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Phoca Thumb L Takhti1 ورزشگاه تختی مشهد
''Phoca'' ( ) is a genus of the earless seals, within the Phocidae, family Phocidae. It now contains just two species, the common seal (or harbour seal) and the spotted seal (or largha seal). Several species formerly listed under this genus have been split into the genera ''Pusa'', ''harp seal, Pagophilus'', and ''ribbon seal, Histriophoca''. Until recently, ''Phoca largha'' has been considered a subspecies of ''Phoca vitulina'' but now is considered its own species. For this reason, the fossil history of the genus is unclear, and it has formerly been used as wastebasket taxon for a number of fossils of uncertain affinity. Species Currently there are two confirmed members: There is also a third unconfirmed member: Former members of ''Phoca'': * ''Histriophoca fasciata'' (ribbon seal) * ''Pusa caspica'' (Caspian seal) * ''Pusa hispida'' (ringed seal) * ''Pusa sibirica'' (nerpa or Baikal seal) * ''Pagophilus groenlandica'' (harp seal) Mating ecology Both harbour and spotted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern Taxonomy (biology), taxonomy". Many of his writings were in Latin; his name is rendered in Latin as and, after his 1761 ennoblement, as . Linnaeus was the son of a curate and was born in Råshult, in the countryside of Småland, southern Sweden. He received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and also published the first edition of his ' in the Netherlands. He then returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monogamy
Monogamy ( ) is a social relation, relationship of Dyad (sociology), two individuals in which they form a mutual and exclusive intimate Significant other, partnership. Having only one partner at any one time, whether for life or #Serial monogamy, serial monogamy, contrasts with various forms of non-monogamy (e.g., polygamy or polyamory). The term monogamy, derived from Greek language, Greek for “one marriage,” has multiple context-dependent meanings—genetic, sexual, social, and marital—each varying in interpretation across cultures and disciplines, making its definition complex and often debated. The term is typically used to describe the behavioral ecology and sexual selection of animal mating systems, referring to the state of having only one Mating, mate at any one given time. In a human cultural context, monogamy typically refers to the custom of two individuals, regardless of orientation, committing to a sexually exclusive relationship. Monogamy in humans varies wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mating System
A mating system is a way in which a group is structured in relation to sexual behaviour. The precise meaning depends upon the context. With respect to animals, the term describes which males and females mating, mate under which circumstances. Recognised systems include Monogamy in animals, monogamy, Animal sexual behaviour#Polygamy, polygamy (which includes Polygyny in animals, polygyny, Polyandry in animals, polyandry, and polygynandry), and Promiscuity#Other animals, promiscuity, all of which lead to different mate choice outcomes and thus these systems affect how sexual selection works in the species which practice them. In plants, the term refers to the degree and circumstances of outcrossing. In human sociobiology, the terms have been extended to encompass the formation of relationships such as marriage. In plants The primary mating systems in plants are outcrossing (cross-fertilisation), autogamy (self-fertilisation) and apomixis (asexual reproduction without fertilization, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mating
In biology, mating is the pairing of either opposite-sex or hermaphroditic organisms for the purposes of sexual reproduction. ''Fertilization'' is the fusion of two gametes. '' Copulation'' is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization. Mating may also lead to external fertilization, as seen in amphibians, fishes and plants. For most species, mating is between two individuals of opposite sexes. However, for some hermaphroditic species, copulation is not required because the parent organism is capable of self-fertilization (autogamy); for example, banana slugs. The term ''mating'' is also applied to related processes in bacteria, archaea and viruses. Mating in these cases involves the pairing of individuals, accompanied by the pairing of their homologous chromosomes and then exchange of genomic information leading to formation of recombinant progeny (see mating systems). Animals For animals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Selection
Sexual selection is a mechanism of evolution in which members of one sex mate choice, choose mates of the other sex to mating, mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (intrasexual selection). These two forms of selection mean that some individuals have greater reproductive success than others within a population, for example because they are more Animal sexual behaviour, attractive or prefer more attractive partners to produce offspring. Successful males benefit from frequent mating and monopolizing access to one or more fertile females. Females can maximise the return on the energy they invest in reproduction by selecting and mating with the best males. The concept was first articulated by Charles Darwin who wrote of a "second agency" other than natural selection, in which competition between mate candidates could lead to speciation. The theory was given a mathematical basis by Ronald Fisher in the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mate Selection
Mate choice is one of the primary mechanisms under which evolution can occur. It is characterized by a "selective response by animals to particular stimuli" which can be observed as behavior.Bateson, Paul Patrick Gordon. "Mate Choice." Mate Choice, Cambridge University Press, 1985 In other words, before an animal engages with a potential mate, they first evaluate various aspects of that mate which are indicative of quality—such as the resources or phenotypes they have—and evaluate whether or not those particular trait(s) are somehow beneficial to them. The evaluation will then incur a response of some sort. These mechanisms are a part of evolutionary change because they operate in a way that causes the qualities that are desired in a mate to be more frequently passed on to each generation over time. For example, if female peacocks desire mates who have a colourful plumage, then this trait will increase in frequency over time as male peacocks with a colourful plumage will ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hauling-out
Hauling out is a ethology, behaviour associated with pinnipeds (true seals, sea lions, fur seals and walruses) temporarily leaving the water. Hauling-out typically occurs between periods of foraging activity. Rather than remain in the water, pinnipeds haul out onto land or sea ice for reasons such as reproduction and rest. Hauling out is necessary in seals for mating (with the exception of the Baikal seal) and giving birth (although a distinction is generally made between reproductive aggregations, termed "rookeries", and non-reproductive aggregations, termed "haul-outs"). Other benefits of hauling out may include predator avoidance, thermoregulation, social activity, parasite reduction and rest. There is much variation in haul-out patterns among different seal species.Hoelzel, A. Rus. (2002). ''Marine Mammal Biology: An Evolutionary Approach''. Blackwell Publishing. . p. 197. Haul-out sites may be segregated by age and sex within the same species. Many species of pinniped have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lek Mating
A lek is an aggregation of male animals gathered to engage in competitive displays and courtship rituals, known as lekking, to entice visiting females which are surveying prospective partners with which to mate. It can also refer to a space used by displaying males to defend their own share of territory for the breeding season. A lekking species is characterised by male displays, strong female mate choice, and the conferring of indirect benefits to males and reduced costs to females. Although most prevalent among birds such as black grouse, lekking is also found in a wide range of vertebrates including some bony fish, amphibians, reptiles, mammals, and arthropods including crustaceans and insects. A classical lek consists of male territories in visual and auditory range of each other. An exploded lek, as seen in the kākāpō (the owl parrot), has more widely separated territories, but still in auditory range. Lekking is associated with an apparent paradox: strong sexual s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygynous Animal Mating
Polygyny (; from Ancient Greek#Modern use, Neo-Greek , ) is a mating system in which one male lives and mates with multiple females but each female only mates with a single male. Systems where several females mate with several males are defined either as Promiscuity#Other animals, promiscuity or polygynandry. Lek mating is frequently regarded as a form of polygyny, because one male mates with many females, but lek-based mating systems differ in that the male has no attachment to the females with whom he mates, and that mating females lack attachment to one another.Clutton-Brock T.H. (1989). ‘Review lecture: mammalian mating systems.' ''Proceedings of the Royal Society of London''. Series B, Biological Sciences 236: 339–372. Polygyny is typical of one-male, multi-female groupsBoyd, R., & Silk, J. B. (2009). How Humans Evolved (preferably the downloadable pdf version): WW Norton & Company, New York. and can be found in many species including: elephant seal, spotted hyena, goril ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estrous Cycle
The estrous cycle (, originally ) is a set of recurring physiological changes induced by reproductive hormones in females of mammalian subclass Theria. Estrous cycles start after sexual maturity in females and are interrupted by anestrous phases, otherwise known as "rest" phases, or by pregnancies. Typically, estrous cycles repeat until death. These cycles are widely variable in duration and frequency depending on the species.Bronson, F. H., 1989. Mammalian Reproductive Biology. University of Chicago Press, Chicago, IL, USA. Some animals may display bloody vaginal discharge, often mistaken for menstruation. Many mammals used in commercial agriculture, such as cattle and sheep, may have their estrous cycles artificially controlled with hormonal medications for optimum productivity. The male equivalent, seen primarily in ruminants, is called rut. Differences from the menstrual cycle Mammals share the same reproductive system, including the regulatory hypothalamic system that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
