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Female United States Coast Guard Personnel
Female (symbol: ♀) is the sex of an organism that produces the large non-motile ova (egg cells), the type of gamete (sex cell) that fuses with the male gamete during sexual reproduction. A female has larger gametes than a male. Females and males are results of the anisogamous reproduction system, wherein gametes are of different sizes, unlike isogamy where they are the same size. The exact mechanism of female gamete evolution remains unknown. In species that have males and females, sex-determination may be based on either sex chromosomes, or environmental conditions. Most female mammals, including female humans, have two X chromosomes. Female characteristics vary between different species with some species having pronounced secondary female sex characteristics, such as the presence of pronounced mammary glands in mammals. In humans, the word ''female'' can also be used to refer to gender in the social sense of gender role or gender identity. Etymology and usage The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venus Symbol
A planet symbol (or ''planetary symbol'') is a graphical symbol used in astrology and astronomy to represent a classical planet (including the Sun and the Moon) or one of the modern planets. The symbols were also used in alchemy to represent the metals associated with the planets, and in calendars for their associated days. The use of these symbols derives from Classical Greco-Roman astronomy, though their current shapes are a development of the 16th century. The classical planets, their symbols, days and most commonly associated planetary metals are: The International Astronomical Union (IAU) discourages the use of these symbols in modern journal articles, and their style manual proposes one- and two-letter abbreviations for the names of the planets for cases where planetary symbols might be used, such as in the headings of tables. The modern planets with their traditional symbols and IAU abbreviations are: The symbols of Venus and Mars are also used to represent female and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gender Role
A gender role, also known as a sex role, is a social role encompassing a range of behaviors and attitudes that are generally considered acceptable, appropriate, or desirable for a person based on that person's sex. Gender roles are usually centered on conceptions of masculinity and femininity, although there are exceptions and variations. The specifics regarding these gendered expectations may vary among cultures, while other characteristics may be common throughout a range of cultures. In addition, gender roles (and perceived gender roles) vary based on a person's race or ethnicity. Gender roles influence a wide range of human behavior, often including the clothing a person chooses to wear, the profession a person pursues, the personal relationships a person enters, and how they behave within those relationships. Although gender roles have evolved and expanded, they traditionally keep women in the "private" sphere, and men in the "public" sphere. Various groups, most notab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mating Type
Mating types are the microorganism equivalent to sexes in multicellular lifeforms and are thought to be the ancestor to distinct Sex, sexes. They also occur in macro-organisms such as fungi. Definition Mating types are the microorganism equivalent to sex in higher organisms and occur in isogamy, isogamous and anisogamous species. Depending on the group, different mating types are often referred to by numbers, letters, or simply "+" and "−" instead of "male" and "female", which refer to "Sex, sexes" or differences in size between gametes. Syngamy can only take place between gametes carrying different mating types. Occurrence Reproduction by mating types is especially prevalent in Fungus, fungi. Filamentous ascomycetes usually have two mating types referred to as "MAT1-1" and "MAT1-2", following the yeast mating-type locus (MAT). Under standard nomenclature, MAT1-1 (which may informally be called MAT1) encodes for a regulatory protein with an alpha box motif, while MAT1-2 (informal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isogamy
Isogamy is a form of sexual reproduction that involves gametes of the same morphology (indistinguishable in shape and size), found in most unicellular eukaryotes. Because both gametes look alike, they generally cannot be classified as male or female. Instead, organisms undergoing isogamy are said to have different mating types, most commonly noted as "+" and "−" strains. Etymology The literal meaning of isogamy is "equal marriage" which refers to equal contribution of resources by both gametes to a zygote. The term isogamous was first used in the year 1887. Characteristics of isogamous species Isogamous species often have two mating types. Some isogamous species have more than two mating types, but the number is usually lower than ten. In some extremely rare cases a species can have thousands of mating types. In all cases, fertilization occurs when gametes of two different mating types fuse to form a zygote. Evolution It is generally accepted that isogamy is an an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parthenogenesis
Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development of embryos occur in a gamete (egg or sperm) without combining with another gamete (e.g., egg and sperm fusing). In animals, parthenogenesis means development of an embryo from an unfertilized Gametophyte, egg cell. In plants, parthenogenesis is a component process of apomixis. In algae, parthenogenesis can mean the development of an embryo from either an individual sperm or an individual egg. Parthenogenesis occurs naturally in some plants, algae, invertebrate animal species (including nematodes, some tardigrades, water fleas, some scorpions, aphids, some mites, some bees, some Phasmatodea and parasitic wasps) and a few vertebrates (such as some fish, amphibians, reptiles and birds). This type of reproduction has been induced artificially ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asexual Reproduction
Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the full set of genes of their single parent and thus the newly created individual is genetically and physically similar to the parent or an exact clone of the parent. Asexual reproduction is the primary form of reproduction for single-celled organisms such as archaea and eubacteria, bacteria. Many Eukaryote, eukaryotic organisms including plants, animals, and Fungus, fungi can also reproduce asexually. In vertebrates, the most common form of asexual reproduction is parthenogenesis, which is typically used as an alternative to sexual reproduction in times when reproductive opportunities are limited. Komodo dragons and some monitor lizards can also reproduce asexually. While all prokaryotes reproduce without the formation and fusion of gametes, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermatozoa
A spermatozoon (; also spelled spermatozoön; ; ) is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, that normally develops into an embryo.) Sperm cells contribute approximately half of the nuclear genetic information to the diploid offspring (excluding, in most cases, mitochondrial DNA). In mammals, the sex of the offspring is determined by the sperm cell: a spermatozoon bearing an X chromosome will lead to a female (XX) offspring, while one bearing a Y chromosome will lead to a male (XY) offspring. Sperm cells were first observed in Antonie van Leeuwenhoek's laboratory in 1677. Mammalian spermatozoon structure, function, and size Humans The human sperm cell is the reproductive cell in males and will only survive in warm environments; once it leaves the male body the sperm's survival likelihood is reduced and it may die, thereby ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motility
Motility is the ability of an organism to move independently, using metabolic energy. Definitions Motility, the ability of an organism to move independently, using metabolic energy, can be contrasted with sessility, the state of organisms that do not possess a means of self-locomotion and are normally immobile. Motility differs from mobility, the ability of an object to be moved. The term vagility encompasses both motility and mobility; sessile organisms including plants and fungi often have vagile parts such as fruits, seeds, or spores which may be dispersed by other agents such as wind, water, or other organisms. Motility is genetically determined, but may be affected by environmental factors such as toxins. The nervous system and musculoskeletal system provide the majority of mammalian motility. In addition to animal locomotion, most animals are motile, though some are vagile, described as having passive locomotion. Many bacteria and other microorganisms, and multicellu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproduction System
The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes of differentiated species often have significant differences. These differences allow for a combination of genetic material between two individuals, which allows for the possibility of greater genetic fitness of the offspring. Reproductive System 2001 Body Guide powered by Adam Animals In mammals, the major organs of the reproductive system include the external |
Heterogamous
Heterogamy is a term applied to a variety of distinct phenomena in different scientific domains. Usually having to do with some kind of difference, "hetero", in reproduction, "gamy". See below for more specific senses. Science Reproductive biology In reproductive biology, heterogamy is the alternation of differently organized generations, applied to the alternation between parthenogenetic and a sexual generation. This type of heterogamy occurs for example in some aphids. Alternately, ''heterogamy'' or ''heterogamous'' is often used as a synonym of heterogametic, meaning the presence of two unlike chromosomes in a sex.. For example, XY males and ZW females are called the heterogamous sex. Cell biology In cell biology, heterogamy is a synonym of anisogamy, the condition of having differently sized male and female gametes produced by different sexes or mating types in a species. Botany In botany, a plant is heterogamous when it carries at least two different types of flowers in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gender Of Connectors And Fasteners
In electrical and machine, mechanical trades and manufacturing, each half of a pair of mating Electrical connector, connectors or fasteners is conventionally assigned the designation male or female. The female connector is generally a AC power plugs and sockets, receptacle that receives and holds the male connector. Sometimes the terms plug and socket or jack are used, particularly in reference to Electrical connector#Jacks and plugs, electrical connectors. In some cases, the pins on the connector may have the opposite nominal gender to the mounted connector, such as the RCA connector. The assignment is a direct analogy with male/female Sex organ, genitalia, the part bearing one or more protrusions or which fits inside the other being designated male, in contrast to the part containing the corresponding indentations, or fitting outside the other, being designated female. Extension of the analogy results in the verb to mating, mate being used to describe the process of connecting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sex And Gender Distinction
Though the terms ''sex'' and ''gender'' have been used interchangeably since at least the fourteenth century, in contemporary academic literature they usually have distinct meanings. ''Sex'' generally refers to an organism's biological sex, while ''gender'' usually refers to either social roles based on the sex of a person (gender role) or personal identification of one's own gender based on an internal awareness (gender identity).Prince, Virginia. 2005. "Sex vs. Gender." ''International Journal of Transgenderism''. 8(4). While in ordinary speech, the terms ''sex'' and ''gender'' are often used interchangeably, most contemporary social scientists, behavioral scientists and biologists, many legal systems and government bodies, and intergovernmental agencies such as the WHO make a distinction between gender and sex. In most individuals, the various biological determinants of sex are congruent, and consistent with the individual's gender identity, but in some circumstances, an individ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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