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Concealed Ovulation
Concealed ovulation or hidden estrus is the lack of any perceptible change (e.g., a change in appearance or scent) when an adult female is fertile and near ovulation. Some examples of perceptible changes are swelling and redness of the vulva in baboons and bonobos, and pheromone release in the feline family. In contrast, the females of humans and a few other species that undergo hidden estrus have few external signs of fecundity, making it difficult for a mate to consciously deduce, by means of external signs only, whether or not a female is near ovulation. Human females In humans, an adult woman's fertility peaks for a few days during each roughly monthly cycle. The frequency and length of fertility (the time when a woman can become pregnant) is highly variable between women, and can slightly change for each woman over the course of her lifespan. Humans are considered to have concealed ovulation because there is no outward physiological sign, either to a woman herself or to o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovulation
Ovulation is an important part of the menstrual cycle in female vertebrates where the egg cells are released from the ovaries as part of the ovarian cycle. In female humans ovulation typically occurs near the midpoint in the menstrual cycle and after the follicular phase. Ovulation is stimulated by an increase in luteinizing hormone (LH). The ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilized by sperm. If it is not, it will break down in less than a day. Meanwhile, the uterine lining ( endometrium) continues to thicken to be able to receive a fertilized egg. If no conception occurs, the uterine lining will eventually break down and be shed from the body via the vagina during menstruation. Some people choose to track ovulation in order to improve or aid becoming pregnant by timing intercourse with their ovulation. The signs of ovulation may include cervical muc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Psychology
Evolutionary psychology is a theoretical approach in psychology that examines cognition and behavior from a modern evolutionary perspective. It seeks to identify human psychological adaptations with regard to the ancestral problems they evolved to solve. In this framework, psychological traits and mechanisms are either functional products of natural selection, natural and sexual selection in human evolution, sexual selection or non-adaptive Spandrel (biology), by-products of other adaptive traits. Adaptationist thinking about Physiology, physiological mechanisms, such as the heart, Lung, lungs, and the liver, is common in evolutionary biology. Evolutionary psychologists apply the same thinking in psychology, arguing that just as the heart evolved to pump blood, the liver evolved to detoxify poisons, and the kidneys evolved to filter turbid fluids there is modularity of mind in that different psychological mechanisms evolved to solve different adaptive problems. These evolutionary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infanticide
Infanticide (or infant homicide) is the intentional killing of infants or offspring. Infanticide was a widespread practice throughout human history that was mainly used to dispose of unwanted children, its main purpose being the prevention of resources being spent on weak or disabled offspring. Unwanted infants were usually abandoned to die of exposure, but in some societies they were deliberately killed. Infanticide is generally illegal, but in some places the practice is tolerated, or the prohibition is not strictly enforced. Most Stone Age human societies routinely practiced infanticide, and estimates of children killed by infanticide in the Mesolithic and Neolithic eras vary from 15 to 50 percent. Infanticide continued to be common in most societies after the historical era began, including ancient Greece, Roman Empire, ancient Rome, the Phoenicians, ancient China, ancient Japan, Pre-Islamic Arabia, early modern Europe, Aboriginal Australians, Aboriginal Australia, Indigenous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monogamy
Monogamy ( ) is a social relation, relationship of Dyad (sociology), two individuals in which they form a mutual and exclusive intimate Significant other, partnership. Having only one partner at any one time, whether for life or #Serial monogamy, serial monogamy, contrasts with various forms of non-monogamy (e.g., polygamy or polyamory). The term monogamy, derived from Greek language, Greek for “one marriage,” has multiple context-dependent meanings—genetic, sexual, social, and marital—each varying in interpretation across cultures and disciplines, making its definition complex and often debated. The term is typically used to describe the behavioral ecology and sexual selection of animal mating systems, referring to the state of having only one Mating, mate at any one given time. In a human cultural context, monogamy typically refers to the custom of two individuals, regardless of orientation, committing to a sexually exclusive relationship. Monogamy in humans varies wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coolidge Effect
The Coolidge effect is a biological phenomenon seen in animals, whereby males exhibit renewed sexual interest whenever a new female of reproductive availability is introduced, even after sex with prior but still available sexual partners. To a lesser extent, the effect is also seen among females with regard to their mates. The Coolidge effect can be attributed to an increase in sexual responsiveness, and a shortening of the sexual refractory period. The evolutionary benefit to this phenomenon is that a male can fertilize multiple females. The male may be reinvigorated repeatedly for successful insemination of multiple females. This type of mating system can be referred to as polygyny, where one male has multiple female mates, but each female mates with only one or a few males. The Coolidge effect has been demonstrated to occur in humans across cultures and in both sexes. Origin of the term In a 1974 letter, behavioral endocrinologist Frank A. Beach claims to have introduced the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gray Langur
''Semnopithecus'' is a genus of Old World monkeys native to the Indian subcontinent, with all species with the exception of two being commonly known as gray langurs. Traditionally only the species ''Semnopithecus entellus'' was recognized, but since about 2001 additional species have been recognized. The taxonomy has been in flux, but currently eight species are recognized. Members of the genus ''Semnopithecus'' are terrestrial, inhabiting forest, open lightly wooded habitats, and urban areas on the Indian subcontinent. Most species are found at low to moderate altitudes, but the Nepal gray langur and Kashmir gray langur occur up to in the Himalayas. Characteristics These langurs are largely gray (some more yellowish), with a black face and ears. Externally, the various species mainly differ in the darkness of the hands and feet, the overall color and the presence or absence of a crest. Typically all north Indian gray langurs have their tail tips looping towards their head d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partible Paternity
Partible paternity or shared paternity is a cultural conceptualization of paternity according to which a child is understood to have more than one father; for example, because of an ideology that sees pregnancy as the cumulative result of multiple acts of sexual intercourse. In societies with the concept of partible paternity this often results in the nurture of a child being shared by multiple fathers in a form of polyandric relation to the mother, although this is not always the case. All cultures recognize different types of fatherhood – for example the distinction between biological fatherhood and legal fatherhood, and the corresponding social roles of ''genitor'' and ''pater''. The concept of partible paternity differs from such a distinction because it considers all men who have had sexual intercourse with a woman immediately prior to and during her pregnancy to have contributed biological material to the child, and to have a corresponding legal or moral responsibility t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Chimpanzee
The chimpanzee (; ''Pan troglodytes''), also simply known as the chimp, is a species of great ape native to the forests and savannahs of tropical Africa. It has four confirmed subspecies and a fifth proposed one. When its close relative the bonobo was more commonly known as the pygmy chimpanzee, this species was often called the common chimpanzee or the robust chimpanzee. The chimpanzee and the bonobo are the only species in the genus ''Pan''. Evidence from fossils and DNA sequencing shows that ''Pan'' is a sister taxon to the human lineage and is thus humans' closest living relative. The chimpanzee is covered in coarse black hair but has a bare face, fingers, toes, palms of the hands, and soles of the feet. It is larger and more robust than the bonobo, weighing for males and for females and standing . The chimpanzee lives in groups that range in size from 15 to 150 members, although individuals travel and forage in much smaller groups during the day. The species lives ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bonobos
The bonobo (; ''Pan paniscus''), also historically called the pygmy chimpanzee (less often the dwarf chimpanzee or gracile chimpanzee), is an endangered great ape and one of the two species making up the genus ''Pan (genus), Pan'' (the other being the common chimpanzee, ''Pan troglodytes''). While bonobos are today recognized as a distinct species in their own right, they were initially thought to be a subspecies of ''Pan troglodytes'', because of the physical similarities between the two species. Taxonomically, members of the chimpanzee/bonobo subtribe Panina—composed entirely by the genus ''Pan (genus), Pan''—are collectively termed ''panins''. Bonobos are distinguished from common chimpanzees by relatively long limbs, pinker lips, a darker face, a tail-tuft through adulthood, and parted, longer hair on their heads. Some individuals have sparser, thin hair over parts of their bodies. The bonobo is found in a area within the Congo Basin of the Democratic Republic of the Con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproductive Fitness
Fitness (often denoted w or ω in population genetics models) is a 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 Darwinian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pair Bond
In biology, a pair bond is the strong affinity that develops in some species between a mating pair, often leading to the production and rearing of young and potentially a lifelong bond. Pair-bonding is a term coined in the 1940s that is frequently used in sociobiology and evolutionary biology circles. The term often implies either a lifelong Monogamy in animals, socially monogamous relationship or a stage of mating interaction in socially monogamous species. It is sometimes used in reference to human relationships. Varieties According to evolutionary psychologists David P. Barash and Judith Lipton, from their 2001 book ''The Myth of Monogamy'', there are several varieties of pair bonds: *''Short-term pair-bond:'' a transient mating or associations *''Long-term pair-bond:'' bonded for a significant portion of the life cycle of that pair *''Lifelong pair-bond:'' mated for life *''Social pair-bond:'' attachments for territorial or social reasons *''Clandestine pair-bond:'' quick extr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extended Female Sexuality
Extended female sexuality is where the female of a species Mating, mates despite being infertile. In most species, the female only engages in Copulation (zoology), copulation when she is Fecundity, fertile. However, extended sexuality has been documented in Primate, Old World primates, Bird, pair bonded birds and some insects (such as carrion beetles). Extended sexuality is most prominent in human females who exhibit no change in copulation rate across the Menstrual cycle, ovarian cycle. Although this behaviour incurs costs to females, such as energy and time, many researchers have proposed reasons for its existence. These hypotheses include the male assistance hypothesis, which proposes that females gain non-genetic benefits (such as food and shelter) in exchange for sexual access. A sub-hypothesis of this is Sarah Blaffer Hrdy, Hrdy's, proposing extended female sexuality as an Adaptation, adaptive process aiming to creating Father, paternity confusion in males. Alternative hypothe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
