Bateman's Principle
Bateman's principle, in evolutionary biology, is that in most species, variability in reproductive success (or reproductive variance) is greater in males than in females. It was first proposed by Angus John Bateman (1919–1996), an English geneticist. Bateman suggested that, since males are capable of producing millions of sperm cells with little effort, while females invest much higher levels of energy in order to nurture a relatively small number of eggs, the female plays a significantly larger role in their offspring's reproductive success. Bateman's paradigm thus views females as the limiting factor of parental investment, over which males will compete in order to copulate successfully. Although Bateman's principle served as a cornerstone for the study of sexual selection for many decades, it has recently been subject to criticism. Attempts to reproduce Bateman's experiments in 2012 and 2013 were unable to support his conclusions. Some scientists have criticized Bateman's ex ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Evolutionary Biology
Evolutionary biology is the subfield of biology that studies the evolutionary processes such as natural selection, common descent, and speciation that produced the diversity of life on Earth. In the 1930s, the discipline of evolutionary biology emerged through what Julian Huxley called the Modern synthesis (20th century), modern synthesis of understanding, from previously unrelated fields of biological research, such as genetics and ecology, systematics, and paleontology. The investigational range of current research has widened to encompass the genetic architecture of adaptation, molecular evolution, and the different forces that contribute to evolution, such as sexual selection, genetic drift, and biogeography. The newer field of evolutionary developmental biology ("evo-devo") investigates how embryogenesis is controlled, thus yielding a wider synthesis that integrates developmental biology with the fields of study covered by the earlier evolutionary synthesis. Subfields ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Superb Fairy Wren
The superb fairywren (''Malurus cyaneus'') is a passerine bird in the Australasian wren family, Maluridae, and is common and familiar across south-eastern Australia. It is a sedentary and territorial species, also exhibiting a high degree of sexual dimorphism; the male in breeding plumage has a striking bright blue forehead, ear coverts, mantle, and tail, with a black mask and black or dark blue throat. Non-breeding males, females and juveniles are predominantly grey-brown in colour; this gave the early impression that males were polygamous, as all dull-coloured birds were taken for females. Six subspecies groups are recognized: three larger and darker forms from Tasmania, Flinders and King Island respectively, and three smaller and paler forms from mainland Australia and Kangaroo Island. Like other fairywrens, the superb fairywren is notable for several peculiar behavioural characteristics; the birds are socially monogamous and sexually promiscuous, meaning that although they f ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Variability Hypothesis
The variability hypothesis, also known as the greater male variability hypothesis, is the hypothesis that human males generally display greater variability in traits than human females do. It has often been discussed in relation to human cognitive ability, where some studies appear to show that males are more likely than females to have either very high or very low Intelligence quotient, IQ test scores. In this context, there is controversy over whether such sex-based differences in the variability of intelligence exist, and if so, whether they are caused by genetic differences, environmental conditioning, or a mixture of both. Sex-differences in variability have been observed in many abilities and traits – including physical, psychological and genetic ones – across a wide range of sexual dimorphism, sexually dimorphic species. On the genetic level, the greater phenotype variability in males is likely to be associated with human males being a heterogametic sex, while females ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Parental Investment
Parental investment, in evolutionary biology and evolutionary psychology, is any parental expenditure (e.g. time, energy, resources) that benefits offspring.Clutton-Brock, T.H. 1991. ''The Evolution of Parental Care''. Princeton, NJ: Princeton U. Press. pg. 9Trivers, R.L. (1972). Parental investment and sexual selection. In B. Campbell (Ed.), ''Sexual selection and the descent of man'', 1871-1971 (pp. 136–179). Chicago, IL: Aldine. . Parental investment may be performed by both males and females (called ''biparental care''), females alone (''exclusive maternal care'') or males alone (''exclusive paternal care''). Care can be provided at any stage of the offspring's life, from pre-natal (e.g. egg guarding and Egg incubation, incubation in birds, and placental nourishment in mammals) to post-natal (e.g. food provisioning and protection of offspring). Parental investment theory, a term coined by Robert Trivers in 1972, predicts that the sex that invests more in its offsprin ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Jacanidae
The jacanas (sometimes referred to as Jesus birds or lily trotters) are a group of tropical waders in the family (biology), family Jacanidae. They are found in the tropical regions around the world. They are noted for their elongated toes and toenails that allow them to spread out their weight while foraging on floating or semi-emergent aquatic vegetation. They are also among the somewhat rare groups of birds in which females are larger, and several species maintain Polyandry in animals, harems of males in the breeding season with males solely responsible for incubating eggs and taking care of the chicks. Taxonomy The family Jacanidae was introduced in 1854 by the French naturalists Jean-Charles Chenu and Marc Athanase Parfait Œillet des Murs, Marc des Murs. They used the spelling "Jacaneinae". The modern spelling "Jacanidae" was used by Leonhard Stejneger in 1885. The pronunciation of the word jacana is debated. ''Jacana'' is Linnæus' binomial nomenclature, scientific Latin s ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Phalarope
A phalarope is any of three living species of slender-necked shorebirds in the genus ''Phalaropus'' of the bird family Scolopacidae. Phalaropes are close relatives of the shanks and tattlers, the '' Actitis'' and Terek sandpipers, and also of the turnstones and calidrids. They are especially notable for their unusual nesting behavior and their unique feeding technique. Two species, the red or grey phalarope (''P. fulicarius'') and the red-necked phalarope (''P. lobatus'') breed around the Arctic Circle and winter on tropical oceans. Wilson's phalarope (''P. tricolor'') breeds in western North America and migrates to South America. All are in length, with lobed toes and a straight, slender bill. Predominantly grey and white in winter, their plumage develops reddish markings in summer. Taxonomy The genus ''Phalaropus'' was introduced by French zoologist Mathurin Jacques Brisson in 1760 with the red phalarope (''Phalaropus fulicarius'') as the type species. The English a ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Seahorse
A seahorse (also written ''sea-horse'' and ''sea horse'') is any of 46 species of small marine Osteichthyes, bony fish in the genus ''Hippocampus''. The genus name comes from the Ancient Greek (), itself from () meaning "horse" and () meaning "sea monster" or "sea animal". Having a head and neck suggestive of a horse, seahorses also feature segmented bony armour, an upright posture and a curled prehensile tail. Along with the pipefishes and seadragons (''Phycodurus'' and ''Phyllopteryx'') they form the family Syngnathidae. Evolution and fossil record Anatomical evidence, supported by molecular, physical, and genetic evidence, demonstrates that seahorses are highly modified pipefish. The fossil record of seahorses, however, is very sparse. The best known and best studied fossils are specimens of ''Hippocampus guttulatus'' (though literature more commonly refers to them under the synonym of ''H. ramulosus''), from the Marecchia River formation of Rimini Province, Italy, ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Pseudoscorpion
Pseudoscorpions, also known as false scorpions or book scorpions, are small, scorpion-like arachnids belonging to the order Pseudoscorpiones, also known as Pseudoscorpionida or Chelonethida. Pseudoscorpions are generally beneficial to humans because they prey on Tineola bisselliella, clothes moth larvae, Dermestidae, carpet beetle larvae, Psocoptera, booklice, ants, mites, and small Diptera, flies. They are common in many environments, but they are rarely noticed due to their small size. When people see pseudoscorpions, especially indoors, they often mistake them for ticks or small spiders. Pseudoscorpions often carry out phoresis, a form of commensalism in which one organism uses another for the purpose of transport. Characteristics Pseudoscorpions belong to the class Arachnida. They are small arachnids with a flat, pear-shaped body, and pincer-like pedipalps that resemble those of scorpions. They usually range from in length.Pennsylvania State University, DepartmentEntomol ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Estrus
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 tha ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Lion
The lion (''Panthera leo'') is a large Felidae, cat of the genus ''Panthera'', native to Sub-Saharan Africa and India. It has a muscular, broad-chested body (biology), body; a short, rounded head; round ears; and a dark, hairy tuft at the tip of its tail. It is sexually dimorphic; adult male lions are larger than females and have a prominent mane. It is a social species, forming groups called prides. A lion's pride consists of a few adult males, related females, and cubs. Groups of female lions usually hunt together, preying mostly on medium-sized and large ungulates. The lion is an apex predator, apex and keystone predator. The lion inhabits grasslands, savannahs, and shrublands. It is usually more diurnality, diurnal than other wild cats, but when persecuted, it adapts to being active nocturnality, at night and crepuscular, at twilight. During the Neolithic period, the lion ranged throughout Africa and Eurasia, from Southeast Europe to India, but it has been reduced to fr ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Primate
Primates is an order (biology), order of mammals, which is further divided into the Strepsirrhini, strepsirrhines, which include lemurs, galagos, and Lorisidae, lorisids; and the Haplorhini, haplorhines, which include Tarsiiformes, tarsiers and simians (monkeys and apes). Primates arose 74–63 million years ago first from small terrestrial animal, terrestrial mammals, which adapted for life in tropical forests: many primate characteristics represent adaptations to the challenging environment among Canopy (biology), tree tops, including large brain sizes, binocular vision, color vision, Animal communication, vocalizations, shoulder girdles allowing a large degree of movement in the upper limbs, and opposable thumbs (in most but not all) that enable better grasping and dexterity. Primates range in size from Madame Berthe's mouse lemur, which weighs , to the eastern gorilla, weighing over . There are 376–524 species of living primates, depending on which classification is ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Waved Albatross
The waved albatross (''Phoebastria irrorata''), also known as Galapagos albatross,Remsen Jr., J.V. (2008) is one of three species of the family Diomedeidae that occur in the tropics. When they forage, they follow a straight path to a single site off the coast of Peru, about to the east. During the non-breeding season, these birds reside primarily on the Ecuadorian and Peruvian coasts. Taxonomy Waved albatrosses are a species of albatross belonging to family Diomedeidae of the order Procellariiformes, along with shearwaters, fulmars, storm petrels, and diving petrels. They share certain identifying features. First, they have nasal passages that attach to the upper bill called naricorns, although the nostrils of the albatross are on the sides of the bill. The bills of Procellariiformes are also unique in that they are split into between seven and nine horny plates. Finally, they produce a stomach oil made up of wax esters and triglycerides that is stored in the proventriculus. Th ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |