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Flowering plants contain non-motile sperm inside pollen, while some more basal plants like ferns and some gymnosperms have motile sperm. [2] Sperm cells form during the process known as spermatogenesis, which in amniotes (reptiles and mammals) takes place in the seminiferous tubules of the testicles. [3]
The name gamete was introduced by the German cytologist Eduard Strasburger in 1878. [3] Gametes of both mating individuals can be the same size and shape, a condition known as isogamy. By contrast, in the majority of species, the gametes are of different sizes, a condition known as anisogamy or heterogamy that applies to humans and other ...
An antheridium is a haploid structure or organ producing and containing male gametes (called antherozoids or sperm). The plural form is antheridia, and a structure containing one or more antheridia is called an androecium. [1] Androecium is also the collective term for the stamens of flowering plants.
The nuclei from the gametes fuse, and each gamete contributes half of the genetic material of the zygote. Multiple cell divisions by mitosis (without change in the number of chromosomes) then develop into a multicellular diploid phase or generation. In plants, the diploid phase, known as the sporophyte, produces spores by
The outer parts are known as the genitals or external genitalia, visible at birth in both sexes, [1] while the inner parts are referred to as internal genitalia, which in both sexes, are always hidden. [2] In plants, male reproductive structures include stamens in flowering plants, which produce pollen. [3]
Allogamy, which is also known as cross-fertilisation, refers to the fertilisation of an egg cell from one individual with the male gamete of another. Autogamy which is also known as self-fertilisation, occurs in such hermaphroditic organisms as plants and flatworms; therein, two gametes from one individual fuse.
A gametangium (pl.: gametangia) is a sex organ or cell in which gametes are produced that is found in many multicellular protists, algae, fungi, and the gametophytes of plants. In contrast to gametogenesis in animals , a gametangium is a haploid structure and formation of gametes does not involve meiosis .
The smaller gamete is considered to be male (a sperm cell), whereas the larger gamete is regarded as female (typically an egg cell, if non-motile). [13] [14] There are several types of anisogamy. Both gametes may be flagellated and therefore motile. Alternatively, as in flowering plants, conifers and gnetophytes, neither of the gametes are ...