|
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 e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Biology
Evolutionary biology is the subfield of biology that studies the evolutionary processes ( natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life forms on Earth. Evolution is based on the theory that all species are related and they gradually change over time. In a population, the genetic variations affect the physical characteristics i.e. phenotypes of an organism. These changes in the phenotypes will be an advantage to some organisms, which will then be passed onto their offspring. Some examples of evolution in species over many generations are the Peppered Moth and Flightless birds. In the 1930s, the discipline of evolutionary biology emerged through what Julian Huxley called the modern synthesis of understanding, from previously unrelated fields of biological research, such as genetics and ecology, systematics, and paleontology. The importance of studying Evolutionary bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cinderella Effect
In evolutionary psychology, the Cinderella effect is the phenomenon of higher incidence of different forms of child abuse and mistreatment by stepparents than by biological parents. It takes its name from the fairy tale character Cinderella, which is about a girl who is mistreated by her stepsisters and stepmother. Evolutionary psychologists describe the effect as a byproduct of a bias towards kin, and a conflict between reproductive partners of investing in young that are unrelated to one partner. Background In the early 1970s, a theory arose on the connection between stepparents and child maltreatment. "In 1973, forensic psychiatrist P. D. Scott summarized information on a sample of "fatal battered-baby cases" perpetrated in anger ... 15 of the 29 killers – 52% – were stepfathers."Daly & Wilson (1999), p. 33 Although initially there was no analysis of this raw data, empirical evidence has since been collected on what is now called the Cinderella effect through official rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 (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 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 offspring will be more selective when choo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacanidae
The jacanas (sometimes referred to as Jesus birds or lily trotters) are a group of tropical waders in the 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 rare groups of birds in which females are larger, and several species maintain harems of males in the breeding season with males solely responsible for incubating eggs and taking care of the chicks. Etymology and pronunciation The pronunciation of the word jacana is debated. ''Jacana'' is Linnæus' scientific Latin spelling of the Portuguese ''jaçanã'' which in turn is derived from a Tupi name of the bird, ''ñaha'nã''. The Portuguese word is pronounced approximately . As in façade, Provençal, and araçari, the Ç is meant to be pronounced as an S. US dictionaries give various pronunciations: , , as well as t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phalarope
__NOTOC__ 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 two things: their unusual nesting behavior, and their unique feeding technique. Two species, the red or grey phalarope (''Phalaropus 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 the French zoologist Mathurin Jacques Brisson in 1760 with the red phalarope (''Phalaropus fulicarius'') as t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seahorse
A seahorse (also written ''sea-horse'' and ''sea horse'') is any of 46 species of small marine fish in the genus ''Hippocampus''. "Hippocampus" 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. Habitat Seahorses are mainly found in shallow tropical and temperate salt water throughout the world, from about 45°S to 45°N. They live in sheltered areas such as seagrass beds, estuaries, coral reefs, and mangroves. Four species are found in Pacific waters from North America to South America. In the Atlantic, ''Hippocampus erectus'' ranges from Nova Scotia to Uruguay. '' H. zosterae'', known as the dwarf seahorse, is found in the Bahamas. Colonies have been found in E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 since they prey on clothes moth larvae, carpet beetle larvae, booklice, ants, mites, and small flies. They are tiny, and are rarely noticed due to their small size, despite being common in many environments. When people do see pseudoscorpions, especially indoors, they are often mistaken 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, DepartmentEntomological Notes: Pseudoscorpion Fact Shee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estrus
The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. 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 syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lion
The lion (''Panthera leo'') is a large cat of the genus '' Panthera'' native to Africa and India. It has a muscular, broad-chested body; short, rounded head; round ears; and a hairy tuft at the end 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 large ungulates. The lion is an apex and keystone predator; although some lions scavenge when opportunities occur and have been known to hunt humans, lions typically don't actively seek out and prey on humans. The lion inhabits grasslands, savannas and shrublands. It is usually more diurnal than other wild cats, but when persecuted, it adapts to being active at night and at twilight. During the Neolithic period, the lion ranged throughout Africa and Eurasia from Southeast Euro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primate
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter including humans). Primates arose 85–55 million years ago first from small terrestrial mammals, which adapted to living in the trees of tropical forests: many primate characteristics represent adaptations to life in this challenging environment, including large brains, visual acuity, color vision, a shoulder girdle allowing a large degree of movement in the shoulder joint, and dextrous hands. 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 used. New primate species continue to be discovered: over 25 species were described in the 2000s, 36 in the 2010s, and three in the 2020s. Primates have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waved Albatross
The waved albatross (''Phoebastria irrorata''), also known as Galapagos albatross,Remsen Jr., J.V. (2008) is the only member of the family Diomedeidae located 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. This is u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Seahorse")
.jpg "Click for more on -> Primate")