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Iteroparous
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 calle ... [...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. W ... [...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 Biological reproduction#Other types of reproductive strategies, 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 (explorer), 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 multi ... [...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] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perennial Plant
A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also widely used to distinguish plants with little or no woody growth (secondary growth in girth) from trees and shrubs, which are also technically perennials. Perennialsespecially small flowering plantsthat grow and bloom over the spring and summer, die back every autumn and winter, and then return in the spring from their rootstock or other overwintering structure, are known as herbaceous perennials. However, depending on the rigours of local climate (temperature, moisture, organic content in the soil, microorganisms), a plant that is a perennial in its native habitat, or in a milder garden, may be treated by a gardener as an annual and planted out every year, from seed, from cuttings, or from divisions. Tomato vines, for example, live several y ... [...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 ''Oncorhy ... [...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 ... [...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. The journal also publishes news about the society and advertises student scholarship opportunities. See also * Barbara Hibbs Blake * ''Mammalian Species ''Mammalian Species'' is a peer-reviewed scientific journal published by Oxford University Press on behalf of the American Society of Mammalogists. The journal publishes accounts of 12–35 mammal species yearly. The articles summarize the current ...'' References External links * * Academic journals associated with learned and professional societies Bimonthly journals English-language journals Mammalogy journals Publications established ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agave
''Agave'' (; ; ) is a genus of monocots native to the hot and arid regions of the Americas and the Caribbean, although some ''Agave'' species are also native to tropical areas of North America, such as Mexico. The genus is primarily known for its succulent and xerophytic species that typically form large rosettes of strong, fleshy leaves. ''Agave'' now includes species formerly placed in a number of other genera, such as ''Manfreda'', ×''Mangave'', ''Polianthes'' and ''Prochnyanthes''. 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 flowers only once and then dies; a small number of ''Agave'' species are polycarpic. Maguey flowers are considered edible in many indigenous culinary traditions of Mesoamerica. Along with plants from the closely related genera '' Yucca' ... [...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] |
