[ **up: [[Sex (Biology)]]** ] --- # Gonochorism Gonochorists are organisms that have two distinct sexes, male and female. This is the most common sexual system in animals and is also known as dioecy. [[2025-0313. 'In sexually reproducing isogamous organisms, gametes (or diploid cells in ciliates) are classified into two or more groups called sexes, and mating occurs only between cells of different sexes.'|'In sexually reproducing isogamous organisms, gametes (or diploid cells in ciliates) are classified into two or more groups called sexes, and mating occurs only between cells of different sexes.']][^1] --- - *See:* [[Sex determination]].** --- ## Evolution [[2025-0321. 'When mate search is efficient, disruptive frequency-dependent selection on time allocation to mate search leads to the evolution of searching and nonsearching phenotypes and, ultimately, to the evolution of males and females.'|'When mate search is efficient, disruptive frequency-dependent selection on time allocation to mate search leads to the evolution of searching and nonsearching phenotypes and, ultimately, to the evolution of males and females.']][^2] [^1]: Yoh Iwasa and Akira Sasaki, ‘[[Iwasa & Sasaki. ‘Evolution of the number of sexes’, 1987.|Evolution of the number of sexes]]’, *Evolution* 41, Issue 1, 1 January 1987, p.49. [^2]: Nelson R. Cabej, ‘[[Cabej. ‘Epigenetics of Reproduction in Animals’, 2013.|Epigenetics of Reproduction in Animals]]’, in *Building the Most Complex Structure on Earth* (Elsevier, 2013), p. 101.