SEX REFERS TO the division between many biological species into male and female forms. These forms differ in their chromosomal composition and in those physical aspects that relate to reproduction. Sexual division is common among higher creatures, but is by no means the only arrangement. Many asexual species exist and do not show any disadvantage in evolutionary terms. However, the division, which is billions of years old, seems most likely to have been caused by evolution to increase genetic variation and, hence, survivability of the young. Asexual creatures reproduce through division into daughter creatures that are genetically identical to their mother; on the other hand, male and female partners mating provide a much wider possibility for variation.
Subsequently, evolution has led to changes in the bodies of the species concerned to facilitate the bearing of children by (most commonly, but not exclusively) the female, while males contribute toward reproduction but lack the organs necessary for this task. As males and females have different roles in producing children in humans and most mammals, these differences have been extended to roles in child-rearing, domestic responsibilities, and outdoor work. In some human societies, these differences have become ossified over centuries and have, in the great majority of cases, led to the subjugation and suppression of women and the denial of their equality with men. However, some societies have in modern years or even traditionally adopted more tolerant attitudes toward variations in the distribution of household responsibilities and of gender-based duties.
Just as for humans, many animals do not share the predilection for heterosexual attraction and form homosexual unions on either a temporary or permanent basis. Other creatures appear to have up to as many as five different sexes, all of which contribute in various ways to reproduction and bearing of young. Additionally, some individuals contain both or neither male and female sexual characteristics. Finally, there are creatures whose sexual orientation and physical sexuality change during the course of their lives. The Western philosophical tradition of establishing dichotomous opposites (for example, good-bad, heaven-hell, or black-white) is an inappropriate means of regarding sexuality.
The attempt to restore certain endangered wild animals through mating programs in secure locations is rendered more difficult in some cases by the apparent indifference toward sex of some species, notably giant pandas, which is a behavior without apparent evolutionary advantage other than reducing potential numbers of competitors. However, for most animal species, sexual behavior can include a wide range of exotic and sophisticated courtship ritual. Other species see females consume males after copulation or an apparent lack of connection between the involved parties apart from the physical act. Some animals have been known to conduct systematic rapes of female species and other forms of behavior considered aberrant.
Animals; Biodiversity; Birth Control; Birth Rate; Extinction of Species; Fertility Behavior; Fertility Rate; Gender; Plants; Population; Seeds; Sexually Transmitted Diseases.
The concept of sex is commonly taken to refer to natural or essential properties of an individual as male or female that derive from biological...
Sex is an ambiguous but powerful word. Its reference to, on the one hand, gender differences between men and women and, on the other, sexual interco
Often used as synonym of SEXUAL REPRODUCTION . Used in several senses. Germ cell distinguishes individuals by their abilities to...