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Extra-pair Copulation
Extra-pair copulation (EPC) is a mating behaviour in monogamous species. Monogamy is the practice of having only one sexual partner at any one time, forming a long-term bond and combining efforts to raise offspring together; mating outside this pairing is extra-pair copulation. Across the animal kingdom, extra-pair copulation is common in monogamous species, and only a very few pair-bonded species are thought to be exclusively sexually monogamous. EPC in the animal kingdom has mostly been studied in birds and mammals. Possible benefits of EPC can be investigated within non-human species, such as birds. For males, a number of theories are proposed to explain extra-pair copulations. One such hypothesis is that males maximise their reproductive success by copulating with as many females as possible outside of a pair bond relationship because their parental investment is lower, meaning they can copulate and leave the female with minimum risk to themselves. Females, on the other hand ... [...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] |
Copulation (zoology)
In zoology, copulation is animal sexual behavior in which a male introduces sperm into the female's body, especially directly into her reproductive tract. This is an aspect of mating. Many aquatic animals use external fertilization, whereas internal fertilization may have developed from a need to maintain gametes in a liquid medium in the Late Ordovician epoch. Internal fertilization with many vertebrates (such as all reptiles, some fish, and most birds) occurs via cloacal copulation, known as cloacal kiss (see also hemipenis), while most mammals copulate vaginally, and many basal vertebrates reproduce sexually with external fertilization. In spiders and insects Spiders are often confused with insects, but they are not insects; instead, they are arachnids. Spiders have separate male and female sexes. Before mating and copulation, the male spider spins a small web and ejaculates on to it. He then stores the sperm in reservoirs on his large pedipalps, from which he tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleiotropic
Pleiotropy () is a condition in which a single gene or genetic variant influences multiple phenotypic traits. A gene that has such multiple effects is referred to as a ''pleiotropic gene''. Mutations in pleiotropic genes can impact several traits simultaneously, often because the gene product is used in various cells and affects different biological targets through shared signaling pathways. Pleiotropy can result from several distinct but potentially overlapping mechanisms, including gene pleiotropy, developmental pleiotropy, and selectional pleiotropy. Gene pleiotropy occurs when a gene product interacts with multiple proteins or catalyzes different reactions. Developmental pleiotropy refers to mutations that produce several phenotypic effects during development. Selectional pleiotropy occurs when a single phenotype influences evolutionary fitness in multiple ways (depending on factors such as age and sex). There are also three main types of genetic pleiotropic effects when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meta-analysis
Meta-analysis is a method of synthesis of quantitative data from multiple independent studies addressing a common research question. An important part of this method involves computing a combined effect size across all of the studies. As such, this statistical approach involves extracting effect sizes and variance measures from various studies. By combining these effect sizes the statistical power is improved and can resolve uncertainties or discrepancies found in individual studies. Meta-analyses are integral in supporting research grant proposals, shaping treatment guidelines, and influencing health policies. They are also pivotal in summarizing existing research to guide future studies, thereby cementing their role as a fundamental methodology in metascience. Meta-analyses are often, but not always, important components of a systematic review. History The term "meta-analysis" was coined in 1976 by the statistician Gene V. Glass, Gene Glass, who stated ''"Meta-analysis refers t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black-capped Chickadees
The black-capped chickadee (''Poecile atricapillus'') is a small, nonmigratory, North American passerine bird that lives in deciduous and mixed forests. It is a member of the Paridae family, also known as tits. It has a distinct black cap on its head, a black bib underneath, and white cheeks. It has a white belly, buff sides, and grey wings, back, and tail. The bird is well known for its vocalizations, including its ''fee-bee'' call and its ''chick-a-dee-dee-dee'' call, from which it derives its name. The black-capped chickadee is widely distributed throughout North America, ranging from the northern United States to southern Canada and all the way up to Alaska and Yukon. It feeds primarily on insects and seeds, and is known for its ability to cache food for use during the winter. The hippocampus of the black-capped chickadee grows during the caching season, which is believed to help it better remember its cache locations. The black-capped chickadee is a social bird and forms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swallows
The swallows, martins, and saw-wings, or Hirundinidae are a family of passerine songbirds found around the world on all continents, including occasionally in Antarctica. Highly adapted to aerial feeding, they have a distinctive appearance. The term "swallow" is used as the common name for ''barn swallow, Hirundo rustica'' in the UK and Ireland. Around 90 species of Hirundinidae are known, divided into 21 genus, genera, with the greatest diversity found in Africa, which is also thought to be where they evolved as hole-nesters. They also occur on a number of oceanic islands. A number of European and North American species are long-distance bird migration, migrants; by contrast, the West and South African swallows are nonmigratory. This family comprises two subfamilies: Pseudochelidoninae (the river martins of the genus ''Pseudochelidon'') and Hirundininae (all other swallows, martins, and saw-wings). In the Old World, the name "martin" tends to be used for the squarer-tailed specie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetics
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinians, Augustinian friar working in the 19th century in Brno, was the first to study genetics scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring over time. He observed that organisms (pea plants) inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene. Phenotypic trait, Trait inheritance and Molecular genetics, molecular inheritance mechanisms of genes are still primary principles of genetics in the 21st century, but modern genetics has expanded to study the function and behavior of genes. Gene structure and function, variation, and distribution are studied within the context of the Cell (bi ... [...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] |
Mammals
A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,640 extant species of mammals have been described and divided into 27 orders. The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the even-toed ungulates (including pigs, camels, and whales), and the Carnivora (including cats, dogs, and seals). Mammals are the only living members of Synapsida; this clade, together with Sauropsida (reptiles and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hylobates Lar Pair Of White And Black 02
The genus ''Hylobates'' is one of the four genera of gibbons. Its name means "forest walker", from the Greek (, "forest") and (, "one who treads"). It was once considered the only genus, but recently its subgenera (''Hoolock'' ormerly ''Bunopithecus'' ''Nomascus'', and ''Symphalangus'') have been elevated to the genus level. ''Hylobates'' remains the most species-rich and widespread of gibbon genera, ranging from southern China (Yunnan) to western and central Java. Individuals within this genus are characterized by 44 chromosomes and often have a ring of white fur around their faces. Classification * Family Hylobatidae: gibbons ** Genus ''Hylobates'' *** Lar gibbon or white-handed gibbon, ''Hylobates lar'' **** Malaysian lar gibbon, ''Hylobates lar lar'' **** Carpenter's lar gibbon, ''Hylobates lar carpenteri'' **** Central lar gibbon, ''Hylobates lar entelloides'' **** Sumatran lar gibbon, ''Hylobates lar vestitus'' **** Yunnan lar gibbon, ''Hylobates lar yunnanensi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
