Male

Information about Male

This article is about the Male sex. For the city, see Malé. For other uses, see Male (disambiguation).

Male (♂) refers to the sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilisation. A male cannot reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and asexually.

Not all species share a common sex-determination system. In humans and most animals, sex is determined genetically but in other species it can be determined due to social, environmental, or other factors. The existence of two sexes seems to have been selected across different evolutionary lineages (see Convergent Evolution). Accordingly, sex is defined operationally across species by the type of gametes produced (ie: spermatozoa vs. ova) and differences between males and females in one lineage are not always predictive of differences in another.

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. 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. Female being the more dominant species, female gametes override any male gamete present.

Secondary sex characteristics

Main article: Secondary sex characteristic

In those species with two sexes, males may differ from females in ways other than production of spermatozoa. Males are generally smaller than females in seed plants (the pollen grain is the male plant) and many fishes and birds, but larger in many mammals, including humans. In birds, the male often exhibits a colourful plumage that attracts females.

Sex determination

Main article: Sex-determination system

The sex of a particular organism may be determined by a number of factors. These may be genetic or environmental, or may naturally change during the course of an organism's life. Although most species with male and female sexes have individuals that are either male or female, hermaphroditic animals have both male and female reproductive organs.

Genetic determination

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. During reproduction, a male can give either an X sperm or a Y sperm, while a female can only give an X egg. A Y sperm and an X egg produce a boy, while an X sperm and an X egg produce a girl. 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. Members of Hymenoptera, such as ants and bees, are determined by haplodiploidy, where most males are haploid and females and some sterile males are diploid.

Environmental determination

In some species of reptiles, including alligators, sex is determined by the temperature at which the egg is incubated. Other species, such as some snails, practise sex change: adults start out male, then become female. In tropical clown fish, the dominant individual in a group becomes female while the other ones are male.

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

Anatomy

All males, regardless of independent origin, kingdom, or other phylogenetic subdivision, share at least the anatomy to produce male gametes. Some have sophisticated organs and organ systems designed to produce, dispense, and deliver the gamete to a location suitable for ovum fertilisation.

Even where structures and cell types have arisen independently, "sperm" is ordinarily used to refer to the male gamete. Among animals that undergo internal fertilization, "penis" is often used to refer to an organ inserted into the female for insemination.

Symbols

A common symbol used to represent the male gender is the Mars symbol, ♂ (Unicode: U+2642 Alt codes: Alt+11)—a circle with an arrow pointing northeast. This is a stylized representation of the Roman god Mars' shield and spear.

Female (♀) is the sex of an organism, or a part of an organism, which produces ova (egg cells). The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon is produced by the male.
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ovum (plural ova) is a haploid female reproductive cell or gamete. The word is derived from Latin, meaning egg or egg cell. Both animals and embryophytes have ova. The term ovule
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Fertilization (also known as conception, fecundation and syngamy), is fusion of gametes to form a new organism of the same species. In animals, the process involves a sperm fusing with an ovum, which eventually leads to the development of an embryo.
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Sexual reproduction is a union that results in increasing genetic diversity of the offspring. It is characterized by two processes: meiosis, involving the halving of the number of chromosomes; and fertilisation, involving the fusion of two gametes and the restoration of the
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A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. Most sexual organisms have two sexes. In many cases, sex determination is genetic: males and females have different alleles or even different genes that
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Genetics is the science of heredity and variation in living organisms.^[1]^[2] Knowledge of the inheritance of characteristics has been implicitly used since prehistoric times for improving crop plants and animals through selective breeding.
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An evolutionary lineage is a sequence of species, that form a line of descent, each new species the direct result of speciation from an immediate ancestral species.^[1]^[2] Lineages are subsets of the evolutionary tree of life.
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In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches^[1].
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An operational definition is a showing of something—such as a variable, term, or object—in terms of the specific process or set of validation tests used to determine its presence and quantity.
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Sexual dimorphism is the systematic difference in form between individuals of different sex in the same species. Examples include size, color, and the presence or absence of parts of the body used in courtship displays or fights, such as ornamental feathers, horns, antlers or tusks.
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Chytridiomycota
M.J. Powell 2007^[1]

Type species
Chytridium spp.
A. Braun, 1851

Classes

Chytridiomycetes
Monoblepharidomycetes
Chytridiomycota is a phylum of the Fungi kingdom.
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Bacillariophyceae

Orders

Centrales
Pennales

Diatoms (Greek: διά (dia) = "through" + τέμνειν
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Plantae
Haeckel, 1866^[1]

Divisions

Green algae

Chlorophyta
Charophyta

Land plants (embryophytes)

Non-vascular land plants (bryophytes)

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diploid sporophyte, the generation of a plant or alga that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants and in some green algae.
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Secondary sex characteristics are traits that distinguish the two sexes of a species, but that are not directly part of the reproductive system. Some have argued that in general they evolved to give an individual an advantage over its rivals in courtship.
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Pollen is a fine to coarse powder consisting of microgametophytes (pollen grains), which produce the male gametes (sperm cells) of seed plants. The pollen grain with its hard coat protects the sperm cells during the process of their movement between the stamens
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Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season.
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hermaphrodite is an organism that posses both male and female genetalia.^[1] In many species, hermaphroditism is a common part of the life-cycle, particularly in some asexual animals and some plants.
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Mammalia
Linnaeus, 1758

Subclasses & Infraclasses

Subclass †Allotheria*
Subclass Prototheria
Subclass Theria

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The XY sex-determination system is the sex-determination system found in humans, most other mammals, some insects (Drosophila) and some plants (Ginkgo). In the XY sex-determination system, females have two of the same kind of sex chromosome (XX), and are called
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Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division.]] A chromosome is a single large macromolecule of DNA, and constitutes a physically organized form of DNA in a cell.
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BOY is a Canadian indie pop band.

The band consists of vocalist and general instrumentalist Stephen Kozmeniuk, drummer Maurie Kaufmann, bassist Steve Payne, guitarist Rolla Olak and guitarist James Robertson.

BOY's first two CDs were released on Bumstead Records.
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A girl is a female child, as opposed to a boy, a male child. The age at which a female person transitions from girl to woman varies in different societies; typically the transition from adolescence to maturity is taken to occur in the late teens.
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