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Modern Human Diversity

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Is the biological concept of race useful for studying physical variation in the ... on geographic location, skin color, body size, head shape, and hair texture. ... – PowerPoint PPT presentation

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Title: Modern Human Diversity


1
Chapter 13
  • Modern Human Diversity

2
Chapter Outline
  • What are the causes of physical variability in
    animals?
  • Is the biological concept of race useful for
    studying physical variation in the human species?
  • Is there validity to studying differences in
    intelligence from one population to another?

3
Variation and Evolution
  • In humans, most behavioral patterns are
    culturally learned or acquired.
  • Other characteristics are determined by an
    interaction between genes and environment.

4
Genetic Variability
  • Gene pools of populations contain various
    alternative alleles.
  • When the environment changes, their gene pool
    confers the possibility for physical alteration
    to meet the change.
  • When a species is separated into different
    regions, populations differ in the frequency
    with which genetic variability is expressed.

5
The Meaning of Race
  • Early anthropologists classified Homo sapiens
    into races based on geographic location, skin
    color, body size, head shape, and hair texture.
  • The presence of individuals who did not fit the
    type challenged these racial classifications.
  • No examples of pure racial types could be found.

6
Race and Human Variation Limitations
  • Race is an arbitrary category, making agreement
    on any classification impossible.
  • Humans are complex genetically and often the
    genetic basis of traits on which racial studies
    are based is poorly understood.
  • Race exists as a cultural as well as a biological
    category.

7
Factors in Variation of Skin Color
  • Transparency or thickness of the skin.
  • Distribution of blood vessels.
  • Amount of carotene and melanin in a given area of
    skin.

8
Factors in Variation of Skin Color
  • Exposure to sunlight increases the amount of
    melanin, darkening the skin.
  • Selective mating, as well as geographic location,
    plays a part in skin color distribution.

9
Racism
  • Racism is a social problem.
  • Racist individuals react on the basis of social
    stereotypes instead of scientific facts.
  • Behavioral characteristics attributed to race can
    be explained with culture rather than biology.
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