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Semelparity
Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered semelparous if it is characterized by a single reproductive episode before death, and iteroparous if it is characterized by multiple reproductive cycles over the course of its lifetime. Iteroparity can be further divided into continuous iteroparity (primates including humans and chimpanzees) and seasonal iteroparity (birds, dogs, etc.) Some botanists use the parallel terms monocarpy and polycarpy. (See also plietesials.) In truly semelparous species, death after reproduction is part of an overall strategy that includes putting all available resources into maximizing reproduction, at the expense of future life (see § Trade-offs). In any iteroparous population there will be some individuals who die between their first and second reproductive episodes, but unless this is part of a syndrome of programmed death after reproduction, this would not be called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fecundity
Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population as opposed to a sole organism, while in population biology, it is considered similar to fertility, the natural capability to produce offspring, measured by the number of gametes (eggs), seed set, or asexual propagules. Superfecundity refers to an organism's ability to store another organism's sperm (after copulation) and fertilize its own eggs from that store after a period of time, essentially making it appear as though fertilization occurred without sperm (i.e. parthenogenesis). Human demography Human demography considers only human fecundity, at its culturally differing rates, while population biology studies all organisms. The term ''fecundity'' in population biology is often used to describe the rate of offspring production after one time step (often annual). In this sense, fecundity may include both birth rates and survival of young to that time step. Whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monocarpy
Monocarpic plants are those that flower and set seeds only once, and then die. The term is derived from Greek (''mono'', "single" + ''karpos'', "fruit" or "grain"), and was first used by Alphonse de Candolle. Other terms with the same meaning are ''hapaxanth'' and ''semelparous''. The antonym is polycarpic, a plant that flowers and sets seeds many times during its lifetime; the antonym of semelparous is ''iteroparous''. Plants which flower en masse (gregariously) before dying are known as plietesials. The term ''hapaxanth'' is most often in conjunction with describing some of the taxa of Arecaceae (palms) and some species of bamboo, but rarely used otherwise; its antonym is ''pleonanth''. This was first used by Alexander Braun. Monocarpic plants are not necessarily annuals, because some monocarpic plants can live a number of years before they will flower. In some monocarpic plants, flowering signals senescence, while in others the production of fruits and seeds causes changes w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oncorhynchus Nerka 2
''Oncorhynchus'' is a genus of fish in the family Salmonidae; it contains the Pacific salmon and Pacific trout. The name of the genus is derived from the Greek ὄγκος (ónkos, “lump, bend”) + ῥύγχος (rhúnkhos, “snout”), in reference to the hooked snout (the "kype") that the males develop during mating season. Range Salmon and trout with native ranges in waters draining to the Pacific Ocean are members of the genus. Their range extends from Beringia southwards, roughly to Taiwan in the west and Mexico to the east. In North America, some subspecies of '' O. clarkii'' are native in the Rocky Mountains and Great Basin, while others are native to the Rio Grande and western tributaries of the Mississippi River Basin which drain to the Gulf of Mexico, rather than to the Pacific. Several species of ''Oncorhynchus'' have been introduced into non-native waters around the globe, establishing self-sustaining wild populations. The six Pacific salmons of ''Oncorhynch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oncorhynchus
''Oncorhynchus'' is a genus of fish in the family Salmonidae; it contains the Pacific salmon and Pacific trout. The name of the genus is derived from the Greek ὄγκος (ónkos, “lump, bend”) + ῥύγχος (rhúnkhos, “snout”), in reference to the hooked snout (the "kype") that the males develop during mating season. Range Salmon and trout with native ranges in waters draining to the Pacific Ocean are members of the genus. Their range extends from Beringia southwards, roughly to Taiwan in the west and Mexico to the east. In North America, some subspecies of '' O. clarkii'' are native in the Rocky Mountains and Great Basin, while others are native to the Rio Grande and western tributaries of the Mississippi River Basin which drain to the Gulf of Mexico, rather than to the Pacific. Several species of ''Oncorhynchus'' have been introduced into non-native waters around the globe, establishing self-sustaining wild populations. The six Pacific salmons of ''Oncorhync ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labord's Chameleon
Labord's chameleon (''Furcifer labordi'') is a semelparous species of chameleon, a lizard in the family Chamaeleonidae. The species is endemic to Madagascar. Etymology The specific name, ''labordi'', is in honor of French adventurer Jean Laborde. Geographic range Laborde's chameleon is associated with spiny and deciduous forests in the south-west regions of Madagascar. Life cycle Like other ''Furcifer'' species ('' F. antimena'', '' F. lateralis''), ''F. labordi'' has an obligate year-long lifecycle. It lives for only about 4 to 5 months, making it the shortest lifespan ever recorded for a four-legged vertebrate. In their natural habitat, eggs hatch with the first rains in November. Their initial growth is rapid, and adulthood is reached by January, at which time they breed. By late February or early March, females have deposited the eggs which will hatch the next year, and the entire population dies until the next hatching. No other tetrapod has exhibited such a short lifes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plietesials
Plietesials are plants that grow for a number of years, flower gregariously (synchronously), set seed and then die. The length of the cycle can vary between 8 and 16 years. For example, the neelakurinji plant flowers every 12 years and bloomed as expected in 2006 and 2018 in the Munnar region of Kerala, India. Certain species of unrelated families of flowering plants (including Poaceae, Arecaceae, Scrophulariaceae, Fabaceae, Apocynaceae, and Acanthaceae) are plietesial. The term plietesial has been used in reference to perennial monocarpic plants "of the kind most often met with in the Strobilanthinae" (a subtribe of Acanthaceae containing Strobilanthes and allied genera) that usually grow gregariously, flower simultaneously following a long interval, set seed, and die. Other commonly used expressions or terms describing a plietesial life history include gregarious flowering, mast seeding, and supra-annual synchronized semelparity (semelparity = monocarpy).Daniel, Thomas F. 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycarpy
Polycarpic plants are those that flower and set seeds many times before dying. A term of identical meaning is pleonanthic and iteroparous. Polycarpic plants are able to reproduce multiple times due to at least some portion of its meristems being able to maintain a vegetative state in some fashion so that it may reproduce again. This type of reproduction seems to be best suited for plants who have a fair amount of security in their environment as they do continuously reproduce. Generally, in reference to life-history theory, plants will sacrifice their ability in one regard to improve themselves in another regard, so for polycarpic plants that may strive towards continued reproduction, they might focus less on their growth. However, these aspects may not necessarily be directly correlated and some plants, notably invasive species, do not follow this general trend and actually show a fairly long lifespan with frequent reproduction. To an extent, there does seem to be an importance of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
R/K Selection Theory
In ecology, ''r''/''K'' selection theory relates to the selection of combinations of traits in an organism that trade off between quantity and quality of offspring. The focus on either an increased quantity of offspring at the expense of individual parental investment of ''r''-strategists, or on a reduced quantity of offspring with a corresponding increased parental investment of ''K''-strategists, varies widely, seemingly to promote success in particular environments. The concepts of quantity or quality offspring are sometimes referred to as "cheap" or "expensive", a comment on the expendable nature of the offspring and parental commitment made. The stability of the environment can predict if many expendable offspring are made or if fewer offspring of higher quality would lead to higher reproductive success. An unstable environment would encourage the parent to make many offspring, because the likelihood of all (or the majority) of them surviving to adulthood is slim. In contrast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastrointestinal Bleeding
Gastrointestinal bleeding (GI bleed), also called gastrointestinal hemorrhage (GIB), is all forms of bleeding in the gastrointestinal tract, from the mouth to the rectum. When there is significant blood loss over a short time, symptoms may include vomiting red blood, vomiting black blood, bloody stool, or black stool. Small amounts of bleeding over a long time may cause iron-deficiency anemia resulting in feeling tired or heart-related chest pain. Other symptoms may include abdominal pain, shortness of breath, pale skin, or passing out. Sometimes in those with small amounts of bleeding no symptoms may be present. Bleeding is typically divided into two main types: upper gastrointestinal bleeding and lower gastrointestinal bleeding. Causes of upper GI bleeds include: peptic ulcer disease, esophageal varices due to liver cirrhosis and cancer, among others. Causes of lower GI bleeds include: hemorrhoids, cancer, and inflammatory bowel disease among others. Diagnosis typi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involved in a wide range of physiological processes, including stress response, immune response, and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte levels, and behavior. Some common naturally occurring steroid hormones are cortisol (), corticosterone (), cortisone () and aldosterone (). (Note that cortisone and aldosterone are isomers.) The main corticosteroids produced by the adrenal cortex are cortisol and aldosterone. Classes * Glucocorticoids such as cortisol affect carbohydrate, fat, and protein metabolism, and have anti-inflammatory, immunosuppressive, anti-proliferative, and vasoconstrictive effects. Anti-inflammatory effects are mediated by blocking the action of inflammatory medi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sow With Piglet
Sow or SOW may refer to: * Sowing, the process of planting Female animals * Badger * Bear * Guinea pig * Hedgehog * Suidae ** Wild boar ** Pig Arts, entertainment and media * Sow (band), a musical project of Anna Wildsmith * "Sow", a poem by Sylvia Plath * Sow (playing card), common name for the Deuce in cards games in southern Germany Places * Show Low Regional Airport (IATA airport code), Arizona, US * Sowerby Bridge railway station (Network Rail station code), England * River Sow, England People * Aminata Sow Fall (born 1941), Senegalese author * Abdoul Salam Sow (born 1970), Guinean footballer * Abdoulaye Sékou Sow (1931–2013), former Prime Minister of Mali * Abdourahmane Sow (born 1942), Minister of the Interior of Senegal, chair of the World Scout Committee * Baba Sow (born 1995), Senegalese footballer * Daouda Sow (politician) (1933–2009), Senegalese politician * Daouda Sow (boxer) (born 1983), boxer * Fatou Ndiaye Sow (1937–2004), Senegalese poet * Ismaël ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichnotropis
''Ichnotropis'' is a genus of African lizards in the family Lacertidae. Species in the genus ''Ichnotropis'' are commonly called rough-scaled lizards."''Ichnotropis'' ". The Reptile Database. www.reptile-database.org. Species The following six species are recognized as being valid. *'' Ichnotropis bivittata'' Bocage, 1866 - Angolan rough-scaled lizard *'' Ichnotropis capensis'' ( A. Smith, 1838) - Cape rough-scaled lizard, ornate rough-scaled lizard, Smith's rough-scaled sand lizard *'' Ichnotropis chapini'' K.P. Schmidt, 1919 *'' Ichnotropis grandiceps'' Broadley, 1967 - Caprivi rough-scaled lizard *'' Ichnotropis microlepidota'' Marx, 1956 - Marx's rough-scaled lizard *'' Ichnotropis tanganicana'' Boulenger, 1917 - Tanzanian rough-scaled lizard, ''Nota bene'': A binomial authority in parentheses indicates that the species was originally described in a genus other than ''Ichnotropis''. References Further reading * Boulenger GA (1887). ''Catalogue of the Lizards in the Bri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
