A peacock displays his long, colored feathers, an example of his secondary sexual characteristics.

Secondary sex characteristics are traits that distinguish the two sexes of a species, but that are not directly part of the reproductive system. They are believed to have evolved to give an individual an advantage over its rivals in courtship. They are opposed to the primary sexual characteristics: the sex organs. Download high resolution version (800x638, 152 KB)Peacock displaying. ... Download high resolution version (800x638, 152 KB)Peacock displaying. ... Peacock re-directs here; for alternate uses see Peacock (disambiguation). ... Two feathers Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds. ... This article or section does not cite its references or sources. ... The reproductive system is the ensembles and interactions of organs and/or substances within an organism that strictly pertain to reproduction. ... This article is about evolution in biology. ... This article does not cite any references or sources. ... A sex organ, or primary sexual characteristic, narrowly defined, is any of those parts of the body (which are not always bodily organs according to the strict definition) which are involved in sexual reproduction and constitute the reproductive system in an complex organism; namely: Male: penis (notably the glans penis... Genitalia masculina externa A sex organ, or primary sexual characteristic, as narrowly defined, is any of those anatomical parts of the body which are involved in sexual reproduction and constitute the reproductive system in a complex organism; namely: Male: testicles, penis, prepuce, scrotum, prostate, seminal vesicles, epididymis, Cowpers glands...

Well known secondary sex characteristics include facial hairs of male lions, and long feathers of peacock. In humans, the most visible are breasts of females and beard and moustache of males. Secondary sex characteristics include the tusks of sea lions, the plumage of many male birds, the chemical indicators of many insects, etc. For other uses, see Lion (disambiguation). ... Peacock re-directs here; for alternate uses see Peacock (disambiguation). ... okay that is all ... For the slang term, see Beard (female companion). ... Edgar Allan Poe grew a moustache later in his life. ...

In humans

Sexual differentiation begins during gestation, when the gonads form. General habitus and shape of body and face, as well as sex hormone levels, are similar in prepubertal boys and girls. As puberty progresses and sex hormone levels rise, obvious differences appear. Sexual differentiation is the process of development of the differences between males and females from an undifferentiated zygote (fertilized egg). ... Gestation is the carrying of an embryo or fetus inside a female viviparous animal. ... A sex organ, or primary sexual characteristic, narrowly defined, is any of those parts of the body (which are not always bodily organs according to the strict definition) which are involved in sexual reproduction and constitute the reproductive system in an complex organism; namely: Male: penis (notably the glans penis... Puberty refers to the process of physical changes by which a childs body becomes an adult body capable of reproduction. ...

Male levels of testosterone directly induce growth of the penis, and indirectly (via dihydrotestosterone (DHT)) the prostate. Estradiol and other hormones cause breasts to develop in females. However, fetal or neonatal androgens may modulate later breast development by reducing the capacity of breast tissue to respond to later estrogen. Testosterone is a steroid hormone from the androgen group. ... The penis (plural penises, penes) is an external male sexual organ. ... For other uses, see DHT (disambiguation). ... The prostate is a compound tubuloalveolar exocrine gland of the male mammalian reproductive system. ... Estradiol (17β-estradiol) (also oestradiol) is a sex hormone. ... Hormone is also the NATO reporting name for the Soviet/Russian Kamov Ka-25 military helicopter. ... For other uses, see Breast (disambiguation). ... Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors. ... Estriol. ...

In males, testosterone directly increases size and mass of muscles, vocal cords, and bones, enhancing strength, deepening the voice, and changing the shape of the face and skeleton. Converted into DHT in the skin, it accelerates growth of androgen-responsive facial and body hair. Taller stature is largely a result of later puberty and slower epiphyseal fusion. Testosterone is a steroid hormone from the androgen group. ... A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... The vocal cords, also known as vocal folds, are composed of twin infoldings of mucous membrane stretched horizontally across the human larynx. ... This article is about the skeletal organs. ... The human voice consists of sound made by a human using the vocal folds for talking, singing, laughing, crying and screaming. ... For other uses, see Face (disambiguation). ... For other uses, see Skeleton (disambiguation). ... Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors. ... Puberty refers to the process of physical changes by which a childs body becomes an adult body capable of reproduction. ...

In females, breasts are the most obvious 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 menses. okay that is all ... Estriol. ... This article is about female reproductive anatomy. ... The endometrium is the inner membrane of the mammalian uterus. ... Menstrual cycle The menstrual cycle is a recurring cycle of physiologic changes that occurs in the females of several mammals, including human beings and other apes. ...

female sex characteristics

male sex characteristics

In humans, secondary sex characteristics include: Image File history File links Size of this preview: 239 × 598 pixelsFull resolution (455 × 1139 pixel, file size: 154 KB, MIME type: image/jpeg) The picture shows a young woman with labels of her sexual characteristics source:http://de. ... Image File history File links Size of this preview: 239 × 598 pixelsFull resolution (455 × 1139 pixel, file size: 154 KB, MIME type: image/jpeg) The picture shows a young woman with labels of her sexual characteristics source:http://de. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

• Male
  • abdominal and chest hair, also more hairs on other parts of body
  • more facial hair
  • taller stature, on average
  • higher waist to hip ratio, on average
  • broader shoulders and chest, wider than hips^[1]
  • heavier skull and bone structure
  • greater muscle mass and physical strength
  • a prominent Adam's apple and deep voice
  • fat deposits mainly around the abdomen and waist^{[citation needed]} ("apple shape")
  • coarser skin texture
  • on average, larger hands and feet than women^{[citation needed]}
  • lower digit ratio, on average^{[citation needed]}

• Female
  • enlarged breasts
  • shorter stature, on average
  • lower waist to hip ratio, on average
  • wider in hips^[2]
  • less facial hair
  • high voice
  • functional mammary glands
  • more subcutaneous fat
  • fat deposits mainly around the buttocks, thighs and hips ("pear shape")
  • smoother skin texture
  • higher digit ratio, on average^{[citation needed]}

This article is about the Male sex. ... The term abdominal hair refers to the hair that grows on the abdomen (belly) of humans and non-human mammals, in the region between the pubic area and the thorax (chest). ... The term chest hair is generally used to describe hair that grows on the chest of human males, in the region between the neck and the abdomen. ... One kind of modern beard. ... Stature redirects here. ... Waist-to-hip ratio or Waist-hip ratio (WHR) is the ratio of the girth of waist and the girth of hip. ... This article is about the body part. ... For other uses of Skull, see Skull (disambiguation). ... This article is about the skeletal organs. ... A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... For other uses, see Adams apple (disambiguation). ... The human voice consists of sound made by a human using the vocal folds for talking, singing, laughing, crying and screaming. ... For other uses, see FAT. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... The human abdomen (from the Latin word meaning belly) is the part of the body between the pelvis and the thorax. ... Waistline The waist is the part of the abdomen between the ribcage and hips. ... The digit ratio is the ratio of the lengths of different digits, fingers or toes, typically as measured from the bottom crease where the finger joins the hand to the tip of the finger. ... For other uses, see Female (disambiguation). ... For other uses, see Breast (disambiguation). ... Stature redirects here. ... Waist-to-hip ratio or Waist-hip ratio (WHR) is the ratio of the girth of waist and the girth of hip. ... In anatomy, the hip is the bony projection of the femur which is known as the greater trochanter, and the overlying muscle and fat. ... One kind of modern beard. ... Mammary glands are the organs that, in the female mammal, produce milk for the sustenance of the young. ... It has been suggested that this article or section be merged into Adipose tissue. ... For other uses, see FAT. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... Bottom commonly refers to the human buttocks but also has other uses. ... In humans the thigh is the area between the pelvis and buttocks and the knee. ... In anatomy, the hip is the bony projection of the femur which is known as the greater trochanter, and the overlying muscle and fat. ... Beyond overall skin structure, refer below to: See-also. ... The digit ratio is the ratio of the lengths of different digits, fingers or toes, typically as measured from the bottom crease where the finger joins the hand to the tip of the finger. ...

See also

• Puberty
• Virilization
• Sex differences in humans
• Sexual dimorphism

Puberty refers to the process of physical changes by which a childs body becomes an adult body capable of reproduction. ... In biology and medicine, virilization refers to the development of changes which make a male body different from a female body. ... This article is about biological sex differences. ... Female (left) and male Common Pheasant, illustrating the dramatic difference in both color and size, between the sexes Sexual dimorphism is the systematic difference in form between individuals of different sex in the same species. ...

Notes

References

• http://www.columbia.edu/itc/hs/pubhealth/modules/reproductiveHealth/anatomy.html