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Secondary sex characteristic

 
Secondary Sex Characteristic

 
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Secondary sex characteristic
 
 
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Secondary sex characteristics are traits that distinguish the two sex
Sex

In biology, sex is a process of combining and mixing genetics traits, often resulting in the specialization of organisms into male and female types ....
es of a species, but that are not directly part of the reproductive system
Reproductive system

The reproductive system is a system of Organ within an organism which work together for the purpose of reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system....
. They are believed to be the product of sexual selection
Sexual selection

Sexual selection is the theory proposed by Charles Darwin that states that certain evolutionary traits can be explained by intraspecific competition....
 for traits which give an individual an advantage over its rivals in courtship
Courtship

Courtship is the traditional dating period before engagement and marriage. During a courtship, a couple dates to get to know each other and decide if there will be an engagement....
, and aggressive
Aggression

In psychology, as well as other social science and behavioral sciences, aggression refers to behavior between members of the same species that is intended to cause pain or harm....
 interactions.






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Peacock
Secondary sex characteristics are traits that distinguish the two sex
Sex

In biology, sex is a process of combining and mixing genetics traits, often resulting in the specialization of organisms into male and female types ....
es of a species, but that are not directly part of the reproductive system
Reproductive system

The reproductive system is a system of Organ within an organism which work together for the purpose of reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system....
. They are believed to be the product of sexual selection
Sexual selection

Sexual selection is the theory proposed by Charles Darwin that states that certain evolutionary traits can be explained by intraspecific competition....
 for traits which give an individual an advantage over its rivals in courtship
Courtship

Courtship is the traditional dating period before engagement and marriage. During a courtship, a couple dates to get to know each other and decide if there will be an engagement....
, and aggressive
Aggression

In psychology, as well as other social science and behavioral sciences, aggression refers to behavior between members of the same species that is intended to cause pain or harm....
 interactions. They are distinguished from the primary sexual characteristics: the sex organ
Sex organ

A sex organ, or primary sexual characteristic, as narrowly defined, is any of the anatomical parts of the body which are involved in sexual reproduction and constitute the reproductive system in a complex organism; in mammals, these include:...
s, which are directly necessary for reproduction to occur.

Well known secondary sex characteristics include manes of male lion
Lion

The lion is a member of the family Felidae and one of four big cats in the genus Panthera. With exceptionally large males exceeding 250 kg in weight, it is the second-largest living cat after the tiger....
s and long feathers of peacocks. In humans, the most visible are breast
Breast

The breast is the upper ventral region of an animal?s torso, particularly that of mammals, including human beings. The breasts of a female primate?s body contain the mammary glands, which secrete milk used to feed infants....
s of females and beard
Beard

A beard is the hair that grows on a person's chin, cheeks, neck, and the area above the upper lip. Typically, only males going through puberty, or post-pubescent males are able to grow beards....
 and moustache
Moustache

A moustache is facial hair grown on the upper lip. Often the term implies that the wearer grows only upper-lip hair while shaving the hair on his chin and cheeks....
 of males. Secondary sex characteristics also include the tusks of sea lions, the plumage of many male birds, and the chemical indicators of insects.

In humans

Sexual differentiation
Sexual differentiation

Sexual differentiation is the process of development of the differences between males and females from an undifferentiated zygote . As male and female individuals develop from zygotes into fetuses, into infants, children, adolescents, and eventually into adults, sex and gender differences at many levels develop: genes, chromosomes, gonads, ho...
 begins during gestation
Gestation

Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during mammalian pregnancy can have one or more gestations at the same time ....
, when the gonads are formed. General habitus
Habitus

Habitus is a complex concept, but in its simplest usage could be understood as a set of acquired patterns of thought, behavior, and Taste . These patterns, or "dispositions", are the result of internalization of culture or objective social structures through the experience of an individual or group....
 and shape of body and face, as well as sex hormone levels, are similar in prepubertal boys and girls. As puberty
Puberty

Puberty refers to the process of physical changes by which a child's body becomes an adult body capable of reproduction. Puberty is initiated by hormone signals from the brain to the gonads ....
 progresses and sex hormone levels rise, differences appear, though puberty causes some similar changes in male and female bodies.

Male levels of testosterone
Testosterone

Testosterone is a steroid hormone from the androgen group. In mammals, testosterone is primarily secreted in the testis of males and the ovaries of females, although small amounts are also secreted by the adrenal glands....
 directly induce growth of the testicles and penis
Penis

The penis is an external sex organ of certain biologically male organisms, in both vertebrates and invertebrates.The penis is a reproductive organ, technically an intromittent organ, and for Eutheria, additionally serves as the external organ of urination....
, and indirectly (via dihydrotestosterone
Dihydrotestosterone

Dihydrotestosterone While DHT is best known for its roles in causing male pattern hair loss and prostate problems, it is crucial to virilization and is necessary to mitigate estrogen's effects in men....
 (DHT)) the prostate
Prostate

The prostate is a compound tubuloalveolar exocrine gland of the male mammalian reproductive system. Females do not have a prostate gland, although females do have tiny paraurethral Skene's glands connected to the distal third of the urethra in the prevaginal space that are homologous to the prostate....
. Estradiol
Estradiol

Estradiol is a sex hormone. Mislabelled the "female" hormone, it is also present in males; it represents the major estrogen in humans. Estradiol has not only a critical impact on reproductive and sexual functioning, but also affects other organs including bone structure....
 and other hormones cause breast
Breast

The breast is the upper ventral region of an animal?s torso, particularly that of mammals, including human beings. The breasts of a female primate?s body contain the mammary glands, which secrete milk used to feed infants....
s to develop in females. However, fetal or neonatal androgen
Androgen

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....
s may modulate later breast development by reducing the capacity of breast tissue to respond to later estrogen
Estrogen

Estrogens are a group of steroid compounds, named for their importance in the estrous cycle, and functioning as the primary female sex hormone....
.

In males, testosterone
Testosterone

Testosterone is a steroid hormone from the androgen group. In mammals, testosterone is primarily secreted in the testis of males and the ovaries of females, although small amounts are also secreted by the adrenal glands....
 directly increases size and mass of muscle
MUSCLE

MUSCLE is public domain, multiple sequence alignment software for protein and nucleotide sequences.MUSCLE is integrated into UGENE bioinformatics tool as a plugin....
s, vocal cords, and bone
Bone

Bones are rigid organ that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red blood cell and white blood cells and store minerals....
s, deepening the voice
Human voice

The human voice consists of sound Voice production by a human being using the vocal folds for Speech communication, singing, Laughter, crying, screaming, etc....
, and changing the shape of the face
Face

The term face refers to the central sense organ complex, for those animals that have one, normally on the ventral surface of the head and can depending on the definition in the human case, include the hair, forehead, eyebrow, eyes, nose, ears, cheeks, mouth, lips, philtrum, tooth, skin, and chin....
 and skeleton
Skeleton

In biology, a skeleton is a rigid framework that provides protection and structure in many types of animal, particularly those of the phylum Chordata and of the superphylum Ecdysozoa....
. Converted into DHT in the skin, it accelerates growth of androgen
Androgen

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....
-responsive facial and body hair, but may slow and eventually stop the growth of head hair. Taller stature is largely a result of later puberty
Puberty

Puberty refers to the process of physical changes by which a child's body becomes an adult body capable of reproduction. Puberty is initiated by hormone signals from the brain to the gonads ....
 and slower epiphyseal fusion.

In females, breasts are a manifestation of higher levels of estrogen
Estrogen

Estrogens are a group of steroid compounds, named for their importance in the estrous cycle, and functioning as the primary female sex hormone....
; 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
Uterus

The uterus is a major female hormone-responsive reproductive sex organ of most mammals, including humans. It is within the uterus that the fetus develops during gestation....
, proliferation of the endometrium
Endometrium

The endometrium is the inner membrane of the mammalian uterus....
, and menses
Menstrual cycle

The menstrual cycle is a recurring cycle of physiology changes that occurs in reproductive-age females. Overt menstruation occurs primarily in humans and close evolutionary relatives such as chimpanzees....
.

Androgenic Hair
In humans, secondary sex characteristics include:

  • Male
    Malé

    Mal? , population 104,403 , is the Capital , the largest city in terms of population, and the name of an island in the Maldives. It is located at the southern edge of North Male' Atoll Kaafu Atoll....
    • Growth of body hair, including underarm
      Underarm hair

      Underarm Hair is the composition of hair in the underarm area. This hair, as most of the other body hair, normally starts to appear at puberty and growth is usually complete by the end of teen age....
      , abdominal
      Abdominal hair

      The term abdominal hair refers to the hair that grows on the human abdomen of humans and non-human mammals, in the region between the pubic area and the thorax ....
      , chest
      Chest hair

      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 human abdomen....
      , and pubic hair
      Pubic hair

      Although fine Vellus is present in the area in childhood, the term pubic hair is generally restricted to the heavier, longer and coarser hair that develops with puberty as an effect of rising levels of androgens....
    • Greater mass of thigh muscles in front of the femur, rather than behind it as is typical in mature females
    • Growth of facial hair
      Facial hair

      Facial hair is a secondary sex characteristic in human males. Many men start developing facial hair in the later years of puberty, approximately between 18-20 years old and most men don't finish developing a fully adult beard until their early 20s or even later....
    • Enlargement of larynx and deepening of voice
      Human voice

      The human voice consists of sound Voice production by a human being using the vocal folds for Speech communication, singing, Laughter, crying, screaming, etc....
    • Increased stature
      Human height

      Human height varies according to both Nature versus nurture. The particular human genome that an individual inherits is a large part of the first variable and a combination of health and environmental factors present before adulthood are a major part of the second determinant ....
      ; adult males taller than adult females, on average
    • Heavier skull
      Skull

      The skull is a bone structure found in the head of many animals. The skull supports the structures of the face and protects the head against injury....
       and bone
      Bone

      Bones are rigid organ that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red blood cell and white blood cells and store minerals....
       structure
    • Increased muscle
      MUSCLE

      MUSCLE is public domain, multiple sequence alignment software for protein and nucleotide sequences.MUSCLE is integrated into UGENE bioinformatics tool as a plugin....
       mass and strength
    • Broadening of shoulder
      Shoulder

      In human anatomy, the shoulder joint comprises the part of the body where the humerus attaches to the scapula. The shoulder refers to the group of structures in the region of the joint....
      s and chest; shoulders wider than hips
    • Increased secretions of oil and sweat glands, often causing acne and body odor
    • Coarsening or rigidity of skin texture, due to less subcutaneous fat
    • A prominent Adam's apple
      Adam's apple

      The laryngeal prominence?commonly known as the Adam's Apple?is a feature of the human neck. This lump, or protrusion, is formed by the angle of the thyroid cartilage surrounding the larynx....
    • Fat
      Fat

      Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemistry, fats are generally ester of glycerol and fatty acids....
       deposits mainly around the abdomen
      Human abdomen

      The human abdomen is the part of the body between the pelvis and the chest. Anatomically, the abdomen stretches from the thorax at the thoracic diaphragm to the pelvis at the pelvic brim....
       and waist
      Waist

      The waist is the part of the Human abdomen between the rib cage and Hip . On proportionate people, the waist is the narrowest part of the torso....
    • Higher waist to hip ratio
      Waist-hip ratio

      Waist-hip ratio or Waist-to-hip ratio is the ratio of the circumference of the waist to that of the hips. It is calculated by measuring the waist circumference and dividing by the hip circumference at its widest part ....
       than prepubescent or adult females or prepubescent males, on average
    • On average, larger hands and feet than prepubescent or adult females or prepubescent males
    • Lower digit ratio
      Digit ratio

      The digit ratio is the ratio of the lengths of different fingers, fingers or toes, typically as measured from the bottom crease where the finger joins the hand to the tip of the finger....
      , on average


  • Female
    Female

    Female is the sex of an organism, or a part of an organism, which produces mobile ovum . The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male....
    • Enlargement of breasts
    • Growth of body hair, most prominently underarm
      Underarm hair

      Underarm Hair is the composition of hair in the underarm area. This hair, as most of the other body hair, normally starts to appear at puberty and growth is usually complete by the end of teen age....
       and pubic hair
      Pubic hair

      Although fine Vellus is present in the area in childhood, the term pubic hair is generally restricted to the heavier, longer and coarser hair that develops with puberty as an effect of rising levels of androgens....
    • Greater development of thigh muscles in back (behind the femur) than in front of it
    • Vagina
      Vagina

      The vagina is a fibromuscular cylinder tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles....
      l and uterine
      Uterus

      The uterus is a major female hormone-responsive reproductive sex organ of most mammals, including humans. It is within the uterus that the fetus develops during gestation....
       growth
    • Decreased stature; adult females shorter stature
      Human height

      Human height varies according to both Nature versus nurture. The particular human genome that an individual inherits is a large part of the first variable and a combination of health and environmental factors present before adulthood are a major part of the second determinant ....
       than adult males, on average
    • Widening of hip
      Hip (anatomy)

      In anatomy, the hip or coxa in medical termonology is the bone projection of the femur which is known as the greater trochanter, and the overlying muscle and fat....
      s; lower waist to hip ratio
      Waist-hip ratio

      Waist-hip ratio or Waist-to-hip ratio is the ratio of the circumference of the waist to that of the hips. It is calculated by measuring the waist circumference and dividing by the hip circumference at its widest part ....
       than adult males, on average
    • Decreased secretions of oil and sweat glands, causing less acne and body odor
    • Changed distribution in weight and fat; more subcutaneous fat
      Subcutaneous fat

      Subcutaneous fat is found just beneath the skin as opposed to visceral fat which is found in the peritoneal cavity. Subcutaneous fat can be measured using body fat calipers giving a rough estimate of total body adiposity....
       and fat
      Fat

      Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemistry, fats are generally ester of glycerol and fatty acids....
       deposits mainly around the buttocks
      Buttocks

      The buttocks are rounded portions of the anatomy located on the posterior of the pelvic region of the apes, including humans and many other bipeds or quadrupeds....
      , thigh
      Thigh

      In human anatomy the thigh is the area between the pelvis and the knee. Anatomically, it is part of the Human leg.The single bone in the thigh is called the femur....
      s and hip
      Hip (anatomy)

      In anatomy, the hip or coxa in medical termonology is the bone projection of the femur which is known as the greater trochanter, and the overlying muscle and fat....
      s
    • Higher digit ratio
      Digit ratio

      The digit ratio is the ratio of the lengths of different fingers, fingers or toes, typically as measured from the bottom crease where the finger joins the hand to the tip of the finger....
      , on average


See also

  • Sexual selection in human evolution
    Sexual selection in human evolution

    When Charles Darwin initially proposed his theory on sexual selection, there was considerable scepticism on its application to human evolution. More recently, the role of sexual selection in human evolution has begun to gain wide acceptance....
  • Puberty
    Puberty

    Puberty refers to the process of physical changes by which a child's body becomes an adult body capable of reproduction. Puberty is initiated by hormone signals from the brain to the gonads ....
  • Virilization
    Virilization

    In biology and medicine, virilization refers to the biological development of sex differences, changes which make a male body different from a female body....
  • Estrogenic fat
    Estrogenic fat

    Estrogenic fat is a form of adipose tissue which develops under the influence of estrogen, and particularly estradiol, in women....
  • Sex differences in humans
  • Sexual dimorphism
    Sexual dimorphism

    Sexual dimorphism is the systematic difference in form between individuals of different sex in the same species. Examples include color , size, and the presence or absence of parts of the body used in courtship displays or fights, such as ornamental feathers, horns, antlers or tusks....
  • Body shape
    Body shape

    Human body shape is a complex phenomenon with sophisticated detail and function. The general shape or figure of a person is defined mainly by skeletal structure, muscles and fat....
  • Female body shape
    Female body shape

    Female body shape has a bearing on a wide range of human activities, and there are and have been widely different ideals of it in different cultures and at different times....