Gonochoristic

Gonochoristic describes organisms whose individuals are strictly male or strictly female, with each organism belonging to one sex for its entire life. The term is used across plants and animals to denote separate sexes rather than hermaphroditic systems, where an individual may have both male and female reproductive organs or switch between sexes.

In plants, the equivalent condition is dioecy, where individual plants are either male or female and produce flowers corresponding to their sex on separate individuals. Dioecious species are common in various plant groups, and the pattern influences ecology, reproduction, and population dynamics.

In the animal kingdom, gonochorism is widespread among vertebrates such as humans, birds, and many fishes, as well as numerous invertebrate lineages. By contrast, some groups exhibit hermaphroditism, either simultaneous (both male and female functions present in the same individual at the same time) or sequential (sex changes during the organism’s life). Reproductive strategies can thus vary within closely related species.

Sex determination in gonochoristic species may be genetic, such as XY or ZW systems, or influenced by environmental factors in some taxa. The defining feature of gonochorism is the lifelong separation of sexes into distinct individuals, which promotes outcrossing and genetic diversity but requires encounters between male and female individuals for reproduction.