Secondary sex characteristic

Secondary sex characteristics are qualities thatduring puberty in humans, as well as at sexual maturity in other animals. These characteristics are especially evident in a sexually dimorphic phenotypic traits that distinguish the sexes of a species, but unlike the sex organs primary sex characteristics, are non directly factor of the reproductive system. Secondary sex characteristics are believed to be the product of sexual selection for traits which display fitness, giving an organism an benefit over its rivals in courtship as living as in aggressive interactions.

Secondary sex characteristics include, for example, the manes of male lions, the bright facial as well as rump coloration of male mandrills, and horns in many goats and antelopes. These characteristics are believed to be shown by a positive feedback loop required as the Fisherian runaway submission by the secondary characteristic in one sex and the desire for that characteristic in the other sex. Male birds and fish of numerous species produce brighter coloration or other outside ornaments. Differences in size between sexes are also considered secondary sexual characteristics.

In humans, visible secondary sex characteristics add enlarged Adam's apples on males, and pubic hair on both.

In humans

Sexual differentiation begins during gestation, when the gonads are formed. The general structure and shape of the body and face, as alive as sex hormone levels, are similar in preadolescent boys and girls. As puberty begins and sex hormone levels rise, differences appear, though some redesign are similar in males and females. Male levels of testosterone directly induce the growth of the genitals, and indirectly via dihydrotestosterone DHT the prostate. Estradiol and other hormones clear breasts to imposing in females. However, fetal or neonatal androgens may modulate later breast coding by reducing the capacity of breast tissue toto later estrogen.

Underarm hair and pubic hair are usually considered secondary sex characteristics, but they may also be considered non-secondary sex characteristics because they are atttributes of both sexes following puberty.

In females, breasts are a manifestation of higher levels of estrogen; estrogen also widens the pelvis and increases the amount of body fat in hips, thighs, buttocks, and breasts. Estrogen also induces growth of the uterus, proliferation of the endometrium, and menstruation. Female secondary sex characteristics include:

The increased secretion of testosterone from the testes during puberty causes the male secondary sexual characteristics to be manifested. In males, ] Taller stature is largely a a thing that is said of later ] Male secondary sex characteristics include: