Male

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This article is about the male sex. Male_sentence_0

For the city, see Malé. Male_sentence_1

For other uses, see Male (disambiguation). Male_sentence_2

A male () organism is the physiological sex that produces the gamete known as sperm. Male_sentence_3

A male gamete can fuse with a larger female gamete, or ovum, in the process of fertilization. Male_sentence_4

A male cannot reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and asexually. Male_sentence_5

Most male mammals, including male humans, have a Y chromosome, which codes for the production of larger amounts of testosterone to develop male reproductive organs. Male_sentence_6

Not all species share a common sex-determination system. Male_sentence_7

In most animals, including humans, sex is determined genetically; however, species such as Cymothoa exigua change sex depending on the number of females present in the vicinity. Male_sentence_8

Male can also be used to refer to gender. Male_sentence_9

Overview Male_section_0

The existence of two sexes seems to have been selected independently across different evolutionary lineages (see convergent evolution). Male_sentence_10

The repeated pattern is sexual reproduction in isogamous species with two or more mating types with gametes of identical form and behavior (but different at the molecular level) to anisogamous species with gametes of male and female types to oogamous species in which the female gamete is very much larger than the male and has no ability to move. Male_sentence_11

There is a good argument that this pattern was driven by the physical constraints on the mechanisms by which two gametes get together as required for sexual reproduction. Male_sentence_12

Accordingly, sex is defined across species by the type of gametes produced (i.e.: spermatozoa vs. ova) and differences between males and females in one lineage are not always predictive of differences in another. Male_sentence_13

Male/female dimorphism between organisms or reproductive organs of different sexes is not limited to animals; male gametes are produced by chytrids, diatoms and land plants, among others. Male_sentence_14

In land plants, female and male designate not only the female and male gamete-producing organisms and structures but also the structures of the sporophytes that give rise to male and female plants. Male_sentence_15

Symbol and usage Male_section_1

Symbol Male_section_2

A common symbol used to represent the male sex is the Mars symbol ♂, a circle with an arrow pointing northeast. Male_sentence_16

The Unicode code-point is: Male_sentence_17

Male_description_list_0

  • U+2642 ♂ MALE SIGN (HTML ♂ · ♂)Male_item_0_0

The symbol is identical to the planetary symbol of Mars. Male_sentence_18

It was first used to denote sex by Carl Linnaeus in 1751. Male_sentence_19

The symbol is sometimes seen as a stylized representation of the shield and spear of the Roman god. Male_sentence_20

Mars. Male_sentence_21

According to Stearn, however, this derivation is "fanciful" and all the historical evidence favours "the conclusion of the French classical scholar Claude de Saumaise (Salmasius, 1588–1683)" that it is derived from θρ, the contraction of a Greek name for the planet Mars, which is Thouros. Male_sentence_22

Usage Male_section_3

In addition to its meaning in the context of biology, male can also refer to gender or a shape of connectors. Male_sentence_23

Sex determination Male_section_4

Main article: Sex-determination system Male_sentence_24

The sex of a particular organism may be determined by a number of factors. Male_sentence_25

These may be genetic or environmental, or may naturally change during the course of an organism's life. Male_sentence_26

Although most species have only two sexes (either male or female), hermaphroditic animals, such as worms, have both male and female reproductive organs. Male_sentence_27

Genetic determination Male_section_5

Most mammals, including humans, are genetically determined as such by the XY sex-determination system where males have an XY (as opposed to XX) sex chromosome. Male_sentence_28

It is also possible in a variety of species, including humans, to be XX male or have other karyotypes. Male_sentence_29

During reproduction, a male can give either an X sperm or a Y sperm, while a female can only give an X egg. Male_sentence_30

A Y sperm and an X egg produce a male, while an X sperm and an X egg produce a female. Male_sentence_31

The part of the Y-chromosome which is responsible for maleness is the sex-determining region of the Y-chromosome, the SRY. Male_sentence_32

The SRY activates Sox9, which forms feedforward loops with FGF9 and PGD2 in the gonads, allowing the levels of these genes to stay high enough in order to cause male development; for example, Fgf9 is responsible for development of the spermatic cords and the multiplication of Sertoli cells, both of which are crucial to male sexual development. Male_sentence_33

The ZW sex-determination system, where males have a ZZ (as opposed to ZW) sex chromosome may be found in birds and some insects (mostly butterflies and moths) and other organisms. Male_sentence_34

Members of the insect order Hymenoptera, such as ants and bees, are often determined by haplodiploidy, where most males are haploid and females and some sterile males are diploid. Male_sentence_35

Environmental determination Male_section_6

In some species of reptiles, such as alligators, sex is determined by the temperature at which the egg is incubated. Male_sentence_36

Other species, such as some snails, practice sex change: adults start out male, then become female. Male_sentence_37

In tropical clown fish, the dominant individual in a group becomes female while the other ones are male. Male_sentence_38

In some arthropods, sex is determined by infection. Male_sentence_39

Bacteria of the genus Wolbachia alter their sexuality; some species consist entirely of ZZ individuals, with sex determined by the presence of Wolbachia. Male_sentence_40

Secondary sex characteristics Male_section_7

Main article: Secondary sex characteristic Male_sentence_41

In those species with two sexes, males may differ from females in ways other than the production of spermatozoa. Male_sentence_42

In many insects and fish, the male is smaller than the female. Male_sentence_43

In seed plants, which exhibit alternation of generations, the female and male parts are both included within the sporophyte sex organ of a single organism. Male_sentence_44

In mammals, including humans, males are typically larger than females. Male_sentence_45

In humans, males have more body hair and muscle mass. Male_sentence_46

In birds, the male often exhibits a colorful plumage that attracts females. Male_sentence_47

See also Male_section_8

Male_unordered_list_1


Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Male.