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Semelparity And Iteroparity
Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered ''semelparous'' if it is characterized by a single reproduction, reproductive episode before death, and ''iteroparous'' if it is characterized by multiple reproductive cycle, 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 Botany, 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, § Trade-offs). In any ''iteroparous'' population there will be some individuals who happen to die after their first and before any second reproductive episode, but unless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproduction
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. There are two forms of reproduction: Asexual reproduction, asexual and Sexual reproduction, sexual. In asexual reproduction, an organism can reproduce without the involvement of another organism. Asexual reproduction is not limited to unicellular organism, single-celled organisms. The cloning of an organism is a form of asexual reproduction. By asexual reproduction, an organism creates a genetically similar or identical copy of itself. The evolution of sexual reproduction is a major puzzle for biologists. The two-fold cost of sexual reproduction is that only 50% of organisms reproduce and organisms only pass on 50% of their genes.John Maynard Smith ''The Evolution of Sex'' 1978. Sexual reproduction typically requires the sexual interaction of two specialized reproductive cells, called gametes, which contain half t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphibian
Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excluding the amniotes (tetrapods with an amniotic membrane, such as modern reptiles, birds and mammals). All extant taxon, extant (living) amphibians belong to the monophyletic subclass (biology), subclass Lissamphibia, with three living order (biology), orders: Anura (frogs and toads), Urodela (salamanders), and Gymnophiona (caecilians). Evolved to be mostly semiaquatic, amphibians have adapted to inhabit a wide variety of habitats, with most species living in freshwater ecosystem, freshwater, wetland or terrestrial ecosystems (such as riparian woodland, fossorial and even arboreal habitats). Their biological life cycle, life cycle typically starts out as aquatic animal, aquatic larvae with gills known as tadpoles, but some species have devel ... [...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 () (cortisone and aldosterone are isomers). The main corticosteroids produced by the adrenal cortex are cortisol and aldosterone. The etymology of the '' cortico-'' part of the name refers to the adrenal cortex, which makes these steroid hormones. Thus a corticosteroid is a "cortex steroid". Classes * Glucocorticoids such as cortisol affect carbohydrate, fat, and protein metabolism, and have anti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
R/K Selection Theory
In ecology, 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 reduced individual parental investment of -strategists, or on a reduced quantity of offspring with a corresponding increased parental investment of -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 stab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bamboo
Bamboos are a diverse group of mostly evergreen perennial plant, perennial flowering plants making up the subfamily (biology), subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family, in the case of ''Dendrocalamus sinicus'' having individual stalks (Culm (botany), culms) reaching a length of , up to in thickness and a weight of up to . The internodes of bamboos can also be of great length. ''Kinabaluchloa, Kinabaluchloa wrayi'' has internodes up to in length. and ''Arthrostylidium schomburgkii'' has internodes up to in length, exceeded in length only by Cyperus papyrus, papyrus. By contrast, the stalks of the tiny bamboo Raddiella, ''Raddiella vanessiae'' of the savannas of French Guiana measure only in length by about in width. The origin of the word "bamboo" is uncertain, but it most likely comes from the Dutch language, Dutch or Portuguese language, Portuguese language, which originally borrowed it from Malay langua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lobelia Telekii
''Lobelia telekii'' is a species of flowering plant in the family Campanulaceae, that is found only in the alpine zones of Mount Kenya, Mount Elgon, and the Aberdare Mountains of East Africa. It occurs at higher altitudes on well-drained sloped hillsides. It is a semelparous species, putting all its reproductive effort into producing single large inflorescence up to tall, and then dying. Inflorescences of ''L. telekii'' also possesses a large pith-volume for internal water storage and marcescent foliage which could provide insulation. It secretes a polysaccharide into this reservoir, which may be useful for its survival in the cold climate. The plant is named after the Austro-Hungarian explorer, Count Sámuel Teleki. ''L. telekii'' plants usually consist of a single rosette, which grows for several decades, flowers once, and then dies. However, a very small number of plants have multiple rosettes connected by an underground stem. Each flower is subtended by a long hair ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agave
''Agave'' (; ; ) is a genus of monocots native to the arid regions of the Americas. The genus is primarily known for its succulent and xerophytic species that typically form large Rosette (botany), rosettes of strong, fleshy leaves. Many plants in this genus may be considered perennial, because they require several to many years to mature and flower. However, most ''Agave'' species are more accurately described as monocarpic rosettes or multiannuals, since each individual rosette semelparity, flowers only once and then dies; a small number of ''Agave'' species are polycarpic. Along with plants from the closely related genera ''Yucca'', ''Hesperoyucca'', and ''Hesperaloe,'' various ''Agave'' species are popular ornamental plants in hot, dry climates, as they require very little supplemental water to survive. Most ''Agave'' species grow very slowly. Some ''Agave'' species are known by the common name "century plant". is a Spanish word that refers to all of the large-leafed pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Mammalogy
The ''Journal of Mammalogy'' is a bimonthly peer-reviewed scientific journal published by Oxford University Press on behalf of the American Society of Mammalogists. Both the society and the journal were established in 1919. The journal covers research on mammals throughout the world, including their ecology, genetics, conservation, behavior, systematics, morphology, and physiology Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst .... The journal also publishes news about the society and advertises student scholarship opportunities. See also * Barbara Hibbs Blake * '' Mammalian Species'' References External links * * Academic journals associated with learned and professional societies Bimonthly journals English-language journals Mammalogy journals Academic journals esta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dasyuridae
The Dasyuridae are a family of marsupials native to Australia and New Guinea, including 71 extant species divided into 17 genera. Many are small and mouse-like or shrew-like, giving some of them the name marsupial mice or marsupial shrews, but the group also includes the cat-sized quolls, as well as the Tasmanian devil. They are found in a wide range of habitats, including grassland, underground, forests, and mountains, and some species are arboreal or semiaquatic. The Dasyuridae are often called the 'marsupial carnivores', as most members of the family are insectivores. Characteristics Most dasyurids are roughly the size of mice, but a few species are much larger. The smallest species is the Pilbara ningaui, which is from in length, and weighs just , while the largest, the Tasmanian devil, is long, and weighs from . The smaller dasyurids typically resemble shrews or mice in appearance, with long tails and narrow, pointed noses. The larger species bear a resemblance to such pla ... [...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 Br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sceloporus Bicanthalis
''Sceloporus bicanthalis'', the trans volcanic bunchgrass lizard, is a species of lizard in the family Phrynosomatidae, first described by Hobart Muir Smith as a subspecies of '' Sceloporus aeneus'' in 1937. It is endemic to Mexico. It was classified by the IUCN as a species with low risk. No subspecies are recognized. Description ''Sceloporus bicanthalis'' is a small, viviparous lizard measuring on average in snout–vent length. Distribution and habitat ''Sceloporus bicanthalis'' ranges eastwards from the eastern Valley of Mexico to the eastern end the Trans-Mexican Volcanic Belt, and into the northern Sierra Madre de Oaxaca The Sierra Madre de Oaxaca is a mountain range in southeastern Mexico. It is primarily in the state of Oaxaca, and extends north into the states of Puebla and Veracruz. Geography The mountain range begins at Pico de Orizaba, and extends in a sout .... This species is associated with tussock (bunchgrass) grassland habitats within open pine forests at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
