Mating in the context of Linebreeding

In anthropology, kinship is the web of social relationships that form an important part of the lives of all humans in all societies, although its exact meanings even within this discipline are often debated. Anthropologist Robin Fox says that the study of kinship is the study of what humans do with these basic facts of life – mating, gestation, parenthood, socialization, siblingship etc. Human society is unique, he argues, in that we are "working with the same raw material as exists in the animal world, but [we] can conceptualize and categorize it to serve social ends." These social ends include the socialization of children and the formation of basic economic, political and religious groups.

Kinship can refer both to the patterns of social relationships themselves, or it can refer to the study of the patterns of social relationships in one or more human cultures (i.e. kinship studies). Over its history, anthropology has developed a number of related concepts and terms in the study of kinship, such as descent, descent group, lineage, affinity/affine, consanguinity/cognate and fictive kinship. Further, even within these two broad usages of the term, there are different theoretical approaches.

In biology, offspring are the young creation of living organisms, produced either by sexual or asexual reproduction. Collective offspring may be known as a brood or progeny. This can refer to a set of simultaneous offspring, such as the chicks hatched from one clutch of eggs, or to all offspring produced over time, as with the honeybee. Offspring can occur after mating, artificial insemination, or as a result of cloning.

Human offspring (descendants) are referred to as children; male children are sons and female children are daughters (see Kinship).

In electrical and mechanical trades and manufacturing, each half of a pair of mating connectors or fasteners is conventionally designated as male or female, a distinction referred to as its gender. The female connector is generally a receptacle that receives and holds the male connector. Alternative terms such as plug and socket or jack are sometimes used, particularly for electrical connectors.

The assignment is a direct analogy with male and female genitalia. The part bearing one or more protrusions, or which fits inside the other, is designated male, while the one with the corresponding indentations, or fitting outside the other, is designated female. Extension of the analogy results in the verb to mate being used to describe the process of connecting two corresponding parts together.

In the zoological field of ethology, a dominance hierarchy (formerly and colloquially called a pecking order) is a type of social hierarchy that arises when members of animal social groups interact, creating a ranking system. Different types of interactions can result in dominance depending on the species, including ritualized displays of aggression or direct physical violence.

In social living groups, members are likely to compete for access to limited resources and mating opportunities. Rather than fighting each time they meet, individuals of the same sex establish a relative rank, with higher-ranking individuals often gaining more access to resources and mates. Based on repetitive interactions, a social order is created that is subject to change each time a dominant animal is challenged by a subordinate one.

Sexual selection is a mechanism of evolution in which members of one sex choose mates of the other sex to 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 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 early 20th century. Sexual selection can lead males to extreme efforts to demonstrate their fitness to be chosen by females, producing sexual dimorphism in secondary sexual characteristics, such as the ornate plumage of birds-of-paradise and peafowl, or the antlers of deer. Depending on the species, these rules can be reversed. This is caused by a positive feedback mechanism known as a Fisherian runaway, where the passing-on of the desire for a trait in one sex is as important as having the trait in the other sex in producing the runaway effect. Although the sexy son hypothesis indicates that females would prefer male offspring, Fisher's principle explains why the sex ratio is most often 1:1. Sexual selection is widely distributed in the animal kingdom, and is also found in plants and fungi.

Marine mammals are mammals that rely on marine ecosystems for their existence. They include animals such as cetaceans, pinnipeds, sirenians, sea otters and polar bears. They are an informal group, unified only by their reliance on marine environments for feeding and survival.

Marine mammal adaptation to an aquatic lifestyle varies considerably between species. Both cetaceans and sirenians are fully aquatic and therefore are obligate water dwellers. Pinnipeds are semiaquatic; they spend the majority of their time in the water but need to return to land for important activities such as mating, breeding and molting. Sea otters tend to live in kelp forests and estuaries. In contrast, the polar bear is mostly terrestrial and only go into the water on occasions of necessity, and are thus much less adapted to aquatic living. The diets of marine mammals vary considerably as well; some eat zooplankton, others eat fish, squid, shellfish, or seagrass, and a few eat other mammals. While the number of marine mammals is small compared to those found on land, their roles in various ecosystems are large, especially concerning the maintenance of marine ecosystems, through processes including the regulation of prey populations. This role in maintaining ecosystems makes them of particular concern as 23% of marine mammal species are currently threatened.

Animal sexual behaviour takes many different forms, including within the same species. Common mating or reproductively motivated systems include monogamy, polygyny, polyandry, polygamy and promiscuity. Other sexual behaviour may be reproductively motivated (e.g. sex apparently due to duress or coercion and situational sexual behaviour) or non-reproductively motivated (e.g. homosexual sexual behaviour, bisexual sexual behaviour, cross-species sex, sexual arousal from objects or places, sex with dead animals, etc.).

When animal sexual behaviour is reproductively motivated, it is often termed mating or copulation; for most non-human mammals, mating and copulation occur at oestrus (the most fertile period in the mammalian female's reproductive cycle), which increases the chances of successful impregnation. Some animal sexual behaviour involves competition, sometimes fighting, between multiple males. Females often select males for mating only if they appear strong and able to protect themselves. The male that wins a fight may also have the chance to mate with a larger number of females and will therefore pass on his genes to their offspring.

The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring are sterile. These barriers maintain the integrity of a species by reducing gene flow between related species.

The mechanisms of reproductive isolation have been classified in a number of ways. Zoologist Ernst Mayr classified the mechanisms of reproductive isolation in two broad categories: pre-zygotic for those that act before fertilization (or before mating in the case of animals) and post-zygotic for those that act after it. The mechanisms are genetically controlled and can appear in species whose geographic distributions overlap (sympatric speciation) or are separate (allopatric speciation).

Migration, in ecology, is the large-scale movement of members of a species to a different environment. Migration is a natural behavior and component of the life cycle of many species of mobile organisms, not limited to animals, though animal migration is the best known type. Migration is often cyclical, frequently occurring on a seasonal basis, and in some cases on a daily basis. Species migrate to take advantage of more favorable conditions with respect to food availability, safety from predation, mating opportunity, or other environmental factors.

Migration is most commonly seen in the form of animal migration, the physical movement by animals from one area to another. That includes bird, fish, and insect migration. However, plants can be said to migrate, as seed dispersal enables plants to grow in new areas, under environmental constraints such as temperature and rainfall, resulting in changes such as forest migration.

In biology, a weapon is a specialized physical trait that is used by animals to compete with other individuals for resources. Most commonly, the term refers to structures that males use to fight other males off for access to mates. They can also be used to defend resources in intraspecific competition, or to ward off predators. Examples of weapons include horns and antlers, both among the most recognizable weapons, though even within those categories, the structure of the specific weaponry is often unique to the species, with a wide variety of designs observed across many genera.

Many weapons evolve through sexual selection, as they are most often used to fight off competitors for access to mates. A mate is won in battle either by a male chasing off a fellow competitor or killing it, usually leaving the victor as the only option for the female to reproduce with, favoring males with particularly effective weaponry. More broadly, weaponry in animals may consist of any specialized morphology that is present within an organism to aid in its advantage against rivals. Many hypotheses have been produced by researchers to possibly explain the mechanisms behind the evolution of weapons, with studies detailing the intensity, duration, and conclusion of intraspecific combat, as well as analyzing the rapid diversification within species. 

Onychophora /ɒnɪˈkɒfərə/ (from Ancient Greek: ονυχής, onyches, "claws"; and φέρειν, pherein, "to carry"), commonly known as velvet worms (for their velvety texture and somewhat wormlike appearance) or more ambiguously as peripatus /pəˈrɪpətəs/ (after the first described genus, Peripatus), is a phylum of elongate, soft-bodied, many-legged animals. In appearance they have variously been compared to worms with legs, caterpillars, and slugs. They prey upon other invertebrates, which they catch by ejecting an adhesive slime. Approximately 200 species of velvet worms have been described, although the true number is likely to be much greater.

The two extant families of velvet worms are Peripatidae and Peripatopsidae. They show a peculiar distribution, with the peripatids being predominantly equatorial and tropical, while the peripatopsids are all found south of the equator. It is the only phylum within Animalia that is wholly endemic to terrestrial environments, at least among extant members. Velvet worms are generally considered close relatives of the Arthropoda and Tardigrada, with which they form the proposed taxon Panarthropoda. This makes them of palaeontological interest, as they can help reconstruct the ancestral arthropod. Only two fossil species are confidently assigned as onychophorans: Antennipatus from the Late Carboniferous, and Cretoperipatus from the Late Cretaceous, the latter belonging to Peripatidae. In modern zoology, they are known for their mating behaviours and for some species bearing live young.

In zoology, copulation is animal sexual behavior in which a male introduces sperm into the female's body, especially directly into the female's 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.

A breeder is a person who selectively breeds carefully selected mates, normally of the same breed, to sexually reproduce offspring with specific, consistently replicable qualities and characteristics. This might be as a farmer, agriculturalist, or hobbyist, and can be practiced on a large or small scale, for food, fun, or profit.

Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and other consequences that may arise from expression of deleterious recessive traits resulting from incestuous sexual relationships and consanguinity.

Inbreeding results in homozygosity which can increase the chances of offspring being affected by recessive traits. In extreme cases, this usually leads to at least temporarily decreased biological fitness of a population (called inbreeding depression), which is its ability to survive and reproduce. An individual who inherits such deleterious traits is colloquially referred to as inbred. The avoidance of expression of such deleterious recessive alleles caused by inbreeding, via inbreeding avoidance mechanisms, is the main selective reason for outcrossing. Crossbreeding between populations sometimes has positive effects on fitness-related traits, but also sometimes leads to negative effects known as outbreeding depression. However, increased homozygosity increases the probability of fixing beneficial alleles and also slightly decreases the probability of fixing deleterious alleles in a population. Inbreeding can result in purging of deleterious alleles from a population through purifying selection.

Assortative mating (also referred to as positive assortative mating or homogamy) is a mating pattern and a form of sexual selection in which individuals with similar phenotypes or genotypes mate with one another more frequently than would be expected under a random mating pattern.

A majority of the phenotypes that are subject to assortative mating are body size, visual signals (e.g. color, pattern), and sexually selected traits such as crest size.

Polygamy (from Late Greek πολυγαμία polygamía, "state of marriage to many spouses") is the practice of marrying multiple spouses. When a man is married to more than one wife at the same time, it is called polygyny. When a woman is married to more than one husband at the same time, it is called polyandry. In contrast, in sociobiology and zoology, researchers use "polygamy" more broadly to refer to any form of multiple mating.

In contrast to polygamy, monogamy is marriage consisting of only two parties. Like "monogamy", the term "polygamy" is often used in a de facto sense, applied regardless of whether a state recognizes the relationship. In many countries, the law only recognises monogamous marriages (a person can only have one spouse, and bigamy is illegal), but adultery is not illegal, leading to a situation of de facto polygamy being allowed without legal recognition for non-official "spouses".