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Sexual Ornament
A biological ornament is a characteristic of an animal that appears to serve a decorative function rather than a utilitarian function. Many are secondary sexual characteristics, and others appear on young birds during the period when they are dependent on being fed by their parents. Ornaments are used in displays to attract mates, which may lead to the evolutionary process known as sexual selection. An animal may shake, lengthen, or spread out its ornament in order to get the attention of the opposite sex, which will in turn choose the most attractive one with which to mate. Ornaments are most often observed in males, and choosing an extravagantly ornamented male benefits females as the genes that produce the ornament will be passed on to her offspring, increasing their own reproductive fitness. As Ronald Fisher noted, the male offspring will inherit the ornament while the female offspring will inherit the preference for said ornament, which can lead to a positive feedback loop kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Sexual Characteristic
Secondary sex characteristics are features that appear during puberty in humans, and at sexual maturity in other animals. These characteristics are particularly evident in the sexually dimorphic phenotypic traits that distinguish the sexes of a species, but unlike the sex organs (primary sex characteristics), are not directly part of the reproductive system. Secondary sex characteristics are believed to be the product of sexual selection for traits which display fitness, giving an organism an advantage over its rivals in courtship and in aggressive interactions. Secondary sex characteristics include, for example, the manes of male lions, the bright facial and rump coloration of male mandrills, and horns in many goats and antelopes. These characteristics are believed to be produced by a positive feedback loop known as the Fisherian runaway produced by the secondary characteristic in one sex and the desire for that characteristic in the other sex. Male birds and fish of many speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signalling Theory
Within evolutionary biology, signalling theory is a body of theoretical work examining communication between individuals, both within species and across species. The central question is when organisms with conflicting interests, such as in sexual selection, should be expected to provide honest signals (no presumption being made of conscious intention) rather than cheating. Mathematical models describe how signalling can contribute to an evolutionarily stable strategy. Signals are given in contexts such as mate selection by females, which subjects the advertising males' signals to selective pressure. Signals thus evolve because they modify the behaviour of the receiver to benefit the signaller. Signals may be honest, conveying information which usefully increases the fitness of the receiver, or dishonest. An individual can cheat by giving a dishonest signal, which might briefly benefit that signaller, at the risk of undermining the signalling system for the whole population. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Coot (Fulica Atra)- Adult Feeding Juvenile W IMG 8302
The Eurasian coot (''Fulica atra''), also known as the common coot, or Australian coot, is a member of the rail and crake bird family, the Rallidae. It is found in Europe, Asia, Australia, New Zealand and parts of North Africa. It has a slaty-black body, a glossy black head and a white bill with a white frontal shield. The sexes are similar. Similar looking coot species are found throughout the world, with the largest variety of coot species living in South America. Taxonomy The Eurasian coot was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his ''Systema Naturae'' under its current binomial name ''Fulica atra''. Linnaeus specified the locality as Europe but this is now restricted to Sweden. The binomial name is from Latin: ''Fulica'' means "coot", and ''atra'' means "black". Four subspecies are recognised: * ''F. a. atra'' Linnaeus, 1758 – Europe and north Africa to Japan, India, southeast Asia, Philippines and Borneo * ''F. a. l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peafowl
Peafowl is a common name for three bird species in the genera '' Pavo'' and '' Afropavo'' within the tribe Pavonini of the family Phasianidae, the pheasants and their allies. Male peafowl are referred to as peacocks, and female peafowl are referred to as peahens, although peafowl of either sex are often referred to colloquially as "peacocks." The two Asiatic species are the blue or Indian peafowl originally of the Indian subcontinent, and the green peafowl of Southeast Asia; the one African species is the Congo peafowl, native only to the Congo Basin. Male peafowl are known for their piercing calls and their extravagant plumage. The latter is especially prominent in the Asiatic species, which have an eye-spotted "tail" or "train" of covert feathers, which they display as part of a courtship ritual. The functions of the elaborate iridescent colouration and large "train" of peacocks have been the subject of extensive scientific debate. Charles Darwin suggested that they ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Courtship Display
A courtship display is a set of display behaviors in which an animal, usually a male, attempts to attract a mate; the mate exercises choice, so sexual selection acts on the display. These behaviors often include ritualized movement ("dances"), vocalizations, mechanical sound production, or displays of beauty, strength, or agonistic ability. Male display In some species, males will perform ritualized movements to attract females. The male six-plumed bird-of-paradise ( ''Parotia lawesii'') exemplifies male courtship display with its ritualized "ballerina dance" and unique occipital and breast feathers that serve to stimulate the female visual system. In ''Drosophila subobscura,'' male courtship display is seen through the male's intricate wing scissoring patterns and rapid sidestepping. These stimulations, along with many other factors, result in subsequent copulation or rejection. In other species, males may exhibit courtship displays that serve as both visual and auditory st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peacock Courting Peahen
Peafowl is a common name for three bird species in the genera '' Pavo'' and ''Afropavo'' within the tribe Pavonini of the family Phasianidae, the pheasants and their allies. Male peafowl are referred to as peacocks, and female peafowl are referred to as peahens, although peafowl of either sex are often referred to colloquially as "peacocks." The two Asiatic species are the blue or Indian peafowl originally of the Indian subcontinent, and the green peafowl of Southeast Asia; the one African species is the Congo peafowl, native only to the Congo Basin. Male peafowl are known for their piercing calls and their extravagant plumage. The latter is especially prominent in the Asiatic species, which have an eye-spotted "tail" or "train" of covert feathers, which they display as part of a courtship ritual. The functions of the elaborate iridescent colouration and large "train" of peacocks have been the subject of extensive scientific debate. Charles Darwin suggested that they se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orb-weaver Spider
Orb-weaver spiders are members of the spider family (biology), family Araneidae. They are the most common group of builders of spiral wheel-shaped spider web, webs often found in gardens, fields, and forests. The English word "orb" can mean "circular", hence the English name of the group. Araneids have eight similar eyes, hairy or spiny legs, and no stridulation, stridulating organs. The family has a cosmopolitan distribution, including many well-known large or brightly colored garden spiders. With 3,108 species in 186 genus, genera worldwide, the Araneidae comprise the third-largest family of spiders (behind the Salticidae and Linyphiidae). Araneid webs are constructed in a stereotypical fashion, where a framework of nonsticky spider silk, silk is built up before the spider adds a final spiral of silk covered in sticky droplets. Spider web#Orb web construction, Orb webs are also produced by members of other spider families. The long-jawed orb weavers (Tetragnathidae) were former ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Deer Stag 2009 Denmark
Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondary color (made from magenta and yellow) in the CMYK color model, and is the complementary color of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy. Red pigment made from ochre was one of the first colors used in prehistoric art. The Ancient Egyptians and Mayans colored their faces red in ceremonies; Roman generals had their bodies colored red to celebrate victories. It was also an important color in China, where it was used to color early pottery and later the gates and walls of palaces. In the Renaissance, the brilliant red costumes for the nobility and wealthy were dyed with kermes and cochineal. The 19th century brought ... [...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. A lek can also indicate an available plot of space able to be utilized 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, and 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 kakapo (the owl parrot), has more widely separated territories, but still in auditory range. Lekking is associated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-tailed Widowbird
The long-tailed widowbird (''Euplectes progne''), also known as the "sakabula", is a species of bird in the family Ploceidae.Mackworth-Praed, C.W., and C.H. Grant. (1960). ''Birds of Eastern and North Eastern Africa''. Longmans, Green and Co LTD.; London The species are found in Angola, Botswana, the DRCongo, Kenya, Lesotho, South Africa, Eswatini, and Zambia.Hall, B. P. and R. E. Moreau. (1970). An atlas of speciation in African passerine birds. British Museum of Natural History, London. The long-tailed widowbird is a medium-sized bird and one of the most common in the territories it inhabits.Andersson, M. (1982). "Female choice selects for extreme tail length in a widowbird." ''Nature'', 299: 818–820. Adult breeding males are almost entirely black with orange and white shoulders (epaulets), long, wide tails, and a bluish white bill. Females are rather inconspicuous, their feathers streaked tawny and black with pale patches on the chest, breast and back, narrow tail feathers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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