Anisogamous

Different forms of anisogamy: A) anisogamy of motile cells, B) oogamy (egg cell and sperm cell">egg_cell.html" ;"title="oogamy ( oogamy (egg cell and sperm cell), C) anisogamy of non-motile cells (egg cell and spermatia).">283x283px Anisogamy is a form of sexual reproduction">egg cell">oogamy (egg cell and sperm cell), C) anisogamy of non-motile cells (egg cell and spermatia).">283x283px Anisogamy is a form of sexual reproduction that involves the union or fusion of two

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s that differ in size and/or form. The smaller gamete is

male Male (Mars symbol, symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization. A male organism cannot sexual reproduction, repro ...

, a

sperm cell Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, w ...

, whereas the larger gamete is

female 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 a ...

, typically an

egg cell The egg cell, or ovum (plural ova), is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is ...

. Anisogamy is predominant among multicellular organisms. In both plants and animals gamete size difference is the fundamental difference between

s and