2011 *'' Halicephalobus similigaster'' (Andrássy, 1952) ''Macramphis'' *'' Macramphis stercorarius'' ''Mesorhabditis'' *''Mesorhabditis acris'' *''Mesorhabditis irregularis'' *''Mesorhabditis oschei'' *''Mesorhabditis spiculigera'' ''Neorha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhabditida
Rhabditida is an order of free-living, zooparasitic, and phytoparasitic microbivorous nematodes living in soil. The Cephalobidae, Panagrolaimidae, Steinernematidae, and Strongyloididae seem to be closer to the Tylenchia, regardless of whether these are merged with the Rhabditia or not.Tree of Life Web Project (2002b)Nematoda Version of 2002-JAN-01. Retrieved 2008-NOV-02. Families Rhabditida * Myolaimina **''Incertae sedis'' *** Myolaimoidea ****Myolaimidae *Rhabditina ** Bunonematomorpha *** Bunonematoidea ****Bunonematidae ** Diplogasteromorpha *** Cylindrocorporoidea ****Cylindrocorporidae *** Diplogasteroidea **** Cephalobiidae ****Diplogasteridae ****Diplogasteroididae ** Rhabditomorpha *** Mesorhabditoidea ****Peloderidae *** Rhabditoidea ****Rhabditidae * Spirurina ** Ascaridomorpha *** Ascaridoidea **** Acanthocheilidae ****Anisakidae ****Ascarididae ****Heterocheilidae **** Raphidascarididae *** Cosmocercoidea ****Atractidae ****Kathlaniidae *** Seuratoidea **** Cuc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caenorhabditis Briggsae
''Caenorhabditis briggsae'' is a small nematode, closely related to ''Caenorhabditis elegans''. The differences between the two species are subtle. The male tail in ''C. briggsae'' has a slightly different morphology from ''C. elegans''. Other differences include changes in vulval precursor competence and the placement of the excretory duct opening. ''C. briggsae'' is frequently used to study the differences between it and the more intimately understood ''C. elegans'', especially at the DNA and protein sequence level. Several mutant strains of ''C. briggsae'' have also been isolated that facilitate genetic analysis of this organism. ''C. briggsae'', like ''C. elegans'', is a hermaphrodite. The genome sequence for ''C. briggsae'' was determined in 2003. History ''C. briggsae'' was initially discovered by Margaret Briggs in 1944. The first individuals were isolated from a pile of leaves found on the Palo Alto campus of Stanford University. Briggs, who was studying for her MS, ide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
