Gametes

An individual that produces exclusively large gametes is female, and one that produces exclusively small gametes is male.

Gametes can be identical in form and function (known as isogamy ), but in many cases an asymmetry has evolved such that two sex-specific types of gametes (heterogametes) exist (known as anisogamy ).

In centric diatoms, the small male gametes have one flagellum while the female gametes are large and non-motile ( oogamous ).

In either case, gametes may be externally similar, particularly in size ( isogamy ), or may have evolved an asymmetry such that the gametes are different in size and other aspects ( anisogamy ).

In many organisms, the haploid stage has been reduced to just gametes specialized to recombine and form a new diploid organism; in others, the gametes are capable of undergoing cell division to produce multicellular haploid organisms.

In the majority of species with sex specialization, organisms are either male (producing only male gametes) or female (producing only female gametes).

Thus an individual that produces exclusively large gametes ( ova in humans) is called female, and one that produces exclusively small gametes ( spermatozoa in humans) is called male.

From a practical point of view, growing and raising coral – from catching the floating gametes to keeping nursery structures clean – is a massive undertaking.

When its representative at the workshop was asked if her clients were seeking synthetic gametes she replied, somewhat reluctantly, that they were not.

In their initial campaign they cited research which suggested that almost half of people in Scotland would consider donating gametes to those who need help to conceive.

In vitro gametogenesis is an assisted reproduction technology which involves the creation of gametes by converting somatic cells – skin, blood or hair – into pluripotent stem cells.

Also, the pattern of cell division that transforms eukaryotic stem cells into gametes ( sperm cells in males or ova – egg cells – in females) is different from that of the somatic cell division in the cells of the body.

Animals hatnote Hoverflies mating Most sexually reproducing animals spend their lives as diploid organisms, with the haploid stage reduced to single cell gametes.

An individual that produces both types of gametes is a hermaphrodite ; in some cases hermaphrodites are able to self-fertilize and produce offspring on their own, without a second organism.

An individual that produces both types of gametes is called hermaphrodite (a name applicable also to people with one testis and one ovary).

As an example, the chromosomes of common wheat are believed to be derived from three different ancestral species, each of which had 7 chromosomes in its haploid gametes.

At certain stages of the life cycle, germ cells produce gametes.

Autogamy which is also known as self-fertilisation, occurs in such hermaphroditic organisms as plants and flatworms; therein, two gametes from one individual fuse.

Because homologous chromosomes usually differ genetically, gametes usually differ genetically from one another.

Because the number of chromosomes is halved during meiosis, gametes can fuse (i.e. fertilization ) to form a diploid zygote that contains two copies of each chromosome, one from each parent.