Categories Uncategorized

I.9.5 Race

The term race or racial group refers to dividing the human species into groups. The most widely used human racial types are those based on visual traits (such as skin color, cranial, facial features, or type of hair).

As per Theodosus Dobzhansky,

Race is a group of population which are reproductively isolated to the extent that the exchange of genes between them is absent or so slow that the genetic differences are not diminished.

Features of race as per definition by Theodosus Dobzhansky,

  1. Group Of Population : All populations have their own gene pool with differing gene frequency. If race is defined in term of gene frequencies, all populations would qualify to be called a race. Race is higher in hierarchy than populations, and consists of many populations that have gene frequencies related to one another.
  2. Genetic Differences : The group of populations forming a race have some genes in very high frequency and some in very low frequency and these genetic differences characterize a race. ‘ Such differences in gene frequency arise partly as a result of
    selection and partly as a result of chance.
  3. Reproductively Isolated : The group of populations forming races are reproductively isolate. This reproductive isolation, in fact, maintains the genetic differences between the races. The reproductive isolation, however, is not complete. Whenever races expand their range and come into contact of
    other races, they potentially hybridize and a now gene-frequency is set up.
  4. Biological Concept : Race is different from national, religious, and cultural groups. Indians or Germans are not racial groups, they are national groups. Buddhists and Protestants are religious groups. Aryans and Dravidians are linguistic groups. Race
    is a biological concept and there is no race except biological races. Such races are identified because of differing gene frequencies resulting from isolation, hybridization, selection, small mutations, and chance.

Races may “be defined as group of population that share a common gene pool and is differentiated from other groups in gene-frequencies.

The characters upon which races are distinguished-

  1. must be non-adaptive hence least influenced by environmental factors.
  2. must be hereditary hence genetic in origin.

Morphological Bases

A. Morphoscopic

This include morphological features that cannot be measured but can only be visually discriminated. This includes skin color, hair color texture & shape and colour of eye

I. Skin Colour : Skin colour depends upon two factors smaller vessels of dermis and concentration of melanin, a pigment in the outer layer of skin, formed in special pigment cells called melanocytes located in the deeper layer of skin. Skin colour is Polygenic and multiple allelic not following simple Mendelian inheritance.

In white skinned people, there is minimum of melanin on the outer surface thus allowing even slightest of sun-shine reach to the deeper layer of skin for protection against cold and synthesis of Vitamin D.

There are three distinct categories of people based on the skin colour :

  1. Leucoderm : Various shades of. white e.g. Caucasoid.
  2. Xanthoderm : Various shades of yellow e g.Mongoloid
  3. Melanoderm : Skin colour dark eg.Negroid.

II. Hair Colour, Texture & Form :  The colour varies from light blonde to brown (Caucasoid), brown to brown black (Mongoloid) and brown black (Negroid). The difference in the hair colour is due to difference in the melanin pigment –

Texture varies from fine  to medium to coarse in Caucasoid, Mongoloid and  Negroid  races respectively excepting Chinese and Japanese among mongoloid who have course hair.

The hair form is generally classified into 3 groups :

  1. Cymotrichous or wavy of caucasoid and can be classified as broad wavy, narrow wavy and curly wa
  2. Leiotrichous or smooth of monaoloids and can be  differentiated as stretched smooth, flat smooth.
  3. Ulotrichous or woolly or kinky of Negroids and can be differentiated as frizzly, filfil and  pepper corn.

Races can also be differentiated on the basis of hair-whorls, clockwise, or anticlockwise, though the former is common. Two whorls also sometimes appear.

III. Body Build : Racial differences can be perceived depending upon the body-build in following way-

  • CAUCASOID- Linear to lateral Slender to rugged
  •  MONGOLOID- More lateral than linear
  • NEGROID – Lateral with traces of linear

IV. Eye-Shape And Colour : On the basis of shape of the eye, races can be divided into mongoloid and Non-mongoloid Mongoloid-eye is characterized by (a) Oblique paplebral fissure, the outer angle being higher than the lower angle (b) a narrow slit inner or complete.

  • Epicanthic fold is fold of skin hanging over the free edge of upper eye lid, and is of four types :
  1. Inner epicanthic fold : at the inner edge of upper eye lid, most pronounced in infants and women.
  2. Complete epicanthic fold : at the complete edge of upper eye-lid.
  3. External epicanthic fold : at the outer edge of upper eye-lid, most pronounced, at advanced age.
  4. Median epicanthic fold : at the middle part of edge of
    upper eye-lid. At advanced age

Colour of the eye varies from light blue to brown b-lack and is due to the pigments on both back and front side of iris if pigments are only on back” side, blue eye-colour results. When it is on both sides, brown-black eye-colour results.

  • CAUCASOID- Light Blue to to Light Brown
  • MONGOLOID- Light Brown to Dark Brown
  • NEGROID- Dark Brown to Brown Black.

B. Morphometric

V. Cephalic Index (C.l.) and Cranial Index (C.l.) : Shape of the head is largely genetic though environment also has some role to play eg European immigrarits in US have somewhat altered shape of the head, though out crossing with different racial groups
Hay have led to altered sha Nutrition also influences shape of the head to some extent. Cephalic Index is expressed as percentage of the breadth of head in relation to the length of the head ie.

        •                    Breadth x 100
        •                          Length
Type Cephalic Index Example
Dolicocepahlic (long or narrow) < 76 Negroid-Caucasoid
Mesocephalic (Medium) < 81 Mongo-Neg-Caucasoid
Brachycephalic (Broad) >81 Monaoloid-Caucasoid

VI. Facial Index : Face may show prognathism (Protrusion of jaw), or Orthognathism (no protrusion). Prognathism may result due to projection of alveolar margins of upper, and lower jaw (alveolar prognathism), or projection of the complete jaw (Facial prognathism)

Facial Index show sex-based differences because females have shorter and broader faces. The facial Index is described as percentage of length in relation to breadth

length of face x 100
Breadth

Type Facial Index Race
Euryproscopic (Broad) <84 Caucasoid
Mesoproscopic (Medium) <88 Mongoloid
Leptoproscopic >88 , Negroid

VII. Nasal index

The shape of the nose seems to be an adaptive feature because platyrrhine condition seems to be heat-adaptation because the broad nostrils permit exit of greater Quantity of warm air from lungs thus providing a coolinq effect. Leptorrhine condition seems to be a cold-adaption because the narrow elongated nostrils provide enough surface area for the incoming air to be warmed. Besides, it is influenced by age and sex because children
and females show platyrrhine condition.

    1. Leptorrhine
    2. Mesorrhihe
    3. Platyrrhine

 

VIII. Stature

Stature Height Main races
1 Tall (Tall. Very Tall. Giant) > 170cm Caucasoid, Nilotic Negro
(Including Sum Haiout of India)
2 Medium (Below Medium,
Medium. Above Medium)
170-160 cm Mediterranean.                 Eskimo.

Dravidian

3. Short (Pigmy. Very Short, Short) < 160 cm Andamanese. Negrillos.

Johann Friedrich Blumenbach’s classification, first proposed in 1779, was widely used in the 19th century, with many variations.

  • the Ethiopian/black race.
  • the Caucasian race/white race
  • the Mongolian/yellow race
  • the American/red race
  • the Malayan/brown race

American anthropologist Carleton S. Coon, divided humanity into five races:

  • Caucasoid (White) race
  • Negroid (Black) race
  • Capoid (Bushmen/Hottentots) race
  • Mongoloid (Oriental/Amerindian) race
  • Australoid (Australian Aborigine and Papuan) race

Major Races of the World

1 Caucasoid : This includes large number of ethnic groups that includes Mediterranean (distributed in Portugal, Spain. France Italy. Greece -Turkey, parts of North Africa, Arabia, Iran. Afghanistan, Pakistan and India)., Nordic (Scandinavia, Baltic region,North Germany, North France, Belgium. British Island. US etc.) Alpine (Central Europe, Denmark. Norway. North Italy etc.) East Baltic ( Poland, Russia, Finland etc.) Armenoid (Turkey Syria, Palestine, Iraq. Iran etc). Keltic (Scotland, Wales) Lapp (Sweden, North Finland, Norway etc); Polynesian (Polynesian island of pacific Such as New Zealand. Samoa, Hawaii etc) Ainu (North Japan) etc

They are characterized by

    1. skin ranging from white to dark brown;
    2. Hair vary from flat wavy to.different degrees of  curliness
    3. Hair texture is usually medium to fine ;
    4. body and face hair is usually moderate to abundant:
    5. Head form ranges from dolicocephalic to brachycephalifc;
    6. Nose ranges from leptorrhine to mesorrhihe never platyrrhine. with high nasal bridge:
    7. No prognathism of face;
    8. Cheek bodes are usually not prominent;
    9. lips usually thin ;
    10. forehead high and colour of the eye is of lighter shades.

2. Australoid Or Archaic Caucasoid : They rasemble caucasoid and form two main groups – The Australian aborigines and pre-Dravidian or Veddoid. the former distributed in Australia and the latter in South and Central India (Bhil, Gond. Kadir, Oraon  and .Sri Lanka (Veddoid). These people suggest an admix of an archaic caucasoid with Negroid.

3. Mongoloids : They also include diverse ethnic groups represented by classic Mongoloid (Siberia, North China, Mongolia Tibet): the arctic^or Eskimoids (arctic coast of North America. Greenland, Alaska etc); Indonesian – Malay (South China. Burma Thailand, Malay Peninsula, Philippines, Japan, Indonesia etc.) American Indian or American indian North, middle South America).

Mongoloids are characterized by

    1. black, straight, coarse head hair;
    2. skin colour is yellow or yellow brown’;
    3. Hair is scanty on face and body;
    4. broad flat face has prominent check bones:
    5. epicanthic fold on the eye lid

4. Negroid : They are basically comprised of African Negro and Oceanic Nearo The African Negro includes true Negros. Nilotic Negros. Bantu, Bushman-Hottentot and Negrillo True Negros are found in West^f the Nilotic Negro in the upper Nile Valley, Bantu in Central and South Africa. Bushman in Kalahari desert of South West Africa, hottentot in South West Africa and Negrillo in equatorial forest of Congo region Negrillos are African Pygmy Pygmies are very short people”, also distributed in oceanic and Asiatic regions Such Pygmies are called Negrito. The Oceanic Negros include Negritos and Melanesian Papuans. The Andamanese. Semang, Aeta. Tapiro are the important representatives of Negritos, distributed in Andamans. East Sumatra, Philippine islanB and New Guinea respectively Melanesians papuans are distributed in New Guinea. Fiji and neighbouring Island.

Negroids are characterized by

      1. woolly or frizzly black hair,
      2. colour of the skin is dark brown or black,
      3. nose is broad and flat;
      4. lips are thick and everted,
      5. eyes are black,
      6. ears are with little lobe
      7. facial prograthism is well marked
      8. the head is predominantly long etc.

Leave a Reply