Human Variation
How and Why are Humans Different?
Natural Selection
1. Variation (Every species has a lot of variety
within it).
2. Heritability (Individuals pass on traits to
their offspring)
3. Environmental Fitness (Individuals who
are better adapted to their environment will
produce more offspring and pass on their
trais to the next generation)
Do Human Subgroups Exist?
 Race is a socially constructed term
 Anthropologists state that race does not
scientifically exist
 More genetic variation exists within
races than between them (All humans
share 99.9 % of the same genetic code).
 Race is viewed as a myth or folklore
Anthropological Response to Race
 Anthropologists believe that physical
differences among humans develop as a
response to climatic, geographical, or
cultural conditions.
 I.e. dark skin provides survival value in
hot climates
 Race (Social Darwinism) has been used
by society to justify immoral political
ideas like slavery, genocide, and
apartheid.
Benefits of Diversity
Like variation amongst all other animals,
variation will allow for the continuity of the
human race
The Question of Race
 The following video will discuss the
scientific explanation for race. The video
asks “If we all have the same ancestors,
why do we look so different?”
 Knowledge/Understanding: Explain
some of the answers given to explain
human adaptation from the video
(characteristics that changed in humans
to adapt to new environmental
conditions)
 Humans have come from Africa (most
variations of humans found in Africa)
 150 thousand years ago in Africa
 80 thousand years ago – migration to
Mesibitania
 Spread over Eurasia
 Leap across baring strait to new world
 Light skin covered in hair
 Sweat from work, lose hair and skin
becomes dark
 Vitamin D not produced well in dark skin
so skin becomes lighter – Vitamin D
makes use of calcium for strong bones
and also enhances immune system.
 DNA balancing act between colour of
skin and what is needed to help body
survive
 Thinking/Inquiry: If race is not
scientific, why do we feel the need to
identify a person based on their race?
 Application: If you were debating “social
Darwinists” what arguments would you
use to convince them that their ideas
are wrong?
THE EYES OF NYE: Human Characteristics and
Adaptations
http://www.youtube.com/watch?v=1EyeNi6
qsfs
http://www.youtube.com/watch?v=LzGM1nv
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http://www.youtube.com/watch?v=aCDcl9s
9Vh4&feature=related