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Sexual Selection In Scaled Reptiles
Sexual selection in scaled reptiles studies how sexual selection manifests in snakes and lizards, which constitute the order Squamata of reptiles. Each of the over three thousand snakes use different tactics in acquiring mates. Ritual combat between males for the females they want to mate with includes topping, a behavior exhibited by most viperids in which one male will twist around the vertically elevated fore body of its opponent and forcing it downward. It is common for neck biting to occur while the snakes are entwined. Male-male competition Snakes In the species Japanese striped snake (''Elaphe quadrivirgata''), competition involves males maintaining body contact with their opponent and exerting pressure by pushing, topping, or entwining in order to subdue him. Male snakes employ a variety of strategies to help them entice the female into mating. The red-sided garter snake (''Thamnophis sirtalis'') population in Alberta, Canada hibernates for the majority of the y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garter Snake Tooth
A garter is an article of clothing comprising a narrow band of fabric fastened about the leg to keep up stockings. In the eighteenth to twentieth centuries, they were tied just below the knee, where the leg is most slender, to keep the stocking from slipping. The advent of elastic has made them less necessary from this functional standpoint, although they are still often worn for fashion. Garters have been widely worn by men and women, depending on fashion trends. Garters in fashion In Elizabethan fashions, men wore garters with their hose, and colourful garters were an object of display. In Shakespeare's ''Twelfth Night'', "cross braced" garters (a long garter tied above and below the knee and crossed between), as worn by the character Malvolio, are an object of some derision. In male fashion for much of the 20th century a type of garter for holding up socks was used as a part of male dress; it is considered somewhat archaic now. Use in wedding traditions There is a Western ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pheromone
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals. There are ''alarm signal, alarm pheromones'', ''food trail pheromones'', ''sex pheromones'', and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology. Background The portmanteau word "pheromone" was coined by Peter Karlson and Martin Lüscher in 1959, based on the Greek φερω ''pheroo'' ('I carry') and ὁρμων ''hormon'' ('stimulating'). P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress (biology)
Stress, either physiological, biological or psychological, is an organism's response to a stressor such as an environmental condition. Stress is the body's method of reacting to a condition such as a threat, challenge or physical and psychological barrier. There are two hormones that an individual produces during a stressful situation, these are well known as adrenaline and cortisol. There are two kinds of stress hormone levels. Resting (basal) cortisol levels are normal everyday quantities that are essential for standard functioning. Reactive cortisol levels are increases in cortisol in response to stressors. Stimuli that alter an organism's environment are responded to by multiple systems in the body. In humans and most mammals, the autonomic nervous system and hypothalamic-pituitary-adrenal (HPA) axis are the two major systems that respond to stress. The sympathoadrenal medullary (SAM) axis may activate the fight-or-flight response through the sympathetic nervous system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White's Skink
White's skink (''Liopholis whitii)'', also known commonly as White's rock skink, is a species of lizard in the family Scincidae. The species is endemic to Australia. Etymology The specific name, ''whitii'', is in honour of Irish surgeon and naturalist John White. Geographic range ''L. whitii'' is widespread in south-eastern Australia, including Tasmania and many Bass Strait islands. Habitat The preferred natural habitats of ''L. whitii'' are forest, shrubland, and rocky areas, at altitudes from sea level to . White's skinks prefer a habitat with rocks, shrubby heathland and minimal human environmental disturbance. They also dig tunnels underground and have two entrances to the tunnel if needing an escape route. They also have well covered and hidden entrances to avoid predators. Description The White's skink is a stocky slow-growing medium-sized species, growing to a maximum snout-to-vent length (SVL) of about . That matures at ~ (SVL) in both sexes, this size is typical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fitness (biology)
Fitness (often denoted w or ω in population genetics models) is the quantitative representation of individual reproductive success. It is also equal to the average contribution to the gene pool of the next generation, made by the same individuals of the specified genotype or phenotype. Fitness can be defined either with respect to a genotype or to a phenotype in a given environment or time. The fitness of a genotype is manifested through its phenotype, which is also affected by the developmental environment. The fitness of a given phenotype can also be different in different selective environments. With asexual reproduction, it is sufficient to assign fitnesses to genotypes. With sexual reproduction, recombination scrambles alleles into different genotypes every generation; in this case, fitness values can be assigned to alleles by averaging over possible genetic backgrounds. Natural selection tends to make alleles with higher fitness more common over time, resulting in Darwin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White's Skink, Freycinet Peninsula, Cropped
White's is a gentlemen's club in St James's, London. Founded in 1693 as a hot chocolate shop in Mayfair, it is the oldest gentleman's club in London. It moved to its current premises on St James's Street in 1778. Status White's is the oldest gentlemen's club in London, founded in 1693, and is considered by many to be the most exclusive private club in London. Notable current members include Charles III, and the Prince of Wales. Former British Prime Minister David Cameron, whose father Ian Cameron had been the club's chairman, was a member for fifteen years but resigned in 2008, over the club's declining to admit women. However, he has since rejoined. White's continues to maintain its tradition as an establishment exclusively for gentlemen; brief exceptions were made for the visits by Queen Elizabeth II in 1991 and 2016. White's is a member of the Association of London Clubs. In January 2018, calling themselves 'Women in Whites', a group of female protesters infiltrated t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eunectes Murinus
The green anaconda (''Eunectes murinus''), also known as the giant Emerald anaconda, common anaconda, common water boa or sucuri, is a boa species found in South America. It is the heaviest and one of the longest known extant snake species. Like all boas, it is a non-venomous constrictor. The term "anaconda" often refers to this species, though the term could also apply to other members of the genus ''Eunectes''. Fossils of the snake date back to the Late Pleistocene in the Gruta do Urso locality. Etymology The green anaconda's specific name is derived from the Latin ', meaning 'of mice', for being thought to prey on mice. Description The green anaconda is the world's heaviest and one of the world's longest snakes, reaching a length of up to long. More typical mature specimens reportedly can range up to , with adult females, with a mean length of about , being generally much larger than the males, which average around . Weights are less well studied, though reportedly ran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyandry
Polyandry (; ) is a form of polygamy in which a woman takes two or more husbands at the same time. Polyandry is contrasted with polygyny, involving one male and two or more females. If a marriage involves a plural number of "husbands and wives" participants of each gender, then it can be called polygamy, group marriage, group or conjoint marriage. In its broadest use, polyandry refers to sexual relations with multiple males within or without marriage. Of the 1,231 societies listed in the 1980 Ethnographic Atlas, 186 were found to be monogamous, 453 had occasional polygyny, 588 had more frequent polygyny, and 4 had polyandry.''Ethnographic Atlas Codebook'' derived from George P. Murdock's ''Ethnographic Atlas'' recording the marital composition of 1,231 societies from 1960 to 1980. Polyandry is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygyny
Polygyny (; from Neoclassical Greek πολυγυνία (); ) is the most common and accepted form of polygamy around the world, entailing the marriage of a man with several women. Incidence Polygyny is more widespread in Africa than in any other continent. Some scholars see the slave trade's impact on the male-to-female sex ratio as a key factor in the emergence and fortification of polygynous practices in regions of Africa. Polygyny is most common in a region known as the "polygamy belt" in West Africa and Central Africa, with the countries estimated to have the highest polygamy prevalence in the world being Burkina Faso, Mali, Gambia, Niger and Nigeria. In the region of sub-Saharan Africa, polygyny is common and deeply rooted in the culture, with 11% of the population of sub-Saharan Africa living in such marriages (25% of the Muslim population and 3% of the Christian population, as of 2019). Polygyny is especially widespread in West Africa, with the countries estimated to h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
